add comments for godoc

block/block.go

@@ -5,6 +5,7 @@ import (
 	"github.com/yofu/dxf/table"
 )
 
+// Block represents each BLOCK.
 type Block struct {
 	Name        string
 	Description string
@@ -15,6 +16,7 @@ type Block struct {
 	Coord       []float64
 }
 
+// NewBlock create a new Block.
 func NewBlock(name, desc string) *Block {
 	b := &Block{
 		Name:        name,
@@ -27,6 +29,8 @@ func NewBlock(name, desc string) *Block {
 	return b
 }
 
+
+// Format writes data to formatter.
 func (b *Block) Format(f *format.Formatter) {
 	f.WriteString(0, "BLOCK")
 	f.WriteHex(5, b.handle)
@@ -47,30 +51,36 @@ func (b *Block) Format(f *format.Formatter) {
 	f.WriteString(100, "AcDbBlockEnd")
 }
 
+// String outputs data using default formatter.
 func (b *Block) String() string {
 	f := format.New()
 	return b.FormatString(f)
 }
 
+// FormatString outputs data using given formatter.
 func (b *Block) FormatString(f *format.Formatter) string {
 	b.Format(f)
 	return f.Output()
 }
 
+// Handle returns a handle value of BLOCK.
 func (b *Block) Handle() int {
 	return b.handle
 }
+// SetHandle sets handles to BLOCK and ENDBLK.
 func (b *Block) SetHandle(v *int) {
 	b.handle = *v
 	(*v)++
 	b.endhandle = *v
 	(*v)++
 }
 
+// Layer returns BLOCK's Layer.
 func (b *Block) Layer() *table.Layer {
 	return b.layer
 }
 
+// SetLayer sets Layer to BLOCK.
 func (b *Block) SetLayer(layer *table.Layer) {
 	b.layer = layer
 }

block/blocks.go

@@ -1,11 +1,14 @@
+// BLOCK section
 package block
 
 import (
 	"github.com/yofu/dxf/format"
 )
 
+// Blocks represents BLOCKS section.
 type Blocks []*Block
 
+// New creates a new Blocks.
 func New() Blocks {
 	b := make([]*Block, 3)
 	b[0] = NewBlock("*Model_Space", "")
@@ -14,6 +17,7 @@ func New() Blocks {
 	return b
 }
 
+// WriteTo writes BLOCKS data to formatter.
 func (bs Blocks) WriteTo(f *format.Formatter) {
 	f.WriteString(0, "SECTION")
 	f.WriteString(2, "BLOCKS")
@@ -23,11 +27,13 @@ func (bs Blocks) WriteTo(f *format.Formatter) {
 	f.WriteString(0, "ENDSEC")
 }
 
+// Add adds a new block to BLOCKS section.
 func (bs Blocks) Add(b *Block) Blocks {
 	bs = append(bs, b)
 	return bs
 }
 
+// SetHandle sets handles to each block.
 func (bs Blocks) SetHandle(v *int) {
 	for _, b := range bs {
 		b.SetHandle(v)

class/classes.go

@@ -1,33 +1,41 @@
+// CLASSES section
 package class
 
 import (
 	"github.com/yofu/dxf/format"
 )
 
+// Class represents each CLASS.
 type Class struct {
 }
 
+// Format writes data to formatter.
 func (c *Class) Format(f *format.Formatter) {
 	f.WriteString(0, "CLASS")
 }
 
+// String outputs data using default formatter.
 func (c *Class) String() string {
 	f := format.New()
 	return c.FormatString(f)
 }
 
+// FormatString outputs data using given formatter.
 func (c *Class) FormatString(f *format.Formatter) string {
 	c.Format(f)
 	return f.Output()
 }
 
+// Classes represents CLASSES section.
 type Classes []*Class
 
+// New creates a new Classes.
 func New() Classes {
 	c := make([]*Class, 0)
 	return c
 }
 
+// WriteTo writes CLASSES data to formatter.
 func (cs Classes) WriteTo(f *format.Formatter) {
 	f.WriteString(0, "SECTION")
 	f.WriteString(2, "CLASSES")
@@ -37,6 +45,7 @@ func (cs Classes) WriteTo(f *format.Formatter) {
 	f.WriteString(0, "ENDSEC")
 }
 
