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A little bit better

af/merge-core
James Jackson-South 10 years ago
parent
3fd6ee3536
commit
d61fae265e
4 changed files with 142 additions and 14 deletions
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  1. 147
      src/ImageSharp/Formats/Png/PngDecoderCore.cs
  2. 2
      tests/ImageSharp.Tests/FileTestBase.cs
  3. 4
      tests/ImageSharp.Tests/TestImages.cs
  4. 3
      tests/ImageSharp.Tests/TestImages/Formats/Png/interlaced.png

147
src/ImageSharp/Formats/Png/PngDecoderCore.cs
View File

@ -503,7 +503,7 @@ namespace ImageSharp.Formats
throw new ImageFormatException("Unknown filter type.");
}
this.ProcessDefilteredScanline(scanline, y, pixels, Adam7FirstColumn[pass], Adam7ColumnIncrement[pass]);
this.ProcessInterlacedDefilteredScanline(scanline, y, pixels, Adam7FirstColumn[pass], Adam7ColumnIncrement[pass]);
Swap(ref scanline, ref previousScanline);
}
@ -526,20 +526,17 @@ namespace ImageSharp.Formats
/// <param name="defilteredScanline">The de-filtered scanline</param>
/// <param name="row">The current image row.</param>
/// <param name="pixels">The image pixels</param>
/// <param name="startIndex">The column start index. Always 0 for none interlaced images.</param>
/// <param name="increment">The column increment. Always 1 for none interlaced images.</param>
private void ProcessDefilteredScanline<TColor, TPacked>(byte[] defilteredScanline, int row, PixelAccessor<TColor, TPacked> pixels, int startIndex = 0, int increment = 1)
private void ProcessDefilteredScanline<TColor, TPacked>(byte[] defilteredScanline, int row, PixelAccessor<TColor, TPacked> pixels)
where TColor : struct, IPackedPixel<TPacked>
where TPacked : struct
{
TColor color = default(TColor);
switch (this.PngColorType)
{
case PngColorType.Grayscale:
int factor = 255 / ((int)Math.Pow(2, this.header.BitDepth) - 1);
byte[] newScanline1 = ToArrayByBitsLength(defilteredScanline, this.bytesPerScanline, this.header.BitDepth);
for (int x = startIndex; x < this.header.Width; x += increment)
for (int x = 0; x < this.header.Width; x++)
{
byte intensity = (byte)(newScanline1[x] * factor);
color.PackFromBytes(intensity, intensity, intensity, 255);
@ -550,7 +547,7 @@ namespace ImageSharp.Formats
case PngColorType.GrayscaleWithAlpha:
for (int x = startIndex; x < this.header.Width; x += increment)
for (int x = 0; x < this.header.Width; x++)
{
int offset = 1 + (x * this.bytesPerPixel);
@ -571,7 +568,7 @@ namespace ImageSharp.Formats
{
// If the alpha palette is not null and has one or more entries, this means, that the image contains an alpha
// channel and we should try to read it.
for (int x = startIndex; x < this.header.Width; x += increment)
for (int x = 0; x < this.header.Width; x++)
{
int index = newScanline[x];
int pixelOffset = index * 3;
@ -595,7 +592,7 @@ namespace ImageSharp.Formats
}
else
{
for (int x = startIndex; x < this.header.Width; x += increment)
for (int x = 0; x < this.header.Width; x++)
{
int index = newScanline[x];
int pixelOffset = index * 3;
@ -613,7 +610,7 @@ namespace ImageSharp.Formats
case PngColorType.Rgb:
for (int x = startIndex; x < this.header.Width; x += increment)
for (int x = 0; x < this.header.Width; x++)
{
int offset = 1 + (x * this.bytesPerPixel);
@ -629,7 +626,7 @@ namespace ImageSharp.Formats
case PngColorType.RgbWithAlpha:
for (int x = startIndex; x < this.header.Width; x += increment)
for (int x = 0; x < this.header.Width; x++)
{
int offset = 1 + (x * this.bytesPerPixel);
@ -646,6 +643,129 @@ namespace ImageSharp.Formats
}
}
/// <summary>
/// Processes the interlaced de-filtered scanline filling the image pixel data
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <param name="defilteredScanline">The de-filtered scanline</param>
/// <param name="row">The current image row.</param>
/// <param name="pixels">The image pixels</param>
/// <param name="pixelOffset">The column start index. Always 0 for none interlaced images.</param>
/// <param name="increment">The column increment. Always 1 for none interlaced images.</param>
private void ProcessInterlacedDefilteredScanline<TColor, TPacked>(byte[] defilteredScanline, int row, PixelAccessor<TColor, TPacked> pixels, int pixelOffset = 0, int increment = 1)
where TColor : struct, IPackedPixel<TPacked>
where TPacked : struct
{
TColor color = default(TColor);
switch (this.PngColorType)
{
case PngColorType.Grayscale:
int factor = 255 / ((int)Math.Pow(2, this.header.BitDepth) - 1);
byte[] newScanline1 = ToArrayByBitsLength(defilteredScanline, this.bytesPerScanline, this.header.BitDepth);
for (int x = pixelOffset; x < this.header.Width; x += increment)
{
byte intensity = (byte)(newScanline1[x - pixelOffset] * factor);
color.PackFromBytes(intensity, intensity, intensity, 255);
pixels[x, row] = color;
}
break;
case PngColorType.GrayscaleWithAlpha:
for (int x = pixelOffset, o = 1; x < this.header.Width; x += increment, o += this.bytesPerPixel)
{
byte intensity = defilteredScanline[o];
byte alpha = defilteredScanline[o + this.bytesPerSample];
color.PackFromBytes(intensity, intensity, intensity, alpha);
pixels[x, row] = color;
}
break;
case PngColorType.Palette:
byte[] newScanline = ToArrayByBitsLength(defilteredScanline, this.bytesPerScanline, this.header.BitDepth);
if (this.paletteAlpha != null && this.paletteAlpha.Length > 0)
{
// If the alpha palette is not null and has one or more entries, this means, that the image contains an alpha
// channel and we should try to read it.
for (int x = pixelOffset; x < this.header.Width; x += increment)
{
int index = newScanline[x - pixelOffset];
int offset = index * 3;
byte a = this.paletteAlpha.Length > index ? this.paletteAlpha[index] : (byte)255;
if (a > 0)
{
byte r = this.palette[offset];
byte g = this.palette[offset + 1];
byte b = this.palette[offset + 2];
color.PackFromBytes(r, g, b, a);
}
else
{
color.PackFromBytes(0, 0, 0, 0);
}
pixels[x, row] = color;
}
}
else
{
for (int x = pixelOffset; x < this.header.Width; x += increment)
{
int index = newScanline[x - pixelOffset];
int offset = index * 3;
byte r = this.palette[offset];
byte g = this.palette[offset + 1];
byte b = this.palette[offset + 2];
color.PackFromBytes(r, g, b, 255);
pixels[x, row] = color;
}
}
break;
case PngColorType.Rgb:
for (int x = pixelOffset, o = 1; x < this.header.Width; x += increment, o += this.bytesPerPixel)
{
byte r = defilteredScanline[o];
byte g = defilteredScanline[o + this.bytesPerSample];
byte b = defilteredScanline[o + (2 * this.bytesPerSample)];
color.PackFromBytes(r, g, b, 255);
pixels[x, row] = color;
}
break;
case PngColorType.RgbWithAlpha:
for (int x = pixelOffset, o = 1; x < this.header.Width; x += increment, o += this.bytesPerPixel)
{
byte r = defilteredScanline[o];
byte g = defilteredScanline[o + this.bytesPerSample];
byte b = defilteredScanline[o + (2 * this.bytesPerSample)];
byte a = defilteredScanline[o + (3 * this.bytesPerSample)];
color.PackFromBytes(r, g, b, a);
pixels[x, row] = color;
}
break;
}
}
/// <summary>
/// Reads a text chunk containing image properties from the data.
/// </summary>
@ -838,6 +958,11 @@ namespace ImageSharp.Formats
chunk.Length = BitConverter.ToInt32(this.chunkLengthBuffer, 0);
}
/// <summary>
/// Returns the correct number of columns for each interlaced pass.
/// </summary>
/// <param name="pass">Th current pass index</param>
/// <returns>The <see cref="int"/></returns>
private int ComputeColumnsAdam7(int pass)
{
int width = this.header.Width;

