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/* Example code to show how to use pangocairo to render arbitrary shapes
* inside a text layout, positioned by Pango. This has become possibly
* using the following API added in Pango 1.18:
*
* pango_cairo_context_set_shape_renderer ()
*
* This examples uses a small parser to convert shapes in the format of
* SVG paths to cairo instructions. You can typically extract these from
* the SVG file's <path> elements directly.
*
* The code then searches for the Unicode bullet character in the layout
* text and automatically adds PangoAttribtues to the layout to replace
* each of the with a rendering of the GNOME Foot logo.
*
*
* Written by Behdad Esfahbod, 2007
*
* Permission to use, copy, modify, distribute, and sell this example
* for any purpose is hereby granted without fee.
* It is provided "as is" without express or implied warranty.
*/
#include <stdio.h>
#include <string.h>
#include <pango/pangocairo.h>
#define BULLET "•"
const char text[] =
"The GNOME project provides two things:\n"
"\n"
" • The GNOME desktop environment\n"
" • The GNOME development platform\n"
" • Planet GNOME";
typedef struct {
double width, height;
const char *path;
} MiniSvg;
static MiniSvg GnomeFootLogo = {
96.2152, 118.26,
"M 86.068,1 C 61.466,0 56.851,35.041 70.691,35.041 C 84.529,35.041 110.671,0 86.068,0 z "
"M 45.217,30.699 C 52.586,31.149 60.671,2.577 46.821,4.374 C 32.976,6.171 37.845,30.249 45.217,30.699 z "
"M 11.445,48.453 C 16.686,46.146 12.12,23.581 3.208,29.735 C -5.7,35.89 6.204,50.759 11.445,48.453 z "
"M 26.212,36.642 C 32.451,35.37 32.793,9.778 21.667,14.369 C 10.539,18.961 19.978,37.916 26.212,36.642 L 26.212,36.642 z "
"M 58.791,93.913 C 59.898,102.367 52.589,106.542 45.431,101.092 C 22.644,83.743 83.16,75.088 79.171,51.386 C 75.86,31.712 15.495,37.769 8.621,68.553 C 3.968,89.374 27.774,118.26 52.614,118.26 C 64.834,118.26 78.929,107.226 81.566,93.248 C 83.58,82.589 57.867,86.86 58.791,93.913 L 58.791,93.913 z "
"\0"
};
static void
mini_svg_render (MiniSvg *shape,
cairo_t *cr,
gboolean do_path)
{
double x, y;
const char *p;
char op[2];
int len;
cairo_get_current_point (cr, &x, &y);
cairo_translate (cr, x, y);
for (p = shape->path; sscanf (p, "%1s %n", op, &len), p += len, *p;)
switch (*op)
{
case 'M':
{
sscanf (p, "%lf,%lf %n", &x, &y, &len); p += len;
cairo_move_to (cr, x, y);
break;
}
case 'L':
{
sscanf (p, "%lf,%lf %n", &x, &y, &len); p += len;
cairo_line_to (cr, x, y);
break;
}
case 'C':
{
double x1, y1, x2, y2, x3, y3;
sscanf (p, "%lf,%lf %lf,%lf %lf,%lf %n", &x1, &y1, &x2, &y2, &x3, &y3, &len); p += len;
cairo_curve_to (cr, x1, y1, x2, y2, x3, y3);
break;
}
case 'z':
{
cairo_close_path (cr);
break;
}
default:
{
g_warning ("Invalid MiniSvg operation '%c'", *op);
break;
}
}
if (!do_path)
cairo_fill (cr);
}
static void
mini_svg_shape_renderer (cairo_t *cr,
PangoAttrShape *attr,
gboolean do_path,
gpointer data G_GNUC_UNUSED)
{
MiniSvg *shape = (MiniSvg *) attr->data;
double scale_x, scale_y;
scale_x = (double) attr->ink_rect.width / (PANGO_SCALE * shape->width );
scale_y = (double) attr->ink_rect.height / (PANGO_SCALE * shape->height);
cairo_rel_move_to (cr,
(double) attr->ink_rect.x / PANGO_SCALE,
(double) attr->ink_rect.y / PANGO_SCALE);
cairo_scale (cr, scale_x, scale_y);
mini_svg_render (shape, cr, do_path);
}
static PangoLayout *
get_layout (cairo_t *cr)
{
PangoLayout *layout;
PangoAttrList *attrs;
PangoRectangle ink_rect = {1 * PANGO_SCALE, -11 * PANGO_SCALE, 8 * PANGO_SCALE, 10 * PANGO_SCALE};
PangoRectangle logical_rect = {0 * PANGO_SCALE, -12 * PANGO_SCALE, 10 * PANGO_SCALE, 12 * PANGO_SCALE};
const char *p;
/* Create a PangoLayout, set the font and text */
layout = pango_cairo_create_layout (cr);
pango_cairo_context_set_shape_renderer (pango_layout_get_context (layout),
mini_svg_shape_renderer, NULL, NULL);
pango_layout_set_text (layout, text, -1);
attrs = pango_attr_list_new ();
/* Set gnome shape attributes for all bullets */
for (p = text; (p = strstr (p, BULLET)); p += strlen (BULLET))
{
PangoAttribute *attr;
attr = pango_attr_shape_new_with_data (&ink_rect,
&logical_rect,
&GnomeFootLogo,
NULL, NULL);
attr->start_index = p - text;
attr->end_index = attr->start_index + strlen (BULLET);
pango_attr_list_insert (attrs, attr);
}
pango_layout_set_attributes (layout, attrs);
pango_attr_list_unref (attrs);
return layout;
}
static void
draw_text (cairo_t *cr, int *width, int *height)
{
PangoLayout *layout = get_layout (cr);
/* Adds a fixed 10-pixel margin on the sides. */
if (width || height)
{
pango_layout_get_pixel_size (layout, width, height);
if (width)
*width += 20;
if (height)
*height += 20;
}
cairo_move_to (cr, 10, 10);
pango_cairo_show_layout (cr, layout);
g_object_unref (layout);
}
int main (int argc, char **argv)
{
cairo_t *cr;
char *filename;
cairo_status_t status;
cairo_surface_t *surface;
int width, height;
if (argc != 2)
{
g_printerr ("Usage: cairoshape OUTPUT_FILENAME\n");
return 1;
}
filename = argv[1];
/* First create and use a 0x0 surface, to measure how large
* the final surface needs to be */
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
0, 0);
cr = cairo_create (surface);
draw_text (cr, &width, &height);
cairo_destroy (cr);
cairo_surface_destroy (surface);
/* Now create the final surface and draw to it. */
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
width, height);
cr = cairo_create (surface);
cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
cairo_paint (cr);
cairo_set_source_rgb (cr, 0.0, 0.0, 0.5);
draw_text (cr, NULL, NULL);
cairo_destroy (cr);
/* Write out the surface as PNG */
status = cairo_surface_write_to_png (surface, filename);
cairo_surface_destroy (surface);
if (status != CAIRO_STATUS_SUCCESS)
{
g_printerr ("Could not save png to '%s'\n", filename);
return 1;
}
return 0;
}
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