+// SetHandle sets handles to each class.
 func (cs Classes) SetHandle(v *int) {
 	return
 }

color/colornumber.go

@@ -1,8 +1,10 @@
+// Color Number
 package color
 
+// AutoCAD color index number (code 62)
 type ColorNumber uint8
 
-// 1 - 9
+// color number: 1 - 9
 const (
 	Red ColorNumber = iota + 1
 	Yellow
@@ -15,7 +17,7 @@ const (
 	Grey192
 )
 
-// 250 - 255
+// color number: 250 - 255
 const (
 	Grey51 = iota + 250
 	Grey91
@@ -25,6 +27,7 @@ const (
 	Grey255
 )
 
+// color number to RGB equivalents
 var (
 	ColorRGB = [][]uint8{
 		[]uint8{0, 0, 0},       // 0

drawing/drawing.go

@@ -1,3 +1,4 @@
+// Package drawing defines Drawing struct for DXF.
 package drawing
 
 import (
@@ -15,6 +16,7 @@ import (
 	"os"
 )
 
+// Drawing contains DXF drawing data.
 type Drawing struct {
 	FileName     string
 	Layers       map[string]*table.Layer
@@ -29,6 +31,7 @@ type Drawing struct {
 	PlotStyle    handle.Handler
 }
 
+// New creates a new Drawing.
 func New() *Drawing {
 	d := new(Drawing)
 	d.Layers = make(map[string]*table.Layer)
@@ -78,18 +81,22 @@ func (d *Drawing) saveFile(filename string) error {
 	return nil
 }
 
+// Save saves the drawing file.
+// If it is the first time, use SaveAs(filename).
 func (d *Drawing) Save() error {
 	if d.FileName == "" {
 		return errors.New("filename is blank, use SaveAs(filename)")
 	}
 	return d.saveFile(d.FileName)
 }
 
+// SaveAs saves the drawing file as given filename.
 func (d *Drawing) SaveAs(filename string) error {
 	d.FileName = filename
 	return d.saveFile(filename)
 }
 
+// setHandle sets all the handles contained in Drawing.
 func (d *Drawing) setHandle() {
 	h := 1
 	for _, s := range d.Sections[1:] {
@@ -98,6 +105,8 @@ func (d *Drawing) setHandle() {
 	d.Sections[0].SetHandle(&h)
 }
 
+// Layer returns the named layer if exists.
+// If setcurrent is true, set current layer to it.
 func (d *Drawing) Layer(name string, setcurrent bool) (*table.Layer, error) {
 	if l, exist := d.Layers[name]; exist {
 		if setcurrent {
@@ -108,6 +117,8 @@ func (d *Drawing) Layer(name string, setcurrent bool) (*table.Layer, error) {
 	return nil, fmt.Errorf("layer %s doesn't exist", name)
 }
 
+// AddLayer adds a new layer with given name, color and line type.
+// If setcurrent is true, set current layer to it.
 func (d *Drawing) AddLayer(name string, cl color.ColorNumber, lt *table.LineType, setcurrent bool) (*table.Layer, error) {
 	if l, exist := d.Layers[name]; exist {
 		if setcurrent {
@@ -125,6 +136,7 @@ func (d *Drawing) AddLayer(name string, cl color.ColorNumber, lt *table.LineType
 	return l, nil
 }
 
+// ChangeLayer changes current layer to the named layer.
 func (d *Drawing) ChangeLayer(name string) error {
 	if l, exist := d.Layers[name]; exist {
 		d.CurrentLayer = l
@@ -133,6 +145,7 @@ func (d *Drawing) ChangeLayer(name string) error {
 	return errors.New(fmt.Sprintf("layer %s doesn't exist", name))
 }
 
+// LineType returns the named line type if exists.
 func (d *Drawing) LineType(name string) (*table.LineType, error) {
 	lt, err := d.Sections[TABLES].(table.Tables)[table.LTYPE].Contains(name)
 	if err != nil {
@@ -141,14 +154,17 @@ func (d *Drawing) LineType(name string) (*table.LineType, error) {
 	return lt.(*table.LineType), nil
 }
 
+// Entities returns slice of all entities contained in Drawing.
 func (d *Drawing) Entities() (entity.Entities) {
 	return d.Sections[ENTITIES].(entity.Entities)
 }
 
+// AddEntity adds a new entity.
 func (d *Drawing) AddEntity(e entity.Entity) {
 	d.Sections[4] = d.Sections[4].(entity.Entities).Add(e)
 }
 
+// Point creates a new POINT at (x, y, z).
 func (d *Drawing) Point(x, y, z float64) (*entity.Point, error) {
 	p := entity.NewPoint()
 	p.Coord = []float64{x, y, z}
@@ -157,6 +173,7 @@ func (d *Drawing) Point(x, y, z float64) (*entity.Point, error) {
 	return p, nil
 }
 
