diff options
Diffstat (limited to 'libgo/go/image/jpeg/writer.go')
| -rw-r--r-- | libgo/go/image/jpeg/writer.go | 50 |
1 files changed, 24 insertions, 26 deletions
diff --git a/libgo/go/image/jpeg/writer.go b/libgo/go/image/jpeg/writer.go index 099298e462e..375d8a66d5a 100644 --- a/libgo/go/image/jpeg/writer.go +++ b/libgo/go/image/jpeg/writer.go @@ -21,7 +21,7 @@ func min(x, y int) int { } // div returns a/b rounded to the nearest integer, instead of rounded to zero. -func div(a int, b int) int { +func div(a, b int32) int32 { if a >= 0 { return (a + (b >> 1)) / b } @@ -268,14 +268,14 @@ func (e *encoder) emit(bits, nBits uint32) { } // emitHuff emits the given value with the given Huffman encoder. -func (e *encoder) emitHuff(h huffIndex, value int) { +func (e *encoder) emitHuff(h huffIndex, value int32) { x := theHuffmanLUT[h][value] e.emit(x&(1<<24-1), x>>24) } // emitHuffRLE emits a run of runLength copies of value encoded with the given // Huffman encoder. -func (e *encoder) emitHuffRLE(h huffIndex, runLength, value int) { +func (e *encoder) emitHuffRLE(h huffIndex, runLength, value int32) { a, b := value, value if a < 0 { a, b = -value, value-1 @@ -286,7 +286,7 @@ func (e *encoder) emitHuffRLE(h huffIndex, runLength, value int) { } else { nBits = 8 + uint32(bitCount[a>>8]) } - e.emitHuff(h, runLength<<4|int(nBits)) + e.emitHuff(h, runLength<<4|int32(nBits)) if nBits > 0 { e.emit(uint32(b)&(1<<nBits-1), nBits) } @@ -347,15 +347,15 @@ func (e *encoder) writeDHT() { // writeBlock writes a block of pixel data using the given quantization table, // returning the post-quantized DC value of the DCT-transformed block. // b is in natural (not zig-zag) order. -func (e *encoder) writeBlock(b *block, q quantIndex, prevDC int) int { +func (e *encoder) writeBlock(b *block, q quantIndex, prevDC int32) int32 { fdct(b) // Emit the DC delta. - dc := div(b[0], (8 * int(e.quant[q][0]))) + dc := div(b[0], 8*int32(e.quant[q][0])) e.emitHuffRLE(huffIndex(2*q+0), 0, dc-prevDC) // Emit the AC components. - h, runLength := huffIndex(2*q+1), 0 + h, runLength := huffIndex(2*q+1), int32(0) for zig := 1; zig < blockSize; zig++ { - ac := div(b[unzig[zig]], (8 * int(e.quant[q][zig]))) + ac := div(b[unzig[zig]], 8*int32(e.quant[q][zig])) if ac == 0 { runLength++ } else { @@ -383,9 +383,9 @@ func toYCbCr(m image.Image, p image.Point, yBlock, cbBlock, crBlock *block) { for i := 0; i < 8; i++ { r, g, b, _ := m.At(min(p.X+i, xmax), min(p.Y+j, ymax)).RGBA() yy, cb, cr := color.RGBToYCbCr(uint8(r>>8), uint8(g>>8), uint8(b>>8)) - yBlock[8*j+i] = int(yy) - cbBlock[8*j+i] = int(cb) - crBlock[8*j+i] = int(cr) + yBlock[8*j+i] = int32(yy) + cbBlock[8*j+i] = int32(cb) + crBlock[8*j+i] = int32(cr) } } } @@ -408,9 +408,9 @@ func rgbaToYCbCr(m *image.RGBA, p image.Point, yBlock, cbBlock, crBlock *block) } pix := m.Pix[offset+sx*4:] yy, cb, cr := color.RGBToYCbCr(pix[0], pix[1], pix[2]) - yBlock[8*j+i] = int(yy) - cbBlock[8*j+i] = int(cb) - crBlock[8*j+i] = int(cr) + yBlock[8*j+i] = int32(yy) + cbBlock[8*j+i] = int32(cb) + crBlock[8*j+i] = int32(cr) } } } @@ -450,12 +450,10 @@ func (e *encoder) writeSOS(m image.Image) { var ( // Scratch buffers to hold the YCbCr values. // The blocks are in natural (not zig-zag) order. - yBlock block - cbBlock [4]block - crBlock [4]block - cBlock block + b block + cb, cr [4]block // DC components are delta-encoded. - prevDCY, prevDCCb, prevDCCr int + prevDCY, prevDCCb, prevDCCr int32 ) bounds := m.Bounds() rgba, _ := m.(*image.RGBA) @@ -466,16 +464,16 @@ func (e *encoder) writeSOS(m image.Image) { yOff := (i & 2) * 4 p := image.Pt(x+xOff, y+yOff) if rgba != nil { - rgbaToYCbCr(rgba, p, &yBlock, &cbBlock[i], &crBlock[i]) + rgbaToYCbCr(rgba, p, &b, &cb[i], &cr[i]) } else { - toYCbCr(m, p, &yBlock, &cbBlock[i], &crBlock[i]) + toYCbCr(m, p, &b, &cb[i], &cr[i]) } - prevDCY = e.writeBlock(&yBlock, 0, prevDCY) + prevDCY = e.writeBlock(&b, 0, prevDCY) } - scale(&cBlock, &cbBlock) - prevDCCb = e.writeBlock(&cBlock, 1, prevDCCb) - scale(&cBlock, &crBlock) - prevDCCr = e.writeBlock(&cBlock, 1, prevDCCr) + scale(&b, &cb) + prevDCCb = e.writeBlock(&b, 1, prevDCCb) + scale(&b, &cr) + prevDCCr = e.writeBlock(&b, 1, prevDCCr) } } // Pad the last byte with 1's. |