RGB separation

[bdiscount]

I'm using a Dell Axim X51v. I placed color rects on form with known RGB and the numbers I get i put thru you formula. I did see the ques you posted and forgot but now I will pick them using that info. Thanks for your help.

[bdiscount]

Yes I missed the - sign I am sure your right. Thanks for staying on this.

[DavidN]

You can always inspect the bits of the returned color value to validate what you should be getting. In basic4ppc the returned color value is of type DECIMAL, which is 32-bits. Which is 4 bytes. I took a look at the values in the bytes and deduced that 3 of the bytes corresponded to the R, G, and B color values respectively. The fourth byte was discarded; it probably corresponds to the Alpha value used on the desktop (but not the mobile device). A function to extract the RGB color values could be written using bit operations to shift and mask the relavant bits, but you's need to use the bitwise object library. Or you could just do some math as suggested in the previous posts. Depending on how the compiler optimizes the code, the bitwise approach may be faster. Or not. At some point I'll code it up and benchmark it. However, Erel may introduce a getRGBcolor function in a future version of basic4ppc, that I'd use.

[bdiscount]

I have converted number to hex and got bytes the first =FF which means it negative the remaining 3 bytes tell me the same as specci results.
I hope the RGB sub comes out soon. I am tring to save a portion of a image on the form ie: x,y,wide,high,save/open

I will keep trying.

[agraham]

Originally Posted by bdiscount

I have converted number to hex and got bytes the first =FF which means it negative the remaining 3 bytes tell me the same as specci results.

That first byte is a fourth value, Alpha, that on the desktop represents transparency. The value you have is actually 255 meaning totally opaque. Zero would be totally transparent. It only appears negative because a colour value is actually four 8 bits values (0 to 255) packed into a 32 bit integer and Alpha occupies the sign bit at the top of the number.