tsai
/
ImageSharp
mirror of https://github.com/SixLabors/ImageSharp
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

Fix accuracy of progressive decoding

af/merge-core
James Jackson-South 8 years ago
parent
1293fa15e3
commit
c550225378
1 changed files with 9 additions and 7 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Unified View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 16
      src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsScanDecoder.cs

16
src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsScanDecoder.cs
View File

@ -842,7 +842,9 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
while (k <= e) while (k <= e)
{ {
ref byte z = ref PdfJsQuantizationTables.DctZigZag[k]; int offsetZ = offset + PdfJsQuantizationTables.DctZigZag[k];
int sign = Unsafe.Add(ref blockDataRef, offsetZ) < 0 ? -1 : 1;
switch (this.successiveACState) switch (this.successiveACState)
{ {
case 0: // Initial state case 0: // Initial state
@ -881,7 +883,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
continue; continue;
case 1: // Skipping r zero items case 1: // Skipping r zero items
case 2: case 2:
ref short blockRef = ref Unsafe.Add(ref blockDataRef, offset + z); ref short blockRef = ref Unsafe.Add(ref blockDataRef, offsetZ);
if (blockRef != 0) if (blockRef != 0)
{ {
int bit = this.ReadBit(stream); int bit = this.ReadBit(stream);
@ -890,7 +892,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
return; return;
} }
blockRef += (short)(bit << this.successiveState); blockRef += (short)(sign * (bit << this.successiveState));
} }
else else
{ {
@ -903,7 +905,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
break; break;
case 3: // Set value for a zero item case 3: // Set value for a zero item
ref short blockRef2 = ref Unsafe.Add(ref blockDataRef, offset + z); ref short blockRef2 = ref Unsafe.Add(ref blockDataRef, offsetZ);
if (blockRef2 != 0) if (blockRef2 != 0)
{ {
int bit = this.ReadBit(stream); int bit = this.ReadBit(stream);
@ -912,7 +914,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
return; return;
} }
blockRef2 += (short)(bit << this.successiveState); blockRef2 += (short)(sign * (bit << this.successiveState));
} }
else else
{ {
@ -922,7 +924,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
break; break;
case 4: // Eob case 4: // Eob
ref short blockRef3 = ref Unsafe.Add(ref blockDataRef, offset + z); ref short blockRef3 = ref Unsafe.Add(ref blockDataRef, offsetZ);
if (blockRef3 != 0) if (blockRef3 != 0)
{ {
int bit = this.ReadBit(stream); int bit = this.ReadBit(stream);
@ -931,7 +933,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
return; return;
} }
blockRef3 += (short)(bit << this.successiveState); blockRef3 += (short)(sign * (bit << this.successiveState));
} }
break; break;

Write Preview
Loading…
Cancel
Save