+// Line creates a new LINE from (x1, y1, z1) to (x2, y2, z2).
 func (d *Drawing) Line(x1, y1, z1, x2, y2, z2 float64) (*entity.Line, error) {
 	l := entity.NewLine()
 	l.Start = []float64{x1, y1, z1}
@@ -166,6 +183,7 @@ func (d *Drawing) Line(x1, y1, z1, x2, y2, z2 float64) (*entity.Line, error) {
 	return l, nil
 }
 
+// Circle creates a new CIRCLE at (x, y, z) with radius r.
 func (d *Drawing) Circle(x, y, z, r float64) (*entity.Circle, error) {
 	c := entity.NewCircle()
 	c.Center = []float64{x, y, z}
@@ -175,6 +193,7 @@ func (d *Drawing) Circle(x, y, z, r float64) (*entity.Circle, error) {
 	return c, nil
 }
 
+// Polyline creates a new POLYLINE with given vertices.
 func (d *Drawing) Polyline(closed bool, vertices ...[]float64) (*entity.Polyline, error) {
 	p := entity.NewPolyline()
 	p.SetLayer(d.CurrentLayer)
@@ -188,6 +207,7 @@ func (d *Drawing) Polyline(closed bool, vertices ...[]float64) (*entity.Polyline
 	return p, nil
 }
 
+// LwPolyline creates a new LWPOLYLINE with given vertices.
 func (d *Drawing) LwPolyline(closed bool, vertices ...[]float64) (*entity.LwPolyline, error) {
 	size := len(vertices)
 	l := entity.NewLwPolyline(size)
@@ -202,6 +222,7 @@ func (d *Drawing) LwPolyline(closed bool, vertices ...[]float64) (*entity.LwPoly
 	return l, nil
 }
 
+// ThreeDFace creates a new 3DFACE with given points.
 func (d *Drawing) ThreeDFace(points [][]float64) (*entity.ThreeDFace, error) {
 	f := entity.New3DFace()
 	if len(points) < 3 {
@@ -220,6 +241,7 @@ func (d *Drawing) ThreeDFace(points [][]float64) (*entity.ThreeDFace, error) {
 	return f, nil
 }
 
+// Text creates a new TEXT str at (x, y, z) with given height.
 func (d *Drawing) Text(str string, x, y, z, height float64) (*entity.Text, error) {
 	t := entity.NewText()
 	t.Coord1 = []float64{x, y, z}
@@ -235,6 +257,8 @@ func (d *Drawing) addObject(o object.Object) {
 	d.Sections[5] = d.Sections[5].(object.Objects).Add(o)
 }
 
+// Group adds given entities to the named group.
+// If the named group doesn't exist, create it.
 func (d *Drawing) Group(name, desc string, es ...entity.Entity) (*object.Group, error) {
 	if g, exist := d.Groups[name]; exist {
 		g.AddEntity(es...)
@@ -247,6 +271,8 @@ func (d *Drawing) Group(name, desc string, es ...entity.Entity) (*object.Group,
 	return g, nil
 }
 
+// AddGroup adds given entities to the named group.
+// If the named group doesn't exist, returns error.
 func (d *Drawing) AddToGroup(name string, es ...entity.Entity) error {
 	if g, exist := d.Groups[name]; exist {
 		g.AddEntity(es...)

drawing/section.go

@@ -4,13 +4,16 @@ import (
 	"github.com/yofu/dxf/format"
 )
 
+// Section is interface for DXF sections.
 type Section interface {
 	WriteTo(*format.Formatter)
 	SetHandle(*int)
 }
 
+// SectionType represents Section names (code 2)
 type SectionType int
 
+// Section name: code 2
 const (
 	HEADER SectionType = iota
 	CLASSES
@@ -20,6 +23,8 @@ const (
 	OBJECTS
 )
 
+// SectionTypeString converts SectionType to string.
+// If SectionType is out of range, it returns empty string.
 func SectionTypeString(s SectionType) string {
 	switch s {
 	case HEADER:
@@ -39,6 +44,8 @@ func SectionTypeString(s SectionType) string {
 	}
 }
 
+// SectionTypeValue converts string to SectionType.
+// If string is unknown SectionType, it returns -1.
 func SectionTypeValue(s string) SectionType {
 	switch s {
 	case "HEADER":