Question

I’ve looked around, but don’t see this question – maybe its too easy, but I don’t have it.

If I have file containing color values like:

255,
65535,
65280 ( I think this is green)

is there a way to either:

1. convert these to a System.Drawing.Color type or….better yet..
2. have .NET accept them as is to represent the color?

thanks,

Answer 1

From your comments on an earlier version of this answer it seems that each number in the file represents one colour, and that these are packed bytes:

65280 (= 0xFF00) -> (0, 255, 0)
65535 (= 0xFFFF) -> (255, 255, 0)

So you want the low byte in the first (red?) part of the triple, and the next higher byte in the second (blue?) part of the triple. I am guessing that values over 65535 would go into the third byte of the triple.

You can do this easily using bit masking and bit shift operators:

int r = n && 0xFF;
int g = (n >> 8) & 0xFF;
int b = (n >> 16) & 0xFF;

i.e. shift it right by 8 bits each time, and select out the bottom 8 bits.

NOTE: You can also do this directly using Color.FromArgb(Int32), which saves you from having to do the unpacking. But this will only work if the numbers in your file are packed in the right way. They would need to be in AARRGGBB format. For example, 255 (0x000000FF) = Blue, 65280 (0x0000FF00) = Green, 16711680 (0x00FF0000) = Red. I am not sure whether your numbers are in the right order which is why I have covered the explicit unpacking technique.