iphone - UIImagePickerController imagePicker 不适合 iPhone 4 屏幕

Question

我让用户使用 UIImagePickerControllerSourceTypePhotoLibrary 选择图像。

然后我有以下方法来获取编辑后的图像，应用叠加层，然后将其传递到我的 PostPictureViewController 进行显示。在显示时，我希望图像保持其原始长宽比并适合屏幕。

它在使用 4.3 sdk 的模拟器上运行良好，但是当我将其放在 iPhone 4 视网膜显示屏上时，图像会缩放到左上角，并且只有 1/4 的图像全屏显示，从而消除了原始宽高比!

如何缩小它以适合屏幕，就像在模拟器上一样？

我也尝试完全摆脱覆盖层，只返回原始和编辑后的图像进行显示，但即​​使这样也不能保持其原始的宽高比!!!

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{        
    // Access the cropped image from info dictionary
    image = [info objectForKey:@"UIImagePickerControllerEditedImage"];

    // Combine image with overlay before saving!!
    image = [self addOverlayToImage:image];

    overlayGraphicView.image = nil;

    // Take the picture image to the post picture view controller
    postPictureView = [[PostPictureViewController alloc] init:image];    
    [picker pushViewController:postPictureView animated:YES];

    [picker release],picker = nil;
}

这是我的添加叠加图像功能:

- (UIImage*) addOverlayToImage:(UIImage*)originalImage
{
    //CGRect cgRect =[[UIScreen mainScreen] bounds];
    CGSize size = originalImage.size;

    if (UIGraphicsBeginImageContextWithOptions != NULL) {
        // Use for iPhone 4 Retina
        UIGraphicsBeginImageContextWithOptions(size, YES, 0.0);
    } else {
        UIGraphicsBeginImageContext(size);
    }

    UIImage* overlayImage = [UIImage imageNamed:overlayGraphicName];

    [originalImage drawAtPoint:CGPointMake(0,0)];

    [(UIImage *)overlayImage drawAtPoint:CGPointMake(0,(originalImage.size.height/2 - overlayImage.size.height/2) + 20)];

    UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
    [finalImage retain];

    UIGraphicsEndImageContext();

    return finalImage;
}

最后在我的 PostPictureViewController 中我在 viewdidload 中显示图像:

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self.view setBackgroundColor:[UIColor blackColor]];

    // Load the picker image for viewing
    UIImageView *pickerView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320, 480)];
    [pickerView setImage:pickerImage];
    pickerView.contentMode = UIViewContentModeScaleAspectFit;
    [self.view addSubview:pickerView];
    [pickerView release],pickerView=nil;
}

在这个用于显示图像的 viewdidload 方法中，如果我这样做:

UIImageView *pickerView = [[UIImageView alloc] initWithImage:pickerImage];

那么图像在模拟器上不会垂直居中于屏幕，而是从 0,0 开始，实际上使用 CGRectMake 定义框架宽度和高度时，图像会在屏幕上居中。

显然，对于 iPhone 4，我也尝试过更改此设置:

UIImageView *pickerView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 640, 960)];

但是图像仍然被放大到比屏幕更高更大!

Answer 1

您可以在界面构建器中将 ImageView 的属性设置为aspectfit。这应该有帮助。或者通过编程您可以使用imageView.contentMode = UIViewContentModeScaleAspectFit;