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re-using pre allocated pixel row in GetPixelRow

pull/673/head
popow 8 years ago
parent
09955daa33
commit
66b75503c5
1 changed files with 9 additions and 6 deletions
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  1. 15
      src/ImageSharp/Processing/Processors/Normalization/AdaptiveHistEqualizationSWProcessor.cs

15
src/ImageSharp/Processing/Processors/Normalization/AdaptiveHistEqualizationSWProcessor.cs
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@ -63,16 +63,18 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
using (System.Buffers.IMemoryOwner<int> histogramBuffer = memoryAllocator.Allocate<int>(this.LuminanceLevels, AllocationOptions.Clean)) using (System.Buffers.IMemoryOwner<int> histogramBuffer = memoryAllocator.Allocate<int>(this.LuminanceLevels, AllocationOptions.Clean))
using (System.Buffers.IMemoryOwner<int> histogramBufferCopy = memoryAllocator.Allocate<int>(this.LuminanceLevels, AllocationOptions.Clean)) using (System.Buffers.IMemoryOwner<int> histogramBufferCopy = memoryAllocator.Allocate<int>(this.LuminanceLevels, AllocationOptions.Clean))
using (System.Buffers.IMemoryOwner<int> cdfBuffer = memoryAllocator.Allocate<int>(this.LuminanceLevels, AllocationOptions.Clean)) using (System.Buffers.IMemoryOwner<int> cdfBuffer = memoryAllocator.Allocate<int>(this.LuminanceLevels, AllocationOptions.Clean))
using (System.Buffers.IMemoryOwner<TPixel> pixelRowBuffer = memoryAllocator.Allocate<TPixel>(tileWidth, AllocationOptions.Clean))
{ {
Span<int> histogram = histogramBuffer.GetSpan(); Span<int> histogram = histogramBuffer.GetSpan();
Span<int> histogramCopy = histogramBufferCopy.GetSpan(); Span<int> histogramCopy = histogramBufferCopy.GetSpan();
Span<int> cdf = cdfBuffer.GetSpan(); Span<int> cdf = cdfBuffer.GetSpan();
Span<TPixel> pixelRow = pixelRowBuffer.GetSpan();
int maxHistIdx = 0; int maxHistIdx = 0;
// Build the histogram of grayscale values for the current grid. // Build the histogram of grayscale values for the current grid.
for (int dy = -halfTileWith; dy < halfTileWith; dy++) for (int dy = -halfTileWith; dy < halfTileWith; dy++)
{ {
Span<TPixel> rowSpan = this.GetPixelRow(source, (int)x - halfTileWith, dy, tileWidth); Span<TPixel> rowSpan = this.GetPixelRow(source, pixelRow, (int)x - halfTileWith, dy, tileWidth);
int maxIdx = this.AddPixelsToHistogram(rowSpan, histogram, this.LuminanceLevels); int maxIdx = this.AddPixelsToHistogram(rowSpan, histogram, this.LuminanceLevels);
if (maxIdx > maxHistIdx) if (maxIdx > maxHistIdx)
{ {
@ -99,11 +101,11 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
targetPixels[x, y].FromVector4(new Vector4(luminanceEqualized)); targetPixels[x, y].FromVector4(new Vector4(luminanceEqualized));
// Remove top most row from the histogram, mirroring rows which exceeds the borders. // Remove top most row from the histogram, mirroring rows which exceeds the borders.
Span<TPixel> rowSpan = this.GetPixelRow(source, x - halfTileWith, y - halfTileWith, tileWidth); Span<TPixel> rowSpan = this.GetPixelRow(source, pixelRow, x - halfTileWith, y - halfTileWith, tileWidth);
maxHistIdx = this.RemovePixelsFromHistogram(rowSpan, histogram, this.LuminanceLevels, maxHistIdx); maxHistIdx = this.RemovePixelsFromHistogram(rowSpan, histogram, this.LuminanceLevels, maxHistIdx);
// Add new bottom row to the histogram, mirroring rows which exceeds the borders. // Add new bottom row to the histogram, mirroring rows which exceeds the borders.
rowSpan = this.GetPixelRow(source, x - halfTileWith, y + halfTileWith, tileWidth); rowSpan = this.GetPixelRow(source, pixelRow, x - halfTileWith, y + halfTileWith, tileWidth);
int maxIdx = this.AddPixelsToHistogram(rowSpan, histogram, this.LuminanceLevels); int maxIdx = this.AddPixelsToHistogram(rowSpan, histogram, this.LuminanceLevels);
if (maxIdx > maxHistIdx) if (maxIdx > maxHistIdx)
{ {
@ -121,12 +123,15 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
/// Get the a pixel row at a given position with a length of the tile width. Mirrors pixels which exceeds the edges. /// Get the a pixel row at a given position with a length of the tile width. Mirrors pixels which exceeds the edges.
/// </summary> /// </summary>
/// <param name="source">The source image.</param> /// <param name="source">The source image.</param>
/// <param name="rowPixels">Pre-allocated pixel row span of the size of a tile width.</param>
/// <param name="x">The x position.</param> /// <param name="x">The x position.</param>
/// <param name="y">The y position.</param> /// <param name="y">The y position.</param>
/// <param name="tileWidth">The width in pixels of a tile.</param> /// <param name="tileWidth">The width in pixels of a tile.</param>
/// <returns>A pixel row of the length of the tile width.</returns> /// <returns>A pixel row of the length of the tile width.</returns>
private Span<TPixel> GetPixelRow(ImageFrame<TPixel> source, int x, int y, int tileWidth) private Span<TPixel> GetPixelRow(ImageFrame<TPixel> source, Span<TPixel> rowPixels, int x, int y, int tileWidth)
{ {
rowPixels.Clear();
if (y < 0) if (y < 0)
{ {
y = Math.Abs(y); y = Math.Abs(y);
@ -140,7 +145,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
// Special cases for the left and the right border where GetPixelRowSpan can not be used // Special cases for the left and the right border where GetPixelRowSpan can not be used
if (x < 0) if (x < 0)
{ {
var rowPixels = new TPixel[tileWidth];
int idx = 0; int idx = 0;
for (int dx = x; dx < x + tileWidth; dx++) for (int dx = x; dx < x + tileWidth; dx++)
{ {
@ -152,7 +156,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
} }
else if (x + tileWidth > source.Width) else if (x + tileWidth > source.Width)
{ {
var rowPixels = new TPixel[tileWidth];
int idx = 0; int idx = 0;
for (int dx = x; dx < x + tileWidth; dx++) for (int dx = x; dx < x + tileWidth; dx++)
{ {

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