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Use GetPixelRowSpan to access pixels, fixes #1429

pull/1431/head
Brian Popow 6 years ago
parent
dea0737464
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7040ca7abe
1 changed files with 30 additions and 40 deletions
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  1. 70
      src/ImageSharp/Processing/Processors/Normalization/AdaptiveHistogramEqualizationProcessor{TPixel}.cs

70
src/ImageSharp/Processing/Processors/Normalization/AdaptiveHistogramEqualizationProcessor{TPixel}.cs
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@ -86,42 +86,39 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
new Rectangle(0, 0, sourceWidth, tileYStartPositions.Count),
in operation);
ref TPixel pixelsBase = ref source.GetPixelReference(0, 0);
// Fix left column
ProcessBorderColumn(ref pixelsBase, cdfData, 0, sourceWidth, sourceHeight, this.Tiles, tileHeight, xStart: 0, xEnd: halfTileWidth, luminanceLevels);
ProcessBorderColumn(source, cdfData, 0, sourceHeight, this.Tiles, tileHeight, xStart: 0, xEnd: halfTileWidth, luminanceLevels);
// Fix right column
int rightBorderStartX = ((this.Tiles - 1) * tileWidth) + halfTileWidth;
ProcessBorderColumn(ref pixelsBase, cdfData, this.Tiles - 1, sourceWidth, sourceHeight, this.Tiles, tileHeight, xStart: rightBorderStartX, xEnd: sourceWidth, luminanceLevels);
ProcessBorderColumn(source, cdfData, this.Tiles - 1, sourceHeight, this.Tiles, tileHeight, xStart: rightBorderStartX, xEnd: sourceWidth, luminanceLevels);
// Fix top row
ProcessBorderRow(ref pixelsBase, cdfData, 0, sourceWidth, this.Tiles, tileWidth, yStart: 0, yEnd: halfTileHeight, luminanceLevels);
ProcessBorderRow(source, cdfData, 0, sourceWidth, this.Tiles, tileWidth, yStart: 0, yEnd: halfTileHeight, luminanceLevels);
// Fix bottom row
int bottomBorderStartY = ((this.Tiles - 1) * tileHeight) + halfTileHeight;
ProcessBorderRow(ref pixelsBase, cdfData, this.Tiles - 1, sourceWidth, this.Tiles, tileWidth, yStart: bottomBorderStartY, yEnd: sourceHeight, luminanceLevels);
ProcessBorderRow(source, cdfData, this.Tiles - 1, sourceWidth, this.Tiles, tileWidth, yStart: bottomBorderStartY, yEnd: sourceHeight, luminanceLevels);
// Left top corner
ProcessCornerTile(ref pixelsBase, cdfData, sourceWidth, 0, 0, xStart: 0, xEnd: halfTileWidth, yStart: 0, yEnd: halfTileHeight, luminanceLevels);
ProcessCornerTile(source, cdfData, 0, 0, xStart: 0, xEnd: halfTileWidth, yStart: 0, yEnd: halfTileHeight, luminanceLevels);
// Left bottom corner
ProcessCornerTile(ref pixelsBase, cdfData, sourceWidth, 0, this.Tiles - 1, xStart: 0, xEnd: halfTileWidth, yStart: bottomBorderStartY, yEnd: sourceHeight, luminanceLevels);
ProcessCornerTile(source, cdfData, 0, this.Tiles - 1, xStart: 0, xEnd: halfTileWidth, yStart: bottomBorderStartY, yEnd: sourceHeight, luminanceLevels);
// Right top corner
ProcessCornerTile(ref pixelsBase, cdfData, sourceWidth, this.Tiles - 1, 0, xStart: rightBorderStartX, xEnd: sourceWidth, yStart: 0, yEnd: halfTileHeight, luminanceLevels);
ProcessCornerTile(source, cdfData, this.Tiles - 1, 0, xStart: rightBorderStartX, xEnd: sourceWidth, yStart: 0, yEnd: halfTileHeight, luminanceLevels);
// Right bottom corner
ProcessCornerTile(ref pixelsBase, cdfData, sourceWidth, this.Tiles - 1, this.Tiles - 1, xStart: rightBorderStartX, xEnd: sourceWidth, yStart: bottomBorderStartY, yEnd: sourceHeight, luminanceLevels);
ProcessCornerTile(source, cdfData, this.Tiles - 1, this.Tiles - 1, xStart: rightBorderStartX, xEnd: sourceWidth, yStart: bottomBorderStartY, yEnd: sourceHeight, luminanceLevels);
}
}
/// <summary>
/// Processes the part of a corner tile which was previously left out. It consists of 1 / 4 of a tile and does not need interpolation.
