32-bit color

What could the "non color data" that is talked about be?

You already named it. It's the alpha channel. Transparency is a picture element attribute not related to color.

Right. I realized that I already named it about 30 minutes after I posted the last question.

What I don't understand is how the display could have 32-bit color (8 bits per pixel plus an alpha channel) because I thought that the alpha channel was never sent to the display.

Does that make sense?

Now I get your point. Yeah, that does seem like a misnomer in a way.

In the video memory, 32 bits are set aside for a pixel's attributes, so the bit depth could be thought of as 32-bits per pixel from the perspective of the memory map. But, yeah, I agree with you that no more than 24-bits of RGB data get sent to the display.

On the other hand, those 8 remaining bits do influence the RGB data that gets sent, so it is a 32-bit structure in that sense. It all depends on how you look at it I guess.

Do any "real" 32 bit color systems actually exist? And, if so, which colour do they drop a bit from to get to 32? (3x11 = 33, 3x10=30) I see that according wiki even those that aren't 3x8 + 8 bits of extras are usually 3x10 + 2 bits of padding:

+32-bit color+
+"32-bit color" is generally a misnomer in regard to display color depth. While actual 32-bit color at ten to eleven bits per channel produces over 4.2 billion distinct colors, the term “32-bit color” is most often a misuse referring to 24-bit color images with an additional eight bits of non-color data (I.E.: alpha, Z or bump data), or sometimes even to plain 24-bit data.+
+Systems using more than 24 bits in a 32-bit pixel for actual color data exist, but most of them opt for a 30-bit implementation with two bits of padding so that they can have an even 10 bits of color for each channel, similar to many HiColor systems.+

(from http://en.wikipedia.org/wiki/Color_depth)

Cheers

Rod