@ -23,11 +23,6 @@ namespace SixLabors.ImageSharp.Quantizers
/// </summary>
private readonly Dictionary < TPixel , byte > colorMap = new Dictionary < TPixel , byte > ( ) ;
/// <summary>
/// The pixel buffer, used to reduce allocations.
/// </summary>
private readonly byte [ ] pixelBuffer = new byte [ 4 ] ;
/// <summary>
/// Stores the tree
/// </summary>
@ -43,6 +38,11 @@ namespace SixLabors.ImageSharp.Quantizers
/// </summary>
private TPixel [ ] palette ;
/// <summary>
/// The transparent index
/// </summary>
private byte transparentIndex ;
/// <summary>
/// Initializes a new instance of the <see cref="OctreeQuantizer{TPixel}"/> class.
/// </summary>
@ -61,6 +61,7 @@ namespace SixLabors.ImageSharp.Quantizers
this . colors = ( byte ) maxColors . Clamp ( 1 , 2 5 5 ) ;
this . octree = new Octree ( this . GetBitsNeededForColorDepth ( this . colors ) ) ;
this . palette = null ;
this . colorMap . Clear ( ) ;
return base . Quantize ( image , this . colors ) ;
}
@ -72,7 +73,8 @@ namespace SixLabors.ImageSharp.Quantizers
// pass of the algorithm by avoiding transforming rows of identical color.
TPixel sourcePixel = source [ 0 , 0 ] ;
TPixel previousPixel = sourcePixel ;
byte pixelValue = this . QuantizePixel ( sourcePixel ) ;
var rgba = default ( Rgba32 ) ;
byte pixelValue = this . QuantizePixel ( sourcePixel , ref rgba ) ;
TPixel [ ] colorPalette = this . GetPalette ( ) ;
TPixel transformedPixel = colorPalette [ pixelValue ] ;
@ -91,7 +93,7 @@ namespace SixLabors.ImageSharp.Quantizers
if ( ! previousPixel . Equals ( sourcePixel ) )
{
// Quantize the pixel
pixelValue = this . QuantizePixel ( sourcePixel ) ;
pixelValue = this . QuantizePixel ( sourcePixel , ref rgba ) ;
// And setup the previous pointer
previousPixel = sourcePixel ;
@ -117,24 +119,57 @@ namespace SixLabors.ImageSharp.Quantizers
protected override void InitialQuantizePixel ( TPixel pixel )
{
// Add the color to the Octree
this . octree . AddColor ( pixel , this . pixelBuffer ) ;
var rgba = default ( Rgba32 ) ;
this . octree . AddColor ( pixel , ref rgba ) ;
}
/// <inheritdoc/>
protected override TPixel [ ] GetPalette ( )
{
return this . palette ? ? ( this . palette = this . octree . Palletize ( Math . Max ( this . colors , ( byte ) 1 ) ) ) ;
if ( this . palette = = null )
{
this . palette = this . octree . Palletize ( Math . Max ( this . colors , ( byte ) 1 ) ) ;
this . transparentIndex = this . GetTransparentIndex ( ) ;
}
return this . palette ;
}
/// <summary>
/// Returns the index of the first instance of the transparent color in the palette.
/// </summary>
/// <returns>
/// The <see cref="int"/>.
