Address lint errors

internal/cops/braille/braille.go

@@ -62,7 +62,7 @@ func Draw(dst *display.Display, r image.Rectangle, src image.Image, sp image.Poi
 	DrawBitmap(dst, r, bits, sp, on)
 }
 
-// DrawBitmap
+// DrawBitmap FIXME
 func DrawBitmap(dst *display.Display, r image.Rectangle, src BitmapReader, sp image.Point, fg color.Color) {
 	w, h := r.Dx(), r.Dy()
 	for y := 0; y < h; y++ {

internal/cops/displaydraw/displaydraw.go

@@ -7,7 +7,9 @@ import (
 	"github.com/borkshop/bork/internal/cops/display"
 )
 
-func AsciiBox(d *display.Display, r image.Rectangle, fg, bg color.Color) {
+// ASCIIBox draws a box onto a display with given foreground and background
+// colors using ASCII "|" and "-", with "." and "'' for corners.
+func ASCIIBox(d *display.Display, r image.Rectangle, fg, bg color.Color) {
 	r.Max = r.Max.Sub(image.Point{1, 1})
 	for y := r.Min.Y + 1; y < r.Max.Y; y++ {
 		d.Set(r.Min.X, y, "|", fg, bg)
@@ -23,15 +25,18 @@ func AsciiBox(d *display.Display, r image.Rectangle, fg, bg color.Color) {
 	d.Set(r.Max.X, r.Max.Y, "'", fg, bg)
 }
 
-func SpaceBox(d *display.Display, r image.Rectangle, m image.Point, c color.Color) {
+// SpaceBox draws a border on the interior of the given rectangle.
+// The border shows a color filled cells, but copying the screen will reveal
+// "|" and "-" characters with the same foreground and background.
+func SpaceBox(d *display.Display, r image.Rectangle, b image.Point, c color.Color) {
 	for y := r.Min.Y; y < r.Max.Y; y++ {
-		for x := 0; x < m.X; x++ {
+		for x := 0; x < b.X; x++ {
 			d.Set(r.Min.X+x, y, "|", c, c)
 			d.Set(r.Max.X-x-1, y, "|", c, c)
 		}
 	}
 	for x := r.Min.X; x < r.Max.X; x++ {
-		for y := 0; y < m.Y; y++ {
+		for y := 0; y < b.Y; y++ {
 			d.Set(x, r.Min.Y+y, "-", c, c)
 			d.Set(x, r.Max.Y-y-1, "-", c, c)
 		}

internal/cops/examples/borkart/main.go

@@ -12,12 +12,12 @@ import (
 )
 
 func main() {
-	if err := Main(); err != nil {
+	if err := run(); err != nil {
 		fmt.Printf("%v\n", err)
 	}
 }
 
-func Main() error {
+func run() error {
 
 	term := terminal.New(os.Stdout.Fd())
 	defer term.Restore()

internal/cops/examples/brailleline/main.go

@@ -12,12 +12,12 @@ import (
 )
 
 func main() {
-	if err := Main(); err != nil {
+	if err := run(); err != nil {
 		fmt.Printf("%v\n", err)
 	}
 }
 
-func Main() error {
+func run() error {
 	w, h := 32, 16
 	pb := image.Rect(0, 0, w, h)
 	bb := braille.Bounds(pb)

internal/cops/examples/braillematrix/main.go

@@ -12,12 +12,12 @@ import (
 )
 
 func main() {
-	if err := Main(); err != nil {
+	if err := run(); err != nil {
 		fmt.Printf("%v\n", err)
 	}
 }
 
-func Main() error {
+func run() error {
 
 	w, h := 16, 16
 	pb := image.Rect(0, 0, w, h)

internal/cops/examples/braillewave/main.go

@@ -14,12 +14,12 @@ import (
 )
 
 func main() {
-	if err := Main(); err != nil {
+	if err := run(); err != nil {
 		fmt.Printf("%v\n", err)
 	}
 }
 
-func Main() error {
+func run() error {
 	term := terminal.New(os.Stdout.Fd())
 	defer term.Restore()
 	term.SetRaw()

internal/cops/examples/earthgif/earthgif.go

@@ -15,12 +15,12 @@ import (
 )
 
 func main() {
-	if err := Main(); err != nil {
+	if err := run(); err != nil {
 		fmt.Printf("%v\n", err)
 	}
 }
 
