ios 截图 图片合成 画纯色UIimage

1、截取部分UIImage

-(UIImage *)clipImageFromImage:(UIImage *)orgImage  Rect:(CGRect)clipRect{    CGImageRef imageRef = orgImage.CGImage;    CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, clipRect);    CGSize size;    size = clipRect.size;    UIGraphicsBeginImageContext(size);    CGContextRef context = UIGraphicsGetCurrentContext();    CGContextDrawImage(context, clipRect, subImageRef);    UIImage* clipImage = [UIImage imageWithCGImage:subImageRef];    CGImageRelease(subImageRef);    UIGraphicsEndImageContext();    return clipImage;}

2图片合成：

- (UIImage *)addImage:(UIImage *)image1 toImage:(UIImage *)image2 {    UIGraphicsBeginImageContext(image1.size);    [image1 drawInRect:CGRectMake(0, 0, image1.size.width, image1.size.height)];    [image2 drawInRect:CGRectMake(0, 0, image2.size.width, image2.size.height)];    UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    return resultingImage;}

 3画纯色UIImage

CGSize imageSize = CGSizeMake(50, 50);UIGraphicsBeginImageContextWithOptions(imageSize, 0, [UIScreen mainScreen].scale);[[UIColor colorWithRed:0 green:0 blue:0 alpha:1.0] set];UIRectFill(CGRectMake(0, 0, imageSize.width, imageSize.height));UIImage *pressedColorImg = UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();