Re: Creating a color image with NSBitmapImageRep and greyscale data
Re: Creating a color image with NSBitmapImageRep and greyscale data
- Subject: Re: Creating a color image with NSBitmapImageRep and greyscale data
- From: David Spooner <email@hidden>
- Date: Tue, 27 Nov 2007 20:55:18 -0700
Sorry, I meant to also say that an alternative to this quick and
dirty approach is to consider the input greyscale value as the hue
component of an HSB (or related) colorspace and perform a standard
conversion from HSB to RGB (using a fixed saturation and brightness).
dave
On 27-Nov-07, at 8:34 PM, David Spooner wrote:
The preceding line sets the r, g and b components uniformly for each
output pixel, so you'll always get grey. You might try distributing
each input pixel p across r, g and b along the lines of...
int bpr = [bitmap bytesPerRow];
for (int i = 0; i < height; ++i) {
char *row = bitmapData + i * bpr;
for (int j = 0; j < width; ++j) {
uint16_t p = pixels[i * width + j];
unsigned char *rgb = row + j * 3;
rgb[0] = p & 0x3f;
rgb[1] = (p >> 6) & 0x3f;
rgb[2] = (p >> 12);
}
}
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