/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 * bltGraph.c --
 *
 * This module implements a graph widget for the BLT toolkit.
 *
 * The graph widget was created by Sani Nassif and George Howlett.
 *
 * Copyright 2015 George A. Howlett. All rights reserved.  
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions are
 *   met:
 *
 *   1) Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *   2) Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the
 *      distribution.
 *   3) Neither the name of the authors nor the names of its contributors
 *      may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
 *   4) Products derived from this software may not be called "BLT" nor may
 *      "BLT" appear in their names without specific prior written
 *      permission from the author.
 *
 *   THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY EXPRESS OR IMPLIED
 *   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *   DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *   BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 *   OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 *   IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/*
 * To do:
 *
 * 2) Update manual pages.
 *
 * 3) Update comments.
 *
 * 5) Surface and vector graphs
 *
 * 7) Arrows for line markers
 *
 */

#define BUILD_BLT_TK_PROCS 1
#include "bltInt.h"

#ifdef HAVE_STRING_H
  #include <string.h>
#endif /* HAVE_STRING_H */

#include <X11/Xutil.h>

#include "bltAlloc.h"
#include "bltMath.h"
#include "bltHash.h"
#include "bltChain.h"
#include "bltConfig.h"
#include "bltSwitch.h"
#include "bltOp.h"
#include "bltBind.h"
#include "bltPs.h"
#include "bltBg.h"
#include "bltPicture.h"
#include "tkDisplay.h"
#include "bltGraph.h"
#include "bltGrAxis.h"
#include "bltGrLegd.h"
#include "bltGrElem.h"
#include "bltGrLegd.h"
#include "bltInitCmd.h"

#ifdef WIN32
  #include <tkPlatDecls.h>
#endif

/* 
 * Objects in the graph have their own class names.  These class names are
 * used for the resource database and bindings.  Example.
 *
 *      option add *X.title "X Axis Title" widgetDefault
 *      .g marker bind BitmapMarker <Enter> { ... }
 *
 * The option database trick is performed by creating a temporary window
 * when an object is initially configured.  The class name of the temporary
 * window will be from the list below.
 */
static const char *objectClassNames[] = {
    "unknown",                          /* 0 */
    "X",                                /* 1 */
    "Y",                                /* 2 */
    "Z",                                /* 3 */
    "Legend",                           /* 4 */
    "BarElement",                       /* 5 */
    "ContourElement",                   /* 6 */
    "LineElement",                      /* 7 */
    "StripElement",                     /* 8 */
    "BitmapMarker",                     /* 9 */
    "ImageMarker",                      /* 10 */
    "LineMarker",                       /* 11 */
    "PolygonMarker",                    /* 12 */
    "RectangleMarker",                  /* 13 */
    "TextMarker",                       /* 14 */
    "WindowMarker",                     /* 15 */
    "LegendEntry",                      /* 16 */
    "Isoline",                          /* 17 */
};

static Blt_OptionParseProc ObjToMapElements;
static Blt_OptionPrintProc MapElementsToObj;
static Blt_CustomOption mapElementsOption = {
    ObjToMapElements, MapElementsToObj, NULL, (ClientData)0,
};

BLT_EXTERN Blt_CustomOption bltLinePenOption;
BLT_EXTERN Blt_CustomOption bltBarPenOption;
BLT_EXTERN Blt_CustomOption bltBarModeOption;
BLT_EXTERN Blt_SwitchCustom bltXAxisSwitch;
BLT_EXTERN Blt_SwitchCustom bltYAxisSwitch;

#define DEF_ASPECT_RATIO                "0.0"
#define DEF_AXIS_SPACING                "0"
#define DEF_BAR_BASELINE                "0.0"
#define DEF_BAR_MODE                    "normal"
#define DEF_BAR_WIDTH                   "0.9"
#define DEF_BACKGROUND                  STD_NORMAL_BACKGROUND
#define DEF_BORDERWIDTH                 STD_BORDERWIDTH
#define DEF_BUFFER_ELEMENTS             "yes"
#define DEF_BUFFER_GRAPH                "1"
#define DEF_CURSOR                      "crosshair"
#define DEF_FONT                        "{Sans Serif} 12"
#define DEF_HALO                        "2m"
#define DEF_HALO_BAR                    "0.1i"
#define DEF_HEIGHT                      "4i"
#define DEF_HIGHLIGHT_BACKGROUND        STD_NORMAL_BACKGROUND
#define DEF_HIGHLIGHT_COLOR             RGB_BLACK
#define DEF_HIGHLIGHT_WIDTH             "2"
#define DEF_INVERT_XY                   "0"
#define DEF_JUSTIFY                     "center"
#define DEF_MARGIN_SIZE                 "0"
#define DEF_MARGIN_VAR          (char *)NULL
#define DEF_PLOT_BACKGROUND     RGB_WHITE
#define DEF_PLOT_BORDERWIDTH    "1"
#define DEF_PLOT_PADX           "0"
#define DEF_PLOT_PADY           "0"
#define DEF_PLOT_RELIEF         "solid"
#define DEF_RELIEF              "flat"
#define DEF_SHOW_VALUES         "no"
#define DEF_STACK_AXES          "no"
#define DEF_TAKE_FOCUS          ""
#define DEF_TITLE               (char *)NULL
#define DEF_TITLE_COLOR         STD_NORMAL_FOREGROUND
#define DEF_WIDTH               "5i"
#define DEF_DATA                (char *)NULL
#define DEF_DATA_COMMAND        (char *)NULL
#define DEF_MAP_ELEMENTS        "all"
#define DEF_STRETCH_TO_FIT      "1"
#define DEF_COLOR_BAR           (char *)NULL

static Blt_ConfigSpec configSpecs[] =
{
    {BLT_CONFIG_FLOAT, "-aspect", "aspect", "Aspect", DEF_ASPECT_RATIO, 
        Blt_Offset(Graph, aspect), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_PIXELS_NNEG, "-axisspacing", "axisspacing", "Axisspacing",
        DEF_AXIS_SPACING, Blt_Offset(Graph, axisSpacing),
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_BACKGROUND, "-background", "background", "Background",
        DEF_BACKGROUND, Blt_Offset(Graph, normalBg), 0},
    {BLT_CONFIG_CUSTOM, "-barmode", "barMode", "BarMode", DEF_BAR_MODE, 
        Blt_Offset(Graph, mode), BLT_CONFIG_DONT_SET_DEFAULT, 
        &bltBarModeOption},
    {BLT_CONFIG_FLOAT, "-barwidth", "barWidth", "BarWidth", 
        DEF_BAR_WIDTH, Blt_Offset(Graph, barWidth), 0},
    {BLT_CONFIG_FLOAT, "-baseline", "baseline", "Baseline",
        DEF_BAR_BASELINE, Blt_Offset(Graph, baseline), 0},
    {BLT_CONFIG_SYNONYM, "-bd", "borderWidth"},
    {BLT_CONFIG_SYNONYM, "-bg", "background"},
    {BLT_CONFIG_SYNONYM, "-bm", "bottomMargin"},
    {BLT_CONFIG_PIXELS_NNEG, "-borderwidth", "borderWidth", "BorderWidth",
        DEF_BORDERWIDTH, Blt_Offset(Graph, borderWidth),
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_PIXELS_NNEG, "-bottommargin", "bottomMargin", "Margin",
        DEF_MARGIN_SIZE, Blt_Offset(Graph, reqBottomMarginSize),
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_OBJ, "-bottomvariable", "bottomVariable", "BottomVariable",
        DEF_MARGIN_VAR, Blt_Offset(Graph, bottomMarginVarObjPtr), 
        BLT_CONFIG_NULL_OK},
    {BLT_CONFIG_BITMASK, "-bufferelements", "bufferElements", "BufferElements",
        DEF_BUFFER_ELEMENTS, Blt_Offset(Graph, flags),
        BLT_CONFIG_DONT_SET_DEFAULT, (Blt_CustomOption *)BACKING_STORE},
    {BLT_CONFIG_BITMASK, "-buffergraph", "bufferGraph", "BufferGraph",
        DEF_BUFFER_GRAPH, Blt_Offset(Graph, flags),
        BLT_CONFIG_DONT_SET_DEFAULT, (Blt_CustomOption *)DOUBLE_BUFFER},
    {BLT_CONFIG_ACTIVE_CURSOR, "-cursor", "cursor", "Cursor",
        DEF_CURSOR, Blt_Offset(Graph, cursor), BLT_CONFIG_NULL_OK},
    {BLT_CONFIG_STRING, "-data", "data", "Data", 
        (char *)NULL, Blt_Offset(Graph, data), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_SYNONYM, "-fg", "foreground"},
    {BLT_CONFIG_FONT, "-font", "font", "Font",
        DEF_FONT, Blt_Offset(Graph, titleTextStyle.font), 0},
    {BLT_CONFIG_COLOR, "-foreground", "foreground", "Foreground",
        DEF_TITLE_COLOR, Blt_Offset(Graph, titleTextStyle.color), 0},
    {BLT_CONFIG_PIXELS_NNEG, "-halo", "halo", "Halo", DEF_HALO, 
        Blt_Offset(Graph, halo), 0},
    {BLT_CONFIG_PIXELS_NNEG, "-height", "height", "Height", DEF_HEIGHT, 
        Blt_Offset(Graph, reqHeight), 0},
    {BLT_CONFIG_COLOR, "-highlightbackground", "highlightBackground",
        "HighlightBackground", DEF_HIGHLIGHT_BACKGROUND, 
        Blt_Offset(Graph, highlightBgColor), 0},
    {BLT_CONFIG_COLOR, "-highlightcolor", "highlightColor", "HighlightColor",
        DEF_HIGHLIGHT_COLOR, Blt_Offset(Graph, highlightColor), 0},
    {BLT_CONFIG_PIXELS_NNEG, "-highlightthickness", "highlightThickness",
        "HighlightThickness", DEF_HIGHLIGHT_WIDTH, 
        Blt_Offset(Graph, highlightWidth), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_BITMASK, "-invertxy", "invertXY", "InvertXY", DEF_INVERT_XY,
        Blt_Offset(Graph, flags), BLT_CONFIG_DONT_SET_DEFAULT,
        (Blt_CustomOption *)INVERTED},
    {BLT_CONFIG_JUSTIFY, "-justify", "justify", "Justify", DEF_JUSTIFY, 
        Blt_Offset(Graph, titleTextStyle.justify), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_PIXELS_NNEG, "-leftmargin", "leftMargin", "Margin", 
        DEF_MARGIN_SIZE, Blt_Offset(Graph, reqLeftMarginSize), 
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_OBJ, "-leftvariable", "leftVariable", "LeftVariable",
        DEF_MARGIN_VAR, Blt_Offset(Graph, leftMarginVarObjPtr),
        BLT_CONFIG_NULL_OK},
    {BLT_CONFIG_SYNONYM, "-lm", "leftMargin"},
    {BLT_CONFIG_CUSTOM, "-mapelements", "mapElements", "MapElements",
        DEF_MAP_ELEMENTS, Blt_Offset(Graph, flags),
        ALL_GRAPHS | BLT_CONFIG_DONT_SET_DEFAULT, &mapElementsOption},
    {BLT_CONFIG_BACKGROUND, "-plotbackground", "plotBackground", "Background",
        DEF_PLOT_BACKGROUND, Blt_Offset(Graph, plotBg), 0},
    {BLT_CONFIG_PIXELS_NNEG, "-plotborderwidth", "plotBorderWidth", 
        "PlotBorderWidth", DEF_PLOT_BORDERWIDTH, 
        Blt_Offset(Graph, plotBorderWidth), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_PAD, "-plotpadx", "plotPadX", "PlotPad", DEF_PLOT_PADX, 
        Blt_Offset(Graph, padX), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_PAD, "-plotpady", "plotPadY", "PlotPad", DEF_PLOT_PADY, 
        Blt_Offset(Graph, padY), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_RELIEF, "-plotrelief", "plotRelief", "Relief", DEF_PLOT_RELIEF,
        Blt_Offset(Graph, plotRelief), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_RELIEF, "-relief", "relief", "Relief", DEF_RELIEF, 
        Blt_Offset(Graph, relief), BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_PIXELS_NNEG, "-rightmargin", "rightMargin", "Margin",
        DEF_MARGIN_SIZE, Blt_Offset(Graph, reqRightMarginSize),
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_OBJ, "-rightvariable", "rightVariable", "RightVariable",
        DEF_MARGIN_VAR, Blt_Offset(Graph, rightMarginVarObjPtr), 
        BLT_CONFIG_NULL_OK},
    {BLT_CONFIG_SYNONYM, "-rm", "rightMargin"},
    {BLT_CONFIG_BITMASK, "-stackaxes", "stackAxes", "StackAxes", DEF_STACK_AXES,
        Blt_Offset(Graph, flags), BLT_CONFIG_DONT_SET_DEFAULT,
        (Blt_CustomOption *)STACK_AXES},
    {BLT_CONFIG_BITMASK, "-stretchtofit", "stretchToFit", "StretchToFit",
        DEF_STRETCH_TO_FIT, Blt_Offset(Graph, flags),
        ALL_GRAPHS | BLT_CONFIG_DONT_SET_DEFAULT,
        (Blt_CustomOption *)STRETCH_TO_FIT},
    {BLT_CONFIG_STRING, "-takefocus", "takeFocus", "TakeFocus", DEF_TAKE_FOCUS,
        Blt_Offset(Graph, takeFocus), BLT_CONFIG_NULL_OK},
    {BLT_CONFIG_STRING, "-title", "title", "Title", DEF_TITLE,
        Blt_Offset(Graph, title), BLT_CONFIG_NULL_OK},
    {BLT_CONFIG_SYNONYM, "-tm", "topMargin"},
    {BLT_CONFIG_PIXELS_NNEG, "-topmargin", "topMargin", "Margin",
        DEF_MARGIN_SIZE, Blt_Offset(Graph, reqTopMarginSize),
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_OBJ, "-topvariable", "topVariable", "TopVariable",
        DEF_MARGIN_VAR, Blt_Offset(Graph, topMarginVarObjPtr),
        BLT_CONFIG_NULL_OK},
    {BLT_CONFIG_PIXELS_NNEG, "-width", "width", "Width", DEF_WIDTH, 
        Blt_Offset(Graph, reqWidth), 0},
    {BLT_CONFIG_PIXELS_NNEG, "-plotwidth", "plotWidth", "PlotWidth", 
        (char *)NULL, Blt_Offset(Graph, reqPlotWidth), 
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_PIXELS_NNEG, "-plotheight", "plotHeight", "PlotHeight", 
        (char *)NULL, Blt_Offset(Graph, reqPlotHeight), 
        BLT_CONFIG_DONT_SET_DEFAULT},
    {BLT_CONFIG_END, NULL, NULL, NULL, NULL, 0, 0}
};

