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use transposed buffer in ResizeProcessor

pull/731/head
Anton Firszov 7 years ago
parent
c1afe359db
commit
30a26d52f8
2 changed files with 14 additions and 48 deletions
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  1. 31
      src/ImageSharp/Processing/Processors/Transforms/ResizeKernel.cs
  2. 31
      src/ImageSharp/Processing/Processors/Transforms/ResizeProcessor.cs

31
src/ImageSharp/Processing/Processors/Transforms/ResizeKernel.cs
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@ -78,7 +78,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
/// <param name="sourceX">The source row position.</param>
/// <returns>The weighted sum</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public Vector4 ConvolveRows(Span<Vector4> rowSpan, int sourceX)
public Vector4 Convolve(Span<Vector4> rowSpan, int sourceX)
{
ref float horizontalValues = ref this.GetStartReference();
int left = this.Left;
@ -105,7 +105,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
/// <param name="sourceX">The source row position.</param>
/// <returns>The weighted sum</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public Vector4 ConvolveExpandRows(Span<Vector4> rowSpan, int sourceX)
public Vector4 ConvolveExpand(Span<Vector4> rowSpan, int sourceX)
{
ref float horizontalValues = ref this.GetStartReference();
int left = this.Left;
@ -123,32 +123,5 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
return result;
}
/// <summary>
/// Computes the sum of vectors in 'firstPassPixels' at a row pointed by 'x',
/// weighted by weight values, pointed by this <see cref="ResizeKernel"/> instance.
/// </summary>
/// <param name="firstPassPixels">The buffer of input vectors in row first order</param>
/// <param name="x">The row position</param>
/// <param name="sourceY">The source column position.</param>
/// <returns>The weighted sum</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public Vector4 ConvolveColumnsAndUnPremultiply(Buffer2D<Vector4> firstPassPixels, int x, int sourceY)
{
ref float verticalValues = ref this.GetStartReference();
int left = this.Left;
// Destination color components
Vector4 result = Vector4.Zero;
for (int i = 0; i < this.Length; i++)
{
float yw = Unsafe.Add(ref verticalValues, i);
int index = left + i + sourceY;
result += firstPassPixels[x, index] * yw;
}
return result.UnPremultiply();
}
}
}

31
src/ImageSharp/Processing/Processors/Transforms/ResizeProcessor.cs
View File

@ -233,10 +233,9 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
// A 2-pass 1D algorithm appears to be faster than splitting a 1-pass 2D algorithm
// First process the columns. Since we are not using multiple threads startY and endY
// are the upper and lower bounds of the source rectangle.
// TODO: Using a transposed variant of 'firstPassPixels' could eliminate the need for the WeightsWindow.ComputeWeightedColumnSum() method, and improve speed!
using (Buffer2D<Vector4> firstPassPixels = source.MemoryAllocator.Allocate2D<Vector4>(width, source.Height))
using (Buffer2D<Vector4> firstPassPixelsTransposed = source.MemoryAllocator.Allocate2D<Vector4>(source.Height, width))
{
firstPassPixels.MemorySource.Clear();
firstPassPixelsTransposed.MemorySource.Clear();
var processColsRect = new Rectangle(0, 0, source.Width, sourceRectangle.Bottom);
@ -247,8 +246,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
{
for (int y = rows.Min; y < rows.Max; y++)
{
ref Vector4 firstPassRow =
ref MemoryMarshal.GetReference(firstPassPixels.GetRowSpan(y));
Span<TPixel> sourceRow = source.GetPixelRowSpan(y);
Span<Vector4> tempRowSpan = tempRowBuffer.Span;
@ -260,8 +257,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
for (int x = minX; x < maxX; x++)
{
ResizeKernel window = this.horizontalKernelMap.Kernels[x - startX];
Unsafe.Add(ref firstPassRow, x) =
window.ConvolveExpandRows(tempRowSpan, sourceX).UnPremultiply();
firstPassPixelsTransposed[y, x] = window.ConvolveExpand(tempRowSpan, sourceX).UnPremultiply();
}
}
else
@ -269,8 +265,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
for (int x = minX; x < maxX; x++)
{
ResizeKernel window = this.horizontalKernelMap.Kernels[x - startX];
Unsafe.Add(ref firstPassRow, x) =
window.ConvolveRows(tempRowSpan, sourceX);
firstPassPixelsTransposed[y, x] =
window.Convolve(tempRowSpan, sourceX);
}
}
}
@ -294,12 +290,11 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
{
for (int x = 0; x < width; x++)
{
Span<Vector4> firstPassColumn = firstPassPixelsTransposed.GetRowSpan(x);
// Destination color components
Vector4 destinationVector = window.ConvolveColumnsAndUnPremultiply(
firstPassPixels,
x,
sourceY);
destinationVector = destinationVector.Compress();
Vector4 destinationVector = window.Convolve(firstPassColumn, sourceY);
destinationVector = destinationVector.UnPremultiply().Compress();
ref TPixel pixel = ref Unsafe.Add(ref targetRow, x);
pixel.PackFromVector4(destinationVector);
@ -309,12 +304,10 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
{
for (int x = 0; x < width; x++)
{
// Destination color components
Vector4 destinationVector = window.ConvolveColumnsAndUnPremultiply(
firstPassPixels,
x,
sourceY);
Span<Vector4> firstPassColumn = firstPassPixelsTransposed.GetRowSpan(x);
// Destination color components
Vector4 destinationVector = window.Convolve(firstPassColumn, sourceY).UnPremultiply();
ref TPixel pixel = ref Unsafe.Add(ref targetRow, x);
pixel.PackFromVector4(destinationVector);
}

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