Is there a way to check if a single frame image has been loaded as contiguous in memory without allocating an IMemoryGroup<T>?

[DrkWzrd]

Just the question in the title.

[JimBobSquarePants]

You can actually enforce it.

https://docs.sixlabors.com/articles/imagesharp/memorymanagement.html#enforcing-contiguous-buffers

[DrkWzrd]

@JimBobSquarePants

Yeah, I know I can enforce it, but I want to know if exists a way to know it, because if you can fiddle with the bytes of an image instance that is provided by another one library (to make buffer copies, etc), I need to know if I have to use the 'memorygroup' to traverse the 'memories' or just make a 'dangerous get memory' from the image. Or maybe I'm missing something.

The point is this code I'm using right now

private void CopyToBuffer(Int32Rect sourceRect, int stride, int bytesPerPixel, Span<byte> actualBuffer)
{
    for (int y = 0; y < sourceRect.Height; y++)
    {
        Span<byte> bufferRowSection = actualBuffer.Slice(y * stride + sourceRect.X * bytesPerPixel, sourceRect.Width * bytesPerPixel);

        Memory<Bgra32> sourceRowMemory = Source.DangerousGetPixelRowMemory(y + sourceRect.Y);
        Span<Bgra32> sourceRowSectionSpan = sourceRowMemory.Span.Slice(sourceRect.X, sourceRect.Width);
        Span<byte> rawSourceRowSectionSpan = MemoryMarshal.Cast<Bgra32, byte>(sourceRowSectionSpan);
        rawSourceRowSectionSpan.CopyTo(bufferRowSection);
    }
}

My point is "If I would know if the image is a contiguous block, when copying an Int32Rect(0,0,w,h), I could do a block copy, instead of traverse every row".

Again, maybe I'm missing something.

Offtopic, is there a more efficient way to do what I intent I'm not seeing?

[JimBobSquarePants]

There’s actually an example at the docs link.

Configuration customConfig = Configuration.Default.Clone();
customConfig.PreferContiguousImageBuffers = true;

using (Image<Rgba32> image = new(customConfig, 4096, 4096))
{
    if (!image.DangerousTryGetSinglePixelMemory(out Memory<Rgba32> memory))
    {
        throw new Exception(
            "This can only happen with multi-GB images or when PreferContiguousImageBuffers is not set to true.");
    }

    using (MemoryHandle pinHandle = memory.Pin())
    {
        void* ptr = pinHandle.Pointer;

        // You can now pass 'ptr' to native API-s.
        // Make sure to keep 'pinHandle', and 'image' alive while native resource work with the pointer.
        // Make sure to Dispose() them afterwards.
    }
}