UIImage像素設置RGB值

所有我想要做的就是檢查特定像素的RGB值，並且與其旁邊的像素相同，並將第一個像素的RGB值設置爲兩個像素的RGB之間的範圍值UIImage像素設置RGB值

這裏的代碼

int width = img.size.width; 
int height = img.size.height; 


// the pixels will be painted to this array 
uint32_t *pixels = (uint32_t *) malloc(width * height * sizeof(uint32_t)); 

// clear the pixels so any transparency is preserved 
memset(pixels, 0, width * height * sizeof(uint32_t)); 

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

// create a context with RGBA pixels 
CGContextRef context = CGBitmapContextCreate(pixels, width, height, 8, width * sizeof(uint32_t), colorSpace, 
              kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast); 

// paint the bitmap to our context which will fill in the pixels array 
CGContextDrawImage(context, CGRectMake(0, 0, width, height), [img CGImage]); 

//allocate pixels array 
for(int y = 0; y < height; y++) { 
    for(int x = 0; x < width; x++) { 
     uint8_t *rgbaPixel1 = (uint8_t *) &pixels[y * width + x]; 
     uint8_t *rgbaPixel2 = (uint8_t *) &pixels[y * width + x + 1]; 
     //uint32_t color = r * rgbaPixel[RED] + g * rgbaPixel[GREEN] + b * rgbaPixel[BLUE]; 
     // set the pixels to the color 
     rgbaPixel1[0] = (rgbaPixel1[0] + rgbaPixel2[0]/2); 
     rgbaPixel1[1] = (rgbaPixel1[1] + rgbaPixel2[1]/2); 
     rgbaPixel1[2] = (rgbaPixel1[2] + rgbaPixel2[2]/2); 
     rgbaPixel1[3] = 255; 
    } 
}

但所有我得到的是一些有趣的結果！

有幫助嗎？謝謝:)

來源

2013-12-17 CodeLover

-2

看到這些鏈接，

獲取像素RGB

iPhone : How to change color of particular pixel of a UIImage?

How to get pixel data from a UIImage (Cocoa Touch) or CGImage (Core Graphics)?

Getting RGB pixel data from CGImage

設置像素RGB

iPhone : How to change color of particular pixel of a UIImage?

來源

2013-12-17 17:31:06

鏈接列表並不是一個好的[SO]答案。請解釋鏈接中發生了什麼的細節，以便它成爲一個有用的答案。不僅需要點擊鏈接才能獲得答案，而且鏈接可能會在某個時候成爲死鏈接，不再是有用的答案，這不僅令人不快。 – Joe

我用下面的代碼在正確的添加2條薄紅線和左圖像的。與iOS7配合使用

-(UIImage*)ModifyImage:(UIImage*) img 
{ 
    UIGraphicsBeginImageContext(img.size); 

    [img drawInRect:CGRectMake(0,0,img.size.width,img.size.height) blendMode:kCGBlendModeSourceOut alpha:1.0f]; 

    CGContextRef ctx = UIGraphicsGetCurrentContext(); 
    int w =img.size.width; 
    int cw,ch; 

    cw = img.size.width/35; 
    ch = img.size.height/35; 

    unsigned char* data = CGBitmapContextGetData (ctx); 

    for(int y = 0 ; y < img.size.height ; y++) 
    { 
     for(int x = 0 ; x < img.size.width ; x++) 
     { 
      //int offset = 4*((w * y) + x); 

      int offset = (CGBitmapContextGetBytesPerRow(ctx)*y) + (4 * x); 

      int blue = data[offset]; 
      int green = data[offset+1]; 
      int red  = data[offset+2]; 
      //int alpha = data[offset+3]; 

      if(x <= (cw * 2) || x >= (cw * 35)) 
      { 
       data[offset] = 0; 
       data[offset+1] = 0; 
       data[offset+2] = 255; 
       data[offset+3] = 255; 
      } 
     } 
    } 

    UIImage *rtimg = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 

    return rtimg; 
}

來源

2014-03-22 10:30:49 samcpp

UIImage像素設置RGB值

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