🚀 go-pugleaf

I need a way to set the GDevice color lookup table (clut) with a specific
clut.  I would like a friendly way.  Here's what I do now:

setclut(object)
	objectptr	object;
{
	GDHandle	gdev;
	
	if (object->window==FrontWindow()) {
	gdev=GetGDevice();
	HLock(object->clut);
	SetEntries(0,(*(object->clut))->ctSize,&((*(object->clut))->ctTable));
	(*(*(*gdev)->gdPMap)->pmTable)->ctSeed=(*(object->clut))->ctSeed;
	HUnlock(object->clut);
	}
}

object is just a data structure containing, among other things, a WindowPtr
(object->window) and a Detached clut resource (object->clut).  Note that,
in the above, I also set the Gdevice's ctSeed to match the clut, so that
it won't try to remap all the pixels.

Note also that I am working with Color PixMaps:  RGBForeColor and RGBBackColor
have no meaning here, and I must have the GDevice clut match the PixMap
clut exactly, in order.

The problem with this technique is that it:
	1.  Isn't very friendly (according to IM-V)
	2.  Doesn't set any GDevice clut beyond this MainDevice's.

I can traverse the GDevice list myself, and check for intersections of
GDRects with the content region of the window:

setclut(object)
	objectptr	object;
{
	GDHandle	gdev;
	GDHandle	save;
	
	if (object->window==FrontWindow()) {
		save=GetGDevice();
		gdev=GetMainDevice();
		while (gdev) {
			HLock(gdev);
			if (RectInRgn(&((*gdev)->gdRect),
			((WindowPeek) object->window)->contRgn)) {
				HUnlock(gdev);
				SetGDevice(gdev);
				HLock(object->clut);
				SetEntries(0,(*(object->clut))->ctSize,
					&((*(object->clut))->ctTable));
				(*(*(*gdev)->gdPMap)->pmTable)->ctSeed=
					(*(object->clut))->ctSeed;
				HUnlock(object->clut);
				}
			HUnlock(gdev);
			gdev=GetNextDevice(gdev);
			}
		SetGDevice(save);
		}
	}

For some reason this only finds one GDevice (the main one).  A SysBeep
placed after the while rings once.  Can anyone give me a hint as to why?

I thought the Palette Manager pmExplicit mode would do what I want (and it
would do this traversal for me):  it did not.  It didn't seem to do anything.
What is pmExplicit for?

Setting an exact color map is a common need:  ImageStudio and PixelPaint
both have to do this, and both only work on the MainDevice.  I would like
to work on all attached screens, setting cluts as needed by window positions.
It's not uncommon for me to need to have an 8-bit all grey clut on one
screen and a 4-bit all grey clut on another, and I'd like them all to update
the GDevice cluts so I get perfect colors (grays).  The code above would
do that if it worked (I suppose one could say that about any code...)

Thanks in Advance.

-Eric
                      (defun maybe (x) (maybe (not x)))
Eric K. Olson     olson@endor.harvard.edu     harvard!endor!olson     D0760
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