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/* Taken from
* https://developer.gnome.org/pango/stable/pango-Cairo-Rendering.html */
#include <math.h>
#include <pango/pangocairo.h>
static void draw_text(cairo_t* cr)
{
#define RADIUS 150
#define N_WORDS 10
#define FONT "Sans Bold 27"
PangoLayout* layout;
PangoFontDescription* desc;
int i;
/* Center coordinates on the middle of the region we are drawing
*/
cairo_translate(cr, RADIUS, RADIUS);
/* Create a PangoLayout, set the font and text */
layout = pango_cairo_create_layout(cr);
pango_layout_set_text(layout, "Text", -1);
desc = pango_font_description_from_string(FONT);
pango_layout_set_font_description(layout, desc);
pango_font_description_free(desc);
/* Draw the layout N_WORDS times in a circle */
for (i = 0; i < N_WORDS; i++) {
int width, height;
double angle = (360. * i) / N_WORDS;
double red;
cairo_save(cr);
/* Gradient from red at angle == 60 to blue at angle == 240 */
red = (1 + cos((angle - 60) * G_PI / 180.)) / 2;
cairo_set_source_rgb(cr, red, 0, 1.0 - red);
cairo_rotate(cr, angle * G_PI / 180.);
/* Inform Pango to re-layout the text with the new transformation */
pango_cairo_update_layout(cr, layout);
pango_layout_get_size(layout, &width, &height);
cairo_move_to(cr, -((double)width / PANGO_SCALE) / 2, -RADIUS);
pango_cairo_show_layout(cr, layout);
cairo_restore(cr);
}
/* free the layout object */
g_object_unref(layout);
}
int main(int argc, char** argv)
{
cairo_t* cr;
char* filename;
cairo_status_t status;
cairo_surface_t* surface;
if (argc != 2) {
g_printerr("Usage: cairosimple OUTPUT_FILENAME\n");
return 1;
}
filename = argv[1];
surface =
cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 2 * RADIUS, 2 * RADIUS);
cr = cairo_create(surface);
cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
cairo_paint(cr);
draw_text(cr);
cairo_destroy(cr);
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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