[cairo] Strange bug (?) when painting/cropping recording surface to PDF surface

[Adrian Johnson]

On 10/04/16 03:25, Bernhard R. Fischer wrote:
> Hi!
> 
> _Background_
> In my project a record all drawing operations to a recording surface.
> Finally, to output files I create surfaces of specific backends (PNG,
> PDF, and SVG) and "crop" (the final surface is smaller than the
> recording source surface), rotate, and paint the recording surface to it.
> 
> 
> _Strange Behavior_
> When using PDF as backend, not everything is painted from the source
> (recording) surface to the PDF surface. On PNG and SVG it works as expected.
> 
> 
> _Examples_
> There is a PNG and PDF example to show the behavior. Look at the right
> lower corner: right of the string "015°30" the short black lines in the
> axis are missing compared to the PNG.
> http://www.abenteuerland.at/download/eagle/output.pdf
> http://www.abenteuerland.at/download/eagle/output.png
> 
> 
> _Trigger_
> I observed, that this behavior is triggered as soon as the PDF surface
> is smaller than the recording surface.
> 
> 
> _Code Snippet_
> The following code snippets shows how I create the PDF and PNG surface
> from the recording surface (sfc_).
> 
> 
> 	/* create PDF from sfc_ */
> 	sfc = cairo_pdf_surface_create("output.pdf", width*.7, height*1.3);
> 	dst = cairo_create(sfc);
> 	cairo_rotate(dst, DEG2RAD(15));
> 	cairo_set_source_surface(dst, sfc_, 0, 0);
>         cairo_paint(dst);
>         cairo_show_page(dst);
>         cairo_destroy(dst);
>         cairo_surface_destroy(sfc);
> 
> 
> 	/* create PNG from sfc_ */
>          sfc = cairo_image_surface_create(CAIRO_FORMAT_RGB24, width*.7,
> height*1.3);
>          dst = cairo_create(sfc);
>          cairo_rotate(dst, DEG2RAD(15));
>          cairo_set_source_surface(dst, sfc_, 0, 0);
>          cairo_paint(dst);
>          cairo_show_page(dst);
>          cairo_destroy(dst);
>          cairo_surface_write_to_png(sfc, "output.png");
>          cairo_surface_destroy(sfc);
> 
> 
> Any hints appreciated.

If you can provide a simple test case that reproduces the bug with the
current version of cairo I can look into it.

> 
> Best regards,
> Bernhard
>