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/*
This file is part of the FElt finite element analysis package.
Copyright (C) 1993-2000 Jason I. Gobat and Darren C. Atkinson
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/************************************************************************
* File: scroll.c *
* *
* Description: This file contains the public and private function *
* and variable declarations for the scrollable text *
* mechanism. *
************************************************************************/
# include <stdio.h>
# include <X11/IntrinsicP.h>
# include <X11/StringDefs.h>
# include <X11/Xaw/TextP.h>
# include "scroll.h"
# include "util.h"
static String scroll_table =
"<KeyUp>: ScrollText()\n\
<ConfigureNotify>: ScrollText()";
static XtTranslations scroll_translations;
/************************************************************************
* Function: ScrollText *
* *
* Description: Action procedure interface to ScrollToInsertionPoint(). *
************************************************************************/
static void ScrollText (w, event, params, num_params)
Widget w;
XEvent *event;
String *params;
Cardinal *num_params;
{
ScrollToInsertionPoint (w);
}
/************************************************************************
* Function: AddScrollableTextTranslations *
* *
* Description: Adds translations to the specified text widget to *
* enable a primitive character-based scrolling. *
************************************************************************/
void AddScrollableTextTranslations (text)
Widget text;
{
static XtAppContext app_context = NULL;
static XtActionsRec actions [ ] = {{"ScrollText", ScrollText}};
/* Add the actions to the application context if necessary. */
if (app_context == NULL) {
app_context = XtWidgetToApplicationContext (text);
XtAppAddActions (app_context, actions, XtNumber (actions));
scroll_translations = XtParseTranslationTable (scroll_table);
}
XtVaSetValues (text, XtNrightMargin, 0, NULL);
XtOverrideTranslations (text, scroll_translations);
/* The SetValues really should do this for us. */
((TextWidget) text) -> text.margin.right = 0;
}
/************************************************************************
* Function: ScrollToInsertionPoint *
* *
* Description: Scrolls the text so the insertion point is always *
* visible. The scrolling is accomplished by updating the *
* display position of the string and is rather primitive. *
************************************************************************/
void ScrollToInsertionPoint (text)
Widget text;
{
int ins_pos;
int disp_pos;
int length;
String ptr;
String value;
Boolean caret;
Position l_margin;
Position r_margin;
Dimension width;
XFontStruct *font;
XtVaGetValues (text, XtNdisplayPosition, &disp_pos,
XtNinsertPosition, &ins_pos,
XtNdisplayCaret, &caret,
XtNrightMargin, &r_margin,
XtNleftMargin, &l_margin,
XtNstring, &value,
XtNwidth, &width,
XtNfont, &font, NULL);
/* Check if the translations have been installed. */
if (r_margin != 0)
return;
/* Scroll the text string to the right. */
if (ins_pos <= disp_pos) {
disp_pos = ins_pos - 1;
if (disp_pos < 0)
disp_pos = 0;
/* Scroll the text string to the left. */
} else {
width -= l_margin + r_margin;
width -= GetTextWidth (font, "W", 1); /* the widest character? */
while (1) {
ptr = &value [disp_pos];
length = 0;
while (ptr [length] && GetTextWidth (font, ptr, length) < width)
length ++;
if (ins_pos > disp_pos + length)
disp_pos ++;
else
break;
}
}
/* Scroll to the new position, disabling the caret temporarily. */
if (caret == True)
XtVaSetValues (text, XtNdisplayCaret, False, NULL);
XtVaSetValues (text, XtNdisplayPosition, disp_pos, NULL);
if (caret == True)
XtVaSetValues (text, XtNdisplayCaret, True, NULL);
}
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