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This provides some useful methods you can use if you want to make a PICT object in Cocoa.

My app draws a nice image, incorporating NSBezierPaths and NSAttributedStrings. I’d now like to copy it via the Pasteboard into Canvas 9 (a commercial graphics app). It’s easy to put the data in TIFF, PDF and EPS format onto the general pasteboard. The problem with this is that Canvas seems to interpret these as bitmapped images, not as vector graphics objects. Going the other way, I note that Canvas copies vector graphics objects onto the Pasteboard as NSPICTPboardType; I therefore conclude that I need to make a representation of my image as type PICT. I’ve read quite a few discussions about this, and I understand that there’s no way of doing a simple conversion from PDF to PICT in Cocoa (why not? - the information should all be there in PDF format - if Apple won’t provide it, has anyone else written a converter?).

So I would like to recreate my image as a PICT file, but I can’t seem to do it. I’m happy to use the simple QuickDraw commands if I must (MoveTo, LineTo etc), but my only real experience of Mac programming is in Cocoa (I love Objective C) and in comparison Carbon looks horrendously baroque, and so I’d like to do it as much as possible in Cocoa. I’ve looked at two approaches:

  1. Use QuickDraw commands inside an NSQuickDrawView. But how do I get the PICT data out again? I can get it out as PDF or EPS (dataWithEPSInsideRect and dataWithPDFInsideRect), but I can’t see an option for just getting the PICT data.

  2. Draw into a NSPICTImageRep. But here I’m getting really unstuck. It seems to me that NSPICTImageRep is designed for accessing pre-existing PICT images. The initialiser wants data; all I can do is give it nil. So I tried the following: NSPICTImageRep* theImageRep = [[NSPICTImageRep alloc] initWithData:nil]; [theImageRep setPixelsHigh:100]; [theImageRep setPixelsWide:100]; NSImage* theImage=[[NSImage alloc] initWithSize:(NSSize){100,100}]; [theImage addRepresentation:theImageRep]; [theImage lockFocus]; // do some QuickDraw drawing [theImage unlockFocus];

However, when I try to lockFocus, I get the error message: “Can’t cache image”.

Am I doing something silly, or is it really the case that Cocoa won’t let me generate PICT data?

Any help gratefully received,

JulianBlow

I’m sorry that my post cannot be of help, but I would like to congratulate you on a beautiful post. Too many people post and just ask for code with out really explaining what they are trying to do, or what they have tried up until that point. You on the other hand have come to the table with a good amount of information about your problem, and what you have tried. Good Job.

Have you tried instead to initWithData:[NSData data]] (empty data). Maybe it does not like nil very much…

[NSData data] gives the same error as nil, I’m afraid. I’ve also tried using NSPICTImageRep’s setSize: method to force it to contain something, and still no joy. It seems the NSPICTImageRep is being established properly - it’s being set to a non-NULL value, and records the size I set it. But I can’t fool NSImage that it isn’t just an empty container….

Since I got no replies, I presumed it wasn’t possible, and delved into the baroque badness that is Carbon. It’s not so hard to do, but in case anyone else encounters this problem, I show here my Objective-C class that does it all for you. It simply wraps a few Carbon calls into a tolerably Cocoa-like class;

#import <Cocoa/Cocoa.h> #import <Carbon/Carbon.h>

@interface JBPICTCreator : NSObject { NSSize theSize; PicHandle thePictHandle; }

@implementation JBPICTCreator

@end

You have to do your drawing with QuickDraw calls though, like this: JBPICTCreator* thePICT=[JBPICTCreator JBPICTCreatorWithSize:(NSSize){200,200}]; [thePICT lockFocus]; // do some QuickDraw drawing here [thePICT unlockFocus]; NSData* thePICTData = [thePICT PICTRepresentation];

JulianBlow

I seem to be performing a monologue, but on the offchance that someone else is listening, here’s the latest development in my attempts to make Cocoa more friendly for creating PICT data. Having got a Cocoa object that allows you to record QuickDraw drawing (JBPICTCreator), I wanted a way of doing the drawing without having to re-write all my existing Cocoa routines. So I created a category of NSBezierPath, (called the QuickDrawAddition category). This declares a fillUsingQuickDraw… method and a strokeUsingQuickDraw… method, to fill and stroke the NSBezierPath using QuickDraw commands.

