The 'A' in RGBA: What does it mean?
I know about Red, Green, and Blue, but I'm not so sure about the 'A'. What does it really mean?
I want to know this for this code: Code:
int rgba (int Red, int Green, int Blue, int <WhateverTheAStandsFor>) And I will do this with C++, not original C, unlike the existing Gtk RGBA module. |
Quote:
http://en.wikipedia.org/wiki/RGBA_color_space - are all your WEB search engines blocked ? |
Briefly... the fourth channel ("A") is Alpha, which represents transparency.
A pixel with A=1.0 is "solid." A=0.0 is invisible. A=0.5 is a translucent "ghost." This channel of information is used when blending multiple "layers" of material into a single image. |
please use Google before posting
Alpha Chanel, for transparency |
Yeah, and that's why there is no real 32-bit color, it's 24-bit color + 8-bit alpha channel.
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That depends upon your particular display hardware.
Remember... "RGB(A)" is simply a color space, just like CMYK and HSV(A). It is an agreed-upon method of representing color. The integer (or, as the case may be, floating-point) domain of each value can vary from file to file, application to application, or device to device. The essence of "RGBA" is that "a color value is expressed by a 4-tuple {r,g,b,a}." That's it. That's all. |
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