[cairo] Using gimp c file image

gurnett at telia.com gurnett at telia.com
Thu Dec 17 14:29:18 PST 2009


I'm a bit confused with

cairo_image_surface_create_from_png_stream.

If the resource stream looks exactly like the png file, why is a read_func 
required? 

Is it 
possible just to get the part of the code used by 
cairo_image_surface_create_from_png and use that as the read_func.

Michael




>----Ursprungligt meddelande----
>Från: gurnett at telia.com
>Datum: 2009-12-17 13:52
>Till: <dov.grobgeld at gmail.com>
>Kopia: <cairo at cairographics.org>
>Ärende: Re: [cairo] Using gimp c file image
>
>Thanks.
>
>I am looking at the second option to use i conjunction with a resource. Using 
>resources seems like the best way instead of converting to gimp c images.
>
>Tack så mycket (Thanks alot)
>
>Michael
>
>>----Ursprungligt meddelande----
>>Från: dov.grobgeld at gmail.com
>>Datum: 2009-12-17 13:37
>>Till: "gurnett at telia.com"<gurnett at telia.com>
>>Kopia: <cairo at cairographics.org>
>>Ärende: Re: [cairo] Using gimp c file image
>>
>>You can use gdk_pixbuf and in your build system do:
>>
>>gdk-pixbuf-csource --name=foo_inline foo.png > foo.i
>>
>>And in your c-source do:
>>
>>#include "foo.i"
>>
>>:
>>
>>GdkPixbuf* foo_pixbuf = gdk_pixbuf_new_from_inline(sizeof
>(foo_inline),
>>                           foo_inline,
>>                           FALSE,
>>                           &error);
>>
>>You can then create a image surface through:
>>
>>    cairo_surface_t *surface = cairo_image_surface_create_for_data
>>(gdk_pixbuf_get_pixels(foo_pixbuf),
>>
>>gdk_pixbuf_get_has_alpha(foo_pixbuf) ? CAIRO_FORMAT_ARGB32 :
>>CAIRO_FORMAT_FORMAT_RGB24
>>                                         gdk_pixbuf_get_width(foo_pixbuf),
>>                                         gdk_pixbuf_get_height(foo_pixbuf),
>>                                         gdk_pixbuf_get_rowstride
>(foo_pixbuf));
>>    gdk_pixbuf_unref(foo_pixbuf);
>>
>>
>>There is one problem though, which is that cairo and gdk pixbuf does not
>>agree on the order of R,G,B and alpha. So you will have to swap the data
>>before you do this. (Instead of gdk pixbuf you can use any image library,
>>e.g. libpng, opencv, FreeImage, etc.)
>>
>>Another option if cairo has been compiled with PNG support, is to do:
>>
>>cairo_surface_t * cairo_image_surface_create_from_png_stream
>>                  (cairo_read_func_t read_func,
>>                   void *closure);
>>
>>You will then have to write a read_func instance that will provide data from
>>your baked png file.
>>
>>Hope this helps.
>>
>>Lycka till!
>>Dov
>>
>>On Thu, Dec 17, 2009 at 11:05, gurnett at telia.com <gurnett at telia.com> wrote:
>>
>>> I have an app that has a lot of png files. I've asked previously if it was
>>> possible to use embedded png images with cairo, but this did not seem
>>> possible.
>>> As I really want to bake all this images into the exe I was wondering if it
>>> is
>>> possible to use the gimp c file image format and use that instead of
>>>
>>> image=cairo_image_surface_create_from_png("image.png");
>>>
>>> Thanks
>>>
>>> Michael
>>> --
>>> cairo mailing list
>>> cairo at cairographics.org
>>> http://lists.cairographics.org/mailman/listinfo/cairo>>>>
>
>
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