I-beam cursor color changing based on the background

[Bill Spitzak]

That's xor of the color bits. The blue/red is due to xor'ing with the 
subpixel antialiasing. It is more obvious if you put the cursor over a 
solid colored area where you will see strange colors.

It cannot be achieved with Porter-Duff combinations. I am not sure if 
OpenGL or DirectX supports it. I am also suspicious that overlay 
hardware designed for cursors may not support it either.

This would either require adding something to Wayland to enable xor of a 
cursor, or (more likely) you will have to just set the cursor to blank 
and draw the desired graphics yourself.

Linux programs seem to use a white insertion bar with a black outline, 
so it is visible against all backgrounds. This is despite the fact that 
X11 still supports xor cursors, everybody dropped that as obsolete. OS/X 
appears to use a black insertion bar with a very thin white outline (ie 
partially-transparent white pixels). Both of these work with normal 
compositing.

On 10/14/2015 06:13 AM, John Doerthy wrote:
> Hi,
> Could you please comment on this issue, if you are currently working on
> the Windows-like implementation of the I-beam cursor (cursor for text
> selection) in the graphical interface?
> In Windows, the I-beam cursor, change color based on the background. So,
> most of the time it's black, but when you are on the dark background its
> color cahnges and not only that, but if part of the cursor is on the
> white background and part on the dark background, only the affected
> areas of teh I-beam cursor change the color. Plus if you are over a text
> the part of the cursor that overlays some character has a slightly blue
> or red color (as you can see in the screenshots below)
> Here are some real world examples(screenshots) from Windows 7:
> http://imgur.com/a/IxG7w
> Thank for your response how far are you guys in implementing this feature.
> John
>
>
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