73 lines
2.2 KiB
C
73 lines
2.2 KiB
C
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/* Taken from https://developer.gnome.org/pango/stable/pango-Cairo-Rendering.html */
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#include <math.h>
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#include <pango/pangocairo.h>
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static void
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draw_text (cairo_t *cr)
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{
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#define RADIUS 150
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#define N_WORDS 10
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#define FONT "Sans Bold 27"
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PangoLayout *layout;
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PangoFontDescription *desc;
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int i;
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/* Center coordinates on the middle of the region we are drawing
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*/
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cairo_translate (cr, RADIUS, RADIUS);
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/* Create a PangoLayout, set the font and text */
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layout = pango_cairo_create_layout (cr);
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pango_layout_set_text (layout, "Text", -1);
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desc = pango_font_description_from_string (FONT);
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pango_layout_set_font_description (layout, desc);
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pango_font_description_free (desc);
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/* Draw the layout N_WORDS times in a circle */
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for (i = 0; i < N_WORDS; i++)
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{
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int width, height;
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double angle = (360. * i) / N_WORDS;
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double red;
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cairo_save (cr);
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/* Gradient from red at angle == 60 to blue at angle == 240 */
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red = (1 + cos ((angle - 60) * G_PI / 180.)) / 2;
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cairo_set_source_rgb (cr, red, 0, 1.0 - red);
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cairo_rotate (cr, angle * G_PI / 180.);
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/* Inform Pango to re-layout the text with the new transformation */
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pango_cairo_update_layout (cr, layout);
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pango_layout_get_size (layout, &width, &height);
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cairo_move_to (cr, - ((double)width / PANGO_SCALE) / 2, - RADIUS);
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pango_cairo_show_layout (cr, layout);
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cairo_restore (cr);
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}
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/* free the layout object */
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g_object_unref (layout);
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}
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int main (int argc, char **argv)
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{
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cairo_t *cr;
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char *filename;
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cairo_status_t status;
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cairo_surface_t *surface;
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if (argc != 2)
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{
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g_printerr ("Usage: cairosimple OUTPUT_FILENAME\n");
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return 1;
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}
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filename = argv[1];
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surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
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2 * RADIUS, 2 * RADIUS);
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cr = cairo_create (surface);
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cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
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cairo_paint (cr);
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draw_text (cr);
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cairo_destroy (cr);
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status = cairo_surface_write_to_png (surface, filename);
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cairo_surface_destroy (surface);
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if (status != CAIRO_STATUS_SUCCESS)
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{
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g_printerr ("Could not save png to '%s'\n", filename);
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return 1;
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}
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return 0;
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}
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