Re: Can't invoke gp functions on output panes

Dear Yuri,


Of what i know, on macosx since big sur  and LW8, all drawings to an output-pane should be donw from within the display-callback. On Linux and win it's always ok to do so. (see release notes LW8 (12.6)

Best
Karim

On Sun, Feb 02, 2025 at 03:31:45PM +0100, Yuri Davidovsky (as work at disclosure dot ie) wrote:
> I may be doing something wrong, but not sure what it could be. For some reason calling functions from the graphics-ports package does not seem to work on output panes on my machine. This is the boilerplate functionality that I have used many times before (although it has been a while since and it was on windows), but suddenly it is not working on macos. Have a look at a quick screencast I made (it may be difficult to believe otherwise):
> 
> https://www.disclosure.ie/public/draw-line.mp4
> 
> Basically, what happens is that I am trying to create an empty output pane in a fresh instance of LW, store it in a variable and then try to do something with it, like drawing a line. 
> 
> 
> CL-USER 5 > (setf a (capi:contain (make-instance 'capi:output-pane)))
> #<CAPI:OUTPUT-PANE  80101A14DB>
> 
> CL-USER 6 > (gp:draw-line a 0 0 100 100)
> 
> 
> At that stage it bales out with an error similar to 
> 
> 
> Error: Invoking a method "graphicsPort" on a null pointer.
>   1 (abort) Return to top loop level 0.
> 
> Type :b for backtrace or :c <option number> to proceed.
> Type :bug-form "<subject>" for a bug report template or :? for other options.
> 
> CL-USER 7 : 1 > :b
> Call to INVOKE-DEBUGGER
> Call to ERROR
> Call to OBJC::INVOKE-INTO*
> Call to GRAPHICS-PORTS::SET-GP-COCOA-NSCONTEXT
> Call to GRAPHICS-PORTS::ENSURE-GP-REPRESENTATION-CGCONTEXT
> Call to (METHOD GRAPHICS-PORTS::%LOAD-GRAPHICS-STATE-WITH-ARGS (GRAPHICS-PORTS::GP-COCOA-MIXIN T T T T))
> Call to GRAPHICS-PORTS:DRAW-LINE
> Call to EVAL
> Call to CAPI::CAPI-TOP-LEVEL-FUNCTION
> Call to CAPI::INTERACTIVE-PANE-TOP-LOOP
> Call to MP::PROCESS-SG-FUNCTION
> 
> 
> What could the problem be? It appears to happen with other gp functions too, like draw-text. Seems like it could be an issue with calling into the OS graphic shell library? The OS used is Sequoia 15.1.1 (24B91)
> 
> A strange part is that I also tried to load one of the capi examples 
> 
> (cached-display.lisp in "/Applications/LispWorks 8.0 (64-bit)/Library/lib/8-0-0-0/examples/capi/output-panes/cached-display.lisp”) 
> 
> and it worked fine, meaning it displayed a pane with a grid in the background and the arrow could be drawn in it when dragging the mouse, however when I tried to do the same with the pane that was created by this example code (meaning, drawing a line from the listener), it produced the same outcome as above. Very puzzling.
> 
> Any ideas?
> 

-- 
Karim Haddad

Music Representations Team, IRCAM
Research and development manager.
email	: [email protected]
webpage : http://karim.haddad.free.fr

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