duce several characters, and a single character may require several keys to produce. This may not be the case on your machine, but your users are likely not all using the same keyboard layout, input method or even operating system as you.</p>
<h2><a class="anchor" id="input_key"></a>
Key input</h2>
<p>If you wish to be notified when a physical key is pressed or released or when it repeats, set a key callback.</p>
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