static Blt_SwitchParseProc ObjToElement;
static Blt_SwitchCustom elementSwitch = {
    ObjToElement, NULL, NULL, (ClientData)0,
};

typedef struct {
    Element *elemPtr;
    Axis *xAxisPtr;
    Axis *yAxisPtr;
    Graph *graphPtr;
} TransformSwitches;

static Blt_SwitchSpec transformSpecs[] = 
{
    {BLT_SWITCH_CUSTOM, "-element",  "elemName", (char *)NULL,
        Blt_Offset(TransformSwitches, elemPtr),  0, 0, &elementSwitch},
    {BLT_SWITCH_CUSTOM, "-mapx",  "axisName", (char *)NULL,
        Blt_Offset(TransformSwitches, xAxisPtr),  0, 0, &bltXAxisSwitch},
    {BLT_SWITCH_CUSTOM, "-mapy",  "axisName", (char *)NULL,
        Blt_Offset(TransformSwitches, yAxisPtr),  0, 0, &bltYAxisSwitch},
    {BLT_SWITCH_END}
};


static Blt_SwitchParseProc ObjToFormat;
static Blt_SwitchCustom formatSwitch = {
    ObjToFormat, NULL, NULL, (ClientData)0,
};


static Blt_SwitchParseProc ObjToPixels;
static Blt_SwitchCustom pixelsSwitch = {
    ObjToPixels, NULL, NULL, (ClientData)0,
};

typedef struct {
    const char *name;
    int width, height;
    int format;
    unsigned int flags;
} SnapSwitches;

enum SnapFormats { FMT_PICTURE, FMT_PHOTO, FMT_EMF, FMT_WMF };

#define MAXPECT         (1<<0)

static Blt_SwitchSpec snapSpecs[] = {
    {BLT_SWITCH_CUSTOM,  "-format", "format", (char *)NULL,
        Blt_Offset(SnapSwitches, format), 0, 0, &formatSwitch},
    {BLT_SWITCH_CUSTOM, "-height", "numPixels", (char *)NULL,
        Blt_Offset(SnapSwitches, height), 0, 0, &pixelsSwitch},
    {BLT_SWITCH_CUSTOM, "-width",  "numPixels", (char *)NULL,
        Blt_Offset(SnapSwitches, width),  0, 0, &pixelsSwitch},
    {BLT_SWITCH_BITS_NOARG, "-maxpect",    "", (char *)NULL,
        Blt_Offset(SnapSwitches, flags), 0, MAXPECT},
    {BLT_SWITCH_END}
};

static Tcl_IdleProc DisplayProc;
static Tcl_FreeProc DestroyGraph;
static Tk_EventProc GraphEventProc;
Tcl_ObjCmdProc Blt_GraphInstCmdProc;

static Blt_BindPickProc PickEntry;
static Tcl_ObjCmdProc StripchartCmd;
static Tcl_ObjCmdProc BarchartCmd;
static Tcl_ObjCmdProc ContourCmd;
static Tcl_ObjCmdProc GraphCmd;
static Tcl_CmdDeleteProc GraphInstCmdDeleteProc;

static void GraphToDrawable(Graph *graphPtr, Drawable drawable);

/*
 *---------------------------------------------------------------------------
 *
 * ObjToMapElements --
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
ObjToMapElements(ClientData clientData, Tcl_Interp *interp, Tk_Window tkwin,
                 Tcl_Obj *objPtr, char *widgRec, int offset, int flags)
{
    int *flagsPtr = (int *)(widgRec + offset);
    Graph *graphPtr = (Graph *)widgRec;
    const char *string;
    char c;
    
    string = Tcl_GetString(objPtr);
    c = string[0];
    if ((c == 'a') || (strcmp(string, "all") == 0)) {
        *flagsPtr &= ~MAP_VISIBLE;
    } else if ((c == 'v') || (strcmp(string, "visible") == 0)) {
        *flagsPtr |= MAP_VISIBLE;
    } else {
        Tcl_AppendResult(interp, "bad value \"", string,
                "\": should be all or visible", (char *)NULL);
        return TCL_ERROR;
    }
    graphPtr->flags |= RESET_AXES;
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * MapElementsToObj --
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static Tcl_Obj *
MapElementsToObj(ClientData clientData, Tcl_Interp *interp, Tk_Window tkwin,
                 char *widgRec, int offset, int flags)
{
    int mapflags = *(int *)(widgRec + offset);
    const char *string;
    
    if (mapflags & MAP_VISIBLE) {
        string = "visible";
    } else {
        string = "all";
    }
    return Tcl_NewStringObj(string, -1);
}

/*
 *---------------------------------------------------------------------------
 *
 * Blt_UpdateGraph --
 *
 *      Tells the Tk dispatcher to call the graph display routine at the
 *      next idle point.  This request is made only if the window is
 *      displayed and no other redraw request is pending.
 *
 * Results: None.
 *
 * Side effects:
 *      The window is eventually redisplayed.
 *
 *---------------------------------------------------------------------------
 */
void
Blt_UpdateGraph(ClientData clientData)
{
    Graph *graphPtr = clientData;

    graphPtr->flags |= REDRAW_WORLD;
    if ((graphPtr->tkwin != NULL) && !(graphPtr->flags & REDRAW_PENDING)) {
        Tcl_DoWhenIdle(DisplayProc, graphPtr);
        graphPtr->flags |= REDRAW_PENDING;
    }
}

/*
 *---------------------------------------------------------------------------
 *
 * Blt_EventuallyRedrawGraph --
 *
 *      Tells the Tk dispatcher to call the graph display routine at the
 *      next idle point.  This request is made only if the window is
 *      displayed and no other redraw request is pending.
 *
 * Results: None.
 *
 * Side effects:
 *      The window is eventually redisplayed.
 *
 *---------------------------------------------------------------------------
 */
void
Blt_EventuallyRedrawGraph(Graph *graphPtr) 
{
    if ((graphPtr->tkwin != NULL) && !(graphPtr->flags & REDRAW_PENDING)) {
        Tcl_DoWhenIdle(DisplayProc, graphPtr);
        graphPtr->flags |= REDRAW_PENDING;
    }
}

const char *
Blt_GraphClassName(ClassId classId) 
{
    if ((classId >= CID_NONE) && (classId <= CID_ISOLINE)) {
        return objectClassNames[classId];
    }
    return NULL;
}

void
Blt_GraphSetObjectClass(GraphObj *graphObjPtr, ClassId classId)
{
    graphObjPtr->classId = classId;
    graphObjPtr->className = Blt_GraphClassName(classId);
}

/*
 *---------------------------------------------------------------------------
 *
 * GraphEventProc --
 *
 *      This procedure is invoked by the Tk dispatcher for various events
 *      on graphs.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      When the window gets deleted, internal structures get cleaned up.
 *      When it gets exposed, the graph is eventually redisplayed.
 *
 *---------------------------------------------------------------------------
 */
static void
GraphEventProc(ClientData clientData, XEvent *eventPtr)
{
    Graph *graphPtr = clientData;

    if (eventPtr->type == Expose) {
        if (eventPtr->xexpose.count == 0) {
            graphPtr->flags |= REDRAW_WORLD;
            Blt_EventuallyRedrawGraph(graphPtr);
        }
    } else if ((eventPtr->type == FocusIn) || (eventPtr->type == FocusOut)) {
        if (eventPtr->xfocus.detail != NotifyInferior) {
            if (eventPtr->type == FocusIn) {
                graphPtr->flags |= FOCUS;
            } else {
                graphPtr->flags &= ~FOCUS;
            }
            graphPtr->flags |= REDRAW_WORLD;
            Blt_EventuallyRedrawGraph(graphPtr);
        }
    } else if (eventPtr->type == DestroyNotify) {
        if (graphPtr->tkwin != NULL) {
            Blt_DeleteWindowInstanceData(graphPtr->tkwin);
            graphPtr->tkwin = NULL;
            Tcl_DeleteCommandFromToken(graphPtr->interp, graphPtr->cmdToken);
        }
        if (graphPtr->flags & REDRAW_PENDING) {
            Tcl_CancelIdleCall(DisplayProc, graphPtr);
        }
        Tcl_EventuallyFree(graphPtr, DestroyGraph);
    } else if (eventPtr->type == ConfigureNotify) {
        graphPtr->flags |= (MAP_WORLD | REDRAW_WORLD);
        Blt_EventuallyRedrawGraph(graphPtr);
    }
}

/*
 *---------------------------------------------------------------------------
 *
 * GraphInstCmdDeleteProc --
 *
 *      This procedure is invoked when a widget command is deleted.  If the
 *      widget isn't already in the process of being destroyed, this
 *      command destroys it.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The widget is destroyed.
 *
 *---------------------------------------------------------------------------
 */
static void
GraphInstCmdDeleteProc(ClientData clientData) /* Pointer to widget record. */
{
    Graph *graphPtr = clientData;

    if (graphPtr->tkwin != NULL) {      /* NULL indicates window has
                                         * already been destroyed. */
        Tk_Window tkwin;

        tkwin = graphPtr->tkwin;
        graphPtr->tkwin = NULL;
        Blt_DeleteWindowInstanceData(tkwin);
        Tk_DestroyWindow(tkwin);
    }
}

/*
 *---------------------------------------------------------------------------
 *
 * AdjustMarginPointers --
 *
 *      Sets the margin pointers according to whether the graph is inverted
 *      or not.
 *
 * Results:
 *      None.
 *
 *---------------------------------------------------------------------------
 */
static void
AdjustMarginPointers(Graph *graphPtr) 
{
    if (graphPtr->flags & INVERTED) {
        graphPtr->bottomPtr = graphPtr->margins + MARGIN_Y;
        graphPtr->leftPtr   = graphPtr->margins + MARGIN_X;
        graphPtr->rightPtr  = graphPtr->margins + MARGIN_X2;
        graphPtr->topPtr    = graphPtr->margins + MARGIN_Y2;
    } else {
        graphPtr->bottomPtr = graphPtr->margins + MARGIN_X;
        graphPtr->leftPtr   = graphPtr->margins + MARGIN_Y;
        graphPtr->rightPtr  = graphPtr->margins + MARGIN_Y2;
        graphPtr->topPtr    = graphPtr->margins + MARGIN_X2;
    }
    graphPtr->bottomPtr->side = MARGIN_BOTTOM;
    graphPtr->bottomPtr->name = "bottom";
    graphPtr->leftPtr->side = MARGIN_LEFT;
    graphPtr->leftPtr->name = "left";
    graphPtr->rightPtr->side = MARGIN_RIGHT;
    graphPtr->rightPtr->name = "right";
    graphPtr->topPtr->side = MARGIN_TOP;
    graphPtr->topPtr->name = "top";
}

static int
InitPens(Graph *graphPtr)
{
    Blt_InitHashTable(&graphPtr->penTable, BLT_STRING_KEYS);
    if (Blt_CreatePen(graphPtr, "activeLine", CID_ELEM_LINE, 0, NULL) == NULL) {
        return TCL_ERROR;
    }
    if (Blt_CreatePen(graphPtr, "activeBar", CID_ELEM_BAR, 0, NULL) == NULL) {
        return TCL_ERROR;
    }
    if (Blt_CreatePen(graphPtr, "activeIsoline", CID_ELEM_CONTOUR, 0, NULL) 
        == NULL) {
        return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * Blt_GraphTags --
 *
 *      Sets the binding tags for a graph obj. This routine is called by Tk
 *      when an event occurs in the graph.  It fills an array of pointers
 *      with bind tag addresses.
 *
 *      The object addresses are strings hashed in one of two tag tables:
 *      one for elements and the another for markers.  Note that there's
 *      only one binding table for elements and markers.  [We don't want to
 *      trigger both a marker and element bind command for the same event.]
 *      But we don't want a marker and element with the same tag name to
 *      activate the others bindings. A tag "all" for markers should mean
 *      all markers, not all markers and elements.  As a result, element
 *      and marker tags are stored in separate hash tables, which means we
 *      can't generate the same tag address for both an elements and
 *      marker, even if they have the same name.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      This information will be used by the binding code in bltUtil.c to
 *      determine what graph objects match the current event.  The tags are
 *      placed in tagArr and *nTagsPtr is set with the number of tags
 *      found.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
void
Blt_GraphTags(Blt_BindTable table, ClientData object, ClientData context,
              Blt_Chain chain)
{
    GraphObj *objPtr;
    MakeTagProc *tagProc;
    Graph *graphPtr;
    Blt_Tags tags;
    
    graphPtr = (Graph *)Blt_GetBindingData(table);