2
tests/ImageSharp.Tests/FileTestBase.cs
View File

@ -31,7 +31,7 @@ namespace ImageSharp.Tests
// new TestFile(TestImages.Bmp.Neg_height), // Perf: Enable for local testing only
// new TestFile(TestImages.Png.Blur), // Perf: Enable for local testing only
// new TestFile(TestImages.Png.Indexed), // Perf: Enable for local testing only
new TestFile(TestImages.Png.Splash),
//new TestFile(TestImages.Png.Splash),
new TestFile(TestImages.Png.SplashInterlace),
// new TestFile(TestImages.Png.Filter0), // Perf: Enable for local testing only
// new TestFile(TestImages.Png.Filter1), // Perf: Enable for local testing only

4
tests/ImageSharp.Tests/TestImages.cs
View File

@ -18,9 +18,9 @@ namespace ImageSharp.Tests
public static string Pd => folder + "pd.png";
public static string Blur => folder + "blur.png";
public static string Indexed => folder + "indexed.png";
public static string Splash => folder + "splash-interlaced.png";
public static string Splash => folder + "splash.png";
public static string SplashInterlace => folder + "splash.png";
public static string SplashInterlace => folder + "splash-interlaced.png";
// filtered test images from http://www.schaik.com/pngsuite/pngsuite_fil_png.html
public static string Filter0 => folder + "filter0.png";
public static string Filter1 => folder + "filter1.png";

3
tests/ImageSharp.Tests/TestImages/Formats/Png/interlaced.png
View File

@ -0,0 +1,3 @@
version https://git-lfs.github.com/spec/v1
oid sha256:7e1c92b1a57b762f736e14d480eb016b551ce0dc67aa588b246d838d00c0fc3f
size 17372
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