Question

我在相册表中有照片数据库。我得到阵列中的所有图像并显示在表格中。问题是很少有图像旋转90度。

这是cellForRow方法中的内容。

AlbumInformation * temp=[albumInfoArray objectAtIndex:indexPath.row];
cell.albumPicImageView.image=temp.albumPictureClass;
return cell;

我得到所有图像，但很少旋转。

请帮忙。

提前致谢

Answer 1

请参阅以下样本。在PhotoDisplayViewController.m测试中，您将自动获得答案，无需解释任何人。

案例1：使用UIImageOrientation

ALAssetRepresentation *assetRepresentation = [asset defaultRepresentation];

    UIImage *fullScreenImage = [UIImage imageWithCGImage:[assetRepresentation fullScreenImage] scale:[assetRepresentation scale] orientation:(UIImageOrientation)[assetRepresentation orientation]];

案例2：没有UIImageOrientation

ALAssetRepresentation *assetRepresentation = [asset defaultRepresentation];

    UIImage *fullScreenImage = [UIImage imageWithCGImage:[assetRepresentation fullScreenImage] scale:[assetRepresentation scale] orientation:nil];

当你从断言中读取时，有一些方向如下

 UIImageOrientationUp,            // default orientation
    UIImageOrientationDown,          // 180 deg rotation
    UIImageOrientationLeft,          // 90 deg CCW
    UIImageOrientationRight,         // 90 deg CW
    UIImageOrientationUpMirrored,    // as above but image mirrored along other axis. horizontal flip
    UIImageOrientationDownMirrored,  // horizontal flip
    UIImageOrientationLeftMirrored,  // vertical flip
    UIImageOrientationRightMirrored, // vertical flip

请下载进行此示例演示

<强> MyImagePicker Demo

注意：如果要显示所有相册，则需要在RootViewController.m中更改代码，如下所示

NSUInteger groupTypes = ALAssetsGroupAlbum | ALAssetsGroupEvent | ALAssetsGroupFaces|ALAssetsGroupLibrary|ALAssetsGroupSavedPhotos|ALAssetsGroupPhotoStream;

Answer 2

UIImage有一个assign属性“imageOrientation”; 所以这种方法可以帮到你

（UIImage *）fixOrientation：（UIImage *）aImage {

// No-op if the orientation is already correct  
if (aImage.imageOrientation == UIImageOrientationUp)   
    return aImage;  

// We need to calculate the proper transformation to make the image upright.  
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.  
CGAffineTransform transform = CGAffineTransformIdentity;  

switch (aImage.imageOrientation) {  
    case UIImageOrientationDown:  
    case UIImageOrientationDownMirrored:  
        transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);  
        transform = CGAffineTransformRotate(transform, M_PI);  
        break;  

    case UIImageOrientationLeft:  
    case UIImageOrientationLeftMirrored:  
        transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);  
        transform = CGAffineTransformRotate(transform, M_PI_2);  
        break;  

    case UIImageOrientationRight:  
    case UIImageOrientationRightMirrored:  
        transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);  
        transform = CGAffineTransformRotate(transform, -M_PI_2);  
        break;  
    default:  
        break;  
}  

switch (aImage.imageOrientation) {  
    case UIImageOrientationUpMirrored:  
    case UIImageOrientationDownMirrored:  
        transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);  
        transform = CGAffineTransformScale(transform, -1, 1);  
        break;  

    case UIImageOrientationLeftMirrored:  
    case UIImageOrientationRightMirrored:  
        transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);  
        transform = CGAffineTransformScale(transform, -1, 1);  
        break;  
    default:  
        break;  
}  

// Now we draw the underlying CGImage into a new context, applying the transform  
// calculated above.  
CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,  
                                         CGImageGetBitsPerComponent(aImage.CGImage), 0,  
                                         CGImageGetColorSpace(aImage.CGImage),  
                                         CGImageGetBitmapInfo(aImage.CGImage));  
CGContextConcatCTM(ctx, transform);  
switch (aImage.imageOrientation) {  
    case UIImageOrientationLeft:  
    case UIImageOrientationLeftMirrored:  
    case UIImageOrientationRight:  
    case UIImageOrientationRightMirrored:  
        // Grr...  
        CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);  
        break;  

    default:  
        CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);  
        break;  
}  

// And now we just create a new UIImage from the drawing context  
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);  
UIImage *img = [UIImage imageWithCGImage:cgimg];  
CGContextRelease(ctx);  
CGImageRelease(cgimg);  
return img;

}

iphone桌面中的某些图像会自动旋转

2 个答案: