adding color values per pixel

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holzdolph
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Joined: 2011-08-04T01:41:41-07:00
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adding color values per pixel

Post by holzdolph » 2011-08-04T02:17:44-07:00

Hello guys,

I´m new to ImageMagic++, and just use it for some very simple image creation:
The first <for> loop generates an image (a single XY-plane) from a 3dimensional structure, and the second one contains all border elements of this structure.
Now to make sure my algorithm finds all border elements, they are drawn in a different color, but at the moment the color value is just set to a new one and overwrites the old color.

What I want, is to add a certain color value in the second <for> loop, so i can distinguish between "wrong" and "correct" border elements by just looking at the picture. It´s like in photoshop setting some transparency (or opacity?) to a line drawn over another one, but the first one being still visible.

I tried changing the alpha-lvl, but this only affects the background. Also, there seem to be no +, or == operators for the Color class, which would have made things easy enough.

Here is the code:

Code: Select all

	Magick::Geometry g1(nx_,ny_);
	Magick::Image image(g1, "white");
	image.type( Magick::TrueColorMatteType );	
	image.modifyImage();		//
	Magick::Pixels pixelcache(image);	// allocate image pixel cache of "image"
	Magick::PixelPacket *pixels;			// pointer
	pixels = pixelcache.get(0, 0, nx_, ny_);	// allocate memory for the pixels-pointer
	for(plint i=0; i<nx_; ++i) {
		for(plint j=0; j<ny_; ++j) {
			if (boolmask_->get(i,j,zpos_)) *(pixels+i+j*ny_) = Magick::Color(0,35000,0, 0);
		}
	}
	
	for(list<BorderElement>::iterator i = bla_.begin(); i != bla_.end(); ++i) {
		foo = i->get_pos();
		*(pixels+foo.x+foo.y*ny_) = Magick::Color(35000,200,200, 0);	
	}				
	pixelcache.sync();
	image.magick("png");
	image.write(fname.c_str());
Any Ideas on what to change are welcome,
thanks for any help!

cheers,
Chris

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