ExampleCALayerDelegate.m
// |
// File: ExampleCALayerDelegate.m |
// |
// Abstract: A sample delegate for a CALayer that draws random content into the layer. |
// |
// Version: 1.0 |
// |
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#import "ExampleCALayerDelegate.h" |
@implementation ExampleCALayerDelegate |
static CGFloat randomFloat() |
{ |
CGFloat f = (rand() % RAND_MAX) / (float)(RAND_MAX); |
return f; |
} |
static CGPoint randomPointInBounds(CGRect bounds) |
{ |
CGFloat x = randomFloat() * bounds.size.width + bounds.origin.x; |
CGFloat y = randomFloat() * bounds.size.height + bounds.origin.y; |
return CGPointMake(x, y); |
} |
-(void)drawLayer:(CALayer *)layer inContext:(CGContextRef)context |
{ |
// We aren't interested in the actual content of this layer, we just want to draw something. |
// Towards that end, we'll fill the content with a random color, |
// then fill a randomly generated polygon. |
CGRect bounds = CGContextGetClipBoundingBox(context); |
CGContextSetRGBFillColor(context, randomFloat(), randomFloat(), randomFloat(), 1.0); |
CGContextFillRect(context, bounds); |
int sides = (random() % 18) + 1; |
CGPoint p = randomPointInBounds(bounds); |
CGContextMoveToPoint(context, p.x, p.y); |
for(int i = 0; i < sides; ++i) |
{ |
p = randomPointInBounds(bounds); |
CGContextAddLineToPoint(context, p.x, p.y); |
} |
CGContextClosePath(context); |
CGContextSetRGBFillColor(context, randomFloat(), randomFloat(), randomFloat(), 1.0); |
CGContextEOFillPath(context); |
} |
@end |
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