[gtkada] bitmap-handling with GtkAda

[Frode Tennebø]

On Thursday 21 November 2002 17:28, Karl Ran wrote:
> >>But it seems to me that your clock updates the whole bitmap every
> >>second.
> >>
> >>That's what I'm trying to avoid......somehow :-/
> >
> >Why?
>
> Well, think of a BIG bitmap and a slooow connection from the program
> to the Xserver...

Pixmaps/bitmaps reside on the server, so unless you are redirecting the 
dispay to another xserver across a slooow conection, this should not be 
a problem.

What you want to do is create one window and one pix-/bitmap depending 
on your need, draw the y*h to the pix-/bitmap, (*) do an XCopyArea to 
blit the pix-/bitmap to the window, do an XCopyArea of the window minus 
y pixles to the pixmap with an y pixles offset, draw the y*h to the 
pix-/bitmap, wait the remainder of 100 ms, repeat from (*).

I do four such XCopyArea (BLITs) with clip-masks (sometimes complex 
ones) of app. 900x900 pixles, 5 times-sec. And today it's the 
complexity of the clip-mask which controlls the performance. Normally 
it runs rather nicely.

I don't know if there is an existing GtkAda widget which does this, but 
it would be a nice project. :)

 -Frode

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