Adam Badura wrote:
like RGBA 8:8:8:8 or YUV 4:2:2, etc...
What "etc.."? I need to know such things... :) Or do you have any sugestions for a "general foramt specification"?
I was just giving a few examples of common color encodings, using a rather common scheme, the names of the Channels, and the number of bytes to encode each. http://www.fourcc.org/rgb.php and http://www.fourcc.org/yuv.php give an overview of several common pixel formats.
Why do you use colors in format in which components are integers in range 0...255 and not floats in range 0.0...1.0? I want to know to better understand the task? (I know that WIndows uses such a format and that as I suppose ale the data that is received be devices is finally in this format but do you have any other reasons).
No, no other reasons. Most algorithms which work on images need to be as efficient as possible, so I only convert colors to float if I need to (i.e. repeated subsampling, etc.) Of course I also like to have the matching float colors. OpenGL can use them, at least as a drawing color, I haven't checked if it can use them as texture, too. Unless you need extra high color fidelity (e.g. HDR-Images, Photo post-production) the additional space which is required to store floats is overkill. My main concern is that the color library supports common pixel storage formats so that I can handle raw image buffers without copying them first in a typesafe way, or even more importantly to pass a data structures of consecutive color library pixels as a a raw buffer, like for example (it should demonstrate how such a library might be used, its not meant as a syntax proposal): std::vector<color_library_pixel> img; load_from_file("test.png", img, width, height); legacy_function_which_expects_someptr_to_raw_buffer(&img[0]); color_library_pixel p = img[10 * width + 5] // returns pixel at (5, 10) This makes it possible to write high level image classes, with minimal storage and an efficient interface to lower level code. regards Fabio
Thanks.
Adam Badura
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