iPhoneで画像を切り抜く方法

Question

thisの質問と同じことをしたいと思います。 私のアプリケーションでは、FaceBookで画像を切り抜くように画像をトリミングしたいのですが、チュートリアルやサンプルコードのリンクを教えてください。私が提供したリンクは私の要求を完全に記述する。

Answer 1

任意のプロパティで新しい画像を作成できます。ここに私の機能、魔女はそれを行う。新しい画像の独自のパラメータを使用するだけです。私の場合、画像は切り取られず、元の場所から別の場所にピクセルを移動するだけで効果があります。あなたは別の高さと幅の新しいイメージを初期化する場合は、あなただけの新しいものに、あなたが必要とする古い画像の画素の任意の範囲からコピーすることができます

-(UIImage *)Color:(UIImage *)img 
{ 
    int R; 
    float m_width = img.size.width; 
    float m_height = img.size.height; 
    if (m_width>m_height) R = m_height*0.9; 
    else R = m_width*0.9; 
    int m_wint = (int)m_width;  //later, we will need this parameters in float and int. you may just use "(int)" and "(float)" before variables later, and do not implement another ones 
    int m_hint = (int)m_height; 

    CGRect imageRect; 
    //cheking image orientation. we will work with image pixel-by-pixel, so we need to make top side at the top. 
    if(img.imageOrientation==UIImageOrientationUp 
     || img.imageOrientation==UIImageOrientationDown) 
    { 
     imageRect = CGRectMake(0, 0, m_wint, m_hint); 
    } 
    else 
    { 
     imageRect = CGRectMake(0, 0, m_hint, m_wint); 
    } 
    uint32_t *rgbImage = (uint32_t *) malloc(m_wint * m_hint * sizeof(uint32_t)); 
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
    CGContextRef context = CGBitmapContextCreate(rgbImage, m_wint, m_hint, 8, m_wint *sizeof(uint32_t), colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast); 
    CGContextSetInterpolationQuality(context, kCGInterpolationHigh); 
    CGContextSetShouldAntialias(context, NO); 
    CGContextTranslateCTM(context, 0, m_hint); 
    CGContextScaleCTM(context, 1.0, -1.0); 
    switch (img.imageOrientation) { 
     case UIImageOrientationRight: 
     { 
      CGContextRotateCTM(context, M_PI/2); 
      CGContextTranslateCTM(context, 0, -m_wint);    
     }break; 
     case UIImageOrientationLeft: 
     { 
      CGContextRotateCTM(context, - M_PI/2); 
      CGContextTranslateCTM(context, -m_hint, 0);    
     }break; 
     case UIImageOrientationUp: 
     { 
      CGContextTranslateCTM(context, m_wint, m_hint); 
      CGContextRotateCTM(context, M_PI); 
     } 
     default: 
      break; 
    } 

    CGContextDrawImage(context, imageRect, img.CGImage); 
    CGContextRelease(context); 
    CGColorSpaceRelease(colorSpace); 

    //here is new image. you can change m_wint and m_hint as you whant 
    uint8_t *result = (uint8_t *) calloc(m_wint * m_hint * sizeof(uint32_t), 1); 
    for(int y = 0; y < m_hint; y++) //new m_hint here 
    { 
     float fy=y; 
     double yy = (m_height*( asinf(m_height/(2*R))-asin(((m_height/2)-fy)/R) ))/
     (2*asin(m_height/(2*R))); // (xx, yy) - coordinates of pixel of OLD image 
     for(int x = 0; x < m_wint; x++) //new m_wint here 
     { 
      float fx=x; 
      double xx = (m_width*( asin(m_width/(2*R))-asin(((m_width/2)-fx)/R) ))/
      (2*asin(m_width/(2*R))); 
      uint32_t rgbPixel=rgbImage[(int)yy * m_wint + (int)xx]; 
      int intRedSource = (rgbPixel>>24)&255; 
      int intGreenSource = (rgbPixel>>16)&255; 
      int intBlueSource = (rgbPixel>>8)&255; 
      result[(y * (int)m_wint + x) * 4] = 0; 
      result[(y * (int)m_wint + x) * 4 + 1] = intBlueSource; 
      result[(y * (int)m_wint + x) * 4 + 2] = intGreenSource; 
      result[(y * (int)m_wint + x) * 4 + 3] = intRedSource; 

     } 
    } 

    free(rgbImage); 

    colorSpace = CGColorSpaceCreateDeviceRGB(); 
    context = CGBitmapContextCreate(result, m_wint, m_hint, 8, m_wint * sizeof(uint32_t), colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast ); //new m_wint and m_hint as well 


    CGImageRef image1 = CGBitmapContextCreateImage(context); 
    CGContextRelease(context); 
    CGColorSpaceRelease(colorSpace); 
    UIImage *resultUIImage = [UIImage imageWithCGImage:image1]; 
    CGImageRelease(image1); 


    @try { 
     free(result); 
    } 
    @catch (NSException * e) { 
     NSLog(@"proc. Exception: %@", e); 
    } 

    return resultUIImage; 
} 

Answer 2

CGRect rectImage = CGRectMake（p1.x、p1.y 、p2.x-p1.x、p4.y-p1.y）;

//Create bitmap image from original image data, 
//using rectangle to specify desired crop area 

CGImageRef imageRef = CGImageCreateWithImageInRect([imageForCropping CGImage], rectImage); 
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef]; 
imageView1 = [[UIImageView alloc] initWithFrame:CGRectMake(p1.x, p1.y,p2.x-p1.x p4.y-p1.y)]; 
imageView1.image = croppedImage; 
[self.view addSubview:imageView1]; 
CGImageRelease(imageRef);