    /* 
     * All graph objects (markers, elements, axes, etc) have the same
     * starting fields in their structures, such as "classId", "name",
     * "className", and "tags".
     */
    objPtr = object;
    if (objPtr->deleted) {
        return;                         /* Don't pick deleted objects. */
    }
    tags = NULL;
    tagProc = NULL;
    switch (objPtr->classId) {
    case CID_ELEM_BAR:          
    case CID_ELEM_CONTOUR:
    case CID_ELEM_LINE: 
    case CID_ELEM_STRIP: 
        tags = &graphPtr->elements.tags;
        tagProc = Blt_MakeElementTag;
        break;
    case CID_ISOLINE: 
        tags = &graphPtr->isolines.tags;
        tagProc = Blt_MakeIsolineTag;
        break;
    case CID_LEGEND: 
        tags = &graphPtr->elements.tags;
        tagProc = Blt_MakeElementTag;
        break;
    case CID_AXIS_X:
    case CID_AXIS_Y:
    case CID_AXIS_Z:
        tags = &graphPtr->axes.tags;
        tagProc = Blt_MakeAxisTag;
        break;
    case CID_MARKER_BITMAP:
    case CID_MARKER_IMAGE:
    case CID_MARKER_LINE:
    case CID_MARKER_POLYGON:
    case CID_MARKER_RECTANGLE:
    case CID_MARKER_TEXT:
    case CID_MARKER_WINDOW:
        tags = &graphPtr->markers.tags;
        tagProc = Blt_MakeMarkerTag;
        break;
    case CID_NONE:
        panic("unknown object type");
        break;
    default:
        panic("bogus object type");
        break;
    }
    assert(objPtr->name != NULL);
    /* Always add the name of the object to the tag array. */
    Blt_Chain_Append(chain, (*tagProc)(graphPtr, objPtr->name));
    Blt_Chain_Append(chain, (*tagProc)(graphPtr, objPtr->className));
    Blt_Tags_AppendTagsToChain(tags, objPtr, chain);
    Blt_Chain_Append(chain, (*tagProc)(graphPtr, "all"));
}

/*
 *---------------------------------------------------------------------------
 *
 * GraphExtents --
 *
 *      Generates a bounding box representing the plotting area of the
 *      graph. This data structure is used to clip the points and line
 *      segments of the line element.
 *
 *      The clip region is the plotting area plus such arbitrary extra
 *      space.  The reason we clip with a bounding box larger than the plot
 *      area is so that symbols will be drawn even if their center point
 *      isn't in the plotting area.
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      The bounding box is filled with the dimensions of the plotting
 *      area.
 *
 *---------------------------------------------------------------------------
 */
static void
GraphExtents(Graph *graphPtr, Region2d *regionPtr)
{
    regionPtr->left = (double)(graphPtr->hOffset - graphPtr->padX.side1);
    regionPtr->top = (double)(graphPtr->vOffset - graphPtr->padY.side1);
    regionPtr->right = (double)(graphPtr->hOffset + graphPtr->hRange + 
        graphPtr->padX.side2);
    regionPtr->bottom = (double)(graphPtr->vOffset + graphPtr->vRange + 
        graphPtr->padY.side2);
}

/*
 *---------------------------------------------------------------------------
 *
 * PickEntry --
 *
 *      Finds the closest point from the set of displayed elements,
 *      searching the display list from back to front.  That way, if the
 *      points from two different elements overlay each other exactly, the
 *      one that's on top (visible) is picked.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static ClientData
PickEntry(ClientData clientData, int x, int y, ClientData *contextPtr)
{
    Graph *graphPtr = clientData;
    Element *elemPtr;
    Marker *markerPtr;
    Region2d exts;
    Isoline *isoPtr;
    
    if (graphPtr->flags & MAP_ALL) {
        return NULL;                    /* Don't pick anything until the
                                         * next redraw occurs. */
    }
    GraphExtents(graphPtr, &exts);

    if ((x >= exts.right) || (x < exts.left) || 
        (y >= exts.bottom) || (y < exts.top)) {
        /* 
         * Sample coordinate is in one of the graph margins.  Can only pick
         * an axis.
         */
        return Blt_NearestAxis(graphPtr, x, y);
    }
    /* 
     * From top-to-bottom check:
     *  1. markers drawn on top (-under false).
     *  2  isolines using its display list back to front.
     *  2. elements using its display list back to front.
     *  3. markers drawn under element (-under true).
     */
    markerPtr = Blt_NearestMarker(graphPtr, x, y, FALSE);
    if (markerPtr != NULL) {
        return markerPtr;               /* Found a marker (-under false). */
    }
    isoPtr = Blt_NearestIsoline(graphPtr, x, y);
    if (isoPtr != NULL) {
        return isoPtr;
    }
    elemPtr = Blt_NearestElement(graphPtr, x, y);
    if (elemPtr != NULL) {
        return elemPtr;
    }
    markerPtr = Blt_NearestMarker(graphPtr, x, y, TRUE);
    if (markerPtr != NULL) {
        return markerPtr;               /* Found a marker (-under true) */
    }
    return NULL;                        /* Nothing found. */
}

/*
 *---------------------------------------------------------------------------
 *
 * ConfigureGraph --
 *
 *      Allocates resources for the graph.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Configuration information, such as text string, colors, font,
 *      etc. get set for graphPtr; old resources get freed, if there were
 *      any.  The graph is redisplayed.
 *
 *---------------------------------------------------------------------------
 */
static void
ConfigureGraph(Graph *graphPtr) 
{
    XColor *colorPtr;
    GC newGC;
    XGCValues gcValues;
    unsigned long gcMask;

    /* Don't allow negative bar widths. Reset to an arbitrary value
     * (0.1) */
    if (graphPtr->barWidth <= 0.0f) {
        graphPtr->barWidth = 0.8f;
    }
    graphPtr->inset = graphPtr->borderWidth + graphPtr->highlightWidth;
    if ((graphPtr->reqHeight != Tk_ReqHeight(graphPtr->tkwin)) ||
        (graphPtr->reqWidth != Tk_ReqWidth(graphPtr->tkwin))) {
        Tk_GeometryRequest(graphPtr->tkwin, graphPtr->reqWidth,
            graphPtr->reqHeight);
    }
    Tk_SetInternalBorder(graphPtr->tkwin, graphPtr->borderWidth);
    colorPtr = Blt_Bg_BorderColor(graphPtr->normalBg);

    graphPtr->titleWidth = graphPtr->titleHeight = 0;
    if (graphPtr->title != NULL) {
        unsigned int w, h;

        Blt_Ts_GetExtents(&graphPtr->titleTextStyle, graphPtr->title, &w, &h);
        graphPtr->titleHeight = h;
    }

    /*
     * Create GCs for interior and exterior regions, and a background GC
     * for clearing the margins with XFillRectangle
     */

    /* Margin GC */

    gcValues.foreground = 
        Blt_Ts_GetForeground(graphPtr->titleTextStyle)->pixel;
    gcValues.background = colorPtr->pixel;
    gcMask = (GCForeground | GCBackground);
    newGC = Tk_GetGC(graphPtr->tkwin, gcMask, &gcValues);
    if (graphPtr->drawGC != NULL) {
        Tk_FreeGC(graphPtr->display, graphPtr->drawGC);
    }
    graphPtr->drawGC = newGC;

    if (graphPtr->plotBg != NULL) {
        Blt_Bg_SetChangedProc(graphPtr->plotBg, Blt_UpdateGraph, 
                graphPtr);
    }
    if (graphPtr->normalBg != NULL) {
        Blt_Bg_SetChangedProc(graphPtr->normalBg, Blt_UpdateGraph, 
                graphPtr);
    }
    if (Blt_ConfigModified(configSpecs, "-invertxy", (char *)NULL)) {

        /*
         * If the -inverted option changed, we need to readjust the
         * pointers to the axes and recompute the their scales.
         */

        AdjustMarginPointers(graphPtr);
        graphPtr->flags |= RESET_AXES;
    }
    if (((graphPtr->flags & BACKING_STORE) == 0) && (graphPtr->cache != None)) {
        /*
         * Free the pixmap if we're not buffering the display of elements
         * anymore.
         */
        Tk_FreePixmap(graphPtr->display, graphPtr->cache);
        graphPtr->cache = None;
    }
    /*
     * Reconfigure the crosshairs, just in case the background color of the
     * plotarea has been changed.
     */
    Blt_ConfigureCrosshairs(graphPtr);

    /*
     *  Update the layout of the graph (and redraw the elements) if any of
     *  the following graph options which affect the size of the plotting
     *  area has changed.
     *
     *      -aspect
     *      -borderwidth, -plotborderwidth
     *      -font, -title
     *      -width, -height
     *      -invertxy
     *      -bottommargin, -leftmargin, -rightmargin, -topmargin,
     *      -barmode, -barwidth
     */
    if (Blt_ConfigModified(configSpecs, "-invertxy", "-title", "-font",
                "-*margin", "-*width", "-height", "-barmode", "-*pad*", 
                "-aspect", "-*borderwidth", "-plot*", "-*width", "-*height",
                "-unmaphiddenelements", (char *)NULL)) {
        graphPtr->flags |= RESET_WORLD | CACHE_DIRTY;
    }
    if (Blt_ConfigModified(configSpecs, "-plot*", "-*background",
                           (char *)NULL)) {
        graphPtr->flags |= CACHE_DIRTY;
    }
    graphPtr->flags |= REDRAW_WORLD;
}

/*
 *---------------------------------------------------------------------------
 *
 * DestroyGraph --
 *
 *      This procedure is invoked by Tcl_EventuallyFree or Tcl_Release to
 *      clean up the internal structure of a graph at a safe time (when
 *      no-one is using it anymore).
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Everything associated with the widget is freed up.
 *
 *---------------------------------------------------------------------------
 */
static void
DestroyGraph(DestroyData dataPtr)
{
    Graph *graphPtr = (Graph *)dataPtr;

    if (graphPtr->flags & REDRAW_PENDING) {
        Tcl_CancelIdleCall(DisplayProc, graphPtr);
    }
    Blt_FreeOptions(configSpecs, (char *)graphPtr, graphPtr->display, 0);
    /*
     * Destroy the individual components of the graph: elements, markers,
     * axes, legend, display lists etc.  Be careful to remove them in
     * order. For example, axes are used by elements and markers, so they
     * have to be removed after the markers and elements. Same it true with
     * the legend and pens (they use elements), so can't be removed until
     * the elements are destroyed.
     */
    Blt_DestroyElements(graphPtr);      /* Destroy elements before colormaps. */
    Blt_DestroyMarkers(graphPtr);
    Blt_DestroyLegend(graphPtr);
    Blt_DestroyAxes(graphPtr);
    Blt_DestroyPens(graphPtr);
    Blt_DestroyCrosshairs(graphPtr);
    Blt_DestroyPageSetup(graphPtr);
    Blt_DestroyBarGroups(graphPtr);
    Blt_DestroyElementTags(graphPtr);
    /* Destroy table clients after elements are destroyed. */
    Blt_DestroyTableClients(graphPtr);
    if (graphPtr->bindTable != NULL) {
        Blt_DestroyBindingTable(graphPtr->bindTable);
    }

    /* Release allocated X resources and memory. */
    if (graphPtr->drawGC != NULL) {
        Tk_FreeGC(graphPtr->display, graphPtr->drawGC);
    }
    Blt_Ts_FreeStyle(graphPtr->display, &graphPtr->titleTextStyle);
    if (graphPtr->cache != None) {
        Tk_FreePixmap(graphPtr->display, graphPtr->cache);
    }
    Blt_Free(graphPtr);
}

