Re: Simple SVG Example in C

On 14.09.2012 17:25, Timothy Bolton wrote:
> Hi all,
> 
> I'm looking for a very simple example of getting Cairo to save to an SVG 
> file.  I'm working in ANSI-C.
> 
> I've gone through the documentation as best I could, I've searched 
> Google, mulled over StackOverflow and even cried a little.  So far, I 
> haven't been able to get it to work.  Writing a surface to a PNG works 
> for me, but for whatever reason, I'm at a loss for the SVG.
> 
> I've included a pastebin of the code: http://pastebin.com/bDtFZ9Ww
> 
> The environment that I'm working in is Ubuntu server (11 I think), and 
> I'm using gcc for compiling.

Attached is a new version of that code which actually works.

Changes that I did:

- Instead of using a char array, this now has a char pointer for the filename
(causes less garbage at the end of the filename)
- The broken call to cairo_image_surface_create_for_data() and the usage of
text_surface was removed, it's not important for getting this to work.
- The problem you have was fixed by adding the following at the end of main:

  cairo_destroy(cr);
  cairo_surface_finish(surface);
  cairo_surface_destroy(surface);

Always make sure to destroy ressources when you are done with them.

The call to cairo_surface_finish() isn't strictly needed for your example
because a surface is automatically finished when the last reference to it gets
destroyed. However, this is what makes cairo actually write the svg out.

Cheers,
Uli
-- 
"In the beginning the Universe was created. This has made a lot of
 people very angry and has been widely regarded as a bad move."

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#include "cairo.h"
#include "cairo-svg.h"
int main(int argc, char* argv[])
{
   double font_size = 25.0,
          height    = 200.0,
          left      = 15.0,
          top       = 15.0,
          width     = 200.0;

   char  *filename  = "temp.svg",
         *text      = "This is a Test";

   cairo_surface_t *surface = cairo_svg_surface_create(filename,
                                                       width,
                                                       height);

   //cairo_svg_surface_restrict_to_version (surface, CAIRO_SVG_VERSION_1_1);
   cairo_t* cr = cairo_create (surface);

   int size = height * width;
   int data[size];
   
   cairo_move_to (cr, left, top);

   cairo_text_extents_t te;
   cairo_select_font_face (cr,
                           "Georgia",
                           CAIRO_FONT_SLANT_NORMAL, 
                           CAIRO_FONT_WEIGHT_BOLD);
                                 
   cairo_set_font_size (cr, (double)font_size);
   cairo_text_extents (cr, text, &te);
   cairo_show_text (cr, text);

   cairo_fill(cr);

   cairo_destroy(cr);
   cairo_surface_finish(surface);
   cairo_surface_destroy(surface);
      
   return 0;
}