Re: another theory

[Lars Clausen <lars raeder dk>]

On Fri, 2005-04-01 at 10:32 +0200, Stefan wrote:
> some minutes ago I observed the bahaviour on drawing text with 
> gdk_pixbuf_render_to_drawable_alpha() in diagdkrenderer.c:draw_string(). 
> Supporting that, I used a fix alpha threshold in 'pixels[i*stride+j*4+3] 
> = graybitmap[i*rowstride+j];', i.e. 128. And what I explored is, that in 
> the situations the font is drawn ugly, now the intensity of the color 
> incresed. So ... there are some regions are still drawn and are 
> overdrawn by this method. The transparency then causes the uglyness and 
> egdy font.

That sounds much more like something that could actually cause this bug
that what we've look at before.  

> So the problem is actually a problem with uninvalidated, still present 
> regions in renderer->pixmap which have to be cleared, before redrawing 
> the text again. The update-area logic doesn't pay attention on this.

Notably, the effect also happens under libart renderer.  Which makes
sense with the explanation.

-Lars

-- 
Lars Clausen <lars raeder dk>