Re: Help with transparent pixmaps

[Helmethead <hoshem mel comcen com au>]

umm
try calling gdk_imlib_render() before trying to move the pixmap and mask out of a GdkImlibImage


On Tue, Jan 30, 2001 at 12:59:33PM +0100, Germano Rizzo wrote:
> Hi,
>     I have a problem: I am in need of displaying a pixmap widget with a
> transparent area... but I want to control and change the shape of this area
> each time I create it. So, I have the non-trasparent pixmap in a file (png,
> let's say), and the 'mask' for the alpha channel in a bicolor one. Now, how
> can I assemble the two?? I've checked the header files of gdk_imlib, gdk_h
> and gtkpixmap, and it seems that nothing suits my need... well, I figured it
> could be done with imlib... apparently, not! So I wrote something like:
> 
> [...]
> 
> GtkWidget *pix;
> GdkImlibImage *img,*msk;
> GdkPixmap *pixmap;
> GdkBitmap *bitmap;
> 
> img=gdk_imlib_load_image("a.png");
> msk=gdk_imlib_load_alpha("b.png"); [or load_image, FWIW]
> 
> pixmap=gdk_imlib_move_image(img);
> bitmap=gdk_imlib_move_mask(msk);
> 
> pix=gtk_pixmap_new(pixmap,bitmap);
> 
> [...]
> 
> of course, with the code relative to the app window, etc... When I compile
> it, no problem, but at runtime it gives me an empty window, and says
> 
> Gtk-CRITICAL **: file gtkpixmap.c: line 97 (gtk_pixmap_new): assertion `val
> != NULL' failed
> 
> WHY??? Please help! Is this the right approach? I could use xpm's, but
> they're so... uh... uncomfortable to make and handle! Any idea? Really isn't
> there an Imlib function that loads the alpha channel from a file into an
> existing image?
> 
>     Thanx in advance, and have a nice day,
>         Mano :)
> 
> 
> 
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