/** * 设置图片透明度 * @param alpha 透明度 * @param image 图片 */ -(UIImage *)imageByApplyingAlpha:(CGFloat )alpha image:(UIImage*)image { UIGraphicsBeginImageContextWithOptions(image.size, NO, 0.0f); CGContextRef ctx = UIGraphicsGetCurrentContext(); CGRect area = CGRectMake(0, 0, image.size.width, image.size.height); CGContextScaleCTM(ctx, 1, -1); CGContextTranslateCTM(ctx, 0, -area.size.height); CGContextSetBlendMode(ctx, kCGBlendModeMultiply); CGContextSetAlpha(ctx, alpha); CGContextDrawImage(ctx, area, image.CGImage); UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newImage; }