Re: gdk_pixbuf_composite() issue

[Andrey Tsyvarev <tsyvarev ispras ru>]

Michael wrote:

> I've got a pixbuf, created with gdk_pixbuf_new() (let's call it 
> combined_pixbufs), with a width/height large enough to accommodate two
> pixbufs side-by-side. I then have two smaller pixbufs: pixbuf_one and
> pixbuf_two. I'm trying to use gdk_pixbuf_composite() to combine them
> side-by-side into combined_pixbufs:

> x = 0, y = 0;
> gdk_pixbuf_composite(pixbuf_one, combined_pixbufs, x, y, 
> pixbuf_one_width, pixbuf_one_height, 0.0, 0.0, 1.0, 1.0, 
> GDK_INTERP_BILINEAR, 255);
> x += pixbuf_one_width;
> gdk_pixbuf_composite(pixbuf_two, combined_pixbufs, x, y, 
> pixbuf_two_width, pixbuf_two_height, 0.0, 0.0, 1.0, 1.0, 
> GDK_INTERP_BILINEAR, 255);

> The first pixbuf shows up in combined_pixbufs perfectly. The second one
> is all blurry and stretched. I can change the call with pixbuf_two to
> pixbuf_one (so it copies pixbuf_one twice), and the second time it's
> copied it shows up stretched and blurry, but not the first time.

> Anyone know why this is, or an easier way to combine pixbufs together?

For parameters 'offset_x' and 'offset_y' you would use an offset of
the source pixbuf at the destination pixbuf('x' and 'y' in your code),
not an offset of the first rendering pixel(0.0 and 0.0):

x = 0, y = 0;
gdk_pixbuf_composite(pixbuf_one, combined_pixbufs, x, y,
pixbuf_one_width, pixbuf_one_height, x, y, 1.0, 1.0,
GDK_INTERP_BILINEAR, 255);
x += pixbuf_one_width;
gdk_pixbuf_composite(pixbuf_two, combined_pixbufs, x, y,
pixbuf_two_width, pixbuf_two_height, x, y, 1.0, 1.0,
GDK_INTERP_BILINEAR, 255);

http://library.gnome.org/devel/gdk-pixbuf/stable/gdk-pixbuf-scaling.html#gdk-pixbuf-composite

-- 
Andrey Tsyvarev
 
 Linux Verification Center, ISPRAS
 web:    http://www.linuxtesting.org
 e-mail: tsyvarev ispras ru