/*
 *---------------------------------------------------------------------------
 *
 * CreateGraph --
 *
 *      This procedure creates and initializes a new widget.
 *
 * Results:
 *      The return value is a pointer to a structure describing the new
 *      widget.  If an error occurred, then the return value is NULL and an
 *      error message is left in interp->result.
 *
 * Side effects:
 *      Memory is allocated, a Tk_Window is created, etc.
 *
 *---------------------------------------------------------------------------
 */
static Graph *
CreateGraph(Tcl_Interp *interp, int objc, Tcl_Obj *const *objv, ClassId classId)
{
    Graph *graphPtr;
    Tk_Window tkwin;

    tkwin = Tk_CreateWindowFromPath(interp, Tk_MainWindow(interp), 
        Tcl_GetString(objv[1]), (char *)NULL);
    if (tkwin == NULL) {
        return NULL;
    }
    graphPtr = Blt_AssertCalloc(1, sizeof(Graph));

    /* Initialize the graph data structure. */
    graphPtr->tkwin = tkwin;
    graphPtr->display = Tk_Display(tkwin);
    graphPtr->interp = interp;
    graphPtr->classId = classId;
    graphPtr->borderWidth = 2;
    graphPtr->plotBorderWidth = 1;
    graphPtr->highlightWidth = 2;
    graphPtr->plotRelief = TK_RELIEF_SOLID;
    graphPtr->relief = TK_RELIEF_FLAT;
    graphPtr->flags = RESET_WORLD | DOUBLE_BUFFER | BACKING_STORE;
    graphPtr->nextMarkerId = 1;
    graphPtr->nextIsolineId = 1;
    graphPtr->padLeft = graphPtr->padRight = 0;
    graphPtr->padTop = graphPtr->padBottom = 0;
    graphPtr->axisSpacing = 0;
    
    Blt_Ts_InitStyle(graphPtr->titleTextStyle);
    Blt_Ts_SetAnchor(graphPtr->titleTextStyle, TK_ANCHOR_N);
    Blt_InitHashTable(&graphPtr->dataTables, BLT_STRING_KEYS);

    Blt_InitHashTable(&graphPtr->axes.bindTagTable, BLT_STRING_KEYS);
    Blt_InitHashTable(&graphPtr->axes.nameTable, BLT_STRING_KEYS);
    Blt_InitHashTable(&graphPtr->elements.bindTagTable, BLT_STRING_KEYS);
    Blt_InitHashTable(&graphPtr->elements.nameTable, BLT_STRING_KEYS);
    Blt_InitHashTable(&graphPtr->isolines.bindTagTable, BLT_STRING_KEYS);
    Blt_InitHashTable(&graphPtr->isolines.nameTable, BLT_STRING_KEYS);
    Blt_InitHashTable(&graphPtr->markers.bindTagTable, BLT_STRING_KEYS);
    Blt_InitHashTable(&graphPtr->markers.nameTable, BLT_STRING_KEYS);
    Blt_Tags_Init(&graphPtr->axes.tags);
    Blt_Tags_Init(&graphPtr->elements.tags);
    Blt_Tags_Init(&graphPtr->isolines.tags);
    Blt_Tags_Init(&graphPtr->markers.tags);
    graphPtr->axes.displayList = Blt_Chain_Create();
    graphPtr->elements.displayList = Blt_Chain_Create();
    graphPtr->isolines.displayList = Blt_Chain_Create();
    graphPtr->markers.displayList = Blt_Chain_Create();

    switch (classId) {
    case CID_ELEM_LINE:
        Tk_SetClass(tkwin, "BltGraph");
        break;
    case CID_ELEM_BAR:
        Tk_SetClass(tkwin, "BltBarchart");
        break;
    case CID_ELEM_CONTOUR:
        Tk_SetClass(tkwin, "BltContour");
        break;
    case CID_ELEM_STRIP:
        Tk_SetClass(tkwin, "BltStripchart");
    default:
        Tk_SetClass(tkwin, "???");
        break;
    }
    Blt_SetWindowInstanceData(tkwin, graphPtr);

    if (InitPens(graphPtr) != TCL_OK) {
        goto error;
    }
    if (Blt_DefaultAxes(graphPtr) != TCL_OK) {
        goto error;
    }
    AdjustMarginPointers(graphPtr);
    if (Blt_ConfigureWidgetFromObj(interp, tkwin, configSpecs, objc - 2, 
                objv + 2, (char *)graphPtr, 0) != TCL_OK) {
        goto error;
    }
    AdjustMarginPointers(graphPtr);

    if (Blt_CreatePageSetup(graphPtr) != TCL_OK) {
        goto error;
    }
    if (Blt_CreateCrosshairs(graphPtr) != TCL_OK) {
        goto error;
    }
    if (Blt_CreateLegend(graphPtr) != TCL_OK) {
        goto error;
    }
    if (Blt_CreatePlayback(graphPtr) != TCL_OK) {
        goto error;
    }
    Tk_CreateEventHandler(graphPtr->tkwin, 
        ExposureMask | StructureNotifyMask | FocusChangeMask, GraphEventProc, 
        graphPtr);

    graphPtr->cmdToken = Tcl_CreateObjCommand(interp, Tcl_GetString(objv[1]), 
        Blt_GraphInstCmdProc, graphPtr, GraphInstCmdDeleteProc);
    ConfigureGraph(graphPtr);
    graphPtr->bindTable = Blt_CreateBindingTable(interp, tkwin, graphPtr, 
        PickEntry, Blt_GraphTags);
    Blt_InitHashTable(&graphPtr->colormapTable, BLT_STRING_KEYS);

    Tcl_SetObjResult(interp, objv[1]);
    return graphPtr;

 error:
    DestroyGraph((DestroyData)graphPtr);
    return NULL;
}

/* Widget sub-commands */

/*ARGSUSED*/
static int
XAxisOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_AxisOp(graphPtr, interp, MARGIN_X, objc, objv);
}

static int
X2AxisOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_AxisOp(graphPtr, interp, MARGIN_X2, objc, objv);
}

static int
YAxisOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_AxisOp(graphPtr, interp, MARGIN_Y, objc, objv);
}

static int
Y2AxisOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_AxisOp(graphPtr, interp, MARGIN_Y2, objc, objv);
}

static int
BarOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_ElementOp(graphPtr, interp, objc, objv, CID_ELEM_BAR);
}

/*ARGSUSED*/
static int
LineOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_ElementOp(graphPtr, interp, objc, objv, CID_ELEM_LINE);
}

/*ARGSUSED*/
static int
StripOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_ElementOp(graphPtr, interp, objc, objv, CID_ELEM_STRIP);
}

static int
ElementOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_ElementOp(graphPtr, interp, objc, objv, graphPtr->classId);
}

static int
ConfigureOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    int flags;

    flags = BLT_CONFIG_OBJV_ONLY;
    if (objc == 2) {
        return Blt_ConfigureInfoFromObj(interp, graphPtr->tkwin, configSpecs,
            (char *)graphPtr, (Tcl_Obj *)NULL, flags);
    } else if (objc == 3) {
        return Blt_ConfigureInfoFromObj(interp, graphPtr->tkwin, configSpecs,
            (char *)graphPtr, objv[2], flags);
    } else {
        if (Blt_ConfigureWidgetFromObj(interp, graphPtr->tkwin, configSpecs, 
                objc - 2, objv + 2, (char *)graphPtr, flags) != TCL_OK) {
            return TCL_ERROR;
        }
        ConfigureGraph(graphPtr);
        Blt_EventuallyRedrawGraph(graphPtr);
        return TCL_OK;
    }
}

/* ARGSUSED*/
static int
CgetOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    return Blt_ConfigureValueFromObj(interp, graphPtr->tkwin, configSpecs,
        (char *)graphPtr, objv[2], 0);
}

/*
 *---------------------------------------------------------------------------
 *
 * ExtentsOp --
 *
 *      Reports the size of one of several items within the graph.  The
 *      following are valid items:
 *
 *        "bottommargin"        Height of the bottom margin
 *        "leftmargin"          Width of the left margin
 *        "legend"              x y w h of the legend
 *        "plotarea"            x y w h of the plotarea
 *        "plotheight"          Height of the plot area
 *        "rightmargin"         Width of the right margin
 *        "topmargin"           Height of the top margin
 *        "plotwidth"           Width of the plot area
 *
 * Results:
 *      Always returns TCL_OK.
 *
 *---------------------------------------------------------------------------
 */
/* ARGSUSED*/
static int
ExtentsOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    const char *string;
    char c;
    int length;

    string = Tcl_GetStringFromObj(objv[2], &length);
    c = string[0];
    if ((c == 'p') && (length > 4) && 
        (strncmp("plotheight", string, length) == 0)) {
        Tcl_SetIntObj(Tcl_GetObjResult(interp), graphPtr->y2 - graphPtr->y1);
    } else if ((c == 'p') && (length > 4) &&
        (strncmp("plotwidth", string, length) == 0)) {
        Tcl_SetIntObj(Tcl_GetObjResult(interp), graphPtr->x2 - graphPtr->x1);
    } else if ((c == 'p') && (length > 4) &&
        (strncmp("plotarea", string, length) == 0)) {
        Tcl_Obj *listObjPtr, *objPtr;
        
        listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **)NULL);
        /* x */
        objPtr = Tcl_NewIntObj(graphPtr->x1);
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        /* y */
        objPtr = Tcl_NewIntObj(graphPtr->y1);
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        /* width */
        objPtr = Tcl_NewIntObj(graphPtr->x2 - graphPtr->x1);
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        /* height */
        objPtr = Tcl_NewIntObj(graphPtr->y2 - graphPtr->y1);
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        Tcl_SetObjResult(interp, listObjPtr);
    } else if ((c == 'l') && (length > 2) &&
        (strncmp("legend", string, length) == 0)) {
        Tcl_Obj *listObjPtr, *objPtr;

        listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **)NULL);
        /* x */
        objPtr = Tcl_NewIntObj(Blt_Legend_X(graphPtr));
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        /* y */
        objPtr = Tcl_NewIntObj(Blt_Legend_Y(graphPtr));
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        /* width */
        objPtr = Tcl_NewIntObj(Blt_Legend_Width(graphPtr));
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        /* height */
        objPtr = Tcl_NewIntObj(Blt_Legend_Height(graphPtr));
        Tcl_ListObjAppendElement(interp, listObjPtr, objPtr);
        Tcl_SetObjResult(interp, listObjPtr);
    } else if ((c == 'l') && (length > 2) &&
        (strncmp("leftmargin", string, length) == 0)) {
        Tcl_SetIntObj(Tcl_GetObjResult(interp), graphPtr->leftPtr->width);
    } else if ((c == 'r') && (length > 1) &&
        (strncmp("rightmargin", string, length) == 0)) {
        Tcl_SetIntObj(Tcl_GetObjResult(interp),
                      graphPtr->rightPtr->width);
    } else if ((c == 't') && (length > 1) &&
        (strncmp("topmargin", string, length) == 0)) {
        Tcl_SetIntObj(Tcl_GetObjResult(interp),
                      graphPtr->topPtr->height);
    } else if ((c == 'b') && (length > 1) &&
        (strncmp("bottommargin", string, length) == 0)) {
        Tcl_SetIntObj(Tcl_GetObjResult(interp),
                      graphPtr->bottomPtr->height);
    } else {
        Tcl_AppendResult(interp, "bad extent item \"", objv[2],
            "\": should be plotheight, plotwidth, leftmargin, rightmargin, \
topmargin, bottommargin, plotarea, or legend", (char *)NULL);
        return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * InsideOp --
 *
 *      Returns true of false whether the given point is inside the
 *      plotting area (defined by left,bottom right, top).
 *
 * Results:
 *      Always returns TCL_OK.  interp->result will contain the boolean
 *      string representation.
 *
 *---------------------------------------------------------------------------
 */
/* ARGSUSED*/
static int
InsideOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    int x, y;
    Region2d exts;
    int result;

    if (Tcl_GetIntFromObj(interp, objv[2], &x) != TCL_OK) {
        return TCL_ERROR;
    }
    if (Tcl_GetIntFromObj(interp, objv[3], &y) != TCL_OK) {
        return TCL_ERROR;
    }
    GraphExtents(graphPtr, &exts);
    result = PointInRegion(&exts, x, y);
    Tcl_SetBooleanObj(Tcl_GetObjResult(interp), result);
    return TCL_OK;
}