/// </returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private byte GetTransparentIndex ( )
{
// Transparent pixels are much more likely to be found at the end of a palette
int index = this . colors ;
var trans = default ( Rgba32 ) ;
for ( int i = this . palette . Length - 1 ; i > = 0 ; i - - )
{
this . palette [ i ] . ToRgba32 ( ref trans ) ;
if ( trans . Equals ( default ( Rgba32 ) ) )
{
index = i ;
}
}
return ( byte ) index ;
}
/// <summary>
/// Process the pixel in the second pass of the algorithm
/// </summary>
/// <param name="pixel">The pixel to quantize</param>
/// <param name="rgba">The color to compare against</param>
/// <returns>
/// The quantized value
/// </returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private byte QuantizePixel ( TPixel pixel )
private byte QuantizePixel ( TPixel pixel , ref Rgba32 rgba )
{
if ( this . Dither )
{
@ -143,13 +178,13 @@ namespace SixLabors.ImageSharp.Quantizers
return this . GetClosestPixel ( pixel , this . palette , this . colorMap ) ;
}
pixel . ToXyzwBytes ( this . pixelBuffer , 0 ) ;
if ( this . pixelBuffer [ 3 ] = = 0 )
pixel . ToRgba32 ( ref rgba ) ;
if ( rgba . Equals ( default ( Rgba32 ) ) )
{
return this . colors ;
return this . transparentIndex ;
}
return ( byte ) this . octree . GetPaletteIndex ( pixel , this . pixelBuffer ) ;
return ( byte ) this . octree . GetPaletteIndex ( pixel , ref rgba ) ;
}
/// <summary>
@ -232,8 +267,8 @@ namespace SixLabors.ImageSharp.Quantizers
/// Add a given color value to the Octree
/// </summary>
/// <param name="pixel">The pixel data.</param>
/// <param name="buffer">The buffer array .</param>
public void AddColor ( TPixel pixel , byte [ ] buffer )
/// <param name="rgba">The color .</param>
public void AddColor ( TPixel pixel , ref Rgba32 rgba )
{
// Check if this request is for the same color as the last
if ( this . previousColor . Equals ( pixel ) )
@ -243,18 +278,18 @@ namespace SixLabors.ImageSharp.Quantizers
if ( this . previousNode = = null )
{
this . previousColor = pixel ;
this . root . AddColor ( pixel , this . maxColorBits , 0 , this , buffe r) ;
this . root . AddColor ( pixel , this . maxColorBits , 0 , this , ref rgba ) ;
}
else
{
// Just update the previous node
this . previousNode . Increment ( pixel , buffe r) ;
this . previousNode . Increment ( pixel , ref rgba ) ;
}
}
else
{
this . previousColor = pixel ;
this . root . AddColor ( pixel , this . maxColorBits , 0 , this , buffe r) ;
this . root . AddColor ( pixel , this . maxColorBits , 0 , this , ref rgba ) ;
}
}
@ -286,13 +321,13 @@ namespace SixLabors.ImageSharp.Quantizers
/// Get the palette index for the passed color
/// </summary>
/// <param name="pixel">The pixel data.</param>
/// <param name="buffer">The buffer array .</param>
/// <param name="rgba">The color to map to .</param>
/// <returns>
/// The <see cref="int"/>.
/// </returns>
public int GetPaletteIndex ( TPixel pixel , byte [ ] buffer )
public int GetPaletteIndex ( TPixel pixel , ref Rgba32 rgba )
{
return this . root . GetPaletteIndex ( pixel , 0 , buffe r) ;
return this . root . GetPaletteIndex ( pixel , 0 , ref rgba ) ;
}
/// <summary>
@ -414,17 +449,17 @@ namespace SixLabors.ImageSharp.Quantizers
/// <summary>
/// Add a color into the tree
/// </summary>
/// <param name="pixel">The color</param>
/// <param name="pixel">The pixel color</param>
/// <param name="colorBits">The number of significant color bits</param>
