Re: Printing with xlib & art backend

[Riccardo Mottola]

Hi,

Fred Kiefer wrote:
> I most admit that I don't fully understand the issue here. We never 
> supported GSDefineGState in GSStreamContext and this would have always 
> resulted in an exception when called. Which is one of the known 
> limitation of that code and a reason why we have to drop support for 
> all these backends in the near future.
Right, I'm still investigating, my intention was not to blame Eric at 
all, sorry if it got understood that way.
I see two things:
Eric provided a "new" and an "old" code path, where the old codepath 
composites inside an off-screen windows.
The old-style function, brought from NSImage to NSImageRep was though 
updated and the DPS which requires gState.
What I do not fully understand is why it works for screen and not for 
printing.
> Eric's change should, as far as I see only call GSDefineGState if the 
> context has supportsDrawingGState return YES. Which should only be 
> true for the cairo and the windows backend. I don't see how you should 
> ever end up there for the art or xlib backend. Could you please 
> provide me with a back trace of the stack, when this happens?
That part of code is however unchecked, from what I can understand. I 
tried adding "supportsDrawingGState" before GSDefineGState and 
GSUndefineGState, but then screen rendering gets broken too (well, there 
is no gState for the DPS function).


here the relevant part of the trace:


#2  0x02e9b973 in +[NSException raise:format:] (self=0x22e48e60,
    _cmd=0x22eb81e0, name=0x22e49100, format=0x22eb8270) at 
NSException.m:838
#3  0x03009963 in -[NSObject(GNUstepBase) notImplemented:] 
(self=0x7ffc8084,
    _cmd=0x29e79c38, aSel=0x24fea178) at NSObject+GNUstepBase.m:97
#4  0x09e8e7df in -[GSStreamContext(Ops) GSDefineGState] (self=0x7ffc8084,
    _cmd=0x24fea178) at GSStreamContext.m:365
#5  0x050fa0b4 in -[NSImageRep guiDrawInRect:fromRect:operation:fraction:] (
    self=0x83689f84, _cmd=0x24fea210, dstRect=
        {origin = {x = 0, y = 0}, size = {width = 800, height = 834}}, 
srcRect=
        {origin = {x = 0, y = 0}, size = {width = 800, height = 834}}, 
op=2,
    delta=1) at NSImageRep.m:746
#6  0x050f8fd2 in -[NSImageRep 
drawInRect:fromRect:operation:fraction:respectFlipped:hints:] 
(self=0x83689f84, _cmd=0x24fe7768, dstRect=
        {origin = {x = 0, y = 0}, size = {width = 800, height = 834}}, 
srcRect=
        {origin = {x = 0, y = 0}, size = {width = 800, height = 834}}, 
op=2,
    delta=1, respectFlipped=1 '\001', hints=0x0) at NSImageRep.m:847
#7  0x050f5f2a in -[NSImage 
drawInRect:fromRect:operation:fraction:respectFlipped:hints:] 
(self=0x86f59204, _cmd=0x24fe85b8, dstRect=
    srcRect={origin = {x = 0, y = 0}, size = {width = 800, height = 834}},
    op=2, delta=1, respectFlipped=Variable "respectFlipped" is not 
available.
) at NSImage.m:916
#8  0x050f6d9d in -[NSImageCell drawInteriorWithFrame:inView:] (
    self=0x7eb92084, _cmd=0x24fba1e8, cellFrame=
        {origin = {x = 0, y = 0}, size = {width = 800, height = 834}},
    controlView=0x849f5504) at NSImageCell.m:258
#9  0x05089022 in -[NSCell drawWithFrame:inView:] (self=0x7eb92084,
    _cmd=0x24fcadd8, cellFrame=
        {origin = {x = 0, y = 0}, size = {width = 800, height = 834}},
    controlView=0x849f5504) at NSCell.m:2067
#10 0x050b36d6 in -[NSControl drawCell:] (self=0x849f5504, _cmd=0x24fcadd0,
    aCell=0x7eb92084) at NSControl.m:685
#11 0x050b3722 in -[NSControl drawRect:] (self=0x849f5504, _cmd=0x2504fa88,
    aRect={origin = {x = 0, y = 0}, size = {width = 540, height = 648}})
    at NSControl.m:675
#12 0x051f2090 in -[NSView displayRectIgnoringOpacity:inContext:] (
    self=0x849f5504, _cmd=0x25010480, aRect=
        {origin = {x = 0, y = 0}, size = {width = 540, height = 648}},
    context=0x7ffc8084) at NSView.m:2570
#13 0x05150285 in -[NSView(NSPrintOperation) 
_displayPageInRect:withInfo:knowsPageRange:] (self=0x849f5504, 
_cmd=0x25010400, pageRect=
        {origin = {x = 0, y = 0}, size = {width = 540, height = 648}}, 
info=
      {scaledBounds = {origin = {x = 0, y = 0}, size = {width = 800, 
height = 834}}, paperBounds = {origin = {x = 36, y = 72}, size = {width 
= 540, height = 648}}, sheetBounds = {origin = {x = 36, y = 72}, size = 
{width = 540, height = 648}}, paperSize = {width = 612, height = 792}, 
xpages = 1, ypages = 2, first = 1, last = 2, pageScale = 1, printScale = 
1, nupScale = 1, nup = 1, lastWidth = 540, lastHeight = 648, orient = 
NSPortraitOrientation, pageDirection = 0},
    knowsPageRange=0 '\0') at NSPrintOperation.m:1216
#14 0x05150fec in -[NSPrintOperation(TrulyPrivate) _print] 
(self=0x7f1b4904,
    _cmd=0x25010300) at NSPrintOperation.m:1065
#15 0x05151856 in -[NSPrintOperation(TrulyPrivate) _runOperation] (
    self=0x7f1b4904, _cmd=0x25010280) at NSPrintOperation.m:669
#16 0x0514de82 in -[NSPrintOperation runOperation] (self=0x7f1b4904,
    _cmd=0x2504fc80) at NSPrintOperation.m:516
#17 0x051e6e76 in -[NSView print:] (self=0x849f5504, _cmd=0x3c0036b8,
    sender=0x82fb8004) at NSView.m:3968
#18 0x1c0014e2 in -[AppController print:] (self=0x7eb80004, 
_cmd=0x849f1748,
    sender=0x82fb8004) at AppController.m:897
#19 0x0504b422 in -[NSApplication sendAction:to:from:] (self=0x87573804,
    _cmd=0x24ff7d90, aSelector=0x849f1748, aTarget=0x7eb80004,
    sender=0x82fb8004) at NSApplication.m:2230
#20 0x05119681 in -[NSMenu performActionForItemAtIndex:] (self=0x86043984,
    _cmd=0x24ffaaa0, index=7) at NSMenu.m:1320