使用UIImagePickerController时如何更改裁剪矩形的大小

Question

I need to change the size of the cropping rect when using UIImagePickerController . In my case, I need the user to select images that are 320x385 but the crop rect currently only allows 320x320 (when allow editing is on).

Any ideas?

Answer 1

I have done a similar project. You have to use an image controller. Above your image controller you have to add another image controller (just because this is your crop area) aboveImageController's unfilled/empty part is where you will take. (so you should have an image with 320x480 sized and 320x385 empty in it.)

UIImage *image=theimageView.image;  
CGSize newSize;
newSize.width=320;
newSize.height=385;
UIGraphicsBeginImageContext(newSize);

//x=0 (because widhth : 320) y=0 (aboveImageController's empty part's start) 
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)]; 
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

CGImageRef imageRef = CGImageCreateWithImageInRect([newImage CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef]; 
CGImageRelease(imageRef);

Answer 2

After getting image from image picker and give crop functionality as different module. So user can select the part of image which one they want to crop.

Answer 3

You can use this

UIImage *image1 = [self resizeImage:image width:320 height:385];


-(UIImage *)resizeImage:(UIImage *)image width:(int)wdth height:(int)hght{
    int w = image.size.width;
    int h = image.size.height;
    CGImageRef imageRef = [image CGImage];
    int width, height;
    int destWidth = wdth;
    int destHeight = hght;
    if(w > h){
        width = destWidth;
        height = h*destWidth/w;
    }
    else {
        height = destHeight;
        width = w*destHeight/h;
    }
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef bitmap;
    bitmap = CGBitmapContextCreate(NULL, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedFirst);

    if (image.imageOrientation == UIImageOrientationLeft) {

        CGContextRotateCTM (bitmap, M_PI/2);
        CGContextTranslateCTM (bitmap, 0, -height);

    } else if (image.imageOrientation == UIImageOrientationRight) {

        CGContextRotateCTM (bitmap, -M_PI/2);
        CGContextTranslateCTM (bitmap, -width, 0);

    }
    else if (image.imageOrientation == UIImageOrientationUp) {

    } else if (image.imageOrientation == UIImageOrientationDown) {

        CGContextTranslateCTM (bitmap, width,height);
        CGContextRotateCTM (bitmap, -M_PI);
    }

    CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef);
    CGImageRef ref = CGBitmapContextCreateImage(bitmap);
    UIImage *result = [UIImage imageWithCGImage:ref];
    CGContextRelease(bitmap);
    CGImageRelease(ref);

    return result;

}

Answer 4

The dictionary in the delegate method returns all that:

NSString *const UIImagePickerControllerMediaType;
NSString *const UIImagePickerControllerOriginalImage;
NSString *const UIImagePickerControllerEditedImage;
NSString *const UIImagePickerControllerCropRect;
NSString *const UIImagePickerControllerMediaURL;
NSString *const UIImagePickerControllerReferenceURL;
NSString *const UIImagePickerControllerMediaMetadata;

I assume, you've been using the EditedImage which is pretty much useless ... maybe for some thumbnails ... anyway, the info dictionary contains CropRect data, only thing you have to do is to recalculate the sizes and crop the OriginalImage yourself, using for example this: UIImage: Resize, then Crop

I haven't tested, this is just theory :) ... but in theory, this should work :D