https://wikiti.brandonw.net/index.php?action=history&feed=atom&title=84PCSE%3ABCALLs%3A4D4784PCSE:BCALLs:4D47 - Revision history2026-04-18T00:29:42ZRevision history for this page on the wikiMediaWiki 1.23.5https://wikiti.brandonw.net/index.php?title=84PCSE:BCALLs:4D47&diff=10194&oldid=prevFloppusMaximus: InvertRect2013-10-20T17:20:00Z<p>InvertRect</p>
<p><b>New page</b></p><div>[[Category:84PCSE:BCALLs:By Name|InvertRect]] [[Category:84PCSE:BCALLs:By Name:Drawing|InvertRect]] [[Category:84PCSE:BCALLs:By Address|4D47 - InvertRect]]<br />
== Synopsis ==<br />
'''Hypothesized Official Name:''' InvertRect<br />
<br />
'''BCALL Address:''' 4D47h<br />
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Invert a rectangular area of the LCD.<br />
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=== Inputs ===<br />
* HL = X coordinate of left edge<br />
* DE = X coordinate of right edge (must be greater than or equal to HL and at most 319)<br />
* B = Y coordinate of top edge (from top of screen)<br />
* C = Y coordinate of bottom edge (must be greater than or equal to B and at most 239)<br />
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=== Outputs ===<br />
'''None'''<br />
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=== Destroys ===<br />
* AF<br />
<br />
== Comments ==<br />
The rectangle is drawn only to the LCD, never to the graph buffer.<br />
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Each pixel in the rectangle will be replaced with its bitwise complement, so the resulting colors will be inverted component-wise (e.g., red will be replaced with cyan and vice versa.) Inverting the same rectangle twice will restore the original colors.<br />
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The dimensions of the inverted area are (HL-DE+1) × (C-B+1). The routine doesn't check that the provided coordinates are valid.<br />
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The interrupt state (IFF) is preserved.</div>FloppusMaximus