Easiest way to display a rotated NSString?

Question

Level 1

35 points

Easiest way to display a rotated NSString?

Is there an easy way to rotate and display an NSString?

I'm currently using the following to draw on screen but would like to rotate (either +90 or -90 degrees):


UIFont *smallFont = [UIFont systemFontOfSize:8];
CGPoint textPoint = CGPointMake(10, 10);
[[NSString stringWithString:@"MY STRING"] drawAtPoint:textPoint withFont:smallFont];

I know another option would be to use UILabels and CATransform3D but I can't seem to clear teh screen when calling:


[self setNeedsDisplay];

therefore it just gets messy with text displaying over text. I was using the following:


UIFont *smallFont = [UIFont systemFontOfSize:8];
UILabel *myLabel = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, 120, 50)];
myLabel.font = smallFont;
myLabel.text = [NSString stringWithString:@"MY STRING"];
myLabel.textColor = [UIColor blackColor];
myLabel.backgroundColor = [UIColor clearColor];
myLabel.textAlignment = UITextAlignmentCenter;
CATransform3D landscapeTransform = CATransform3DIdentity;
landscapeTransform = CATransform3DRotate(landscapeTransform, DegreesToRadians(-90), 0, 0, 1);
myLabel.layer.transform = landscapeTransform;
[self addSubview:myLabel];
[myLabel release];

Thanks

iMac, Mac OS X (10.5.4), N/A

Posted on Aug 14, 2008 11:01 AM

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Answer 1

RJShearman Author

Level 1

35 points

Aug 15, 2008 1:43 AM in response to RJShearman

I've managed to get text displayed using CGContextShowTextAtPoint but the problem is the text is upside down.

I can fix the upside down text by doing the following:


CGContextSelectFont (context, "Helvetica", 60, kCGEncodingMacRoman);
CGContextSetCharacterSpacing (context, 10);
CGContextSetTextDrawingMode (context, kCGTextFill);
CGContextSetGrayFillColor(context, 0.0, 1.0);
CGContextSetTextMatrix(context, CGAffineTransformScale( CGAffineTransformIdentity, 1.f, -1.f ) ); // flip
CGContextShowTextAtPoint (context, 100, 200, "Quartz 2D", 9);

I can rotate the text by doing the following:


CGFloat DegreesToRadiansText(CGFloat degrees) {return degrees * M_PI / 180;};
CGContextSelectFont (context, "Helvetica", 60, kCGEncodingMacRoman);
CGContextSetCharacterSpacing (context, 10);
CGContextSetTextDrawingMode (context, kCGTextFill);
CGContextSetGrayFillColor(context, 0.0, 1.0);
CGAffineTransform myTextTransform = CGAffineTransformMakeRotation (DegreesToRadiansText (-90)); // rotate
CGContextSetTextMatrix (context, myTextTransform); // rotate
CGContextShowTextAtPoint (context, 100, 200, "Quartz 2D", 9);

But I can't seem to be able to flip the text AND rotate it before displaying on screen.

Can anyone see what i'm missing?

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Answer 2

RJShearman Author

Level 1

35 points

Aug 15, 2008 4:24 AM in response to RJShearman

Working.

If interested:


CGFloat DegreesToRadiansText(CGFloat degrees) {return degrees * M_PI / 180;};
 
CGContextSelectFont (context, "Helvetica", 60, kCGEncodingMacRoman);
CGContextSetCharacterSpacing (context, 10);
CGContextSetTextDrawingMode (context, kCGTextFill);
CGContextSetGrayFillColor(context, 0.0, 1.0);
CGAffineTransform myTextTransform = CGAffineTransformRotate(CGAffineTransformScale(CGAffineTransformIdentity, 1.f, -1.f ),(DegreesToRadiansText (-90));
CGContextSetTextMatrix (context, myTextTransform);
CGContextShowTextAtPoint (context, 100, 200, "Quartz 2D", 9);

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