为通过UIImagePickerController捕获的图像添加日期和时间

Question

我想使用UIImagePickerController添加日期和时间。

我有一个使用控制器拍照的应用程序，虽然我知道日期存储在元数据中，但我想知道它是否可以轻松地合并到图像中（就像你可以设置数码相机一样）如下例所示：

Answer 1

请注意，这仅适用于导入和包含ImageIO框架的情况。另一个条件是：

  

[UIImagePickerControllerMediaMetadata]仅在使用源类型设置为UIImagePickerControllerSourceTypeCamera的图像选择器时有效，并且仅适用于静止图像。

这是我们从图片中检索日期的方式。如果您允许通过相册选择图像，则此解决方案将无法使用。为此，您需要利用ALAsset。如果你纯粹使用相机（并在iOS7上运行），这个解决方案应该可行。

#import <ImageIO/ImageIO.h>

// Ensure you've set yourself as the UIImagePickerController delegate to ensure this method is called
 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    UIImage* image = info[UIImagePickerControllerOriginalImage];
    image = [self imageWithRenderedDateMetadata:info[UIImagePickerControllerMediaMetadata]
                                        onImage:image];
}

- (UIImage*)imageWithRenderedDateMetadata:(NSDictionary*)metadata onImage:(UIImage*)image
{
    if (!image || !metadata) { return nil; }

    // Get Date String
    // Note: You can format the date string here into a more readable format if you want
    // Here, I'll just use the YYYY:MM:DD HH:MM:SS format given
    NSDictionary *tiffMetadata = metadata[(__bridge id)kCGImagePropertyTIFFDictionary];
    NSString* dateString = tiffMetaData[(__bridge id)kCGImagePropertyTIFFDateTime];

    UIGraphicsBeginImageContext(image.size);

    // Draw the image into the context
    [image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];

    // Position the date in the bottom right
    NSDictionary* attributes = @{NSFontAttributeName :[UIFont boldSystemFontOfSize:30],
                                 NSStrokeColorAttributeName : [UIColor blackColor],
                                 NSForegroundColorAttributeName : [UIColor yellowColor],
                                 NSStrokeWidthAttributeName : @-2.0};

    const CGFloat dateWidth = [dateString sizeWithAttributes:attributes].width;
    const CGFloat dateHeight = [dateString sizeWithAttributes:attributes].height;
    const CGFloat datePadding = 25;

    [dateString drawAtPoint:CGPointMake(image.size.width - dateWidth - datePadding, image.size.height - dateHeight - datePadding)
             withAttributes:attributes];

    // Get the final image
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newImage;
}

你现在有一个UIImage，其中包含日期;最终结果看起来像这样：