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. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
