cairo recording surface leaves target surface empty

martinkalbfuss · **Joined:** Tue Jul 19, 2011 4:09 pm **Posts:** 2

Hi folks,

I try to use the recording surface of cairo. But when I draw it onto another surface, there's nothing.
What's wrong here? Im new to cairo. So it's going to be a stupid mistake. :-P

Code:

#include <stdlib.h>
#include <stdio.h>
#include <cairo/cairo.h>

int main(void)
{
   cairo_surface_t *record = cairo_recording_surface_create(CAIRO_CONTENT_COLOR, NULL);
   cairo_t *record_cr = cairo_create(record);

   cairo_set_source_rgb(record_cr, 1, 0, 0);
   cairo_rectangle(record_cr, 10, 10, 100, 100);
   cairo_fill(record_cr);

   cairo_set_source_rgb(record_cr, 0, 1, 0);
   cairo_rectangle(record_cr, 50, 50, 140, 140);
   cairo_fill(record_cr);

   double x0, y0, width, height;
   cairo_recording_surface_ink_extents(record, &x0, &y0, &width, &height);

   cairo_surface_t *output = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height);
   cairo_t *cr = cairo_create(output);
   cairo_set_source_surface(cr, record, 0, 0);
   cairo_paint(cr);

   cairo_surface_write_to_png(output, "out.png");

   cairo_destroy(record_cr);
   cairo_destroy(cr);
   cairo_surface_destroy(record);
   cairo_surface_destroy(output);

   return EXIT_SUCCESS;
}

tadeboro · **Posted:** Wed Oct 19, 2011 1:20 pm

Hello.

Not sure why things are not woring here (I tested your app and got exactly the same results). I learned that using a constrained surface does produce a file, so the problem is either with unconstrained surface or it's placement when using it as a source for painting.

Cheers,
Tadej

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