#import <Cocoa/Cocoa.h> #import <Carbon/Carbon.h>

@interface NSBezierPath (QuickDrawAddition) -(void) fillUsingQuickDrawWithViewHeight:(int)theViewHeight; -(void) strokeUsingQuickDrawWithViewHeight:(int)theViewHeight asSeparatePICTObjects:(BOOL)separateObjects; -(void) quickDrawWithViewHeight:(int)theViewHeight stroke:(BOOL)withStroke fill:(BOOL)withFill asSeparatePICTObjects:(BOOL)separateObjects; @end

@implementation NSBezierPath (QuickDrawAddition)

// =========================================================== // fillUsingQuickDrawWithViewHeight: // =========================================================== // Fills the contents of the NSBezierPath using QuickDraw commands. // This is a convenience method that calls // quickDrawWithViewHeight:stroke:fill:asSeparatePICTObjects: with stroke NO, // fill YES, and asSeparatePICTObjects as NO. -(void) fillUsingQuickDrawWithViewHeight:(int)theViewHeight { [self quickDrawWithViewHeight:theViewHeight stroke:NO fill:YES asSeparatePICTObjects:NO]; }

// ============================================================ // strokeUsingQuickDrawWithViewHeight:asSeparatePICTObjects: // ============================================================ // Strokes the contents of the NSBezierPath using QuickDraw commands. // asSeparatePICTObjects determines whether line segments are grouped into polygons, // each terminated by a closePath element. // This is a convenience method that calls // quickDrawWithViewHeight:stroke:fill:asSeparatePICTObjects: with stroke NO, // and fill NO. -(void) strokeUsingQuickDrawWithViewHeight:(int)theViewHeight asSeparatePICTObjects:(BOOL)separateObjects { [self quickDrawWithViewHeight:theViewHeight stroke:YES fill:NO asSeparatePICTObjects:separateObjects]; }

// =========================================================== // quickDrawWithViewHeight:stroke:fill:asSeparatePICTObjects: // =========================================================== // Draws the contents of the NSBezierPath using QuickDraw commands. If withStroke, // the resultant path is stroked; if withFill the resultant path is filled. // If asSeparatePICTObjects is true, each segment of the path is drawn as a separate PICT // object, so polygons are not built up. Otherwise, the closePath method of NSBezierPath // is used to determine where one polygon ends and another begins. // Because QuickDraw views are vertically flipped, it is necessary to know the // vertical height of the view the NSBezierPath is being drawn into. // The pen width is set in the current NSBezierPath. // All other drawing attributes have to be set outside this method. -(void) quickDrawWithViewHeight:(int)theViewHeight stroke:(BOOL)withStroke fill:(BOOL)withFill asSeparatePICTObjects:(BOOL)separateObjects { NSPoint associatedPts[3]; NSPoint startPolyPt; NSPoint currentPt=NSMakePoint(0.0,0.0); // in case no initial moveToPoint int j; BOOL drawingAPoly=NO; PolyHandle aPoly; PenSize([self lineWidth],[self lineWidth]); NSBezierPath* newBP = [self bezierPathByFlatteningPath]; // QD can’t do Bezier curves int elementCount=[newBP elementCount];

for(j=0;j<elementCount;j++) {
switch ([newBP elementAtIndex:j associatedPoints:associatedPts]) {
    case NSMoveToBezierPathElement:
	MoveTo(associatedPts[0].x,theViewHeight-associatedPts[0].y);
	currentPt=associatedPts[0];
	break;
    case NSLineToBezierPathElement:
	if(!drawingAPoly) {                      // here's the start of a new poly
	    drawingAPoly=YES;
	    startPolyPt=currentPt;
	    if(!separateObjects) aPoly=OpenPoly();
	    }
	LineTo(associatedPts[0].x,theViewHeight-associatedPts[0].y);
	currentPt=associatedPts[0];
	break;
    case NSCurveToBezierPathElement: // flat path - these shouldn't exist
	break;
    case NSClosePathBezierPathElement:
	if(drawingAPoly) {
	    LineTo(startPolyPt.x,theViewHeight-startPolyPt.y);
	    drawingAPoly=NO;
	    if(!separateObjects) {
		ClosePoly();
		if(withStroke) FramePoly(aPoly);
		if(withFill) PaintPoly(aPoly);
		KillPoly(aPoly);
		}
	    }
	currentPt=startPolyPt;
	break;
    }
}

if(drawingAPoly&&!separateObjects) {    // if polygon left open
ClosePoly();
if(withStroke) FramePoly(aPoly);
if(withFill) PaintPoly(aPoly);
KillPoly(aPoly);
}
} @end

