// [Fact]
public void PrintWeightsData()
{
var size = new Size(500, 500);
var proc = new ResizeProcessor <Rgba32>(KnownResamplers.Bicubic, 200, 200, size);
WeightsBuffer weights = proc.PrecomputeWeights(Configuration.Default.MemoryManager, proc.Width, size.Width);
var bld = new StringBuilder();
foreach (WeightsWindow window in weights.Weights)
{
Span <float> span = window.GetWindowSpan();
for (int i = 0; i < window.Length; i++)
{
float value = span[i];
bld.Append(value);
bld.Append("| ");
}
bld.AppendLine();
}
File.WriteAllText("BicubicWeights.MD", bld.ToString());
// this.Output.WriteLine(bld.ToString());
}
/// <inheritdoc />
protected override void AfterApply(ImageBase <TColor> source, Rectangle sourceRectangle)
{
base.AfterApply(source, sourceRectangle);
this.HorizontalWeights?.Dispose();
this.HorizontalWeights = null;
this.VerticalWeights?.Dispose();
this.VerticalWeights = null;
}
/// <summary>
/// Computes the weights to apply at each pixel when resizing.
/// </summary>
/// <param name="destinationSize">The destination size</param>
/// <param name="sourceSize">The source size</param>
/// <returns>The <see cref="WeightsBuffer"/></returns>
// TODO: Made internal to simplify experimenting with weights data. Make it protected again when finished figuring out how to optimize all the stuff!
internal unsafe WeightsBuffer PrecomputeWeights(int destinationSize, int sourceSize)
{
float ratio = (float)sourceSize / destinationSize;
float scale = ratio;
if (scale < 1F)
{
scale = 1F;
}
IResampler sampler = this.Sampler;
float radius = MathF.Ceiling(scale * sampler.Radius);
WeightsBuffer result = new WeightsBuffer(sourceSize, destinationSize);
for (int i = 0; i < destinationSize; i++)
{
float center = ((i + .5F) * ratio) - .5F;
// Keep inside bounds.
int left = (int)Math.Ceiling(center - radius);
if (left < 0)
{
left = 0;
}
int right = (int)Math.Floor(center + radius);
if (right > sourceSize - 1)
{
right = sourceSize - 1;
}
float sum = 0;
WeightsWindow ws = result.GetWeightsWindow(i, left, right);
result.Weights[i] = ws;
ref float weights = ref ws.Ptr;
for (int j = left; j <= right; j++)
{
float weight = sampler.GetValue((j - center) / scale);
sum += weight;
// weights[j - left] = weight:
Unsafe.Add(ref weights, j - left) = weight;
}
// Normalise, best to do it here rather than in the pixel loop later on.
if (sum > 0)
{
for (int w = 0; w < ws.Length; w++)
{
// weights[w] = weights[w] / sum:
ref float wRef = ref Unsafe.Add(ref weights, w);
wRef = wRef / sum;
}
}
/// <inheritdoc/>
protected override void BeforeApply(ImageBase <TColor> source, Rectangle sourceRectangle)
{
if (!(this.Sampler is NearestNeighborResampler))
{
this.HorizontalWeights = this.PrecomputeWeights(
this.ResizeRectangle.Width,
sourceRectangle.Width);
this.VerticalWeights = this.PrecomputeWeights(
this.ResizeRectangle.Height,
sourceRectangle.Height);
}
}
