Optimization for printing tall images

[jjxtra]

In some cases you have to chunk through images that are very tall (> 2048 pixels height). This allows to print from the raw bit pixel buffers of those images rather than having to save them to png and then pass the png bytes to the print image command.

Chunking code, for reference:

private static IEnumerable<Image<Rgba32>> ExtractChunks(Image<Rgba32> sourceImage)
{
    const int chunkSize = 256;
    for (var y = 0; y < sourceImage.Height; y += chunkSize)
    {
        Rectangle sourceArea = new(0, y, sourceImage.Width, Math.Min(sourceImage.Height - y, chunkSize));
        if (sourceArea.Height < 1)
        {
            yield break;
        }
        Image<Rgba32> targetImage = new(sourceArea.Width, sourceArea.Height);
        int height = sourceArea.Height;
        sourceImage.ProcessPixelRows(targetImage, (sourceAccessor, targetAccessor) =>
        {
            for (int i = 0; i < height; i++)
            {
                Span<Rgba32> sourceRow = sourceAccessor.GetRowSpan(sourceArea.Y + i);
                Span<Rgba32> targetRow = targetAccessor.GetRowSpan(i);
                sourceRow.Slice(sourceArea.X, sourceArea.Width).CopyTo(targetRow);
            }
        });
        yield return targetImage;
    }
}

And example usage:

var mainImage = SixLabors.ImageSharp.Image.Load<Rgba32>(img);
List<byte[]> items = new(16)
{
    e.CenterAlign(),
    e.PrintLine("CENTERED TEXT")
};
foreach (var image in ExtractChunks(mainImage))
{
    var bitPixels = image.ToSingleBitPixelByteArray();
    var bitPixelCommand = e.PrintImageSingleBitPixelByteArray(bitPixels, image.Width, image.Height, false, true);
    items.Add(bitPixelCommand);
}
items.Add(e.FullCutAfterFeed(4));
items.Add(e.FeedLines(4));
await printer.WriteAsync(items.ToArray());

[nivle]

I couldn't get this to work, so I did this