/// <param name="level">The level in the tree</param>
/// <param name="octree">The tree to which this node belongs</param>
/// <param name="buffer">The buffer array .</param>
public void AddColor ( TPixel pixel , int colorBits , int level , Octree octree , byte [ ] buffer )
/// <param name="rgba">The color to map to .</param>
public void AddColor ( TPixel pixel , int colorBits , int level , Octree octree , ref Rgba32 rgba )
{
// Update the color information if this is a leaf
if ( this . leaf )
{
this . Increment ( pixel , buffe r) ;
this . Increment ( pixel , ref rgba ) ;
// Setup the previous node
octree . TrackPrevious ( this ) ;
@ -433,11 +468,11 @@ namespace SixLabors.ImageSharp.Quantizers
{
// Go to the next level down in the tree
int shift = 7 - level ;
pixel . ToXyzwBytes ( buffer , 0 ) ;
pixel . ToRgba32 ( ref rgba ) ;
int index = ( ( buffer [ 2 ] & Mask [ level ] ) > > ( shift - 2 ) ) |
( ( buffer [ 1 ] & Mask [ level ] ) > > ( shift - 1 ) ) |
( ( buffer [ 0 ] & Mask [ level ] ) > > shift ) ;
int index = ( ( rgba . B & Mask [ level ] ) > > ( shift - 2 ) ) |
( ( rgba . G & Mask [ level ] ) > > ( shift - 1 ) ) |
( ( rgba . R & Mask [ level ] ) > > shift ) ;
OctreeNode child = this . children [ index ] ;
@ -449,7 +484,7 @@ namespace SixLabors.ImageSharp.Quantizers
}
// Add the color to the child node
child . AddColor ( pixel , colorBits , level + 1 , octree , buffe r) ;
child . AddColor ( pixel , colorBits , level + 1 , octree , ref rgba ) ;
}
}
@ -523,26 +558,26 @@ namespace SixLabors.ImageSharp.Quantizers
/// </summary>
/// <param name="pixel">The pixel data.</param>
/// <param name="level">The level.</param>
/// <param name="buffer">The buffer array .</param>
/// <param name="rgba">The color to map to .</param>
/// <returns>
/// The <see cref="int"/> representing the index of the pixel in the palette.
/// </returns>
public int GetPaletteIndex ( TPixel pixel , int level , byte [ ] buffer )
public int GetPaletteIndex ( TPixel pixel , int level , ref Rgba32 rgba )
{
int index = this . paletteIndex ;
if ( ! this . leaf )
{
int shift = 7 - level ;
pixel . ToXyzwBytes ( buffer , 0 ) ;
pixel . ToRgba32 ( ref rgba ) ;
int pixelIndex = ( ( buffer [ 2 ] & Mask [ level ] ) > > ( shift - 2 ) ) |
( ( buffer [ 1 ] & Mask [ level ] ) > > ( shift - 1 ) ) |
( ( buffer [ 0 ] & Mask [ level ] ) > > shift ) ;
int pixelIndex = ( ( rgba . B & Mask [ level ] ) > > ( shift - 2 ) ) |
( ( rgba . G & Mask [ level ] ) > > ( shift - 1 ) ) |
( ( rgba . R & Mask [ level ] ) > > shift ) ;
if ( this . children [ pixelIndex ] ! = null )
{
index = this . children [ pixelIndex ] . GetPaletteIndex ( pixel , level + 1 , buffe r) ;
index = this . children [ pixelIndex ] . GetPaletteIndex ( pixel , level + 1 , ref rgba ) ;
}
else
{
@ -557,14 +592,14 @@ namespace SixLabors.ImageSharp.Quantizers
/// Increment the pixel count and add to the color information
/// </summary>
/// <param name="pixel">The pixel to add.</param>
/// <param name="buffer">The buffer array .</param>
public void Increment ( TPixel pixel , byte [ ] buffer )
/// <param name="rgba">The color to map to .</param>
public void Increment ( TPixel pixel , ref Rgba32 rgba )
{
pixel . ToXyzwBytes ( buffer , 0 ) ;
pixel . ToRgba32 ( ref rgba ) ;
this . pixelCount + + ;
this . red + = buffer [ 0 ] ;
this . green + = buffer [ 1 ] ;
this . blue + = buffer [ 2 ] ;
this . red + = rgba . R ;
this . green + = rgba . G ;
this . blue + = rgba . B ;
}
}
}
Nikita Balabaev
9 years ago
