On Thu, May 27, 2010 at 8:40 PM, Graham Cox <graham....@bigpond.com> wrote:
> Thanks Kyle, that seems to look like a fruitful approach. I'm doing the > following, which appears to be enough, i.e. it works. But should I be doing > anything else? > > > NSSize size = [self bounds].size; > NSRect destRect = NSZeroRect; > > destRect.size = size; > > NSMutableData* pdfData = [NSMutableData data]; > CGDataConsumerRef consumer = > CGDataConsumerCreateWithCFData((CFMutableDataRef) pdfData ); > CGRect mediaBox = CGRectMake( 0, 0, size.width, size.height ); > CGContextRef pdfContext = CGPDFContextCreate( consumer, &mediaBox, > NULL ); > CGDataConsumerRelease( consumer ); > > NSGraphicsContext* newGC = [NSGraphicsContext > graphicsContextWithGraphicsPort:pdfContext flipped:YES]; > [NSGraphicsContext saveGraphicsState]; > [NSGraphicsContext setCurrentContext:newGC]; > > CGPDFContextBeginPage( pdfContext, NULL ); > > [self drawContentInRect:destRect fromRect:NSZeroRect withStyle:nil]; > > CGPDFContextEndPage( pdfContext ); > > [NSGraphicsContext restoreGraphicsState]; > > CGPDFContextClose( pdfContext ); > CGContextRelease( pdfContext ); > > return pdfData; > > > This leads me on to a further question about correctly handling > flippedness, which quite honestly has me really confused. > > The objects I'm drawing generally assume a flipped context, i.e. my view is > flipped and so is my entire coordinate system all the way down. I have not > run into any problems with that anywhere, it all works fine. But when I come > to generate the PDF above, I do have some flipping confusion. > > I flip the context to match the expectation of the object itself. Thus text > draws relatively the right way up and in the right place. > > If I take that (flipped) PDF data, use it to create an NSPDFImageRep and > add it to an NSImage, should the image be flipped or not? (Bear in mind this > needs to work on 10.5, so the newer flipped stuff is unavailable to help > sort this confusion out). > Hi Graham, (First, for those following along, flipped images are deprecated in 10.6 along with -[NSImage setFlipped:].) I agree, flipped images are confusing, and you can more or less think of them as deprecated prior to 10.6 as well. This weblog post does a nice job of explaining what everything means and what to do about it: < http://www.noodlesoft.com/blog/2009/02/02/understanding-flipped-coordinate-systems/>. This material is also covered in depth in the WWDC 2007 talk, Cocoa Drawing Techniques. The only reason I can think of off the top of my head to call -setFlipped: on an NSImage is if you plan to lockFocus on the image and you want the context to be a flipped context during drawing. This use case is addressed in 10.6 by the addition of -[NSImage lockFocusFlipped:] which gives you a flipped context without doing anything to the internal state of the image. -Ken Cocoa Frameworks > If I take the resulting image and display it in a cell, what should the > cell do about flipping? For example, if I put the image into NSImageView, it > works correctly and displays right way up. If I write the image to disk it > is imported into Preview right way up. But I have a couple of custom cells > that draw images that show the image wrong way up. What are these cells > doing wrong that I'm not getting? Should they do anything - maybe just > leaving flippedness of the image alone rather than try an match it to the > control's context flippedness is right? I just don't know. I've tried all > combos I can think of and none of them quite nails it. > > --Graham > > > > > > > > On 28/05/2010, at 11:24 AM, Kyle Sluder wrote: > > > On May 27, 2010, at 6:20 PM, Graham Cox <graham....@bigpond.com> wrote: > > > >> Can I not create a PDF context, associate that with a NSPDFImageRep > instead? It appears I'm forced to use NSPrintOperation to do this which is > slightly weird as this has nothing to do with printing, nor do I have a view > readily available to attach to the NSPrintOperation. Surely there's a more > straightforward way than going round the houses like this? > > > > I believe we create a PDF CGContext, wrap it in an NSGraphicsVontext, and > use +setContext: to get our nice vectory goodness. > > > > But I'm going from memory here, and I didn't write that code. > > > > --Kyle Sluder > >> > > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/cocoa-dev/kenferry%40gmail.com > > This email sent to kenfe...@gmail.com > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. 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