Difference between revisions of "84PCSE:BCALLs:4D47"
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(InvertRect) 
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Latest revision as of 09:20, 20 October 2013
Synopsis
Hypothesized Official Name: InvertRect
BCALL Address: 4D47h
Invert a rectangular area of the LCD.
Inputs
 HL = X coordinate of left edge
 DE = X coordinate of right edge (must be greater than or equal to HL and at most 319)
 B = Y coordinate of top edge (from top of screen)
 C = Y coordinate of bottom edge (must be greater than or equal to B and at most 239)
Outputs
None
Destroys
 AF
Comments
The rectangle is drawn only to the LCD, never to the graph buffer.
Each pixel in the rectangle will be replaced with its bitwise complement, so the resulting colors will be inverted componentwise (e.g., red will be replaced with cyan and vice versa.) Inverting the same rectangle twice will restore the original colors.
The dimensions of the inverted area are (HLDE+1) × (CB+1). The routine doesn't check that the provided coordinates are valid.
The interrupt state (IFF) is preserved.