[comp.sys.mac.programmer] Offscreen drawing with palette ??

jenlan@eos (Jennifer S Lanham) (09/08/89)

    I am having a problem using copybits to transfer an image from an
  offscreen buffer where it was drawn, to the screen which has a palette
  attached to it.

  The program does the following:
	1. Opens a port (window) on the screen, and attaches a palette to it.

	2. Draws a "picture" using PmForeColor exclusively.

	3. Creates an offscreen port (as in tech. note).

	4. Draws another picture into the offscreen port using those 
	   same colors.

	5. Copies the offscreen picture to the screen.

  I have used both copybits, and the palette manager successfully,
  but trying to maintain the palette colors across the copybits
  call does not seem to work. 

  I have tried various palette/CTab configurations. It seems the color 
  manager steps in and tries to match the colors.  The palette colors
  are animating colors, though the animation "information" is lost in
  the copybits ( or not present in the offscreen port).

  One must be able to save animation information because the area under
  pull down menus is restored correctly.

  I would appreciate any suggestions on how to do offscreen drawing, and
  copybits while using the palette manager routines.  E-Mail is preferred,
  though posting is OK.

  Thanks,

  J. Lanham				jenlan@eos.arc.nasa.gov