/*
 *---------------------------------------------------------------------------
 *
 * InvtransformOp --
 *
 *      This procedure returns a list of the graph coordinate values
 *      corresponding with the given window X and Y coordinate positions.
 *
 * Results:
 *      Returns a standard TCL result.  If an error occurred while parsing
 *      the window positions, TCL_ERROR is returned, and interp->result
 *      will contain the error message.  Otherwise interp->result will
 *      contain a TCL list of the x and y coordinates.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
InvtransformOp(Graph *graphPtr, Tcl_Interp *interp, int objc, 
               Tcl_Obj *const *objv)
{
    Axis2d axes;
    Tcl_Obj *listObjPtr;
    TransformSwitches args;
    int i, switchesStart;
    
    for (i = 2; i < objc; i++) {
        double x;
        
        if (Blt_ExprDoubleFromObj(NULL, objv[i], &x) != TCL_OK) {
            break;
        }
    }
    switchesStart = i;
    if (switchesStart & 0x1) {
        return TCL_ERROR;
    }
    if (graphPtr->flags & RESET_AXES) {
        Blt_ResetAxes(graphPtr);
    }
    memset(&args, 0, sizeof(args));
    args.elemPtr = NULL;
    args.graphPtr = graphPtr;
    bltXAxisSwitch.clientData = graphPtr;
    bltYAxisSwitch.clientData = graphPtr;
    if (Blt_ParseSwitches(interp, transformSpecs, objc - switchesStart,
        objv + switchesStart, &args, BLT_SWITCH_DEFAULTS) < 0) {
        return TCL_ERROR;
    }
    /* Default: Use the first x and y axes. */
    axes.x = Blt_GetFirstAxis(graphPtr->margins[MARGIN_X].axes);
    axes.y = Blt_GetFirstAxis(graphPtr->margins[MARGIN_Y].axes);
    /* Override if individual axis is specified. */
    if (args.xAxisPtr != NULL) {
        axes.x = args.xAxisPtr;
    } 
    if (args.yAxisPtr != NULL) {
        axes.y = args.yAxisPtr;
    } 
    /* Override if element is specified. */
    if (args.elemPtr != NULL) {
        axes = args.elemPtr->axes;
    }
    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **)NULL);
    for (i = 2; i < switchesStart; i += 2) {
        Point2d point;
        double x, y;

        if ((Blt_ExprDoubleFromObj(interp, objv[i], &x) != TCL_OK) ||
            (Blt_ExprDoubleFromObj(interp, objv[i+1], &y) != TCL_OK)) {
            return TCL_ERROR;
        }
        point = Blt_InvMap2D(graphPtr, x, y, &axes);
        Tcl_ListObjAppendElement(interp, listObjPtr, 
                                 Tcl_NewDoubleObj(point.x));
        Tcl_ListObjAppendElement(interp, listObjPtr, 
                                 Tcl_NewDoubleObj(point.y));
    }
    Tcl_SetObjResult(interp, listObjPtr);
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * TransformOp --
 *
 *      This procedure returns a list of the window coordinates
 *      corresponding with the given graph x and y coordinates.
 *
 * Results:
 *      Returns a standard TCL result.  interp->result contains the list of
 *      the graph coordinates. If an error occurred while parsing the
 *      window positions, TCL_ERROR is returned, then interp->result will
 *      contain an error message.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
TransformOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    Axis2d axes;
    Tcl_Obj *listObjPtr;
    TransformSwitches args;
    int i, switchesStart;
    
    for (i = 2; i < objc; i++) {
        double x;
        
        if (Blt_ExprDoubleFromObj(NULL, objv[i], &x) != TCL_OK) {
            break;
        }
    }
    switchesStart = i;
    if (switchesStart & 0x1) {
        return TCL_ERROR;
    }
    if (graphPtr->flags & RESET_AXES) {
        Blt_ResetAxes(graphPtr);
    }
    memset(&args, 0, sizeof(args));
    args.elemPtr = NULL;
    args.graphPtr = graphPtr;
    bltXAxisSwitch.clientData = graphPtr;
    bltYAxisSwitch.clientData = graphPtr;
    if (Blt_ParseSwitches(interp, transformSpecs, objc - switchesStart,
        objv + switchesStart, &args, BLT_SWITCH_DEFAULTS) < 0) {
        return TCL_ERROR;
    }
    /* Default: Use the first x and y axes. */
    axes.x = Blt_GetFirstAxis(graphPtr->margins[MARGIN_X].axes);
    axes.y = Blt_GetFirstAxis(graphPtr->margins[MARGIN_Y].axes);
    /* Override if individual axis is specified. */
    if (args.xAxisPtr != NULL) {
        axes.x = args.xAxisPtr;
    } 
    if (args.yAxisPtr != NULL) {
        axes.y = args.yAxisPtr;
    } 
    /* Override if element is specified. */
    if (args.elemPtr != NULL) {
        axes = args.elemPtr->axes;
    }

    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **)NULL);
    for (i = 2; i < switchesStart; i += 2) {
        Point2d point;
        double x, y;

        if ((Blt_ExprDoubleFromObj(interp, objv[i], &x) != TCL_OK) ||
            (Blt_ExprDoubleFromObj(interp, objv[i+1], &y) != TCL_OK)) {
            return TCL_ERROR;
        }
        point = Blt_Map2D(graphPtr, x, y, &axes);
        Tcl_ListObjAppendElement(interp, listObjPtr, 
                                 Tcl_NewIntObj(ROUND(point.x)));
        Tcl_ListObjAppendElement(interp, listObjPtr, 
                                 Tcl_NewIntObj(ROUND(point.y)));
    }

    Tcl_SetObjResult(interp, listObjPtr);
    return TCL_OK;
}

#ifndef NO_PRINTER

/*
 *---------------------------------------------------------------------------
 *
 * Print1Op --
 *
 *      Prints the equivalent of a screen snapshot of the graph to the
 *      designated printer.
 *
 * Results:
 *      Returns a standard TCL result.  If an error occurred TCL_ERROR is
 *      returned and interp->result will contain an error message.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
Print1Op(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    BITMAPINFO info;
    void *data;
    TkWinDCState state;
    TkWinBitmap bd;
    DIBSECTION ds;
    Drawable drawable;
    HBITMAP hBitmap;
    HDC hDC;
    DOCINFO di;
    double pageWidth, pageHeight;
    int result;
    double scale, sx, sy;
    int jobId;

    graphPtr->width = Tk_Width(graphPtr->tkwin);
    graphPtr->height = Tk_Height(graphPtr->tkwin);
    if ((graphPtr->width < 2) && (graphPtr->reqWidth > 0)) {
        graphPtr->width = graphPtr->reqWidth;
    }
    if ((graphPtr->height < 2) && (graphPtr->reqHeight > 0)) {
        graphPtr->height = graphPtr->reqHeight;
    }
    if (objc == 2) {
        result = Blt_PrintDialog(interp, &drawable);
        if (result == TCL_ERROR) {
            return TCL_ERROR;
        }
        if (result == TCL_RETURN) {
            return TCL_OK;
        }
    } else {
        if (Blt_GetOpenPrinter(interp, Tcl_GetString(objv[2]), &drawable) 
            != TCL_OK) {
            return TCL_ERROR;
        }
    }
    /*  
     * This is a taken from Blt_SnapPhoto.  The difference is that here
     * we're using the DIBSection directly, without converting the section
     * into a Picture.
     */
    ZeroMemory(&info, sizeof(info));
    info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    info.bmiHeader.biWidth = graphPtr->width;
    info.bmiHeader.biHeight = graphPtr->height;
    info.bmiHeader.biPlanes = 1;
    info.bmiHeader.biBitCount = 32;
    info.bmiHeader.biCompression = BI_RGB;
    hDC = TkWinGetDrawableDC(graphPtr->display, Tk_WindowId(graphPtr->tkwin),
                &state);
    hBitmap = CreateDIBSection(hDC, &info, DIB_RGB_COLORS, &data, NULL, 0);
    TkWinReleaseDrawableDC(Tk_WindowId(graphPtr->tkwin), hDC, &state);
    
    /*
     * Create our own drawable by hand using the DIB we just created.
     * We'll then draw into it using the standard drawing functions.
     */
    bd.type = TWD_BITMAP;
    bd.handle = hBitmap;
    bd.colormap = DefaultColormap(graphPtr->display, 
        DefaultScreen(graphPtr->display));
    bd.depth = Tk_Depth(graphPtr->tkwin);
    
    graphPtr->flags |= RESET_WORLD;
    GraphToDrawable(graphPtr, (Drawable)&bd);

    /*
     * Now that the DIB contains the image of the graph, get the the data
     * bits and write them to the printer device, stretching the image to
     * the fit the printer's resolution.
     */
    result = TCL_ERROR;
    if (GetObject(hBitmap, sizeof(DIBSECTION), &ds) == 0) {
        Tcl_AppendResult(interp, "can't get object: ", Blt_LastError(),
            (char *)NULL);
        goto done;
    }
    hDC = ((TkWinDC *) drawable)->hdc;
    /* Get the resolution of the printer device. */
    sx = (double)GetDeviceCaps(hDC, HORZRES) / (double)graphPtr->width;
    sy = (double)GetDeviceCaps(hDC, VERTRES) / (double)graphPtr->height;
    scale = MIN(sx, sy);
    pageWidth = scale * graphPtr->width;
    pageHeight = scale * graphPtr->height;

    ZeroMemory(&di, sizeof(di));
    di.cbSize = sizeof(di);
    di.lpszDocName = "Graph Contents";
    jobId = StartDoc(hDC, &di);
    if (jobId <= 0) {
        Tcl_AppendResult(interp, "can't start document: ", Blt_LastError(),
            (char *)NULL);
        goto done;
    }
    if (StartPage(hDC) <= 0) {
        Tcl_AppendResult(interp, "error starting page: ", Blt_LastError(),
            (char *)NULL);
        goto done;
    }
    StretchDIBits(hDC, 0, 0, ROUND(pageWidth), ROUND(pageHeight), 0, 0, 
        graphPtr->width, graphPtr->height, ds.dsBm.bmBits, 
        (LPBITMAPINFO)&ds.dsBmih, DIB_RGB_COLORS, SRCCOPY);
    EndPage(hDC);
    EndDoc(hDC);
    result = TCL_OK;
  done:
    DeleteBitmap(hBitmap);
    return result;
}

/*
 *---------------------------------------------------------------------------
 *
 * Print2Op --
 *
 *      Prints directly to the designated printer device.
 *
 * Results:
 *      Returns a standard TCL result.  If an error occurred, TCL_ERROR is
 *      returned and interp->result will contain an error message.
 *
 *---------------------------------------------------------------------------
 */
static int
Print2Op(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    Drawable drawable;
    int result;

    graphPtr->width = Tk_Width(graphPtr->tkwin);
    graphPtr->height = Tk_Height(graphPtr->tkwin);
    if ((graphPtr->width < 2) && (graphPtr->reqWidth > 0)) {
        graphPtr->width = graphPtr->reqWidth;
    }
    if ((graphPtr->height < 2) && (graphPtr->reqHeight > 0)) {
        graphPtr->height = graphPtr->reqHeight;
    }
    if (objc == 2) {
        result = Blt_PrintDialog(interp, &drawable);
        if (result == TCL_ERROR) {
            return TCL_ERROR;
        }
        if (result == TCL_RETURN) {
            return TCL_OK;
        }
    } else {
        result = Blt_GetOpenPrinter(interp, Tcl_GetString(objv[2]), &drawable);
    }
    if (result == TCL_OK) {
        int oldMode;
        HDC hDC;
        double xRatio, yRatio;
        TkWinDC *drawPtr;
        int w, h; 

        drawPtr = (TkWinDC *) drawable;
        hDC = drawPtr->hdc;
        Blt_GetPrinterScale(hDC, &xRatio, &yRatio);
        oldMode = SetMapMode(hDC, MM_ISOTROPIC);
        if (oldMode == 0) {
            Tcl_AppendResult(interp, "can't set mode for printer DC: ",
                Blt_LastError(), (char *)NULL);
            return TCL_ERROR;
        }
        w = ROUND(graphPtr->width * xRatio);
        h = ROUND(graphPtr->height * yRatio);
        SetViewportExtEx(hDC, w, h, NULL);
        SetWindowExtEx(hDC, graphPtr->width, graphPtr->height, NULL);

        Blt_StartPrintJob(interp, drawable);
        graphPtr->flags |= RESET_WORLD;
        GraphToDrawable(graphPtr, drawable);
        Blt_EndPrintJob(interp, drawable);
    }
    return result;
}

