Re: [platform-swt-dev] GTK graphics status

[Silenio_Quarti@xxxxxxx]

When a image has transparency (e.g. icons, gifs with transparent pixel), 
SWT creates
a GdkPixmap for the color part of the image and a GdkBitmap for the mask.

We are using GdkPixBuf to scale the GdkPixmap. If we use a different
algorithm to scale the GdkBitmap, we might have problems, since different
algorithms might replicate different pixels.

So if we use our own algorithm the scale a GdkBitmap, I believe we will 
have to
use it the scale its associated GdkPixmap too.

Right now, we are getting a GdkPixBuf with alha channel from the 
GdkPixmap,
getting the mask data using GdkImage, combining them by replacing the 
alpha
channel with appropriate values (e.g. 1 -> 255, 0 -> 0), scaling the 
GdkPixBuf and
then redering to the destination drawable by calling 
gdk_pixbuf_render_to_drawable_alpha.

This is somewhat inneficient though.

Silenio
 




Havoc Pennington <hp@xxxxxxxxxx>
Sent by: platform-swt-dev-admin@xxxxxxxxxxx
03/18/02 07:00 PM
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        Subject:        Re: [platform-swt-dev] GTK graphics status


Silenio_Quarti@xxxxxxx writes:
> 
> On Motif, we used XImage to get data from a Pixmap, scale the
> data using our own algorithm  and then put the data in a new
> Pixmap.
>

That's probably a reasonable solution. Converting 1-bit data into a
pixbuf seems kind of wrong.

GdkImage is just like XImage so the Motif code should port easily.

Havoc
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