image/gif: be consistent wrt "color map" or "color table" names.

The spec at http://www.w3.org/Graphics/GIF/spec-gif89a.txt always says
"color table" and not "color map".

Change-Id: I4c172e3ade15618cbd616629822ce7d109a200af
Reviewed-on: https://go-review.googlesource.com/9668
Reviewed-by: Rob Pike <r@golang.org>

diff --git a/src/image/gif/reader.go b/src/image/gif/reader.go
index bd452eba723b331e80c29e2d428cd6cdd86e6e31..b71e041e78919114b397892927627545653792e2 100644 (file)
--- a/src/image/gif/reader.go
+++ b/src/image/gif/reader.go
@@ -84,13 +84,13 @@ type decoder struct {
        hasTransparentIndex bool
 
        // Computed.
-       globalColorMap color.Palette
+       globalColorTable color.Palette
 
        // Used when decoding.
        delay    []int
        disposal []byte
        image    []*image.Paletted
-       tmp      [1024]byte // must be at least 768 so we can read color map
+       tmp      [1024]byte // must be at least 768 so we can read color table
 }
 
 // blockReader parses the block structure of GIF image data, which
@@ -166,19 +166,19 @@ func (d *decoder) decode(r io.Reader, configOnly bool) error {
                        if err != nil {
                                return err
                        }
-                       useLocalColorMap := d.imageFields&fColorTable != 0
-                       if useLocalColorMap {
-                               m.Palette, err = d.readColorMap(d.imageFields)
+                       useLocalColorTable := d.imageFields&fColorTable != 0
+                       if useLocalColorTable {
+                               m.Palette, err = d.readColorTable(d.imageFields)
                                if err != nil {
                                        return err
                                }
                        } else {
-                               m.Palette = d.globalColorMap
+                               m.Palette = d.globalColorTable
                        }
                        if d.hasTransparentIndex && int(d.transparentIndex) < len(m.Palette) {
-                               if !useLocalColorMap {
-                                       // Clone the global color map.
-                                       m.Palette = append(color.Palette(nil), d.globalColorMap...)
+                               if !useLocalColorTable {
+                                       // Clone the global color table.
+                                       m.Palette = append(color.Palette(nil), d.globalColorTable...)
                                }
                                m.Palette[d.transparentIndex] = color.RGBA{}
                        }
@@ -262,8 +262,8 @@ func (d *decoder) readHeaderAndScreenDescriptor() error {
        d.height = int(d.tmp[8]) + int(d.tmp[9])<<8
        if fields := d.tmp[10]; fields&fColorTable != 0 {
                d.backgroundIndex = d.tmp[11]
-               // readColorMap overwrites the contents of d.tmp, but that's OK.
-               if d.globalColorMap, err = d.readColorMap(fields); err != nil {
+               // readColorTable overwrites the contents of d.tmp, but that's OK.
+               if d.globalColorTable, err = d.readColorTable(fields); err != nil {
                        return err
                }
        }
@@ -272,19 +272,18 @@ func (d *decoder) readHeaderAndScreenDescriptor() error {
        return nil
 }
 
-func (d *decoder) readColorMap(fields byte) (color.Palette, error) {
+func (d *decoder) readColorTable(fields byte) (color.Palette, error) {
        n := 1 << (1 + uint(fields&fColorTableBitsMask))
        _, err := io.ReadFull(d.r, d.tmp[:3*n])
        if err != nil {
-               return nil, fmt.Errorf("gif: short read on color map: %s", err)
+               return nil, fmt.Errorf("gif: short read on color table: %s", err)
        }
-       colorMap := make(color.Palette, n)
-       j := 0
-       for i := range colorMap {
-               colorMap[i] = color.RGBA{d.tmp[j+0], d.tmp[j+1], d.tmp[j+2], 0xFF}
+       j, p := 0, make(color.Palette, n)
+       for i := range p {
+               p[i] = color.RGBA{d.tmp[j+0], d.tmp[j+1], d.tmp[j+2], 0xFF}
                j += 3
        }
-       return colorMap, nil
+       return p, nil
 }
 
 func (d *decoder) readExtension() error {
@@ -428,18 +427,18 @@ type GIF struct {
        // and implies that each frame's disposal method is 0 (no disposal
        // specified).
        Disposal []byte
-       // Config is the global color map (palette), width and height. A nil or
+       // Config is the global color table (palette), width and height. A nil or
        // empty-color.Palette Config.ColorModel means that each frame has its own
-       // color map and there is no global color map. Each frame's bounds must be
-       // within the rectangle defined by the two points (0, 0) and (Config.Width,
-       // Config.Height).
+       // color table and there is no global color table. Each frame's bounds must
+       // be within the rectangle defined by the two points (0, 0) and
+       // (Config.Width, Config.Height).
        //
        // For backwards compatibility, a zero-valued Config is valid to pass to
        // EncodeAll, and implies that the overall GIF's width and height equals
        // the first frame's bounds' Rectangle.Max point.
        Config image.Config
-       // BackgroundIndex is the background index in the global color map, for use
-       // with the DisposalBackground disposal method.
+       // BackgroundIndex is the background index in the global color table, for
+       // use with the DisposalBackground disposal method.
        BackgroundIndex byte
 }
 
@@ -456,7 +455,7 @@ func DecodeAll(r io.Reader) (*GIF, error) {
                Delay:     d.delay,
                Disposal:  d.disposal,
                Config: image.Config{
-                       ColorModel: d.globalColorMap,
+                       ColorModel: d.globalColorTable,
                        Width:      d.width,
                        Height:     d.height,
                },
@@ -473,7 +472,7 @@ func DecodeConfig(r io.Reader) (image.Config, error) {
                return image.Config{}, err
        }
        return image.Config{
-               ColorModel: d.globalColorMap,
+               ColorModel: d.globalColorTable,
                Width:      d.width,
                Height:     d.height,
        }, nil

diff --git a/src/image/gif/reader_test.go b/src/image/gif/reader_test.go
index 7b6f504367cf8e8983c80e69a0c0acf078bfa8c2..94bd0a7c9499e9e177c49f65e95408e0703e9f1f 100644 (file)
--- a/src/image/gif/reader_test.go
+++ b/src/image/gif/reader_test.go
@@ -17,8 +17,8 @@ import (
 const (
        headerStr = "GIF89a" +
                "\x02\x00\x01\x00" + // width=2, height=1
-               "\x80\x00\x00" // headerFields=(a color map of 2 pixels), backgroundIndex, aspect
-       paletteStr = "\x10\x20\x30\x40\x50\x60" // the color map, also known as a palette
+               "\x80\x00\x00" // headerFields=(a color table of 2 pixels), backgroundIndex, aspect
+       paletteStr = "\x10\x20\x30\x40\x50\x60" // the color table, also known as a palette
        trailerStr = "\x3b"
 )
 
@@ -141,7 +141,7 @@ var testGIF = []byte{
        'G', 'I', 'F', '8', '9', 'a',
        1, 0, 1, 0, // w=1, h=1 (6)
        128, 0, 0, // headerFields, bg, aspect (10)
-       0, 0, 0, 1, 1, 1, // color map and graphics control (13)
+       0, 0, 0, 1, 1, 1, // color table and graphics control (13)
        0x21, 0xf9, 0x04, 0x00, 0x00, 0x00, 0xff, 0x00, // (19)
        // frame 1 (0,0 - 1,1)
        0x2c,