Question

我正在构建一个iOS应用程序，它具有全屏ImagePickerController，捕获的结果图像与ImagePickerController视图中显示的相同。这是我目前的相关代码：

创建和转换ImagePickerController：

    self.imagePicker = [[UIImagePickerController alloc] init];
self.imagePicker.delegate = self;


CGSize screenSize = [[UIScreen mainScreen] bounds].size;

// set the aspect ratio of the camera
float heightRatio = 4.0f / 3.0f;
// calculate the height of the camera based on the screen width
float cameraHeight = floorf(screenSize.width * heightRatio);
// calculate the ratio that the camera height needs to be scaled by
float scale = ceilf((screenSize.height / cameraHeight) * 10.0) / 10.0;

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
    self.imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;


    self.imagePicker.showsCameraControls = NO;
    [self.imagePicker setCameraOverlayView:cameraView];

    // move the controller to the center of the screen
    self.imagePicker.cameraViewTransform = CGAffineTransformMakeTranslation(0, (screenSize.height - cameraHeight) / 2.0);
    // concatenate the scale transform
    self.imagePicker.cameraViewTransform = CGAffineTransformScale(self.imagePicker.cameraViewTransform, scale, scale);
}

捕获图像后，这里是我用来重绘捕获图像以匹配预览的代码：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
 self.image = [info objectForKey:UIImagePickerControllerOriginalImage];
 self.image = [self croppedImage:self.image];

- (UIImage *) croppedImage: (UIImage *)image{

CGSize screenSize = [[UIScreen mainScreen] bounds].size;    
// set the aspect ratio of the camera
float heightRatio = 4.0f / 3.0f;
// calculate the height of the camera based on the screen width
float cameraHeight = floorf(screenSize.width * heightRatio);
// calculate the ratio that the camera height needs to be scaled by
float scale = ceilf((screenSize.height / cameraHeight) * 10.0) / 10.0;


CGSize originalImageSize = [image size];
CGSize newImageSize = CGSizeMake(floorf(originalImageSize.width / scale)* 3/4, floorf(originalImageSize.height / scale)* 3/4);

CGRect newImageRect = CGRectMake((originalImageSize.width - newImageSize.width)/2.0, (originalImageSize.height - newImageSize.height)/2.0, newImageSize.width, newImageSize.height);

return [image croppedImage:newImageRect];
}

所以我的问题是我的CroppedImage方法计算不正确，因为生成的图像似乎比需要的更“放大”。不确定计算中出了什么问题。

注意 - 此应用程序旨在在所有iPhone上正确缩放 - 仅限纵向模式。我目前正在iPhone 6上进行测试。

Answer 1

如果这有助于任何人 - 在我的设备上我能够通过切换来修复它

       CGSize newImageSize = CGSizeMake(floorf(originalImageSize.width / scale)* 3/4, floorf(originalImageSize.height / scale)* 3/4);

到

       CGSize newImageSize = CGSizeMake(floorf(originalImageSize.width / scale), floorf(originalImageSize.height / scale)* 4/3);

只需要乘以4/3而不是3/4所需的高度/比例。我还没有在任何其他设备上测试过这个。只是认为这可能有助于任何人遇到同样的事情。

无法获取UIImage以匹配自定义ImagePickerController预览

1 个答案: