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ImageSharp
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use an offset span instead of buffer

pull/298/head
Scott Williams 9 years ago
parent
e2d26eb810
commit
76e91db9b2
1 changed files with 25 additions and 25 deletions
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  1. 50
      src/ImageSharp/Formats/Jpeg/Port/Components/IDCT.cs

50
src/ImageSharp/Formats/Jpeg/Port/Components/IDCT.cs
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@ -30,7 +30,7 @@
public static void QuantizeAndInverse(QuantizationTables quantizationTables, ref FrameComponent component, int blockBufferOffset, Buffer<short> computationBuffer) public static void QuantizeAndInverse(QuantizationTables quantizationTables, ref FrameComponent component, int blockBufferOffset, Buffer<short> computationBuffer)
{ {
Span<short> qt = quantizationTables.Tables.GetRowSpan(component.QuantizationIdentifier); Span<short> qt = quantizationTables.Tables.GetRowSpan(component.QuantizationIdentifier);
Buffer<short> blockData = component.BlockData; Span<short> blockData = component.BlockData.Slice(blockBufferOffset);
int v0, v1, v2, v3, v4, v5, v6, v7; int v0, v1, v2, v3, v4, v5, v6, v7;
int p0, p1, p2, p3, p4, p5, p6, p7; int p0, p1, p2, p3, p4, p5, p6, p7;
int t; int t;
@ -39,14 +39,14 @@
for (int row = 0; row < 64; row += 8) for (int row = 0; row < 64; row += 8)
{ {
// gather block data // gather block data
p0 = blockData[blockBufferOffset + row]; p0 = blockData[row];
p1 = blockData[blockBufferOffset + row + 1]; p1 = blockData[row + 1];
p2 = blockData[blockBufferOffset + row + 2]; p2 = blockData[row + 2];
p3 = blockData[blockBufferOffset + row + 3]; p3 = blockData[row + 3];
p4 = blockData[blockBufferOffset + row + 4]; p4 = blockData[row + 4];
p5 = blockData[blockBufferOffset + row + 5]; p5 = blockData[row + 5];
p6 = blockData[blockBufferOffset + row + 6]; p6 = blockData[row + 6];
p7 = blockData[blockBufferOffset + row + 7]; p7 = blockData[row + 7];
// dequant p0 // dequant p0
p0 *= qt[row]; p0 *= qt[row];
@ -141,14 +141,14 @@
t = (t < -2040) ? 0 : (t >= 2024) ? 255 : (t + 2056) >> 4; t = (t < -2040) ? 0 : (t >= 2024) ? 255 : (t + 2056) >> 4;
short st = (short)t; short st = (short)t;
blockData[blockBufferOffset + col] = st; blockData[col] = st;
blockData[blockBufferOffset + col + 8] = st; blockData[col + 8] = st;
blockData[blockBufferOffset + col + 16] = st; blockData[col + 16] = st;
blockData[blockBufferOffset + col + 24] = st; blockData[col + 24] = st;
blockData[blockBufferOffset + col + 32] = st; blockData[col + 32] = st;
blockData[blockBufferOffset + col + 40] = st; blockData[col + 40] = st;
blockData[blockBufferOffset + col + 48] = st; blockData[col + 48] = st;
blockData[blockBufferOffset + col + 56] = st; blockData[col + 56] = st;
continue; continue;
} }
@ -208,14 +208,14 @@
p7 = (p7 < 16) ? 0 : (p7 >= 4080) ? 255 : p7 >> 4; p7 = (p7 < 16) ? 0 : (p7 >= 4080) ? 255 : p7 >> 4;
// store block data // store block data
blockData[blockBufferOffset + col] = (short)p0; blockData[col] = (short)p0;
blockData[blockBufferOffset + col + 8] = (short)p1; blockData[col + 8] = (short)p1;
blockData[blockBufferOffset + col + 16] = (short)p2; blockData[col + 16] = (short)p2;
blockData[blockBufferOffset + col + 24] = (short)p3; blockData[col + 24] = (short)p3;
blockData[blockBufferOffset + col + 32] = (short)p4; blockData[col + 32] = (short)p4;
blockData[blockBufferOffset + col + 40] = (short)p5; blockData[col + 40] = (short)p5;
blockData[blockBufferOffset + col + 48] = (short)p6; blockData[col + 48] = (short)p6;
blockData[blockBufferOffset + col + 56] = (short)p7; blockData[col + 56] = (short)p7;
} }
} }
} }

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