ios编程：iPhone How-to:给UIView拍照

基本原理就是主要将UIView的layer描绘到图形上下文。UIView全局拍照和局域拍照的代码如下：

1 UIView全局拍照

- (UIImage *) screenImage:(UIView *)view {
    UIImage *screenImage;
    UIGraphicsBeginImageContext(view.frame.size);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    screenImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return screenImage;
}

2 UIView局域拍照

- (UIImage *) screenImage:(UIView *)view rect:(CGRect)rect {
    CGPoint pt = rect.origin;
    UIImage *screenImage;
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextConcatCTM(context,
    CGAffineTransformMakeTranslation(-(int)pt.x, -(int)pt.y));
    [view.layer renderInContext:context];
    screenImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return screenImage;
}