Question

希望这将是一个重复的问题，但我真的陷入写入png数据块。有人可以帮助我如何从Objective-C中的数据中获取标题？以下是信息Section 4.7.2 , c part, Textual Information。

由于

Answer 1

我认为没有必要关心png数据块，只需尝试下面的代码：

   //load target image, then draw text on the target image
    UIImage * image = [UIImage imageNamed:@"targetImage.png"];
    NSString * text = @"Watermark!";
    CGPoint startPoint = CGPointMake(20, 30);
    UIFont *font = [UIFont boldSystemFontOfSize:12];
    UIGraphicsBeginImageContext(image.size);
    [image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
    CGRect rect = CGRectMake(startPoint.x, startPoint.y, image.size.width, image.size.height);
    [[UIColor whiteColor] set];
    [text drawInRect:CGRectIntegral(rect) withFont:font];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    // Convert UIImage object into NSData (a wrapper for a stream of bytes) formatted according to PNG spec
    NSData *imageData = UIImagePNGRepresentation(newImage);

    //Save imageDate to disk as a png file
    NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *imageSubdirectory = [documentsDirectory stringByAppendingPathComponent:@"watermarkFolderName"];
    NSString *filePath = [imageSubdirectory stringByAppendingPathComponent:@"watermark.png"];
    [imageData writeToFile:filePath atomically:YES];

在png图像中写入文本

1 个答案: