Under low memory conditions, it's often necessary to draw an image by individual bands rather than to draw the entire image at once, and in most cases this method works fine unless the image requires dithering from its source to its destination. The purpose of this app is to show the problem that may occur when copying these individual bands and to provide one possible solution.
Building the Code
This project was built and tested on CodeWarrior 2.1 using CarbonLib 1.1a3. Since this is a Carbon app, the "Carbon Support" folder of the CarbonSDK should be in the same folder as the CodeWarrior IDE. If this is not the case, the CarbonLib library will have to be re-added to the project. In addition, the CarbonLib extension needs to be in the extension folder. The CarbonSDK (which contains the library and the extension) can be found on Apple's website: http://developer.apple.com/sdk/
Restrictions
Nearly every sample requires more memory than the 384KB CodeWarrior sets as the default heap size. If for some reason the memory has been reset to the default (either through converting the project or whatever) the memory should be reset to 1000 - 2000KB (depending on the application). This can be achieved by going to the projects settings (Edit Menu->C-PPC Settings... under CodeWarrior 2.1) and selecting the "PPC Target" under the "Target" tab.
Other Code Notes
This sample used to be a "non-Carbon" sample, but has been carbonized for demonstration purposes. The "old" code has been left in (commented out) in order to compare and contrast the Carbon versus non-Carbon APIs.