s="section note"><dt>Note</dt><dd>Colors with an alpha channel are always assumed to have <a href="https://en.wikipedia.org/wiki/Alpha_compositing">pre-multiplied alpha</a>.</dd></dl>
<p>Other color type do not have an alpha channel but the library still support simple blending operations through the (optional) <code>opacity</code> parameter added to all drawing primitives. This parameter ranges in <code>[0.0f, 1.0f]</code> with</p><ul>
<li><code>opacity = 1.0f</code>: fully opaque drawing. This is the defa