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良い品質で画像をスケーリングする方法。私はこの次のコードを使用していますが、カメラからの画像を使用して撮影すると、別のフレームに表示されます。

-(UIImage *)resizeImage:(UIImage *)image {
int w = image.size.width;
int h = image.size.height; 

CGImageRef imageRef = [image CGImage];

int width, height;

int destWidth = 640;
int destHeight = 480;
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;  
}

とにかく品質に影響を与えずにサイズを小さくする方法がある場合は、提案してください よろしくお願いします

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2 に答える 2

0

カメラ画像の画像を拡大縮小するために、以下のコードを使用しました。役に立ったと思ったら実装してください

- (void)imagePickerController:(UIImagePickerController *)picker
                didFinishPickingImage:(UIImage *)image
                                    editingInfo:(NSDictionary *)editingInfo
{

//// ADDIGN THIS LINE WHEN YOU CAPTURED IMAGE 

    image = [self scaleAndRotateImage:image];
    [self useImage:image];
    [[picker parentViewController] dismissModalViewControllerAnimated:YES];
}

/// THE METHODS ROTATE THE CURRENT CAPTURED IMAGE AT 90 DEGREE OF ANGLE

- (void)scaleAndRotateImage:(UIImage *)image
{
    int kMaxResolution = 320; // Or whatever

    CGImageRef imgRef = image.CGImage;

    CGFloat width = CGImageGetWidth(imgRef);
    CGFloat height = CGImageGetHeight(imgRef);

    CGAffineTransform transform = CGAffineTransformIdentity;
    CGRect bounds = CGRectMake(0, 0, width, height);
    if (width > kMaxResolution || height > kMaxResolution) {
        CGFloat ratio = width/height;
        if (ratio > 1) {
            bounds.size.width = kMaxResolution;
            bounds.size.height = bounds.size.width / ratio;
        }
        else {
            bounds.size.height = kMaxResolution;
            bounds.size.width = bounds.size.height * ratio;
        }
    }

    CGFloat scaleRatio = bounds.size.width / width;
    CGSize imageSize = CGSizeMake(CGImageGetWidth(imgRef), CGImageGetHeight(imgRef));
    CGFloat boundHeight;
    UIImageOrientation orient = image.imageOrientation;
    switch(orient) {

        case UIImageOrientationUp: //EXIF = 1
            transform = CGAffineTransformIdentity;
            break;

        case UIImageOrientationUpMirrored: //EXIF = 2
            transform = CGAffineTransformMakeTranslation(imageSize.width, 0.0);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            break;

        case UIImageOrientationDown: //EXIF = 3
            transform = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;

        case UIImageOrientationDownMirrored: //EXIF = 4
            transform = CGAffineTransformMakeTranslation(0.0, imageSize.height);
            transform = CGAffineTransformScale(transform, 1.0, -1.0);
            break;

        case UIImageOrientationLeftMirrored: //EXIF = 5
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(imageSize.height, imageSize.width);
            transform = CGAffineTransformScale(transform, -1.0, 1.0);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationLeft: //EXIF = 6
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(0.0, imageSize.width);
            transform = CGAffineTransformRotate(transform, 3.0 * M_PI / 2.0);
            break;

        case UIImageOrientationRightMirrored: //EXIF = 7
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeScale(-1.0, 1.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;

        case UIImageOrientationRight: //EXIF = 8
            boundHeight = bounds.size.height;
            bounds.size.height = bounds.size.width;
            bounds.size.width = boundHeight;
            transform = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
            transform = CGAffineTransformRotate(transform, M_PI / 2.0);
            break;

        default:
            [NSException raise:NSInternalInconsistencyException format:@"Invalid image orientation"];

    }

    UIGraphicsBeginImageContext(bounds.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    if (orient == UIImageOrientationRight || orient == UIImageOrientationLeft) {
        CGContextScaleCTM(context, -scaleRatio, scaleRatio);
        CGContextTranslateCTM(context, -height, 0);
    }
    else {
        CGContextScaleCTM(context, scaleRatio, -scaleRatio);
        CGContextTranslateCTM(context, 0, -height);
    }

    CGContextConcatCTM(context, transform);

    CGContextDrawImage(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, width, height), imgRef);
    UIImage *imageCopy = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    [self setRotatedImage:imageCopy];
    //return imageCopy;
}
于 2012-08-27T11:19:30.080 に答える
0

サイズを小さくするには、画像の解像度を妥協する必要があります。画像の新しい WIDTH と HEIGHT を計算することをお勧めします。

これが私のために働いたものです：

これを試して：

-(UIImage*) resizeImage:(CGImageRef)image toWidth:(int)width andHeight:(int)height
{
// create context, keeping original image properties
  CGColorSpaceRef colorspace = CGImageGetColorSpace(image);
  CGContextRef context = CGBitmapContextCreate(NULL, width, height,                                                 CGImageGetBitsPerComponent(image),                                           CGImageGetBytesPerRow(image),
                                             colorspace,
                                             CGImageGetAlphaInfo(image));

       if(context == NULL)
       {
        NSLog(@"Could not re-size");
        return nil; 
       }
      // draw image to context (resizing it)
      CGContextDrawImage(context, CGRectMake(0, 0, width, height), image);
      // extract resulting image from context
      CGImageRef imgRef = CGBitmapContextCreateImage(context);
      CGContextRelease(context);
      UIImage* resizedImage = [UIImage imageWithCGImage:imgRef];
      CGImageRelease(imgRef);
      return resizedImage;  
}
于 2012-08-27T11:03:02.567 に答える