rotating an NSString

In article
,
"Seward S." wrote:

> I am interested in rotating an NSString 90 degrees, in order to
> display a label on a graph's vertical axis. I'm sure there is an easy
> way to do this in Cocoa, but have not been able to figure it out. Can
> someone point me in the right direction? Thanks.

#import <Cocoa/Cocoa.h>

@interface RotatedView : NSView
{
}
@end

@implementation RotatedView

- (id)initWithFrame:(NSRect)frameRect {
if ((self = [super initWithFrame:frameRect]) != nil) {
// Add initialization code here
}
return self;
}

// example of drawing text at an angle.
- (void)drawRect:(NSRect)rect {
NSAffineTransform *t = [NSAffineTransform transform];
[t translateXBy:200. yBy:200.];
[t rotateByDegrees:40.]; // <-- or 90.
[t translateXBy:-200. yBy:-200.];
[t set];
[@"Hello World" drawAtPoint:NSMakePoint(100., 100.)
withAttributes:nil];
[[NSAffineTransform transform] set];
}

@end
 >> Stay informed about: rotating an NSString 

In article ,
David Phillip Oster wrote:

> In article
> ,
> "Seward S." wrote:
>
> > I am interested in rotating an NSString 90 degrees, in order to
> > display a label on a graph's vertical axis. I'm sure there is an easy
> > way to do this in Cocoa, but have not been able to figure it out. Can
> > someone point me in the right direction? Thanks.
>
> #import <Cocoa/Cocoa.h>
>
> @interface RotatedView : NSView
> {
> }
> @end
>
> @implementation RotatedView
>
> - (id)initWithFrame:(NSRect)frameRect {
> if ((self = [super initWithFrame:frameRect]) != nil) {
> // Add initialization code here
> }
> return self;
> }
>
> // example of drawing text at an angle.
> - (void)drawRect:(NSRect)rect {
> NSAffineTransform *t = [NSAffineTransform transform];
> [t translateXBy:200. yBy:200.];
> [t rotateByDegrees:40.]; // <-- or 90.
> [t translateXBy:-200. yBy:-200.];
> [t set];

Doing a "set" of the transform is potentially dangerous (since if the
superview has some special transform, you'll loose it). From the
documentation:

You should use this method sparingly because it removes the existing
transformation matrix, which is an accumulation of transformation
matrices for the screen, window, and any superviews. Instead use the
concat method to add this transformation matrix to the current
transformation matrix.


Instead:

[NSGraphicsContext saveGraphicsState];
[t concat];

> [@"Hello World" drawAtPoint:NSMakePoint(100., 100.)
> withAttributes:nil];
> [[NSAffineTransform transform] set];

[NSGraphicsContext restoreGraphicsState];

> }
>
> @end
 >> Stay informed about: rotating an NSString