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/* $Id$
*
* Copyright © 2004 Keith Packard
*
* This library is free software; you can redistribute it and/or
* modify it either under the terms of the GNU Lesser General Public
* License version 2.1 as published by the Free Software Foundation
* (the "LGPL") or, at your option, under the terms of the Mozilla
* Public License Version 1.1 (the "MPL"). If you do not alter this
* notice, a recipient may use your version of this file under either
* the MPL or the LGPL.
*
* You should have received a copy of the LGPL along with this library
* in the file COPYING-LGPL-2.1; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* You should have received a copy of the MPL along with this library
* in the file COPYING-MPL-1.1
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
* OF ANY KIND, either express or implied. See the LGPL or the MPL for
* the specific language governing rights and limitations.
*
* The Original Code is the cairo graphics library.
*
* The Initial Developer of the Original Code is Keith Packard
*
* Contributor(s):
* Keith Packard <keithp@keithp.com>
*/
autoload Cairo;
namespace Graph {
import Cairo;
public typedef enum { linear, log } scale_kind_t;
public typedef struct {
scale_kind_t kind;
real low, high;
real len;
} scale_t;
real scale (scale_t scale, real value)
{
if (scale.kind == scale_kind_t.log)
{
value = log(value);
scale.low = log (scale.low);
scale.high = log (scale.high);
}
return scale.len * (value - scale.low) / (scale.high - scale.low);
}
public typedef struct {
&scale_t scale;
real major;
real minor;
} axis_t;
public typedef struct {
cairo_t cr;
axis_t left;
axis_t bottom;
} graph_t;
void axis_draw (cairo_t cr, axis_t axis)
{
move_to (cr, scale (axis.scale,axis.scale.low), 0);
line_to (cr, scale (axis.scale,axis.scale.high), 0);
for (real minor = axis.scale.low;
minor <= axis.scale.high;
minor += axis.minor)
{
if ((minor - axis.scale.low) % axis.major != 0)
{
move_to (cr, scale (axis.scale, minor), 0);
rel_line_to (cr, 0, 5);
}
}
for (real major = axis.scale.low; major <= axis.scale.high; major += axis.major)
{
move_to (cr, scale (axis.scale, major), 0);
rel_line_to (cr, 0, 10);
}
stroke (cr);
font_extents_t f = font_extents (cr);
printf ("font extents: %v\n", f);
for (real major = axis.scale.low; major <= axis.scale.high; major += axis.major)
{
string text = sprintf ("%g", major);
text_extents_t e = text_extents (cr, text);
move_to (cr, scale (axis.scale, major) - e.x_advance / 2,
-abs(f.height) * 1.2);
show_text (cr, text);
}
}
public void axes_draw (cairo_t cr, graph_t g)
{
save (cr);
axis_draw (cr, g.bottom);
restore (cr);
save (cr);
set_font_matrix (cr, (matrix_t) {
xx = 1, yx = 0,
xy = 0, yy = -1,
x0 = 0, y0 = 0 });
set_matrix (cr, Matrix::multiply ((matrix_t) {
xx = 0, yx = 1,
xy = 1, yy = 0,
x0 = 0, y0 = 0 }, get_matrix (cr)));
axis_draw (cr, g.left);
restore (cr);
}
public graph_t new (cairo_t cr) {
set_font (cr, "sans-12");
set_font_matrix (cr, (matrix_t) {
xx = 1, yx = 0,
xy = 0, yy = -1,
x0 = 0, y0 = 0 });
translate (cr, 0, height(cr));
Cairo::scale (cr, 1, -1);
set_line_cap (cr, line_cap_t.SQUARE);
translate (cr, width(cr) * .1, height(cr) * .1);
return (graph_t) {
cr = cr,
left = {
scale = &(scale_t) {
kind = scale_kind_t.linear,
len = height(cr) * .8,
low = 0,
high = 10
},
major = 1,
minor = 0.25
},
bottom = {
scale = &(scale_t) {
kind = scale_kind_t.linear,
len = width(cr) * .8,
low = 0,
high = 10
},
major = 1,
minor = 0.25
}
};
}
public void test ()
{
cairo_t cr = Cairo::new (500, 500);
graph_t gr = new (cr);
axes_draw (cr, gr);
}
}
Graph::test ();
for (;;) sleep (1000);
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