An old HyperCard native code plugin (XCMD) for doing all sorts of drawing commands in HyperCard, quickly, and even with color.
XCMDClass.c/.h includes, among other things, implementations of two undocumented HyperCard XCMD callbacks in MyGetMaskAndData and MyChangedMaskAndData, which allow an XCMD to read/change the pixels of the current card's graphics.
This contains the CompileIt source code for xDraw 1, the C source code for xDraw 2, as well as the test stack used during development.
The CheapVersionControl.sit file contains a StuffIt-compressed HyperCard stack that can be used to convert these files from a GitHub-friendly format (Unicode text, Unix line endings, resource fork-only files moved into the data fork, dual-fork files compressed with StuffIt) back into the original Mac format you'd need to run this on an actual Mac or emulator.
No. This outdated code is supplied for educational purposes only.