ios - 尝试将两个 UIImage 合并到 UIImageView 时出错

Question

我正在尝试将几张照片 (UIImages) 合并到 ImageView 中。我正在使用这种方法:

- (UIImage *) addImageToImage:(UIImage *)img withImage2:(UIImage *)img2{

    CGSize size = CGSizeMake(finalPhoto.image.size.width, finalPhoto.image.size.height);
    UIGraphicsBeginImageContext(size);

    CGPoint pointImg1 = CGPointMake(0,0);
    [img drawAtPoint:pointImg1];

    CGPoint pointImg2 = CGPointMake(0,0);
    [img2 drawAtPoint: pointImg2];

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

    return result;
}

问题是它无法进行合并，因为它没有正确的点(我猜......)这是日志:

Jan 17 09:35:20 <Error>: CGContextSaveGState: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextSetBlendMode: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextSetAlpha: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextTranslateCTM: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextScaleCTM: invalid context 0x0
Jan 17 09:35:20  <Error>: CGContextConcatCTM: invalid context 0x0
Jan 17 09:35:20  <Error>: CGContextDrawImage: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextRestoreGState: invalid context 0x0
Jan 17 09:35:20  <Error>: CGContextSaveGState: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextSetBlendMode: invalid context 0x0
Jan 17 09:35:20  <Error>: CGContextSetAlpha: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextTranslateCTM: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextScaleCTM: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextConcatCTM: invalid context 0x0
Jan 17 09:35:20  <Error>: CGContextDrawImage: invalid context 0x0
Jan 17 09:35:20 <Error>: CGContextRestoreGState: invalid context 0x0

此问题发生在 iOS 6 和 iOS 7 上。是否有可行的解决方案？谢谢。

Answer 1

使用下面的代码:

- (UIImage *) addImageToImage:(UIImage *)img withImage2:(UIImage *)img2{
    //merge two images for this code

    CGSize newSize = CGSizeMake(512,512); // Set your bottom image size
    UIGraphicsBeginImageContext(newSize);

    // Use existing opacity as is
    [img drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];///1st image set frame

    // Apply supplied opacity if applicable
    [img2 drawInRect:CGRectMake(165,332,165,120) blendMode:kCGBlendModeNormal alpha:1];//2nd image set frame with alpha value

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return newImage; //return UIImage
}