I have a simple Obj C program that, at the moment, lets you load an image, draws it up, and theoretically should let you zoom and rotate. I'm using NSAffineTranslations.
I want the image to be locked to the upper left (As opposed to the PS/PDF standard of lower left), so I'm using isFlipped, and calling [afTrans scaleXBy:1.0 yBy:-1.0];
The problem is that for some reason, after the first time my drawRect is called, the transformation doesn't happen.
When I load an image, it comes up, and looks correct. If I change the size of the window (Which calls drawRect), the image draws, but is upside-down and reversed. This means that the transformation didn't take effect. I don't see any differences in any of the data the 2nd time through.
here is a stripped down version of the code:
- (void)drawRect:(NSRect)rect
{
// Drawing code here.
// NSLog(@"window type: %d", [[self window] backingType]);
NSAffineTransform *afTrans = [[NSAffineTransform alloc] init];
NSGraphicsContext *context = [NSGraphicsContext currentContext];
NSSize sz;
NSRect windowFrame = [[self window] frame];
NSRect cv =[[[self window] contentView] frame];
float deltaX, deltaY;
NSSize superSize = [[self superview] frame].size;
float height, width, sHeight, sWidth;
NSRect imageRect;
sz = [ image size];
imageRect.size = sz;
imageRect.origin = NSZeroPoint;
height = sz.height ;
width = sz.width ;
// sHeight and sWidth are the hieght and with of the super-view. ie,
// the size of the whole window view including the space for the
// scroll bars, etc, but not including the panel or the borders,
sHeight = superSize.height;
sWidth = superSize.width;
[context saveGraphicsState];
deltaX = 0;
deltaY = 0;
deltaY += height; // account for flipping
[afTrans translateXBy:deltaX yBy:deltaY];
[afTrans scaleXBy:1.0 yBy:-1.0];
[afTrans concat];
NSRect drawingRect = imageRect;
NSRect frame = imageRect;
[self setFrame:frame];
[image drawInRect:drawingRect
fromRect:imageRect
operation:NSCompositeSourceOver
fraction:1];
[afTrans release];
[context restoreGraphicsState];
}
ETA: here's some more code that MIGHT be relevant.
-(void )setImage:( NSImage * )newImage
{
[newImage retain];
[image release];
rotation = 0;
zoom = 1.0;
image = newImage;
NSSize imageSize = [newImage size];
NSRect tFrame = [self frame];
tFrame = [[self window] frame];
tFrame.size.width = MAX(tFrame.size.width, imageSize.width);
tFrame.size.height = MAX(tFrame.size.height, imageSize.height);
[self setFrame:tFrame];
[self setNeedsDisplay:YES];
}