IOS development (85) Scaling Images

1 Preface
Use the CGAffineTransformMakeScale/CGContextScaleCTM function to create an auto scaling transform.

2. code example
ZYViewControllerView. m

 

[Plain]
-(Void) drawRect :( CGRect) rect {
CGMutablePathRef path = CGPathCreateMutable ();
CGRect rectangle = CGRectMake (10.0f, 10.0f, 200366f,
300366f );
// Scale the rectangle by 0.5
CGAffineTransform transform = CGAffineTransformMakeScale (0.5f, 0.5f );
/* Add the rectangle to the path */
CGPathAddRect (path, & transform, rectangle );
/* Get the handle to the current context */
CGContextRef currentContext = UIGraphicsGetCurrentContext ();
/* Add the path to the context */
CGContextAddPath (currentContext, path );
/* Set the fill color to cornflower blue */
[[UIColor colorWithRed: 0.20f green: 0.60f blue: 0.80f alpha: 1.0f] setFill];
/* Set the stroke color to brown */
[[UIColor brownColor] setStroke];
/* Set the line width (for the stroke) to 5 */
CGContextSetLineWidth (currentContext, 5.0f );
/* Stroke and fill the path on the context */
CGContextDrawPath (currentContext, kCGPathFillStroke );
/* Dispose of the path */
CGPathRelease (path );
}