You can also create a cairo surface of the pixbuf through
cairo_image_surface_create_for_data() like this:
int img_width = gdk_pixbuf_get_width(pixbuf);
int img_height = gdk_pixbuf_get_height(pixbuf);
cairo_surface_t *surface
= cairo_image_surface_create_for_data(gdk_pixbuf_get_pixels(pixbuf),
CAIRO_FORMAT_RGB24,
img_width,
img_height,
gdk_pixbuf_get_rowstride(pixbuf));
but beware that you will need to swap R and B when drawing. See the
cairo-circles.c example at:
http://giv.sourceforge.net/gtk-image-viewer/gtkimageviewer_tutorial.html
Regards,
Dov
2009/2/22 Tadej Borovšak <[email protected]>
> Hi.
>
> I missed list the first time (sorry Roei for spamming you).
>
> ---------- Forwarded message ----------
> From: Tadej Borovšak <[email protected]>
> Date: 2009/2/22
> Subject: Re: cairo_surface_t to pixbuf
> To: Roei Azachi <[email protected]>
>
>
> 2009/2/22 Roei Azachi <[email protected]>:
> > Hi,
> > I was wondering if there is a way of converting cairo_surface_t to pixbuf
> > currently I am doing:
> > cairo_surface_write_to_png(oimg2, "tmp.png");
> > pixbuf = gdk_pixbuf_new_from_file("tmp.png", &g_err);
> > I'm sure there is a way, but I don't know how...
> > Thanks,
> > Roei
> > _______________________________________________
> > gtk-list mailing list
> > [email protected]
> > http://mail.gnome.org/mailman/listinfo/gtk-list
> >
>
> Hi.
>
> I only converted cairo's image surfaces to PPM images. I did this by
> obtaining surface's width, height, rowstride and format, then manually
> copied pixel values from surface to PPM.
>
> Simple function for converting surface to pixbuf would look something like
> this:
>
> ------- CODE --------
> GdkPixbuf *
> convert( cairo_surface_t *surface )
> {
> GdkPixbuf *pixbuf;
> gint width = cairo_image_surface_get_width( surface );
> gint height = cairo_image_surface_get_height( surface );
> gint stride = cairo_image_surface_get_stride( surface );
> cairo_format_t format = cairo_image_surface_get_format( surface );
> guchar *data = cairo_image_surface_get_data( surface );
> gint row, col;
>
> if( format == CAIRO_FORMAT_ARGB32 )
> {
> guchar *pixels;
> gint pix_stride;
>
> /* Temporary pointers for iterating. */
> guchar *p_dat, *p_pix;
>
> pixbuf = gdk_pixbuf_new( GDK_COLORSPACE_RGB, TRUE, 8,
> width, height );
> pixels = gdk_pixbuf_get_pixels( pixbuf );
> pix_stride = gdk_pixbuf_get_rowstride( pixbuf );
>
> p_dat = data;
> p_pix = pixels;
>
> for( row = 0; row < height; row++ )
> {
> p_pix = pixels + row * pix_stride;
> p_dat = data + row * stride;
>
> for( col = 0; col < width; col++ )
> {
> /* Copy now. Cairo image surfaces use
> pre-multiplied
> * alpha, this is why we need to
> calculate RGB values. */
> p_pix[0] = p_dat[1] / p_dat[0] * 0xff;
> p_pix[1] = p_dat[2] / p_dat[0] * 0xff;
> p_pix[2] = p_dat[3] / p_dat[0] * 0xff;
> p_pix[3] = p_dat[0];
>
> p_pix += 4;
> p_dat += 4;
> }
> }
> }
> else if( format == CAIRO_FORMAT_RGB24 )
> {
> guchar *pixels;
> gint pix_stride;
>
> /* Temporary pointers for iterating. */
> guchar *p_dat, *p_pix;
>
> pixbuf = gdk_pixbuf_new( GDK_COLORSPACE_RGB, FALSE, 8,
> width, height );
> pixels = gdk_pixbuf_get_pixels( pixbuf );
> pix_stride = gdk_pixbuf_get_rowstride( pixbuf );
>
> p_dat = data;
> p_pix = pixels;
>
> for( row = 0; row < height; row++ )
> {
> p_pix = pixels + row * pix_stride;
> p_dat = data + row * stride;
>
> for( col = 0; col < width; col++ )
> {
> p_pix[0] = p_dat[0];
> p_pix[1] = p_dat[1];
> p_pix[2] = p_dat[2];
>
> p_pix += 3;
> p_dat += 4;
> }
> }
> }
>
> return( pixbuf );
> }
> -------- CODE ---------
>
> Note though that I haven't tested this function, so test it before
> using in real application.
>
> --
> Tadej Borovšak
> [email protected]
> [email protected]
>
>
>
> --
> Tadej Borovšak
> [email protected]
> [email protected]
> _______________________________________________
> gtk-list mailing list
> [email protected]
> http://mail.gnome.org/mailman/listinfo/gtk-list
>
_______________________________________________
gtk-list mailing list
[email protected]
http://mail.gnome.org/mailman/listinfo/gtk-list
