Question

I want to do some scientific image processing on iOS in Obj-C or of course C, all I require to do this is to get a 3D array of the bit values of all the pixels RGBA. UIImage doesn t seem to have a built in function. Do any of you know how to get the pixel values or more preferably a predefined library with those functions in there? Thanks in advance, JEM

Answer 1

https://developer.apple.com/library/mac/#documentation/graphicsimaging/vis/CGBitmapContext/Reference/ reference.html”rel=“nofollow”CGBitmapContext/code>; 指示它使用分配给你的一些记忆(因此,你知道它在哪里,如何取用); 或给核心图表图象,供你使用;CGBmapCongetData>,如果你只用X/6。



例如,(为了简便而故意忽略的检查和一些固定步骤;尽管没有对功能文件进行定义和检查,但寻找我使用的变量)

CGBitmapInfo bitmapInfo =
              kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host;

context =
       CGBitmapContextCreate(
                NULL,
                width, height,
                8,
                width * 4,
                rgbColourSpace,
                bitmapInfo);

CGContextDrawImage(
        context,
        CGRectMake(0.0f, 0.0f, (CGFloat)width, (CGFloat)height),
        [image CGImage]);

uint8_t *pixelPointer = CGBitmapContextGetData(context);

for(size_t y = 0; y < height; y++)
{
    for(size_t x = 0u; x < width; x++)
    {
        if((bitmapInfo & kCGBitmapByteOrder32Little))
        {
            NSLog(@"rgba: %02x %02x %02x %02x",
                 pixelPointer[2], pixelPointer[1],
                 pixelPointer[0], pixelPointer[3]);
        }
        else
        {
            NSLog(@"rgba: %02x %02x %02x %02x",
                 pixelPointer[1], pixelPointer[2],
                 pixelPointer[3], pixelPointer[0]);
        }

        pixelPointer += 4;
    }
}

友情链接