//图片等比缩放合成并处于中心位置显示 - (UIImage *)addImage:(UIImage *)image1 toImage:(UIImage *)image2 { CGSize miSize = self.viewImage.frame.size; CGFloat miAspectRatio = miSize.width / miSize.height; CGFloat img2AspectRatio = image2.size.width / image2.size.height; UIGraphicsBeginImageContextWithOptions(miSize, NO, 0.0f); CGFloat w2 = miSize.width; if (img2AspectRatio < miAspectRatio) { w2 = miSize.width * (img2AspectRatio/miAspectRatio); } CGFloat h2 = w2 / img2AspectRatio;; CGFloat x2 = (miSize.width - w2)/2.0f; CGFloat y2 = (miSize.height - h2)/2.0f; [image2 drawInRect:CGRectMake(x2, y2, w2, h2)]; CGFloat img1AspectRatio = (w2 / img2AspectRatio)/h2; CGFloat w1 = w2 * img1AspectRatio; if (img1AspectRatio < img2AspectRatio) { w1 = w2 * (img1AspectRatio/img2AspectRatio); } CGFloat h1 = h2 * img1AspectRatio; CGFloat x1 = (w2 - w1)/2.0f + x2; CGFloat y1 = (h2 - h1)/2.0f + y2; [image1 drawInRect:CGRectMake(x1, y1, w1, h1)]; UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); // NSString *path = [[NSHomeDirectory()stringByAppendingPathComponent:@"Documents"]stringByAppendingPathComponent:@"image.png"]; // [UIImagePNGRepresentation(resultingImage) writeToFile:path atomically:YES]; return resultingImage; }