/// <inheritdoc/>
protected override void OnFrameApply(ImageFrame <TPixel> source, Rectangle sourceRectangle, Configuration configuration)
{
int startY = sourceRectangle.Y;
int endY = sourceRectangle.Bottom;
int startX = sourceRectangle.X;
int endX = sourceRectangle.Right;
TPixel glowColor = this.GlowColor;
Vector2 center = Rectangle.Center(sourceRectangle);
float finalRadius = this.Radius.Calculate(source.Size());
float maxDistance = finalRadius > 0 ? MathF.Min(finalRadius, sourceRectangle.Width * .5F) : sourceRectangle.Width * .5F;
// Align start/end positions.
int minX = Math.Max(0, startX);
int maxX = Math.Min(source.Width, endX);
int minY = Math.Max(0, startY);
int maxY = Math.Min(source.Height, endY);
// Reset offset if necessary.
if (minX > 0)
{
startX = 0;
}
if (minY > 0)
{
startY = 0;
}
int width = maxX - minX;
using (IMemoryOwner <TPixel> rowColors = source.MemoryAllocator.Allocate <TPixel>(width))
{
// Be careful! Do not capture rowColorsSpan in the lambda below!
Span <TPixel> rowColorsSpan = rowColors.GetSpan();
for (int i = 0; i < width; i++)
{
rowColorsSpan[i] = glowColor;
}
ParallelFor.WithTemporaryBuffer <float>(
minY,
maxY,
configuration,
width,
(y, amounts) =>
{
Span <float> amountsSpan = amounts.GetSpan();
int offsetY = y - startY;
int offsetX = minX - startX;
for (int i = 0; i < width; i++)
{
float distance = Vector2.Distance(center, new Vector2(i + offsetX, offsetY));
amountsSpan[i] = (this.GraphicsOptions.BlendPercentage * (1 - (.95F * (distance / maxDistance)))).Clamp(0, 1);
}
Span <TPixel> destination = source.GetPixelRowSpan(offsetY).Slice(offsetX, width);
this.blender.Blend(source.MemoryAllocator, destination, destination, rowColors.GetSpan(), amountsSpan);
});
}
}
