从UIImage获取位图数据时出现意外错误？

Question

我收到以下错误。并找不到任何相关的谷歌搜索。

零结果..

我的意思..认真，那真是不可思议。

错误： -

Cannot initialize a variable of type 'UInt8 *' (aka 'unsigned char *') with an rvalue of type 'void * _Nullable' 

我的代码： -

UIImage *image = self.image; 
CGImageRef originalImage = [image CGImage]; 
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
CGContextRef bitmapContext = 
CGBitmapContextCreate(NULL,CGImageGetWidth(originalImage),CGImageGetHeight(originalImage), 
         8,CGImageGetWidth(originalImage)*4,colorSpace,kCGImageAlphaPremultipliedLast); 
CGColorSpaceRelease(colorSpace); 
CGContextDrawImage(bitmapContext, CGRectMake(0, 0, 
              CGBitmapContextGetWidth(bitmapContext),CGBitmapContextGetHeight(bitmapContext)), 
        originalImage); 
UInt8 *data = CGBitmapContextGetData(bitmapContext); 

屏幕截图： -

PS： -

我在.mm文件中使用此代码，如果有帮助。

Answer 1

+ (unsigned char) convertUIImageToBitmapRGBA8:(UIImage) image { 

    CGImageRef imageRef = image.CGImage; 

    // Create a bitmap context to draw the uiimage into 
    CGContextRef context = [self newBitmapRGBA8ContextFromImage:imageRef]; 

    if(!context) { 
     return NULL; 
    } 

    size_t width = CGImageGetWidth(imageRef); 
    size_t height = CGImageGetHeight(imageRef); 

    CGRect rect = CGRectMake(0, 0, width, height); 

    // Draw image into the context to get the raw image data 
    CGContextDrawImage(context, rect, imageRef); 

    // Get a pointer to the data  
    unsigned char bitmapData = (unsigned char)CGBitmapContextGetData(context); 

    // Copy the data and release the memory (return memory allocated with new) 
    size_t bytesPerRow = CGBitmapContextGetBytesPerRow(context); 
    size_t bufferLength = bytesPerRow * height; 

    unsigned char *newBitmap = NULL; 

    if(bitmapData) { 
     newBitmap = (unsigned char)malloc(sizeof(unsigned char) bytesPerRow * height); 

     if(newBitmap) { // Copy the data 
      for(int i = 0; i < bufferLength; ++i) { 
       newBitmap[i] = bitmapData[i]; 
      } 
     } 

     free(bitmapData); 

    } else { 
     NSLog(@"Error getting bitmap pixel data\n"); 
    } 

    CGContextRelease(context); 

    return newBitmap; 
} 

+ (CGContextRef) newBitmapRGBA8ContextFromImage:(CGImageRef) image { 
    CGContextRef context = NULL; 
    CGColorSpaceRef colorSpace; 
    uint32_t *bitmapData; 

    size_t bitsPerPixel = 32; 
    size_t bitsPerComponent = 8; 
    size_t bytesPerPixel = bitsPerPixel/bitsPerComponent; 

    size_t width = CGImageGetWidth(image); 
    size_t height = CGImageGetHeight(image); 

    size_t bytesPerRow = width * bytesPerPixel; 
    size_t bufferLength = bytesPerRow * height; 

    colorSpace = CGColorSpaceCreateDeviceRGB(); 

    if(!colorSpace) { 
     NSLog(@"Error allocating color space RGB\n"); 
     return NULL; 
    } 

    // Allocate memory for image data 
    bitmapData = (uint32_t *)malloc(bufferLength); 

    if(!bitmapData) { 
     NSLog(@"Error allocating memory for bitmap\n"); 
     CGColorSpaceRelease(colorSpace); 
     return NULL; 
    } 

    //Create bitmap context 

    context = CGBitmapContextCreate(bitmapData, 
      width, 
      height, 
      bitsPerComponent, 
      bytesPerRow, 
      colorSpace, 
      kCGImageAlphaPremultipliedLast); // RGBA 
    if(!context) { 
     free(bitmapData); 
     NSLog(@"Bitmap context not created"); 
    } 

    CGColorSpaceRelease(colorSpace); 

    return context; 
} 

+ (UIImage) convertBitmapRGBA8ToUIImage:(unsigned char) buffer 
     withWidth:(int) width 
     withHeight:(int) height { 


    size_t bufferLength = width height 4; 
    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer, bufferLength, NULL); 
    size_t bitsPerComponent = 8; 
    size_t bitsPerPixel = 32; 
    size_t bytesPerRow = 4 * width; 

    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB(); 
    if(colorSpaceRef == NULL) { 
     NSLog(@"Error allocating color space"); 
     CGDataProviderRelease(provider); 
     return nil; 
    } 

    CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast; 
    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault; 

    CGImageRef iref = CGImageCreate(width, 
       height, 
       bitsPerComponent, 
       bitsPerPixel, 
       bytesPerRow, 
       colorSpaceRef, 
       bitmapInfo, 
       provider, // data provider 
       NULL,  // decode 
       YES,   // should interpolate 
       renderingIntent); 

    uint32_t* pixels = (uint32_t*)malloc(bufferLength); 

    if(pixels == NULL) { 
     NSLog(@"Error: Memory not allocated for bitmap"); 
     CGDataProviderRelease(provider); 
     CGColorSpaceRelease(colorSpaceRef); 
     CGImageRelease(iref);  
     return nil; 
    } 

    CGContextRef context = CGBitmapContextCreate(pixels, 
       width, 
       height, 
       bitsPerComponent, 
       bytesPerRow, 
       colorSpaceRef, 
       bitmapInfo); 

    if(context == NULL) { 
     NSLog(@"Error context not created"); 
     free(pixels); 
    } 

    UIImage *image = nil; 
    if(context) { 

     CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, width, height), iref); 

     CGImageRef imageRef = CGBitmapContextCreateImage(context); 

     // Support both iPad 3.2 and iPhone 4 Retina displays with the correct scale 
     if([UIImage respondsToSelector:@selector(imageWithCGImage:scale:orientation:)]) { 
      float scale = [[UIScreen mainScreen] scale]; 
      image = [UIImage imageWithCGImage:imageRef scale:scale orientation:UIImageOrientationUp]; 
     } else { 
      image = [UIImage imageWithCGImage:imageRef]; 
     } 

     CGImageRelease(imageRef); 
     CGContextRelease(context); 
    } 

    CGColorSpaceRelease(colorSpaceRef); 
    CGImageRelease(iref); 
    CGDataProviderRelease(provider); 

    if(pixels) { 
     free(pixels); 
    } 
    return image; 
} 

Answer 2

//夫特-3

CGBitmapContextGetData（bitmapContext）已取代CGContext.data

让数据= context.data