ios - 替换CGBitmapContext中的特定颜色

如何替换已经绘制的CGBitmapContext中的特定颜色(RGB值)？

有什么简单的方法吗？

提前致谢。

最佳答案

您需要通过执行以下操作来获得一个指向像素的指针以及有关其格式的信息:

// This assumes the data is RGBA format, 8-bits per channel.
// You'll need to verify that by calling CGBitmapContextGetBitsPerPixel (), etc.
typedef struct RGBA8 {
    UInt8 red;
    UInt8 green;
    UInt8 blue;
    UInt8 alpha;
} RGBA8;

RGBA8* pixels = CGBitmapContextGetData (context);
UInt32 height = CGBitmapContextGetHeight (context);
UInt32 width = CGBitmapContextGetWidth (context);
UInt32 rowBytes = CGBitmapContextGetBytesPerRow (context);
UInt32 x, y;
for (y = 0; y < height; y++)
{
    RGBA8* currentRow = (RGBA8*)((UInt8*)pixels + y * rowBytes);
    for (x = 0; x < width; x++)
    {
        if ((currentRow->red == replaceRed) && (currentRow->green == replaceGreen) &&
            (currentRow->blue == replaceBlue) && (currentRow->alpha == replaceAlpha))
        {
            currentRow->red = newRed;
            currentRow->green = newGreen;
            currentRow->blue = newBlue;
            currentRow->alpha = newAlpha;
        }
        currentRow++;
    }
}

关于ios - 替换CGBitmapContext中的特定颜色，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/12103083/