/// <summary>
/// Fills the bottom right quadrant with all the colors producible by converting iterating over a uint and unpacking it.
/// A better algorithm could be used but it works
/// </summary>
private static void Rainbow(Buffer2D <TPixel> pixels)
{
int left = pixels.Width / 2;
int right = pixels.Width;
int top = pixels.Height / 2;
int bottom = pixels.Height;
int pixelCount = left * top;
uint stepsPerPixel = (uint)(uint.MaxValue / pixelCount);
TPixel c = default;
var t = new Rgba32(0);
for (int x = left; x < right; x++)
{
for (int y = top; y < bottom; y++)
{
t.PackedValue += stepsPerPixel;
var v = t.ToVector4();
// v.W = (x - left) / (float)left;
c.FromVector4(v);
pixels[x, y] = c;
}
}
}
private static TPixel GetBottomRightColor()
{
TPixel bottomRightColor = default;
bottomRightColor.FromVector4(new Vector4(1f, 0f, 1f, 0.5f));
return(bottomRightColor);
}
public override Image <TPixel> GetImage()
{
var result = new Image <TPixel>(this.Configuration, this.Width, this.Height);
TPixel topLeftColor = Color.Red.ToPixel <TPixel>();
TPixel topRightColor = Color.Green.ToPixel <TPixel>();
TPixel bottomLeftColor = Color.Blue.ToPixel <TPixel>();
// Transparent purple:
TPixel bottomRightColor = default;
bottomRightColor.FromVector4(new Vector4(1f, 0f, 1f, 0.5f));
int midY = this.Height / 2;
int midX = this.Width / 2;
for (int y = 0; y < midY; y++)
{
Span <TPixel> row = result.GetPixelRowSpan(y);
row.Slice(0, midX).Fill(topLeftColor);
row.Slice(midX, this.Width - midX).Fill(topRightColor);
}
for (int y = midY; y < this.Height; y++)
{
Span <TPixel> row = result.GetPixelRowSpan(y);
row.Slice(0, midX).Fill(bottomLeftColor);
row.Slice(midX, this.Width - midX).Fill(bottomRightColor);
}
return(result);
}
/// <summary>
/// Fills the bottom left quadrent with 3 horizental bars in Red, Green and Blue with a alpha gradient from left (transparent) to right (solid).
/// </summary>
/// <param name="pixels"></param>
private static void TransparentGradients(Buffer2D <TPixel> pixels)
{
// topLeft
int left = 0;
int right = pixels.Width / 2;
int top = pixels.Height / 2;
int bottom = pixels.Height;
int height = (int)Math.Ceiling(pixels.Height / 6f);
Vector4 red = Rgba32.Red.ToVector4(); // use real color so we can see har it translates in the test pattern
Vector4 green = Rgba32.Green.ToVector4(); // use real color so we can see har it translates in the test pattern
Vector4 blue = Rgba32.Blue.ToVector4(); // use real color so we can see har it translates in the test pattern
TPixel c = default(TPixel);
for (int x = left; x < right; x++)
{
blue.W = red.W = green.W = (float)x / (float)right;
c.FromVector4(red);
int topBand = top;
for (int y = topBand; y < top + height; y++)
{
pixels[x, y] = c;
}
topBand = topBand + height;
c.FromVector4(green);
for (int y = topBand; y < topBand + height; y++)
{
pixels[x, y] = c;
}
topBand = topBand + height;
c.FromVector4(blue);
for (int y = topBand; y < bottom; y++)
{
pixels[x, y] = c;
}
}
}