[Drawkit] Changing margins does not shift drawing objects

[Brad Larson]

I just added the ability to resize the document workspace to our  
drawing client, and in our application I wanted the margins to scale  
as a percentage of the drawing working area.  I noticed that when the  
margins changed, the objects within the drawing did not shift to  
match, causing items that were drawn at the left edge of the working  
area to fall off the drawing and into the margins.

It seems like you'd want the objects to stay at their same relative  
positions in the drawing, and be shifted appropriately by the changing  
margins, but I'm not quite sure where in DrawKit you would handle  
this.  DKDrawableObjects are drawn by specifying their absolute Quartz  
position (using DKGrid's pointForGridLocation:), which includes the  
margin origin in the initial placement calculation.  You'd need to  
recalculate the Quartz positions of all objects using the difference  
between the old and new margins to move them properly.   
DKObjectOwnerLayers might handle this, by responding to the  
kDKDrawingWillChangeMargins and  kDKDrawingDidChangeMargins  
notifications and adjusting all their internal objects to match.

For now, I can do this manually, but it would be nice for this to be  
handled internally.

______________________
Brad Larson
SonoPlot, Inc.
3030 Laura Lane, Suite 120
Middleton, WI 53562