JulianBlow, 28th October 2004

Yes, this is a monologue (well, not anymore), but no, you are not alone. Thanks for that page!! In case I ever need some QuickDraw stuff, I know where to start :-) –CharlesParnot

In Tiger you can use this command to convert an image to PICT:

sips –setProperty format pict --out output.pict

// from http://www.cocoabuilder.com/archive/message/cocoa/2003/7/23/82391 #import <QuickTime/QuickTime.h>

[…]

Michel Vaillant, June 2006

This doesn’t work for me using 10.4.10. The function GraphicsImportGetAsPicture() is unrelible, working some times and other times it returns error -8969 codecBadDataErr - Billy Bob 10/8/07 —-

Very interesting page, after spending many hours on cocoa’s docs, this pages lerned me much more on the question, and resolved me the issue. Thanks, Michel Vaillant

Yes I have had a similar problem but how do you get a PICT with alpha into an NSImage, retaining the alpha, carryout some modification then return the NSImage as a PICT but still containing the alpha.

Any one got any ideas it has been bugging me for days without a solution in sight.

Where are you getting PICT data with alpha? AFAICR, PICT nor QuickDraw support the concept of alpha, let alone implement it. I believe CopyBits will preserve anything in the unused bits of a direct pixel, which is where the alpha shows up, but it doesn’t use this data when rendering to give transparency effects. You might be able to split out that “channel” as a separate bitMap/pixMap which you could use as the mask parameter to CopyDeepMask, which would get you a little way, but since CopyDeepMask isn’t saved in PICTs, it may not help. It may also be that when recording CopyBits in a PICT, the “alpha” channel is simply discarded to save space - this would be reasonable for QuickDraw since for it, these are just unused bits. The only other way to support alpha in a PICT would be to roll your own in PicComments, but since it would be non-standard it’s probably not a useful route except in your own apps. Unless some alpha magic has been added to QuickDraw in the last few years that I don’t know about, I think you’ll find that it’s simply not possible. Use TIFF or PDF instead. –GrahamCox —- Graham I am writing an external for SuperCard. When I obtain the PICT data from SC and pass it into NSImage then manipulate the image the alpha is lost when I pass it back to SC.

However if I use a call to SIPS and either make a PICT with the data from SC or a TIFF the alpha is retained.

If I export the PICT data from SC as a PICT file then open that file with Preview it has alpha. Preview in it’s info box says it has alpha.

I have read in other places that PICT does not support alpha.

Terry Heaford

I googled around and it looks as if there is a way for PICT to support alpha, when it’s embedding a QuickTime compressed image. In this case, the PICT file format is really just acting as a container for the QT image data - sort of a ‘black box’ inside a black box. Provided you use the QT routines to read and write this PICT, alpha is supported. So I would guess that the answer to your question may lie in the QTKit - I haven’t looked but it might include methods for importing and exporting between a QT PICT and NSImage. –GrahamCox

It is also possible to specify a clipping mask or clipping region in a PICT. Many old DTP packages used this technique for EPS files with PICT screen previews. (I used to have lots of code which worked with these PICTs but I’m afraid it is all horribly obsolete at this point in time.)

Here’s yet another way to get PICT data from an NSImage (from my NSImage category, which you can get here: www.eternalstorms.at/developers/):

NSImage myImage = [NSImage imageNamed:@”someImage.png”]; NSPasteboard *pb = [NSPasteboard pasteboardWithName:@”essimagecategory”]; [pb types]; [pb declareTypes:[NSArray arrayWithObject:NSTIFFPboardType] owner:nil]; [pb setData:[myImage TIFFRepresentation] forType:NSTIFFPboardType]; NSData *pictData = pb dataForType:[[NSPICTPboardType] retain]; [pboard releaseGlobally]; / do something with the data here */ [pictData release];

Hope this helps. Take care,

–MatthiasGansrigler