Re: pseudo transparency

[Owen Taylor <otaylor redhat com>]

Sasha Vasko <sasha aftercode net> writes:

> On Monday 14 January 2002 17:10, Sasha Vasko wrote:
> > Owen Taylor wrote:
> > > Olivier Chapuis <olivier chapuis free fr> writes:
> > >>Yes I was not award that this may be so problematic (some Sasha remarks
> > >>go in the same direction). But what I want is to prevent a bad hack which
> <snip>
> > >  * It interferes with the normal operations of window manager which
> > > probably is setting the window background of it's borders for other
> > > reasons. * It doesn't work if you want to shade the terminal background,
> > > which is probably a lot more common than not.
> >
> > You cannot shade but you can tint. By using GC with function set to XOR,
> > you can tint background in 6 "whole" colors: red, green, blue, yellow,
> > cyan, mag. by simple XFillRectangle. Works rather nicely in aterm.
> 
> Actually just after I sent this it occured to me that using XRender it is 
> indeed very easy to shade Window that has ParentRelative background. All one 
> has to do is to use image pixmap 1x1 of desired color (white , grey, black)  
> and alpha pixmap filled with some meaningfull alpha value ( 0x7F for example 
> )  and on each Expose or ConfigureNotify - do XClearArea and XRenderComposite.
> 
> In fact I tried it and it works rather nicely.
> 
> That makes ParentRelative a very interesting alternative.

I don't think RENDER (or plane masks) are actually useful with the
parent-relative thing since you have to _first_ clear, _then_ tint,
which is not going to look OK for ConfigureNotify or when scrolling.

Regards,
                                        Owen