Limitations of MungeBitmap

One of the Newton 2.x OS Q&As
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This document was exported on 7/23/97.

Limitations of MungeBitmap (4/3/97)

Q: When I use MungeBitmap to flip or rotate a grayscale image, it gets corrupted. What's wrong?

A: MungeBitmap does not properly handle bitmaps with a depth greater than 1. You can work around this problem by using kMungeBitmapFunc, which has the same calling conventions and return value as MungeBitmap. kMungeBitmapFunc is provided in the Newton 2.1 Platform file, version 1.2b1 or later.

Calling MungeBitmap with the 'rotateLeft, 'rotateRight, or 'flipHorizontal options will trigger the bug. The 'rotate180 and 'flipVertical arguments to MungeBitmap work correctly with deeper bitmaps.

Note that with the Newton 2.1 OS release in the [English language] Apple MessagePad 2000 and Apple eMate 300 products, the built-in Drawing stationery in NewtonWorks exhibits this bug when rotating gray bitmaps.