#endif /* NO_PRINTER */

/*
 *---------------------------------------------------------------------------
 *
 * ObjToFormat --
 *
 *      Convert a string representing an output format.
 *
 * Results:
 *      The return value is a standard TCL result.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
ObjToFormat(
    ClientData clientData,              /* Not used.*/
    Tcl_Interp *interp,                 /* Interpreter to send results back
                                         * to */
    const char *switchName,             /* Not used. */
    Tcl_Obj *objPtr,                    /* String representation */
    char *record,                       /* Structure record */
    int offset,                         /* Offset to field in structure */
    int flags)                          /* Not used. */
{
    int *formatPtr = (int *)(record + offset);
    char c;
    const char *string;

    string = Tcl_GetString(objPtr);
    c = string[0];
    if ((c == 'p') && (strcmp(string, "picture") == 0)) {
        *formatPtr = FMT_PICTURE;
    } else if ((c == 'p') && (strcmp(string, "photo") == 0)) {
        *formatPtr = FMT_PHOTO;
    } else if ((c == 'i') && (strcmp(string, "image") == 0)) {
        *formatPtr = FMT_PICTURE;
#ifdef WIN32
    } else if ((c == 'e') && (strcmp(string, "emf") == 0)) {
        *formatPtr = FMT_EMF;
    } else if ((c == 'w') && (strcmp(string, "wmf") == 0)) {
        *formatPtr = FMT_WMF;
#endif /* WIN32 */
    } else {
#ifdef WIN32
        Tcl_AppendResult(interp, "bad format \"", string, 
                 "\": should be image, emf, or wmf", (char *)NULL);
#else
        Tcl_AppendResult(interp, "bad format \"", string, 
                 "\": should be image", (char *)NULL);
#endif /* WIN32 */
        return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * ObjToPixels --
 *
 *      Convert a string representing an output format.
 *
 * Results:
 *      The return value is a standard TCL result.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
ObjToPixels(
    ClientData clientData,              /* Not used.*/
    Tcl_Interp *interp,                 /* Interpreter to send results back
                                         * to */
    const char *switchName,             /* Not used. */
    Tcl_Obj *objPtr,                    /* String representation */
    char *record,                       /* Structure record */
    int offset,                         /* Offset to field in structure */
    int flags)                          /* Not used. */
{
    int *numPixelsPtr = (int *)(record + offset);
    Tk_Window tkwin;

    tkwin = Tk_MainWindow(interp);
    return Blt_GetPixelsFromObj(interp, tkwin, objPtr, PIXELS_POS,numPixelsPtr);
}


/*
 *---------------------------------------------------------------------------
 *
 * ObjToElement --
 *
 *      Convert a string representing an element name into its pointer.
 *
 * Results:
 *      The return value is a standard TCL result.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
ObjToElement(
    ClientData clientData,              /* Not used.*/
    Tcl_Interp *interp,                 /* Interpreter to send results back
                                         * to */
    const char *switchName,             /* Not used. */
    Tcl_Obj *objPtr,                    /* String representation */
    char *record,                       /* Structure record */
    int offset,                         /* Offset to field in structure */
    int flags)                          /* Not used. */
{
    TransformSwitches *argsPtr = (TransformSwitches *)record;
    Element **elemPtrPtr = (Element **)(record + offset);
    Element *elemPtr;
    const char *string;

    string = Tcl_GetString(objPtr);
    if (string[0] == '\0') {
        *elemPtrPtr = NULL;
        return TCL_OK;
    }
    if (Blt_GetElement(interp, argsPtr->graphPtr, objPtr, &elemPtr) != TCL_OK) {
        return TCL_ERROR;
    }
    *elemPtrPtr = elemPtr;
    return TCL_OK;
}

#ifdef WIN32
static int InitMetaFileHeader(
    Tk_Window tkwin,
    int width, int height,
    APMHEADER *mfhPtr)
{
    unsigned int *p;
    unsigned int sum;
#define MM_INCH         25.4
    int xdpi, ydpi;

    mfhPtr->key = 0x9ac6cdd7L;
    mfhPtr->hmf = 0;
    mfhPtr->inch = 1440;

    Blt_ScreenDPI(tkwin, &xdpi, &ydpi);
    mfhPtr->bbox.Left = mfhPtr->bbox.Top = 0;
    mfhPtr->bbox.Bottom = (SHORT)((width * 1440)/ (float)xdpi);
    mfhPtr->bbox.Right = (SHORT)((height * 1440) / (float)ydpi);
    mfhPtr->reserved = 0;
    sum = 0;
    for (p = (unsigned int *)mfhPtr; 
         p < (unsigned int *)&(mfhPtr->checksum); p++) {
        sum ^= *p;
    }
    mfhPtr->checksum = sum;
    return TCL_OK;
}

static int
CreateAPMetaFile(Tcl_Interp *interp, HANDLE hMetaFile, HDC hDC, 
                 APMHEADER *mfhPtr, const char *fileName)
{
    HANDLE hFile;
    HANDLE hMem;
    LPVOID buffer;
    int result;
    DWORD count, numBytes;

    result = TCL_ERROR;
    hMem = NULL;
    hFile = CreateFile(
       fileName,                        /* File path */
       GENERIC_WRITE,                   /* Access mode */
       0,                               /* No sharing. */
       NULL,                            /* Security attributes */
       CREATE_ALWAYS,                   /* Overwrite any existing file */
       FILE_ATTRIBUTE_NORMAL,
       NULL);                           /* No template file */
    if (hFile == INVALID_HANDLE_VALUE) {
        Tcl_AppendResult(interp, "can't create metafile \"", fileName, 
                "\":", Blt_LastError(), (char *)NULL);
        return TCL_ERROR;
    }
    if ((!WriteFile(hFile, (LPVOID)mfhPtr, sizeof(APMHEADER), &count, 
                NULL)) || (count != sizeof(APMHEADER))) {
        Tcl_AppendResult(interp, "can't create metafile header to \"", 
                         fileName, "\":", Blt_LastError(), (char *)NULL);
        goto error;
    }
    numBytes = GetWinMetaFileBits(hMetaFile, 0, NULL, MM_ANISOTROPIC, hDC);
    hMem = GlobalAlloc(GHND, numBytes);
    if (hMem == NULL) {
        Tcl_AppendResult(interp, "can't create allocate global memory:", 
                Blt_LastError(), (char *)NULL);
        goto error;
    }
    buffer = (LPVOID)GlobalLock(hMem);
    if (!GetWinMetaFileBits(hMetaFile, numBytes, buffer, MM_ANISOTROPIC, hDC)) {
        Tcl_AppendResult(interp, "can't get metafile bits:", 
                Blt_LastError(), (char *)NULL);
        goto error;
    }
    if ((!WriteFile(hFile, buffer, numBytes, &count, NULL)) ||
        (count != numBytes)) {
        Tcl_AppendResult(interp, "can't write metafile bits:", 
                Blt_LastError(), (char *)NULL);
        goto error;
    }
    result = TCL_OK;
 error:
    CloseHandle(hFile);
    if (hMem != NULL) {
        GlobalUnlock(hMem);
        GlobalFree(hMem);
    }
    return result;
}
#endif /*WIN32*/

/*
 *---------------------------------------------------------------------------
 *
 * ImageChangedProc
 *
 *
 * Results:
 *      None.
 *
 *---------------------------------------------------------------------------
 */
/* ARGSUSED */
static void
ImageChangedProc(ClientData clientData, int x, int y, int w, int h,
                 int imageWidth, int imageHeight)       
{
    Graph *graphPtr = clientData;

    graphPtr->flags |= CACHE_DIRTY;
    Blt_EventuallyRedrawGraph(graphPtr);
}

/*
 *---------------------------------------------------------------------------
 *
 * SnapOp --
 *
 *      Snaps a picture of the graph and stores it in the specified image.
 *
 * Results:
 *      Returns a standard TCL result.  interp->result contains the list of
 *      the graph coordinates. If an error occurred while parsing the
 *      window positions, TCL_ERROR is returned, then interp->result will
 *      contain an error message.
 *
 *      pathName snap imageName ?switches ...?
 *              -width numPixels
 *              -height numPixels
 *              -maxpect
 *              -format 
 *
 *---------------------------------------------------------------------------
 */
static int
SnapOp(Graph *graphPtr, Tcl_Interp *interp, int objc, Tcl_Obj *const *objv)
{
    Pixmap drawable;
    SnapSwitches args;
    const char *imgName;
    int result;
    int w, h, reqWidth, reqHeight;
    
    /* Figure out what the current size of the graph is supposed to be. */
    imgName = Tcl_GetString(objv[2]);
    /* Initialize switches and set defaults. */
    memset(&args, 0, sizeof(args));
    w = Tk_Width(graphPtr->tkwin);
    if (w < 2) {
        w = Tk_ReqWidth(graphPtr->tkwin);
    }
    if ((w < 2) && (graphPtr->reqWidth > 0)) {
        w = graphPtr->reqWidth;
    }
    h = Tk_Height(graphPtr->tkwin);
    if (h < 2) {
        h = Tk_ReqHeight(graphPtr->tkwin);
    }
    if ((h < 2) || (graphPtr->reqHeight > 0)) {
        h = graphPtr->reqHeight;
    }
    args.format = FMT_PICTURE;
    if (Blt_ParseSwitches(interp, snapSpecs, objc - 3, objv + 3, &args, 
                BLT_SWITCH_DEFAULTS) < 0) {
        return TCL_ERROR;
    }
    /* Base the new size on either the image size or the specified size. */
    reqWidth = w;
    reqHeight = h;
    if ((args.format == FMT_PICTURE) || (args.format == FMT_PHOTO)) {
        int iw, ih;
        Tk_Image tkImage;
        
        tkImage = Tk_GetImage(interp, graphPtr->tkwin, imgName,
                              ImageChangedProc, graphPtr);
        if (tkImage == NULL) {
            return TCL_ERROR;
        }
        Tk_SizeOfImage(tkImage, &iw, &ih);
        if (iw > 0 && ih > 0) {
            reqWidth = iw;
            reqHeight = ih;
            if (args.flags & MAXPECT) {
                double xs, ys;
            
                xs = (double)iw / w;
                ys = (double)ih / h;
                if (xs > ys) {
                    reqWidth = (int)(w * ys);
                    reqHeight = (int)(h * ys);
                } else {
                    reqWidth = (int)(w * xs);
                    reqHeight = (int)(h * xs);
                }
            }
        }
    }
    if (args.width > 0) {
        reqWidth = args.width;
    }
    if (args.height > 0) {
        reqHeight = args.height;
    }
    
    /* Always re-compute the layout of the graph before snapping the
     * picture. */
    graphPtr->width  = reqWidth;
    graphPtr->height = reqHeight;
    graphPtr->flags |= RESET_WORLD;
    Blt_MapGraph(graphPtr);

    drawable = Tk_WindowId(graphPtr->tkwin);
    switch (args.format) {
    case FMT_PICTURE:
    case FMT_PHOTO:
        {
            Pixmap pixmap;
            
            if (graphPtr->cache != None) {
                /*
                 * Free the pixmap and indicate that there is no backing store.
                 */
                Tk_FreePixmap(graphPtr->display, graphPtr->cache);
                graphPtr->cache = None;
            }
            pixmap = Blt_GetPixmap(graphPtr->display, drawable, reqWidth, 
                reqHeight, Tk_Depth(graphPtr->tkwin));
            graphPtr->flags |= RESET_WORLD;
            GraphToDrawable(graphPtr, pixmap);
            if (args.format == FMT_PICTURE) {
                result = Blt_SnapPicture(interp, graphPtr->tkwin, pixmap, 0, 0, 
                        reqWidth, reqHeight, reqWidth, reqHeight, imgName, 1.0);
            } else {
                result = Blt_SnapPhoto(interp, graphPtr->tkwin, pixmap, 0, 0,
                        reqWidth, reqHeight, reqWidth, reqHeight, imgName, 1.0);
            }
            Blt_FreePixmap(graphPtr->display, pixmap);
        }
        break;

#ifdef WIN32
        /* FIXME: Can't snap background from hDC of metafiles. */
    case FMT_WMF:
    case FMT_EMF:
        {
            TkWinDC drawableDC;
            TkWinDCState state;
            HDC hRefDC, hDC;
            HENHMETAFILE hMetaFile;
            Tcl_DString ds;
            const char *title;
            
            hRefDC = TkWinGetDrawableDC(graphPtr->display, drawable, &state);
            
            Tcl_DStringInit(&ds);
            Tcl_DStringAppend(&ds, "BLT Graph ", -1);
            Tcl_DStringAppend(&ds, BLT_VERSION, -1);
            Tcl_DStringAppend(&ds, "\0", -1);
            Tcl_DStringAppend(&ds, Tk_PathName(graphPtr->tkwin), -1);
            Tcl_DStringAppend(&ds, "\0", -1);
            title = Tcl_DStringValue(&ds);
            hDC = CreateEnhMetaFile(hRefDC, NULL, NULL, title);
            Tcl_DStringFree(&ds);
            
            if (hDC == NULL) {
                Tcl_AppendResult(interp, "can't create metafile: ",
                                 Blt_LastError(), (char *)NULL);
                return TCL_ERROR;
            }
            
            drawableDC.hdc = hDC;
            drawableDC.type = TWD_WINDC;
            
            graphPtr->width = reqWidth;
            graphPtr->height = reqHeight;
            Blt_MapGraph(graphPtr);
            graphPtr->flags |= RESET_WORLD;
            GraphToDrawable(graphPtr, (Drawable)&drawableDC);
            hMetaFile = CloseEnhMetaFile(hDC);
            if (strcmp(imgName, "CLIPBOARD") == 0) {
                HWND hWnd;
                
                hWnd = Tk_GetHWND(drawable);
                OpenClipboard(hWnd);
                EmptyClipboard();
                SetClipboardData(CF_ENHMETAFILE, hMetaFile);
                CloseClipboard();
                result = TCL_OK;
            } else {
                result = TCL_ERROR;
                if (args.format == FMT_WMF) {
                    APMHEADER mfh;
                    
                    assert(sizeof(mfh) == 22);
                    InitMetaFileHeader(graphPtr->tkwin, reqWidth,
                                       reqHeight, &mfh);
                    result = CreateAPMetaFile(interp, hMetaFile, hRefDC, &mfh, 
                                              imgName);
                } else {
                    HENHMETAFILE hMetaFile2;
                    
                    hMetaFile2 = CopyEnhMetaFile(hMetaFile, imgName);
                    if (hMetaFile2 != NULL) {
                        result = TCL_OK;
                        DeleteEnhMetaFile(hMetaFile2); 
                    }
                }
                DeleteEnhMetaFile(hMetaFile); 
            }
            TkWinReleaseDrawableDC(drawable, hRefDC, &state);
        }
        break;
#endif /*WIN32*/
    default:
        Tcl_AppendResult(interp, "bad snapshot format", (char *)NULL);
        return TCL_ERROR;
    }
    graphPtr->flags |= MAP_WORLD;
    Blt_EventuallyRedrawGraph(graphPtr);
    return result;
}

