两张(多张)图片合成一张图片

下面向经过颜色建立了一张空白图片，而后将目标图片居中在上一个图片中，这里能够经过一样的方法绘制多张图片到一张图片上去

- (UIImage *) drawRectForImage:(UIImage *) image {
    UIImage* rectImage = [UIImage imageWithColor:[UIColor whiteColor] size:CGSizeMake(self.frame.size.width, image.size.height + 20)];
    CGSize finalSize = [rectImage size];

    CGSize imageSize = [image size];

    UIGraphicsBeginImageContext(finalSize);

    [rectImage drawInRect:CGRectMake(0,0,finalSize.width,finalSize.height)];

    [image drawInRect:CGRectMake((finalSize.width - imageSize.width)/2,10,imageSize.width,imageSize.height)];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;

}