ExoQuant is a high-quality, easy to use color quantization library. This is for you if you need one or more of the following:
- Very high-quality color reduction
- Reduction of images including alpha
- Creation of a shared palette for more than one image (or mipmap level)
- Dithering of the reduced image with very little noise
First, of course, you need to include
Then for each image or texture to convert follow the following steps:
Step 1: Initialise and set options.
First you need to init the library by calling
exq_data *pExq; pExq = exq_init();
Then you can set the following options:
Option: Alpha is no transparency
Use this option if you don't use the alpha channel of your image/texture as transparency or if the color is already premultiplied by the alpha. To set this option just call
Step 2: Feed the image data
Now you need to feed the image data to the quantizer. The image data needs to be 32 bits per pixel. The first byte of each pixel needs to be the red channel, the last byte needs to be alpha.
To feed the image data you have to call
exq_feed, which can be called more than once to create a shared palette for more than one image, for example for a texture with several mipmap levels:
exq_feed(pExq, pImage_data, num_pixels);
Step 3: Color reduction
exq_quantize(pExq, num_colors); exq_quantize_hq(pExq, num_colors); exq_quantize_ex(pExq, num_colors, high_quality);
Step 4: Retrieve the palette
exq_get_palette(pExq, pPalette, num_colors);
Step 5: Map the image to the palette
exq_map_image(pExq, num_pixels, pIn, pOut); exq_map_image_ordered(pExq, width, height, pIn, pOut);
Step 6: Clean up
exq_free to free the quantization data:
Copyright (c) 2004 Dennis Ranke
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