/// </summary>
/// <param name="pixelsBase">The output pixels base reference.</param>
/// <param name="source">The source image.</param>
/// <param name="cdfData">The lookup table to remap the grey values.</param>
/// <param name="sourceWidth">The source image width.</param>
/// <param name="cdfX">The x-position in the CDF lookup map.</param>
/// <param name="cdfY">The y-position in the CDF lookup map.</param>
/// <param name="xStart">X start position.</param>
@ -133,9 +130,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
/// or 65536 for 16-bit grayscale images.
/// </param>
private static void ProcessCornerTile(
ref TPixel pixelsBase,
ImageFrame<TPixel> source,
CdfTileData cdfData,
int sourceWidth,
int cdfX,
int cdfY,
int xStart,
@ -146,12 +142,12 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
{
for (int dy = yStart; dy < yEnd; dy++)
{
int dyOffSet = dy * sourceWidth;
Span<TPixel> rowSpan = source.GetPixelRowSpan(dy);
for (int dx = xStart; dx < xEnd; dx++)
{
ref TPixel pixel = ref Unsafe.Add(ref pixelsBase, dyOffSet + dx);
TPixel pixel = rowSpan[dx];
float luminanceEqualized = cdfData.RemapGreyValue(cdfX, cdfY, GetLuminance(pixel, luminanceLevels));
pixel.FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
rowSpan[dx].FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
}
}
}
@ -159,10 +155,9 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
/// <summary>
/// Processes a border column of the image which is half the size of the tile width.
/// </summary>
/// <param name="pixelBase">The output pixels reference.</param>
/// <param name="source">The source image.</param>
/// <param name="cdfData">The pre-computed lookup tables to remap the grey values for each tiles.</param>
/// <param name="cdfX">The X index of the lookup table to use.</param>
/// <param name="sourceWidth">The source image width.</param>
/// <param name="sourceHeight">The source image height.</param>
/// <param name="tileCount">The number of vertical tiles.</param>
/// <param name="tileHeight">The height of a tile.</param>
@ -173,10 +168,9 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
/// or 65536 for 16-bit grayscale images.
/// </param>
private static void ProcessBorderColumn(
ref TPixel pixelBase,
ImageFrame<TPixel> source,
CdfTileData cdfData,
int cdfX,
int sourceWidth,
int sourceHeight,
int tileCount,
int tileHeight,
@ -194,12 +188,12 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
int tileY = 0;
for (int dy = y; dy < yLimit; dy++)
{
int dyOffSet = dy * sourceWidth;
Span<TPixel> rowSpan = source.GetPixelRowSpan(dy);
for (int dx = xStart; dx < xEnd; dx++)
{
ref TPixel pixel = ref Unsafe.Add(ref pixelBase, dyOffSet + dx);
TPixel pixel = rowSpan[dx];
float luminanceEqualized = InterpolateBetweenTwoTiles(pixel, cdfData, cdfX, cdfY, cdfX, cdfY + 1, tileY, tileHeight, luminanceLevels);
pixel.FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
rowSpan[dx].FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
}
tileY++;
@ -213,7 +207,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
/// <summary>
/// Processes a border row of the image which is half of the size of the tile height.
/// </summary>
/// <param name="pixelBase">The output pixels base reference.</param>
/// <param name="source">The source image.</param>
/// <param name="cdfData">The pre-computed lookup tables to remap the grey values for each tiles.</param>
/// <param name="cdfY">The Y index of the lookup table to use.</param>
/// <param name="sourceWidth">The source image width.</param>
@ -226,7 +220,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
/// or 65536 for 16-bit grayscale images.
