如何在iPhone中裁剪图像

Question

我想要做与this问题中所述相同的操作。 在我的应用程序中，我想裁剪图像，就像我们在FaceBook中进行图像裁剪一样，任何人都可以通过优秀教程链接或任何示例代码指导我。我所提供的链接将完全描述我的要求。

Answer 1

您可以使用任何属性创建新图像。这是我的功能，女巫是这么做的。你只需要使用你自己的新图像参数。在我的情况下，图像没有被裁剪，我只是产生了一些效果，将像素从原始位置移动到另一个位置。但是，如果你与另一个高度和宽度初始化新的图像，你可以从你需要旧图像的像素的任何范围复制到新的一个：

-(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

的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);