/*
 *---------------------------------------------------------------------------
 *
 * GraphWidgetCmd --
 *
 *      This procedure is invoked to process the TCL command that
 *      corresponds to a widget managed by this module.  See the user
 *      documentation for details on what it does.
 *
 * Results:
 *      A standard TCL result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *---------------------------------------------------------------------------
 */
static Blt_OpSpec graphOps[] =
{
    {"axis",         1, Blt_VirtualAxisOp, 2, 0, "args ...",},
    {"bar",          1, BarOp,             2, 0, "args ...",},
    {"cget",         2, CgetOp,            3, 3, "option",},
    {"configure",    3, ConfigureOp,       2, 0, "?option value ...?",},
    {"crosshairs",   2, Blt_CrosshairsOp,  2, 0, "args ...",},
    {"element",      2, ElementOp,         2, 0, "args ...",},
    {"extents",      2, ExtentsOp,         3, 3, "item",},
    {"inside",       3, InsideOp,          4, 4, "x y",},
    {"invtransform", 3, InvtransformOp,    4, 0, "x y ?switches ...?",},
    {"isoline",      2, Blt_IsolineOp,     2, 0, "args ..."},
    {"legend",       2, Blt_LegendOp,      2, 0, "args ...",},
    {"line",         2, LineOp,            2, 0, "args ...",},
    {"marker",       1, Blt_MarkerOp,      2, 0, "args ...",},
    {"pen",          2, Blt_PenOp,         2, 0, "args ...",},
    {"postscript",   2, Blt_PostScriptOp,  2, 0, "args ...",},
#ifndef NO_PRINTER
    {"print1",       6, Print1Op,          2, 3, "?printerName?",},
    {"print2",       6, Print2Op,          2, 3, "?printerName?",},
#endif /*NO_PRINTER*/
    {"region",       1, Blt_GraphRegionOp, 2, 0, "oper ?args ...?",},
    {"snap",         2, SnapOp,            3, 0, "imageName ?switches ...?",},
    {"strip",        2, StripOp,           2, 0, "args ...",},
    {"transform",    1, TransformOp,       4, 0, "x y ... ?switches ...?",},
    {"x2axis",       2, X2AxisOp,          2, 0, "args ...",},
    {"xaxis",        2, XAxisOp,           2, 0, "args ...",},
    {"y2axis",       2, Y2AxisOp,          2, 0, "args ...",},
    {"yaxis",        2, YAxisOp,           2, 0, "args ...",},
};
static int numGraphOps = sizeof(graphOps) / sizeof(Blt_OpSpec);

int
Blt_GraphInstCmdProc(ClientData clientData, Tcl_Interp *interp, int objc,
                     Tcl_Obj *const *objv)
{
    Tcl_ObjCmdProc *proc;
    int result;
    Graph *graphPtr = clientData;

    proc = Blt_GetOpFromObj(interp, numGraphOps, graphOps, BLT_OP_ARG1, 
        objc, objv, 0);
    if (proc == NULL) {
        return TCL_ERROR;
    }
    Tcl_Preserve(graphPtr);
    result = (*proc) (clientData, interp, objc, objv);
    Tcl_Release(graphPtr);
    return result;
}

/*
 *---------------------------------------------------------------------------
 *
 * NewGraph --
 *
 *      Creates a new window and TCL command representing an instance of a
 *      graph widget.
 *
 * Results:
 *      A standard TCL result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *---------------------------------------------------------------------------
 */
static int
NewGraph(Tcl_Interp *interp, int objc, Tcl_Obj *const *objv, ClassId classId)
{
    Graph *graphPtr;

    if (objc < 2) {
        Tcl_AppendResult(interp, "wrong # args: should be \"", 
                Tcl_GetString(objv[0]), " pathName ?option value ...?\"", 
                (char *)NULL);
        return TCL_ERROR;
    }
    graphPtr = CreateGraph(interp, objc, objv, classId);
    if (graphPtr == NULL) {
        return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * GraphCmd --
 *
 *      Creates a new window and TCL command representing an instance of a
 *      graph widget.
 *
 * Results:
 *      A standard TCL result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
GraphCmd(ClientData clientData, Tcl_Interp *interp, int objc, 
         Tcl_Obj *const *objv)
{
    return NewGraph(interp, objc, objv, CID_ELEM_LINE);
}

/*
 *---------------------------------------------------------------------------
 *
 * BarchartCmd --
 *
 *      Creates a new window and TCL command representing an instance of a
 *      barchart widget.
 *
 * Results:
 *      A standard TCL result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
BarchartCmd(ClientData clientData, Tcl_Interp *interp, int objc, 
            Tcl_Obj *const *objv)
{
    return NewGraph(interp, objc, objv, CID_ELEM_BAR);
}

/*
 *---------------------------------------------------------------------------
 *
 * StripchartCmd --
 *
 *      Creates a new window and TCL command representing an instance of a
 *      barchart widget.
 *
 * Results:
 *      A standard TCL result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
StripchartCmd(ClientData clientData, Tcl_Interp *interp, int objc,
              Tcl_Obj *const *objv)
{
    return NewGraph(interp, objc, objv, CID_ELEM_STRIP);
}

/*
 *---------------------------------------------------------------------------
 *
 * ContourCmd --
 *
 *      Creates a new window and TCL command representing an instance of a
 *      graph widget.
 *
 * Results:
 *      A standard TCL result.
 *
 * Side effects:
 *      See the user documentation.
 *
 *---------------------------------------------------------------------------
 */
/*ARGSUSED*/
static int
ContourCmd(ClientData clientData, Tcl_Interp *interp, int objc, 
         Tcl_Obj *const *objv)
{
    return NewGraph(interp, objc, objv, CID_ELEM_CONTOUR);
}


/*
 *---------------------------------------------------------------------------
 *
 * DrawMargins --
 *
 *      Draws the exterior region of the graph (axes, ticks, titles, etc)
 *      onto a pixmap. The interior region is defined by the given
 *      rectangle structure.
 *
 *      ---------------------------------
 *      |                               |
 *      |           rectArr[0]          |
 *      |                               |
 *      ---------------------------------
 *      |     |top           right|     |
 *      |     |                   |     |
 *      |     |                   |     |
 *      | [1] |                   | [2] |
 *      |     |                   |     |
 *      |     |                   |     |
 *      |     |                   |     |
 *      |     |                   |     |
 *      |     |                   |     |
 *      |     |left         bottom|     |
 *      ---------------------------------
 *      |                               |
 *      |          rectArr[3]           |
 *      |                               |
 *      ---------------------------------
 *
 *              X coordinate axis
 *              Y coordinate axis
 *              legend
 *              interior border
 *              exterior border
 *              titles (X and Y axis, graph)
 *
 * Returns:
 *      None.
 *
 * Side Effects:
 *      Exterior of graph is displayed in its window.
 *
 *---------------------------------------------------------------------------
 */
static void
DrawMargins(Graph *graphPtr, Drawable drawable)
{
    int site;
    int w, h;

    /*
     * Draw the four outer rectangles which encompass the plotting
     * surface. This clears the surrounding area and clips the plot.
     */
    if ((graphPtr->width > 0) && (graphPtr->y1 > 0)) {
        Blt_Bg_FillRectangle(graphPtr->tkwin, drawable, graphPtr->normalBg, 
                0, 0, graphPtr->width, graphPtr->y1, 0, TK_RELIEF_FLAT);
    }
    h = graphPtr->y2 - graphPtr->y1;
    if ((graphPtr->x1 > 0) && (h > 0)) {
        Blt_Bg_FillRectangle(graphPtr->tkwin, drawable, graphPtr->normalBg, 
                0, graphPtr->y1, graphPtr->x1, h, 0, TK_RELIEF_FLAT);
    }        
    w = graphPtr->width - graphPtr->x2;
    if ((w > 0) && (h > 0)) {
        Blt_Bg_FillRectangle(graphPtr->tkwin, drawable, graphPtr->normalBg, 
                graphPtr->x2, graphPtr->y1, w, h, 0, TK_RELIEF_FLAT);
    }        
    h = graphPtr->height - graphPtr->y2;
    if ((graphPtr->width > 0) && (h > 0)) {
        Blt_Bg_FillRectangle(graphPtr->tkwin, drawable, graphPtr->normalBg, 
                0, graphPtr->y2, graphPtr->width, h, 0, TK_RELIEF_FLAT);
    }        
    w = (graphPtr->x2 - graphPtr->x1) + (2 * graphPtr->plotBorderWidth);
    h = (graphPtr->y2 - graphPtr->y1) + (2 * graphPtr->plotBorderWidth);

    /* Draw 3D border around the plotting area */
    if ((w > 0) && (h > 0) && (graphPtr->plotBorderWidth > 0)) {
        Blt_Bg_DrawRectangle(graphPtr->tkwin, drawable, 
                graphPtr->normalBg,
                graphPtr->x1 - graphPtr->plotBorderWidth,
                graphPtr->y1 - graphPtr->plotBorderWidth,
                w, h, graphPtr->plotBorderWidth, graphPtr->plotRelief);
    }
    site = Blt_Legend_Site(graphPtr);
    if (site & LEGEND_MARGIN_MASK) {
        /* Legend is drawn on one of the graph margins */
        Blt_DrawLegend(graphPtr, drawable);
    } else if (site == LEGEND_WINDOW) {
        Blt_Legend_EventuallyRedraw(graphPtr);
    }
    if (graphPtr->title != NULL) {
        Blt_DrawText(graphPtr->tkwin, drawable, graphPtr->title,
            &graphPtr->titleTextStyle, graphPtr->titleX, graphPtr->titleY);
    }
    Blt_DrawAxes(graphPtr, drawable);
    graphPtr->flags &= ~DRAW_MARGINS;
}

/*
 *---------------------------------------------------------------------------
 *
 * DrawPlot --
 *
 *      Draws the contents of the plotting area.  This consists of the
 *      elements, markers (draw under elements), axis limits, and possibly
 *      the legend.  Typically, the output will be cached into a backing
 *      store pixmap, so that redraws can occur quickly.
 *
 * Results:
 *      None.
 *
 *---------------------------------------------------------------------------
 */
static void
DrawPlot(Graph *graphPtr, Drawable drawable)
{
    int site;
    int x, y, w, h;
    
    DrawMargins(graphPtr, drawable);

    x = graphPtr->x1 - graphPtr->plotBorderWidth;
    y = graphPtr->y1 - graphPtr->plotBorderWidth;
    w = (graphPtr->x2 - graphPtr->x1) + (2 * graphPtr->plotBorderWidth);
    h = (graphPtr->y2 - graphPtr->y1) + (2 * graphPtr->plotBorderWidth);

    if ((w > 0) && (h > 0)) {
        /* Draw the background of the plotting area with 3D border. */
        Blt_Bg_FillRectangle(graphPtr->tkwin, drawable, graphPtr->plotBg,
                             x, y, w, h,
                             graphPtr->plotBorderWidth, graphPtr->plotRelief);
    }
    /* Draw the elements, markers, legend, and axis limits. */
    Blt_DrawMarkers(graphPtr, drawable, MARKER_UNDER);
    Blt_DrawAxes(graphPtr, drawable);
    Blt_DrawGrids(graphPtr, drawable);

    site = Blt_Legend_Site(graphPtr);
    if ((site & LEGEND_PLOTAREA_MASK) && (!Blt_Legend_IsRaised(graphPtr))) {
        Blt_DrawLegend(graphPtr, drawable);
    } else if (site == LEGEND_WINDOW) {
        Blt_Legend_EventuallyRedraw(graphPtr);
    }
    Blt_DrawAxisLimits(graphPtr, drawable);
    Blt_DrawElements(graphPtr, drawable);
    if (Blt_GraphType(graphPtr) == CONTOUR) {
        Blt_DrawAxes(graphPtr, drawable);

