NSImage is making me lose what's left of my hair.

FROM : Michael Heinz
DATE : Wed May 11 14:32:11 2005

My original code using Quartz to render a PDF into a jpeg supported rotations but couldn't zoom in. Thanks to Sven Hoffman, I can now zoom in by using NSImage directly, but now I get a bizarre result when I try to rotate. I've already searched through the list archives, but I can't find anyone whose seen quite this issue:

1. I have a source image, say 240x320.
2. I create a target image, 320x240.
3. I create the NSAffine transform with the translations and rotations as I found in various items in this mail list.
4. Checking with the debugger, the resulting target image is still 320x240.
5. I create a bitmap representation using initWithFocusedViewRect.

6. The size of the resulting image is 240x240?!?

The worst part is that the resulting image isn't cropped, it's *squashed* - it's been scaled down in the longer direction.

The first, obvious, possibility is that rotations require square images, but I didn't see that documented anywhere. Can anyone shed any light on this problem?

Here's the relevant code fragment:

   bmpRect = NSMakeRect(0.0,0.0,bmpSize.width,bmpSize.height);
   
   if (pdfFileOrientation == PDFFilePortrait) {
       docRect = bmpRect;
   } else {
       docRect = NSMakeRect(0.0,0.0,bmpSize.height,bmpSize.width);
   }
   
   [bmpImage lockFocus];
       
   if (landscapeMode) {
       [rot set];
   }
       
   NSBezierPath *bp = [NSBezierPath bezierPathWithRect:bmpRect];
   [[NSColor whiteColor] set];
   [bp fill];
   [document drawInRect:bmpRect
               fromRect:docRect
               operation:NSCompositeSourceOver
               fraction:1.0];
   
   NSBitmapImageRep *bitmap = [[NSBitmapImageRep alloc] initWithFocusedViewRect:bmpRect];    
   [bmpImage unlockFocus];
   
   NSData *jpeg = [[bitmap representationUsingType:NSJPEGFileType properties:dict] retain];
   
   [bitmap release];