使用标准图片格式(jpeg,gif,png等)从文件加载CGImage或NSImage非常简单。
Loading a CGImage or NSImage from a file using a standard image format (jpeg, gif, png et.) is all very simple.
但是,现在我需要从使用libfreetype生成的内存中的字节数组中创建一个CGImage。它真的很容易从格式化的字节数组创建OpenGL纹理,我可以看到如何创建一个CGBitmapContext来写。但我似乎找不到一个简单的方法从原始像素数组创建一个CGImage。
However, I now need to create a CGImage from an array in bytes in memory generated using libfreetype. Its really easy to create OpenGL textures from an array of formatted bytes, and I can see how to create a CGBitmapContext to write to. But I can't seem to find an easy way to create a CGImage from a raw pixel array.
推荐答案CGDataProvider ,让CG从您的提供者请求必要的数据,而不是写入图像缓冲区。
You can create a CGDataProvider, and let CG request the necessary data from your provider, instead of writing to an image buffer.
一个非常简单的例子,生成大小为64x64的黑色 CGImage 。
Here's a very simple example that generates a black CGImage of size 64x64.
CGDataProviderSequentialCallbacks callbacks; callbacks.getBytes = getBytes; CGDataProviderRef provider = CGDataProviderCreateSequential(NULL, &callbacks); CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB(); CGImageRef img = CGImageCreate(64, // width 64, // height 8, // bitsPerComponent 24, // bitsPerPixel 64*3, // bytesPerRow space, // colorspace kCGBitmapByteOrderDefault, // bitmapInfo provider, // CGDataProvider NULL, // decode array NO, // shouldInterpolate kCGRenderingIntentDefault); // intent CGColorSpaceRelease(space); CGDataProviderRelease(provider); // use the created CGImage CGImageRelease(img);,getBytes的定义如下:
and getBytes is defined like this:
size_t getBytes(void *info, void *buffer, size_t count) { memset(buffer, 0x00, count); return count; }当然,您将需要实现其他回调( skipForward , rewind , releaseInfo ),并使用适当的结构或对象 info 。
of course, you will want to implement the other callbacks (skipForward, rewind, releaseInfo), and use a proper structure or object for info.
有关详细信息,请查看 CGImage 和 CGDataProvider 参考。
For more information, check out the CGImage and CGDataProvider references.
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