🚀 go-pugleaf

In article <1992Apr16.154404.7649@daffy.cs.wisc.edu>, mcheng@dunlop.cs.wisc.edu (Michael Cheng) writes:
|> 1) I understand that in Glyph::allocate(Canvas*, const Allocation& allocation,
|> 	Extensions& extension), the allocation informs the glyph how much
|> 	space has been allocated. But what is the purpose of the
|> 	extension? This was never explained.

The extension is the area that the glyph might draw on.  A common approach
is to mark the extension as equivalent to the allocation using Extension::extend.

|> 2) I wish to write dynamic glyphs that change their
|> appearances as data is read from a file.
|> Is it safe to save the Canvas and the allocation passed in Glyph::allocate() 
|> for use in drawing operations?

Patch has this functionality, so generally what one does is wrap a patch around
the area that you want to update.