Question

我正在尝试制作一个简单的应用，它将相机叠加层与UIImagePicker中拍摄的照片相结合。在这个例子中，我想将熊耳的叠加视图与照片结合起来。

- (IBAction)pushTakePhoto:(id)sender {

    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.sourceType = UIImagePickerControllerSourceTypeCamera;
    picker.cameraDevice=UIImagePickerControllerCameraDeviceFront;

    //create overlay UIView
    UIImage *bearEars = [UIImage imageNamed:@"bearEars"];
    UIImageView *imageView = [[UIImageView alloc] initWithImage:bearEars];

    UIView *camerOverlayView = [[UIView alloc] initWithFrame:imageView.frame];
    [camerOverlayView addSubview:imageView];


    [picker setCameraOverlayView:camerOverlayView];

    [self presentViewController:picker animated:YES completion:NULL];


}

上面的代码创建了叠加层，这很好用。下面的代码组合了图像：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

    UIImage *chosenImage = info[UIImagePickerControllerOriginalImage];

    //first we flip the image
    UIImage * flippedImage = [UIImage imageWithCGImage:chosenImage.CGImage scale:chosenImage.scale orientation:UIImageOrientationLeftMirrored];
    chosenImage=flippedImage;

    //now we need to add the ears


    //get pics
    UIImage *backgroundImage = chosenImage;
    UIImage *watermarkImage = [UIImage imageNamed:@"bearEars"];

    //start a workspace
    UIGraphicsBeginImageContext(backgroundImage.size);
    [backgroundImage drawInRect:CGRectMake(0, 0, backgroundImage.size.width, backgroundImage.size.height)];
    //position seems off for some reason
    [watermarkImage drawInRect:CGRectMake(0, 0, backgroundImage.size.width, backgroundImage.size.height)];
    UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    chosenImage=result;


    self.finalImageView.image = chosenImage;

    [picker dismissViewControllerAnimated:YES completion:NULL];

}

当我组合图像时，但是bearEars叠加层不是位于（0,0），而是位于最终图像的中间。我不确定为什么会这样。我只是希望它像在相机视图中一样覆盖图像。任何想法为什么会这样？感谢

Answer 1

我认为图像居中是因为您在drawInRect方法中为两个图像使用相同的rect尺寸。尝试将backgroundImage.size的大小更改为watermarkImage的watermarkImage.size：

[watermarkImage drawInRect:CGRectMake(0, 0, watermarkImage.size.width, watermarkImage.size.height)];

编辑：

要为watermarkImage执行正确的大小，您需要找到缩放大小 - 与最终图像的预览中的图像大小不同。您可以通过将backgroundImage的宽度除以self.view

的宽度来实现

CGFloat scale = backgroundImage.size.width / self.view.frame.size.width;

然后你可以在绘制watermarkImage期间使用这个值：

[watermarkImage drawInRect:CGRectMake(0, 0, watermarkImage.size.width * scale, watermarkImage.size.height * scale)];

希望它有所帮助。

使用UIGraphics组合两个图像时出现问题，图像放置不正确

1 个答案: