iOS-合并两个不同大小的图像

Question

我面临以下问题：由于合并，我必须合并两个图像A和B以创建新图像C。我已经知道如何合并两个图像，但是在这种情况下，我的目标有所不同。我希望图像A将作为图像B的背景。例如，如果图像A的尺寸为500x500，图像B的尺寸为460x460，我希望图像C（合并的图像结果）为500x500，图像B（ 460x460）居中。在此先感谢您的帮助或建议

Answer 1

这是我在应用程序中所做的，但是没有使用UIImageView：

UIImage *bottomImage = [UIImage imageNamed:@"bottom.png"]; //background image

UIImage *image       = [UIImage imageNamed:@"top.png"]; //foreground image

CGSize newSize = CGSizeMake(width, height);

UIGraphicsBeginImageContext( newSize );

// Use existing opacity as is

[bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

// Apply supplied opacity if applicable

[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.8];

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

如果图像已经具有不透明度，则无需进行设置（如在bottomImage中），否则可以进行设置（与图像一样）。

在这之后UIImage创建，那么你可以将它嵌入到你的UIImageView

更新：感谢Ahmet AkkoK-对于Swift（2.2）用户，混合模式宏已更改。CGBlendMode .kCGBlendModeNormal被替换为CGBlendMode.Normal

Answer 2

嘿，我得到了多张图像，并添加了具有不同前景的相同背景。

UIImage *bottomImage = [UIImage imageNamed:@"photo 2.JPG"]; //background image

UIImage *image       = [UIImage imageNamed:@"photo 3.JPG"]; //foreground image

UIImage *image1      = [UIImage imageNamed:@"photo 4.JPG"]; //foreground image

UIImage *image2      = [UIImage imageNamed:@"photo 5.JPG"]; //foreground image

CGSize newSize = CGSizeMake(320, 480);

UIGraphicsBeginImageContext( newSize );

// Use existing opacity as is

[bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

// Apply supplied opacity if applicable

[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.4];

[image1 drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.3];

[image2 drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.2];

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

resultView = [[UIImageView alloc] initWithImage:newImage];

resultView.frame = CGRectMake(0, 0,320,460);

[self.view addSubview:resultView];

Answer 3

刚刚为想要使用Srikar Appal答案的用户提供了快速粘贴功能。（如果背景图片和前景图片的大小不同）

- (UIImage *) mergeImages:(NSString *)bgImageFileName foreGround:(NSString *)fgImageFileName  {

    UIImage *bottomImage = [UIImage imageNamed:bgImageFileName]; //background image

    UIImage *image       = [UIImage imageNamed:fgImageFileName]; //foreground image

    CGSize newSize = CGSizeMake(bottomImage.size.width, bottomImage.size.height);

    UIGraphicsBeginImageContext(newSize);

    // Use existing opacity as is

    [bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

    // Apply supplied opacity if applicable

    // Change xPos, yPos if applicable

    [image drawInRect:CGRectMake(11,11,image.size.width,image.size.height) blendMode:kCGBlendModeNormal alpha:1.0];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return newImage;

}