(Also, again for others following along, on 10.6 you just pass YES for respectFlipped in -[NSImage drawInRect:fromRect:operation:fraction:respectFlipped:hints:]. The implementation is quite similar to the method Paul gives in the post.)
On Thu, May 27, 2010 at 11:17 PM, Ken Ferry <kenfe...@gmail.com> wrote: > Did you read the explanation of flipped contexts vs flipped images, and how > to draw an image right side up into a flipped context? > > Flipped contexts are not deprecated. > > Do you have or can you obtain access to the 2007 WWDC videos? :-) > > -Ken > > > On Thu, May 27, 2010 at 11:11 PM, Graham Cox <graham....@bigpond.com>wrote: > >> Thanks for the link Ken, though confusion still persists. >> >> Seems to be saying don't use -setFlipped: unless you really know what >> you're doing. That concurs with your own advice about not using setFlipped >> unless you're locking focus on the image to get a flipped context for >> drawing. I'm not, since I generate my PDF in a context I create for the >> purpose, THEN add the image rep to an image. >> >> So on the basis that I don't know what I'm doing, I've removed all calls >> to [NSImage setFlipped:] anywhere. In the PDF generating code quoted, I do >> pass YES for flipped because the object itself expects a flipped coordinate >> system, by which I simply mean that when I draw something BELOW something >> else, it has a GREATER Y coordinate value. >> >> Having no flipping anywhere now, unfortunately it's still all over the >> place. >> >> First, if I ask the NSPDFImageRep created using the data generated below >> for its -PDFRepresentation, and write it to disk as a PDF file, it's now >> inverted. Objects are placed in the correct positions relative to >> one-another, but the entire image is upside-down, including any text. >> >> So, I try setting the image to flipped when I add the single PDF image rep >> to it: >> >> NSPDFImageRep* rep = [NSPDFImageRep imageRepWithData:[self >> pdf]]; >> [image addRepresentation:rep]; >> [image setFlipped:YES]; >> >> Now this image appears right-side up in NSImageView, but still writes an >> inverted PDF file and comes into Preview inverted. I can't really see how >> this is possible, since raw PDF data doesn't have any concept of 'flipped', >> does it? That surely means that the original PDF generation is wrong, but if >> I pass NO for flipped, not only is everything still upside-down but text is >> screwed as well, with each glyph individually inverted (which means that if >> the whole image is turned right-way up, any text is inverted). >> >> I've read all the documentation on flipped coordinates and now the blog >> post as well. I'm afraid I'm just as confused as ever. What I need is a >> clear way through this mess. Turning off all flippedness seemed to be that >> but isn't. Now I have no idea what I need to flip and when. >> >> --Graham >> >> >> >> On 28/05/2010, at 3:20 PM, Ken Ferry wrote: >> >> > On Thu, May 27, 2010 at 8:40 PM, Graham Cox <graham....@bigpond.com> >> wrote: >> >> > 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; >> > >> > >> > 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 >> >> > _______________________________________________ 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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