This app copies from two offscreen GWorlds into the left and right halves of the window. The contents of the GWorlds are vertical lines that show all the entries in the color tables associated with the GWorlds. The GWorlds were created as described below.
One commonly asked question is how to use a palette when drawing into a GWorld. The trick is understanding that while setting a palette to a GWorld is permitted, doing so does not change the GWorld’s color table.
The solution is to make a palette from the color table ( or the color table from a palette) and to use that color table to create or update the GWorld. After then doing a SetGWorld you can either draw with Index2Color and RGBForeColor, or you can set the palette to the GWorld and draw with PmForeColor. These techniques are shown in the procedures createRGBForeColorImage and createPmForeColorImage in Palette and GWorld.c.
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.
1) Palette&GWorld (Fat) was constructed using the method described in chapter 6 of “Power Macintosh Programming Starter Kit.” The output of Palette&GWorld.68K.π is Palette&GWorld.PPC.π.rsrc which is used by Palette&GWorld.PPC.π to create Palette&GWorld (Fat).
2) Thanks to Mr. Ed for the demo shell.
Author
JM - Apple Developer Technical Support - dts@apple.com