add doc comments and fix golint warnings

bindings/gotrace_test.go

@@ -3,18 +3,19 @@ package gotraceb
 import (
 	"crypto/sha1"
 	"fmt"
-	gtr "github.com/dennwc/gotrace"
 	"image"
 	"image/color"
 	_ "image/png"
 	"os"
 	"testing"
 	"unsafe"
+
+	gtr "github.com/dennwc/gotrace"
 )
 
 func TestWordSize(t *testing.T) {
 	if uintptr(wordSize) != unsafe.Sizeof(uint(0))*8 {
-		t.Fatalf("%d vs %s", wordSize, unsafe.Sizeof(uint(0))*8)
+		t.Fatalf("%d vs %d", wordSize, unsafe.Sizeof(uint(0))*8)
 	}
 }
 

bitmap.go

@@ -11,8 +11,10 @@ var (
 	allBits  = ^Word(0)
 )
 
+// Word packs multiple bits of a bitmap.
 type Word uint
 
+// NewBitmap creates a new bitmap with given dimensions.
 func NewBitmap(w, h int) *Bitmap {
 	dy := 0
 	if w != 0 {
@@ -24,10 +26,9 @@ func NewBitmap(w, h int) *Bitmap {
 	}
 }
 
-//	Internal bitmap format. The n-th scanline starts at scanline(n) =
-//	(map + n*dy). Raster data is stored as a sequence of potrace_words
-//	(NOT bytes). The leftmost bit of scanline n is the most significant
-//	bit of scanline(n)[0].
+// Bitmap is an internal bitmap format. The n-th scanline starts at scanline(n) = (map + n*dy).
+// Raster data is stored as a sequence of potrace_words (NOT bytes).
+// The leftmost bit of scanline n is the most significant bit of scanline(n)[0].
 type Bitmap struct {
 	W, H int    // width and height, in pixels
 	Dy   int    // words per scanline (not bytes)
@@ -37,12 +38,16 @@ type Bitmap struct {
 func (bm *Bitmap) scanline(y int) []Word { return bm.Map[y*bm.Dy : (y+1)*bm.Dy] }
 func (bm *Bitmap) index(x, y int) *Word  { return &(bm.Map[Word(y*bm.Dy)+Word(x)/wordBits]) }
 func (bm *Bitmap) mask(x int) Word       { return hiBit >> (Word(x) & (wordBits - 1)) }
+
+// Get a bitmap value at given coordinates.
 func (bm *Bitmap) Get(x, y int) bool {
 	if x >= 0 && x < bm.W && y >= 0 && y < bm.H {
 		return ((*bm.index(x, y)) & bm.mask(x)) != 0
 	}
 	return false
 }
+
+// Set a bitmap value at given coordinates.
 func (bm *Bitmap) Set(x, y int, v bool) {
 	if x >= 0 && x < bm.W && y >= 0 && y < bm.H {
 		if v {
@@ -53,7 +58,7 @@ func (bm *Bitmap) Set(x, y int, v bool) {
 	}
 }
 
-// clear the given bitmap. Set all bits to c.
+// Clear the given bitmap. Set all bits to c.
 func (bm *Bitmap) Clear(c bool) {
 	if !c {
 		for i := range bm.Map {
@@ -69,9 +74,9 @@ func (bm *Bitmap) Clear(c bool) {
 	}
 }
 
-// duplicate the given bitmap
-func (b *Bitmap) Clone() *Bitmap {
-	b2 := NewBitmap(b.W, b.H)
-	copy(b2.Map, b.Map)
+// Clone duplicates the given bitmap.
+func (bm *Bitmap) Clone() *Bitmap {
+	b2 := NewBitmap(bm.W, bm.H)
+	copy(b2.Map, bm.Map)
 	return b2
 }