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ImageSharp
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Decoder now performs faster than main

pull/56/head
James Jackson-South 10 years ago
parent
dae509430b
commit
a00b5dd243
1 changed files with 88 additions and 91 deletions
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  1. 179
      src/ImageSharp/Formats/Gif/GifDecoderCore.cs

179
src/ImageSharp/Formats/Gif/GifDecoderCore.cs
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@ -312,12 +312,11 @@ namespace ImageSharp.Formats
TColor[] lastFrame = null;
if (this.graphicsControlExtension != null &&
this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToPrevious)
if (this.graphicsControlExtension != null
&& this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToPrevious)
{
lastFrame = new TColor[imageWidth * imageHeight];
// Array.Copy(this.currentFrame, lastFrame, lastFrame.Length);
using (PixelAccessor<TColor, TPacked> lastPixels = lastFrame.Lock<TColor, TPacked>(imageWidth, imageHeight))
using (PixelAccessor<TColor, TPacked> currentPixels = this.currentFrame.Lock<TColor, TPacked>(imageWidth, imageHeight))
{
@ -325,126 +324,124 @@ namespace ImageSharp.Formats
}
}
int offset, i = 0;
int i = 0;
int interlacePass = 0; // The interlace pass
int interlaceIncrement = 8; // The interlacing line increment
int interlaceY = 0; // The current interlaced line
for (int y = descriptor.Top; y < descriptor.Top + descriptor.Height; y++)
// Lock the current image pixels for fast acces.
using (PixelAccessor<TColor, TPacked> currentPixels = this.currentFrame.Lock<TColor, TPacked>(imageWidth, imageHeight))
{
// Check if this image is interlaced.
int writeY; // the target y offset to write to
if (descriptor.InterlaceFlag)
for (int y = descriptor.Top; y < descriptor.Top + descriptor.Height; y++)
{
// If so then we read lines at predetermined offsets.
// When an entire image height worth of offset lines has been read we consider this a pass.
// With each pass the number of offset lines changes and the starting line changes.
if (interlaceY >= descriptor.Height)
// Check if this image is interlaced.
int writeY; // the target y offset to write to
if (descriptor.InterlaceFlag)
{
interlacePass++;
switch (interlacePass)
// If so then we read lines at predetermined offsets.
// When an entire image height worth of offset lines has been read we consider this a pass.
// With each pass the number of offset lines changes and the starting line changes.
if (interlaceY >= descriptor.Height)
{
case 1:
interlaceY = 4;
break;
case 2:
interlaceY = 2;
interlaceIncrement = 4;
break;
case 3:
interlaceY = 1;
interlaceIncrement = 2;
break;
interlacePass++;
switch (interlacePass)
{
case 1:
interlaceY = 4;
break;
case 2:
interlaceY = 2;
interlaceIncrement = 4;
break;
case 3:
interlaceY = 1;
interlaceIncrement = 2;
break;
}
}
}
writeY = interlaceY + descriptor.Top;
interlaceY += interlaceIncrement;
}
else
{
writeY = y;
}
for (int x = descriptor.Left; x < descriptor.Left + descriptor.Width; x++)
{
offset = (writeY * imageWidth) + x;
int index = indices[i];
writeY = interlaceY + descriptor.Top;
if (this.graphicsControlExtension == null ||
this.graphicsControlExtension.TransparencyFlag == false ||
this.graphicsControlExtension.TransparencyIndex != index)
interlaceY += interlaceIncrement;
}
else
{
// Stored in r-> g-> b-> a order.