        /* Draw 3D border around the plotting area */
        if ((w > 0) && (h > 0) && (graphPtr->plotBorderWidth > 0)) {
            Blt_Bg_DrawRectangle(graphPtr->tkwin, drawable, graphPtr->normalBg,
                x, y, w, h, graphPtr->plotBorderWidth, graphPtr->plotRelief);
        }
    }
}

void
Blt_MapGraph(Graph *graphPtr)
{
    if (graphPtr->flags & RESET_AXES) {
        Blt_ResetAxes(graphPtr);
    }
    if (graphPtr->flags & LAYOUT_NEEDED) {
        Blt_LayoutGraph(graphPtr);
        graphPtr->flags &= ~LAYOUT_NEEDED;
    }
    /* Compute coordinate transformations for graph components */
    if ((graphPtr->vRange > 1) && (graphPtr->hRange > 1)) {
        if (graphPtr->flags & MAP_WORLD) {
            Blt_MapAxes(graphPtr);
        }
        Blt_MapElements(graphPtr);
        Blt_MapMarkers(graphPtr);
        graphPtr->flags &= ~(MAP_ALL);
    }
}

/*
 *---------------------------------------------------------------------------
 *
 * GraphToDrawable --
 *
 *      Draws the entire graph widget into a designated drawable.  This
 *      differs from the DisplayProc procedure in that no caching is done.
 *      The plot area is (elements, markers, etc) is always redrawn.
 *      This is used to create a snapshot of the graph without requiring
 *      the graph to be visible on-screen.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Commands are output to X to display the graph in its current mode.
 *
 *---------------------------------------------------------------------------
 */
static void
GraphToDrawable(Graph *graphPtr, Drawable drawable)
{
    int w, h;
    
    DrawPlot(graphPtr, drawable);
    /* Draw markers above elements */
    Blt_DrawMarkers(graphPtr, drawable, MARKER_ABOVE);
    Blt_DrawActiveElements(graphPtr, drawable);

    /* Don't draw legend in the plot area. */
    if ((Blt_Legend_Site(graphPtr) & LEGEND_PLOTAREA_MASK) && 
        (Blt_Legend_IsRaised(graphPtr))) {
        Blt_DrawLegend(graphPtr, drawable);
    }
    /* Draw 3D border just inside of the focus highlight ring. */
    w = graphPtr->width  - 2 * graphPtr->highlightWidth;
    h = graphPtr->height - 2 * graphPtr->highlightWidth;
    if ((w > 0) && (h > 0) && (graphPtr->borderWidth > 0) &&
        (graphPtr->relief != TK_RELIEF_FLAT)) {
        Blt_Bg_DrawRectangle(graphPtr->tkwin, drawable, 
                graphPtr->normalBg, graphPtr->highlightWidth, 
                graphPtr->highlightWidth, w, h, 
                graphPtr->borderWidth, graphPtr->relief);
    }
    /* Draw focus highlight ring. */
    if ((graphPtr->highlightWidth > 0) && (graphPtr->flags & FOCUS)) {
        GC gc;

        gc = Tk_GCForColor(graphPtr->highlightColor, drawable);
        Tk_DrawFocusHighlight(graphPtr->tkwin, gc, graphPtr->highlightWidth,
            drawable);
    }
}

static void
UpdateMarginTraces(Graph *graphPtr)
{
    if (graphPtr->leftMarginVarObjPtr != NULL) { 
        Tcl_ObjSetVar2(graphPtr->interp, graphPtr->leftMarginVarObjPtr, NULL,
                Tcl_NewIntObj(graphPtr->leftPtr->width),
                TCL_GLOBAL_ONLY);
    }
    if (graphPtr->rightMarginVarObjPtr != NULL) { 
        Tcl_ObjSetVar2(graphPtr->interp, graphPtr->rightMarginVarObjPtr, NULL,
                Tcl_NewIntObj(graphPtr->rightPtr->width),
                TCL_GLOBAL_ONLY);
    }
    if (graphPtr->topMarginVarObjPtr != NULL) { 
        Tcl_ObjSetVar2(graphPtr->interp, graphPtr->topMarginVarObjPtr, NULL,
                Tcl_NewIntObj(graphPtr->topPtr->height),
                TCL_GLOBAL_ONLY);
    }
    if (graphPtr->bottomMarginVarObjPtr != NULL) { 
        Tcl_ObjSetVar2(graphPtr->interp, graphPtr->bottomMarginVarObjPtr, NULL,
                Tcl_NewIntObj(graphPtr->bottomPtr->height),
                TCL_GLOBAL_ONLY);
    }
}

/*
 *---------------------------------------------------------------------------
 *
 * DisplayProc --
 *
 *      This procedure is invoked to display a graph widget.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Commands are output to X to display the graph in its current mode.
 *
 *---------------------------------------------------------------------------
 */
static void
DisplayProc(ClientData clientData)
{
    Graph *graphPtr = clientData;
    Pixmap drawable;
    Tk_Window tkwin;
    int site;
    int w, h;
    
    graphPtr->flags &= ~REDRAW_PENDING;
    if (graphPtr->tkwin == NULL) {
        return;                         /* Window has been destroyed (we
                                         * should not get here) */
    }
    tkwin = graphPtr->tkwin;
#ifdef notdef
    fprintf(stderr, "Calling DisplayProc(%s)\n", Tk_PathName(tkwin));
#endif
    if ((Tk_Width(tkwin) <= 1) || (Tk_Height(tkwin) <= 1)) {
        /* Don't bother computing the layout until the size of the window
         * is something reasonable. */
        return;
    }
    graphPtr->width = Tk_Width(tkwin);
    graphPtr->height = Tk_Height(tkwin);
    Blt_MapGraph(graphPtr);
    if (!Tk_IsMapped(tkwin)) {
        /* The graph's window isn't displayed, so don't bother drawing
         * anything.  By getting this far, we've at least computed the
         * coordinates of the graph's new layout.  */
        return;
    }
    /* Create a pixmap the size of the window for double buffering. */
    if (graphPtr->flags & DOUBLE_BUFFER) {
        drawable = Blt_GetPixmap(graphPtr->display, Tk_WindowId(tkwin), 
                graphPtr->width, graphPtr->height, Tk_Depth(tkwin));
    } else {
        drawable = Tk_WindowId(tkwin);
    }
    if (graphPtr->flags & BACKING_STORE) {
        if ((graphPtr->cache == None) || 
            (graphPtr->cacheWidth != graphPtr->width) ||
            (graphPtr->cacheHeight != graphPtr->height)) {
            if (graphPtr->cache != None) {
                Tk_FreePixmap(graphPtr->display, graphPtr->cache);
            }
            graphPtr->cache = Blt_GetPixmap(graphPtr->display, 
                Tk_WindowId(tkwin), graphPtr->width, graphPtr->height, 
                Tk_Depth(tkwin));
            graphPtr->cacheWidth  = graphPtr->width;
            graphPtr->cacheHeight = graphPtr->height;
            graphPtr->flags |= CACHE_DIRTY;
        }
    }
#ifdef WIN32
    assert(drawable != None);
#endif
    if (graphPtr->flags & BACKING_STORE) {
        if (graphPtr->flags & CACHE_DIRTY) {
            /* The backing store is new or out-of-date. */
            DrawPlot(graphPtr, graphPtr->cache);
            graphPtr->flags &= ~CACHE_DIRTY;
        }
        /* Copy the pixmap to the one used for drawing the entire graph. */
        XCopyArea(graphPtr->display, graphPtr->cache, drawable,
            graphPtr->drawGC, 0, 0, graphPtr->width, graphPtr->height, 0, 0);
    } else {
        DrawPlot(graphPtr, drawable);
    }
    /* Draw markers above elements */
    Blt_DrawMarkers(graphPtr, drawable, MARKER_ABOVE);
    Blt_DrawActiveElements(graphPtr, drawable);
    /* Don't draw legend in the plot area. */
    site = Blt_Legend_Site(graphPtr);
    if ((site & LEGEND_PLOTAREA_MASK) && (Blt_Legend_IsRaised(graphPtr))) {
        Blt_DrawLegend(graphPtr, drawable);
    }
    if (site == LEGEND_WINDOW) {
        Blt_Legend_EventuallyRedraw(graphPtr);
    }
    w = graphPtr->width  - 2 * graphPtr->highlightWidth;
    h = graphPtr->height - 2 * graphPtr->highlightWidth;
    /* Draw 3D border just inside of the focus highlight ring. */
    if ((w > 0) && (h > 0) && (graphPtr->borderWidth > 0) &&
        (graphPtr->relief != TK_RELIEF_FLAT)) {
        Blt_Bg_DrawRectangle(graphPtr->tkwin, drawable, graphPtr->normalBg,
                graphPtr->highlightWidth, graphPtr->highlightWidth, w, h,
                graphPtr->borderWidth, graphPtr->relief);
    }
    /* Draw focus highlight ring. */
    if ((graphPtr->highlightWidth > 0) && (graphPtr->flags & FOCUS)) {
        GC gc;

        gc = Tk_GCForColor(graphPtr->highlightColor, drawable);
        Tk_DrawFocusHighlight(graphPtr->tkwin, gc, graphPtr->highlightWidth,
            drawable);
    }
    /* Disable crosshairs before redisplaying to the screen */
    Blt_DisableCrosshairs(graphPtr);
    XCopyArea(graphPtr->display, drawable, Tk_WindowId(tkwin),
        graphPtr->drawGC, 0, 0, graphPtr->width, graphPtr->height, 0, 0);
    Blt_EnableCrosshairs(graphPtr);
    if (graphPtr->flags & DOUBLE_BUFFER) {
        Tk_FreePixmap(graphPtr->display, drawable);
    }
    graphPtr->flags &= ~RESET_WORLD;
    UpdateMarginTraces(graphPtr);
}

/*LINTLIBRARY*/
int
Blt_GraphCmdInitProc(Tcl_Interp *interp)
{
    static Blt_CmdSpec cmdSpecs[] = {
        {"graph", GraphCmd,},
        {"barchart", BarchartCmd,},
        {"stripchart", StripchartCmd,},
        {"contour", ContourCmd,},
    };
    return Blt_InitCmds(interp, "::blt", cmdSpecs, 4);
}

Graph *
Blt_GetGraphFromWindowData(Tk_Window tkwin)
{
    while (tkwin != NULL) {
        Graph *graphPtr;

        graphPtr = (Graph *)Blt_GetWindowInstanceData(tkwin);
        if (graphPtr != NULL) {
            return graphPtr;
        }
        tkwin = Tk_Parent(tkwin);
    }
    return NULL;
}

int
Blt_GraphType(Graph *graphPtr)
{
    switch (graphPtr->classId) {
    case CID_ELEM_LINE:
        return GRAPH;
    case CID_ELEM_BAR:
        return BARCHART;
    case CID_ELEM_STRIP:
        return STRIPCHART;
    case CID_ELEM_CONTOUR:
        return CONTOUR;
    default:
        return 0;
    }
    return 0;
}

/*
 *---------------------------------------------------------------------------
 *
 * Blt_ReconfigureGraph --
 *
 *      Allocates resources for the graph.
 *
 *---------------------------------------------------------------------------
 */
void
Blt_ReconfigureGraph(Graph *graphPtr)   
{
    ConfigureGraph(graphPtr);
    Blt_ConfigureLegend(graphPtr);
    Blt_ConfigureElements(graphPtr);
    Blt_ConfigureAxes(graphPtr);
    Blt_ConfigureMarkers(graphPtr);
}

/*
 *---------------------------------------------------------------------------
 *
 * Blt_GraphToPicture --
 *
 *      Returns a picture of the graph.
 *
 *---------------------------------------------------------------------------
 */
Blt_Picture
Blt_GraphToPicture(Tcl_Interp *interp, Tk_Window tkwin, float gamma)
{
    Blt_Picture picture;
    Pixmap pixmap;
    const char *className;
    int w, h;
    Graph *graphPtr;
    
    className = Tk_Class(tkwin);
    if ((strcmp(className, "BltGraph") != 0) &&
        (strcmp(className, "BltBarchart") != 0) &&
        (strcmp(className, "BltStripchart") != 0) &&
        (strcmp(className, "BltContour") != 0)) {
        Tcl_AppendResult(interp, "can't grab window of class \"", className, 
                "\"", (char *)NULL);
        return NULL;
    }
    w = Tk_Width(tkwin);
    if (w < 2) {
        w = Tk_ReqWidth(tkwin);
    }
    h = Tk_Height(tkwin);
    if (h < 2) {
        h = Tk_ReqHeight(tkwin);
    }
    pixmap = Blt_GetPixmap(Tk_Display(tkwin), Tk_WindowId(tkwin), w, h,
        Tk_Depth(tkwin));
    graphPtr = Blt_GetWindowInstanceData(tkwin);
    /* Force the graph to be drawn at its normal width and height. */
    graphPtr->width = w;
    graphPtr->height = h;
    Blt_MapGraph(graphPtr);
    graphPtr->flags |= RESET_WORLD;
    GraphToDrawable(graphPtr, pixmap);
    picture = Blt_DrawableToPicture(tkwin, pixmap, 0, 0, w, h, gamma);
    Tk_FreePixmap(Tk_Display(tkwin), pixmap);
    if (picture == NULL) {
        Tcl_AppendResult(interp, "can't grab pixmap from \"",
                Tk_PathName(tkwin), "\"", (char *)NULL);
        return NULL;
    }
    return picture;
}