/// </param>
private static void ProcessBorderRow(
ref TPixel pixelBase,
ImageFrame<TPixel> source,
CdfTileData cdfData,
int cdfY,
int sourceWidth,
@ -244,14 +238,14 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
{
for (int dy = yStart; dy < yEnd; dy++)
{
int dyOffSet = dy * sourceWidth;
Span<TPixel> rowSpan = source.GetPixelRowSpan(dy);
int tileX = 0;
int xLimit = Math.Min(x + tileWidth, sourceWidth - 1);
for (int dx = x; dx < xLimit; dx++)
{
ref TPixel pixel = ref Unsafe.Add(ref pixelBase, dyOffSet + dx);
TPixel pixel = rowSpan[dx];
float luminanceEqualized = InterpolateBetweenTwoTiles(pixel, cdfData, cdfX, cdfY, cdfX + 1, cdfY, tileX, tileWidth, luminanceLevels);
pixel.FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
rowSpan[dx].FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
tileX++;
}
}
@ -410,8 +404,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
[MethodImpl(InliningOptions.ShortMethod)]
public void Invoke(in RowInterval rows)
{
ref TPixel sourceBase = ref this.source.GetPixelReference(0, 0);
for (int index = rows.Min; index < rows.Max; index++)
{
(int y, int cdfY) tileYStartPosition = this.tileYStartPositions[index];
@ -427,11 +419,11 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
int xEnd = Math.Min(x + this.tileWidth, this.sourceWidth);
for (int dy = y; dy < yEnd; dy++)
{
int dyOffSet = dy * this.sourceWidth;
Span<TPixel> rowSpan = this.source.GetPixelRowSpan(dy);
int tileX = 0;
for (int dx = x; dx < xEnd; dx++)
{
ref TPixel pixel = ref Unsafe.Add(ref sourceBase, dyOffSet + dx);
TPixel pixel = rowSpan[dx];
float luminanceEqualized = InterpolateBetweenFourTiles(
pixel,
this.cdfData,
@ -445,7 +437,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
this.tileHeight,
this.luminanceLevels);
pixel.FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
rowSpan[dx].FromVector4(new Vector4(luminanceEqualized, luminanceEqualized, luminanceEqualized, pixel.ToVector4().W));
tileX++;
}
@ -597,15 +589,13 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
[MethodImpl(InliningOptions.ShortMethod)]
public void Invoke(in RowInterval rows)
{
ref TPixel sourceBase = ref this.source.GetPixelReference(0, 0);
for (int index = rows.Min; index < rows.Max; index++)
{
int cdfX = 0;
int cdfY = this.tileYStartPositions[index].cdfY;
int y = this.tileYStartPositions[index].y;
int endY = Math.Min(y + this.tileHeight, this.sourceHeight);
ref int cdfMinBase = ref MemoryMarshal.GetReference(this.cdfMinBuffer2D.GetRowSpan(cdfY));
Span<int> cdfMinSpan = this.cdfMinBuffer2D.GetRowSpan(cdfY);
using IMemoryOwner<int> histogramBuffer = this.allocator.Allocate<int>(this.luminanceLevels);
Span<int> histogram = histogramBuffer.GetSpan();
@ -620,10 +610,10 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
int xlimit = Math.Min(x + this.tileWidth, this.sourceWidth);
for (int dy = y; dy < endY; dy++)
{
int dyOffset = dy * this.sourceWidth;
Span<TPixel> rowSpan = this.source.GetPixelRowSpan(dy);
for (int dx = x; dx < xlimit; dx++)
{
int luminance = GetLuminance(Unsafe.Add(ref sourceBase, dyOffset + dx), this.luminanceLevels);
int luminance = GetLuminance(rowSpan[dx], this.luminanceLevels);
histogram[luminance]++;
}
}
@ -633,7 +623,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Normalization
this.processor.ClipHistogram(histogram, this.processor.ClipLimit);
}
Unsafe.Add(ref cdfMinBase, cdfX) = this.processor.CalculateCdf(ref cdfBase, ref histogramBase, histogram.Length - 1);
cdfMinSpan[cdfX] += this.processor.CalculateCdf(ref cdfBase, ref histogramBase, histogram.Length - 1);
cdfX++;
}

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