int indexOffset = index * 3;
TColor pixel = default(TColor);
pixel.PackFromBytes(colorTable[indexOffset], colorTable[indexOffset + 1], colorTable[indexOffset + 2], 255);
this.currentFrame[offset] = pixel;
writeY = y;
}
i++;
}
}
TColor[] pixels = new TColor[imageWidth * imageHeight];
for (int x = descriptor.Left; x < descriptor.Left + descriptor.Width; x++)
{
int index = indices[i];
// Array.Copy(this.currentFrame, pixels, pixels.Length);
using (PixelAccessor<TColor, TPacked> newPixels = pixels.Lock<TColor, TPacked>(imageWidth, imageHeight))
using (PixelAccessor<TColor, TPacked> currentPixels = this.currentFrame.Lock<TColor, TPacked>(imageWidth, imageHeight))
{
currentPixels.CopyImage(newPixels);
}
if (this.graphicsControlExtension == null
|| this.graphicsControlExtension.TransparencyFlag == false
|| this.graphicsControlExtension.TransparencyIndex != index)
{
// Stored in r-> g-> b-> a order.
int indexOffset = index * 3;
TColor pixel = default(TColor);
pixel.PackFromBytes(colorTable[indexOffset], colorTable[indexOffset + 1], colorTable[indexOffset + 2], 255);
currentPixels[x, writeY] = pixel;
}
ImageBase<TColor, TPacked> currentImage;
i++;
}
}
if (this.decodedImage.Pixels == null)
{
currentImage = this.decodedImage;
currentImage.SetPixels(imageWidth, imageHeight, pixels);
currentImage.Quality = colorTableLength / 3;
TColor[] pixels = new TColor[imageWidth * imageHeight];
if (this.graphicsControlExtension != null && this.graphicsControlExtension.DelayTime > 0)
using (PixelAccessor<TColor, TPacked> newPixels = pixels.Lock<TColor, TPacked>(imageWidth, imageHeight))
{
this.decodedImage.FrameDelay = this.graphicsControlExtension.DelayTime;
currentPixels.CopyImage(newPixels);
}
}
else
{
ImageFrame<TColor, TPacked> frame = new ImageFrame<TColor, TPacked>();
currentImage = frame;
currentImage.SetPixels(imageWidth, imageHeight, pixels);
currentImage.Quality = colorTableLength / 3;
ImageBase<TColor, TPacked> currentImage;
if (this.graphicsControlExtension != null && this.graphicsControlExtension.DelayTime > 0)
if (this.decodedImage.Pixels == null)
{
currentImage.FrameDelay = this.graphicsControlExtension.DelayTime;
currentImage = this.decodedImage;
currentImage.SetPixels(imageWidth, imageHeight, pixels);
currentImage.Quality = colorTableLength / 3;
if (this.graphicsControlExtension != null && this.graphicsControlExtension.DelayTime > 0)
{
this.decodedImage.FrameDelay = this.graphicsControlExtension.DelayTime;
}
}
else
{
ImageFrame<TColor, TPacked> frame = new ImageFrame<TColor, TPacked>();
this.decodedImage.Frames.Add(frame);
}
currentImage = frame;
currentImage.SetPixels(imageWidth, imageHeight, pixels);
currentImage.Quality = colorTableLength / 3;
if (this.graphicsControlExtension != null)
{
if (this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToBackground)
if (this.graphicsControlExtension != null && this.graphicsControlExtension.DelayTime > 0)
{
currentImage.FrameDelay = this.graphicsControlExtension.DelayTime;
}
this.decodedImage.Frames.Add(frame);
}
if (this.graphicsControlExtension != null)
{
for (int y = descriptor.Top; y < descriptor.Top + descriptor.Height; y++)
if (this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToBackground)
{
for (int x = descriptor.Left; x < descriptor.Left + descriptor.Width; x++)
for (int y = descriptor.Top; y < descriptor.Top + descriptor.Height; y++)
{
offset = (y * imageWidth) + x;
// Stored in r-> g-> b-> a order.
this.currentFrame[offset] = default(TColor);
for (int x = descriptor.Left; x < descriptor.Left + descriptor.Width; x++)
{
currentPixels[x, y] = default(TColor);
}
}
}
else if (this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToPrevious)
{
this.currentFrame = lastFrame;
}
}
else if (this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToPrevious)
{
this.currentFrame = lastFrame;
}
}
} // End lock
}
}
}
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