public static IPixelViewModel Crop(IPixelViewModel pixels, int left, int top, int right, int bottom)
{
var(width, height) = (pixels.PixelWidth - left - right, pixels.PixelHeight - top - bottom);
Debug.Assert(width % 8 == 0, $"Cropped image must still have a width/height that's a multiple of 8, but width was {width}.");
Debug.Assert(height % 8 == 0, $"Cropped image must still have a width/height that's a multiple of 8, but height was {height}.");
var pixelData = new short[width * height];
for (int y = 0; y < height; y++)
{
var originalDataStart = pixels.PixelWidth * (y + top) + left;
if (originalDataStart < 0)
{
continue;
}
var croppedDataStart = width * y;
Array.Copy(pixels.PixelData, originalDataStart, pixelData, croppedDataStart, width);
}
return(new ReadonlyPixelViewModel(new SpriteFormat(4, width / 8, height / 8, string.Empty), pixelData));
}
public static IPixelViewModel DuplicateDown(IPixelViewModel pixels, int count)
{
if (count == 1)
{
return(pixels);
}
Debug.Assert(count > 0, $"Cannot duplicate {count} times.");
var pixelData = new short[pixels.PixelWidth * pixels.PixelHeight * count];
for (int y = 0; y < pixels.PixelHeight; y++)
{
var originalDataStart = pixels.PixelWidth * y;
for (int i = 0; i < count; i++)
{
var newDataStart = pixels.PixelWidth * y + pixels.PixelData.Length * i;
Array.Copy(pixels.PixelData, originalDataStart, pixelData, newDataStart, pixels.PixelWidth);
}
}
return(new ReadonlyPixelViewModel(new SpriteFormat(4, pixels.PixelWidth / 8, pixels.PixelHeight / 8 * count, string.Empty), pixelData));
}
