RGB image to CMYK gdi+

[Gopi Nath]

Hello, I am trying to adjust the color balance (CYMK) of an image like this is in photoshop or some other applications. From examples, i tried changing the current RGB to CMYK (for each pixel) using the below code.

for (int i = 0; i < width; i++)
{
for (int j = 0; j < height; j++)
{
tmpbmp->GetPixel(i, j, &clr);

		R = clr.GetR();
		G = clr.GetG();
		B = clr.GetB();

		c = \_cyanclr / 255.0; // \_cyanclr - user input in %
		m = \_magentaclr / 255.0;
		y = \_yellowclr / 255.0;
		k = \_blackclr / 255.0;

		rr = c \* (1.0 - k) + k;
		gg = m \* (1.0 - k) + k;
		bb = y \* (1.0 - k) + k;

		rr = (1.0 - rr) \* 255.0 + 0.5;
		gg = (1.0 - gg) \* 255.0 + 0.5;
		bb = (1.0 - bb) \* 255.0 + 0.5;
		
       // here i dont know how to adjust new RGB with old one
		R += rr;
		G += gg;
		B += bb;

		R = R < 0 ? 0 : (R > 255) ? 255 : R;
		G = G < 0 ? 0 : (G > 255) ? 255 : G;
		B = B < 0 ? 0 : (B > 255) ? 255 : B;			

		output->SetPixel(i, j, Gdiplus::Color(R, G, B));
	}
}

With this code, i am not getting the same result like in photoshop and other applications. I am not sure whether I am doing in right method or not. Please suggest. I am using C++ and gdi+. Regards, Gopinath.

[Lost User]

It is not clear exactly what your problem is or what adjustments you are trying to make to your colours. Maybe you could explain with some examples.

[RedDk]

Whatever works is the right method. There's no "not". Unless all one does is repost code they dug up from elsewhere and hasn't the foggiest idea what they're doing THAT for. :thumbsdown: