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* Chickadee: (chickadee). Game programming toolkit for Guile.
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<a name="Blending-1"></a>
<h4 class="subsection">2.3.7 Blending</h4>
<p>Rendering a scene often involves drawing layers of objects that
overlap each other. Blending determines how two overlapping pixels
are combined in the final image that is rendered to the screen.
Chickadee provides the following blend modes:
</p>
<ul>
<li> <code>replace</code>
Use the latest color, ignoring all others.
</li><li> <code>alpha</code>
Blend pixels according to the values of their alpha channels. This is
the most commonly used blend mode and thus is Chickadee’s default
mode.
</li><li> <code>add</code>
Add all pixel color values together. The more colors blended
together, the more white the final color becomes.
</li><li> <code>subtract</code>
Subtract all pixel color values. The more colors blended together,
the more black the final color becomes.
</li><li> <code>multiply</code>
</li><li> <code>darken</code>
</li><li> <code>lighten</code>
</li><li> <code>screen</code>
</li></ul>
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