Re: Save/Restore a Context

[Adam Fedor]

Fred Kiefer wrote:

> As far as I can see the changes that Georg Fleischmann did do to support 
> the saving and restoring of a graphic context are no longer used by the 
> gui library, is there still a reason to keep this methods and all the 
> overhead they cause for a xgps context? Or to ask the other way round: 
> Is this a concept we should support in princible for DPS?


Well the short answer is no. After an initial reading of the NSView 
-lockFocus documentation, I thought it was necessary, but after A LOT of 
thinking I realized this didn't make sense.

There isn't really a need to use save/restore except in programs that 
are heavily PostScript dependant. You might use save/restore when 
displaying an EPS file, for instance.

> And there is another concept I did not fully understand.That of the 
> viewclip, we have this on the XGContext, where as all other state is on 
> XGGState. Waht is the reasoning behind this and when should the clipview 
> be applied to the XGGState. This is currently only done when restoring a 
>  Context, shouldn't we do it when doing a DPSGrestore?


This is another concept I thought I needed in NSView (it's use was also 
recommended in Programming DPS with X) and realized later it wasn't 
really needed (It's sort of a safty clip rect that's not altered by the 
normal clipping operations, but any program that wanted to be malicious 
about the clip rect, could just as easily alter the viewclip).




--
Adam Fedor, Digital Optics Corp.      | I'm glad I hate spinach, because
http://www.doc.com                    | if I didn't, I'd eat it, and you
                                      | know how I hate the stuff.