[iOS] UIImage를 특정 rect만큼 자르기

원래는 인식기로 crop하지만 그냥 특정 좌표만큼 짜르고 싶을 때 사용

#define DEVICE_HEIGHT ([[UIScreen mainScreen] bounds].size.height)

#define DEVICE_WIDTH ([[UIScreen mainScreen] bounds].size.width)

 /**

 이미지를 rect만큼 잘라주는 함수

 @param image 원본 이미지

 @param rect 좌표 정보

 @return  UIImage 잘라진 이미지

 */

- (UIImage*)imageCrop : (UIImage*)image withGuideRect : (CGRect) guideRect

{

    //guideRect 크기 계산

    NSLog(@"image width = %f, height = %f",image.size.width, image.size.height);

    float xRatio, yRatio;

   float bigValue, smallValue;

    bigValue = (DEVICE_HEIGHT>DEVICE_WIDTH)?DEVICE_HEIGHT:DEVICE_WIDTH;

    smallValue = (DEVICE_HEIGHT>DEVICE_WIDTH)?DEVICE_WIDTH:DEVICE_HEIGHT;

    xRatio = (float)image.size.width / smallValue;

    yRatio = (float)image.size.height / bigValue;

    NSLog(@"%f,%f",xRatio, yRatio);

    CGRect rect = CGRectMake(guideRect.origin.x*xRatio, guideRect.origin.y*yRatio, guideRect.size.width*xRatio, guideRect.size.height*yRatio);

    //이미지 크랍

    NSLog(@"cropedImage width = %f, height = %f",rect.size.width, rect.size.height);

    NSData* rgbpixelData = (NSData*) CGDataProviderCopyData(CGImageGetDataProvider(image.CGImage));

    

    unsigned char* rgbpixelBytes = (unsigned char *)[rgbpixelData bytes];

    

    int bpp = 4;

    int oriW = image.size.width;

    //int oriH = image.size.height;

    int newW = rect.size.width;

    int newH = rect.size.height;

    int newSize = newW * newH * bpp;

    int newX = rect.origin.x;

    int newY = rect.origin.y;

    

    unsigned char * pSrc = rgbpixelBytes;

    unsigned char *pDst = new unsigned char[newSize];

    memset (pDst, 0, newSize * sizeof(unsigned char));

    

    int y = 0;

    for (y = newY; y < newY + newH; ++y)

    {

        unsigned char *pD = pDst + ((y - newY) * newW * bpp);

        unsigned char *pS = pSrc + (y * oriW * bpp) + newX*bpp;

        memcpy (pD, pS, newW * bpp);

    }

    

    NSData *skewrgbImageData = [[NSData alloc] initWithBytes:pDst length:(newSize)];

    delete[] pDst;

    pDst= NULL;

    

    CGDataProviderRef imgrgbDataProvider = CGDataProviderCreateWithCFData((CFDataRef)skewrgbImageData);

    

    int bitsPerComponent = 8;

    int bitsPerPixel = 32;

    int bytesPerRow = 4 * newW;

    

    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();

    CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(image.CGImage);

    if (bitmapInfo & kCGBitmapByteOrder32Big)

    {

        bitmapInfo= kCGBitmapByteOrder32Big | kCGImageAlphaNone;

    }

    else

        bitmapInfo= kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipFirst;

    

    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

    

    CGImageRef imageRef = CGImageCreate(newW, newH, bitsPerComponent, bitsPerPixel, bytesPerRow,colorSpaceRef, bitmapInfo, imgrgbDataProvider, NULL, false, renderingIntent);

    

    UIImage *cropImage = [UIImage imageWithCGImage:imageRef];

    CFRelease(imageRef);

    CGColorSpaceRelease(colorSpaceRef);

    CGDataProviderRelease(imgrgbDataProvider);

    [skewrgbImageData release];

    skewrgbImageData = nil;

    

    CFRelease(rgbpixelData);

    

    return cropImage;

}