-func Main() error {
+func run() error {
 	term := terminal.New(os.Stdin.Fd())
 	defer term.Restore()
 	term.SetRaw()

internal/cops/examples/hicops/hicops.go

@@ -14,12 +14,12 @@ import (
 )
 
 func main() {
-	if err := Main(); err != nil {
+	if err := run(); err != nil {
 		fmt.Printf("%v\n", err)
 	}
 }
 
-func Main() error {
+func run() error {
 	term := terminal.New(os.Stdin.Fd())
 	defer term.Restore()
 	term.SetRaw()

internal/cops/examples/vt/main.go

@@ -13,12 +13,12 @@ import (
 )
 
 func main() {
-	if err := Main(); err != nil {
+	if err := run(); err != nil {
 		fmt.Printf("%v\n", err)
 	}
 }
 
-func Main() error {
+func run() error {
 	term := terminal.New(os.Stdin.Fd())
 	defer term.Restore()
 	term.SetRaw()

internal/cops/vtio/vtio.go

@@ -1,3 +1,5 @@
+// Package vtio provides a tool for drawing a ANSI stream onto a virtualized
+// display.
 package vtio
 
 import (
@@ -12,6 +14,9 @@ import (
 	"github.com/borkshop/bork/internal/cops/display"
 )
 
+// NewDisplayWriter creates an IO writer into which you can write virtual
+// terminal codes (ANSI) and capture the resulting virtualized display state.
+// The implementation of the ANSI language is far from complete.
 func NewDisplayWriter(rect image.Rectangle) *DisplayWriter {
 	dis := display.New(rect)
 	handler := &displayWriterHandler{
@@ -27,15 +32,20 @@ func NewDisplayWriter(rect image.Rectangle) *DisplayWriter {
 	}
 }
 
+// DisplayWriter captures ANSI terminal commands and draws them onto a virtual
+// display.
 type DisplayWriter struct {
 	parser  *ansiterm.AnsiParser
 	handler *displayWriterHandler
 }
 
+// C returns a read channel. This channel will receive a non-blocking write
+// whenever the underlying display changes.
 func (d *DisplayWriter) C() <-chan struct{} {
 	return d.handler.c
 }
 
+// Write draws ANSI virtual terminal bytes onto the underlying virtual display.
 func (d *DisplayWriter) Write(buf []byte) (int, error) {
 	d.handler.lock.Lock()
 	defer d.handler.lock.Unlock()
@@ -50,12 +60,14 @@ func (d *DisplayWriter) Write(buf []byte) (int, error) {
 	return count, err
 }
 
+// Draw captures the current display state.
 func (d *DisplayWriter) Draw(e *display.Display, r image.Rectangle) {
 	d.handler.lock.RLock()
 	defer d.handler.lock.RUnlock()
 	display.Draw(e, r, d.handler.dis, image.ZP, draw.Src)
 }
 
+// Resize reallocates the display with different dimensions.
 func (d *DisplayWriter) Resize(rect image.Rectangle) {
 	d.handler.lock.Lock()
 	defer d.handler.lock.Unlock()

internal/hilbert/hilbert.go

@@ -2,16 +2,24 @@ package hilbert
 
 import "image"
 
+// Scale is the width and height of a Hilbert space-filling curve.
+// The scale must be a power of two.
 type Scale int
 
+// Encode returns the linear index of a point along a Hilbert curve with this
+// scale.
 func (scale Scale) Encode(pt image.Point) int {
 	return Encode(pt, int(scale))
 }
 
+// Decode returns the point at the given offset of a Hilbert curve with this
+// scale.
 func (scale Scale) Decode(hi int) image.Point {
 	return Decode(hi, int(scale))
 }
 
+// Encode returns the linear index of a point along a Hilbert curve for a given
+// scale.
 func Encode(pt image.Point, scale int) int {
 	var rotation image.Point
 	h := 0
@@ -24,6 +32,8 @@ func Encode(pt image.Point, scale int) int {
 	return h
 }
 
+// Decode returns the point corresponding to a given position along a Hilbert
+// curve of particular size.
 func Decode(h int, scale int) image.Point {
 	var pt, rotation image.Point
 	for s := 1; s < scale; s <<= 1 {

internal/input/channel.go

@@ -1,3 +1,7 @@
+// Package input provides an adapter that changes a stream of terminal input
+// into a channel of commands.
+// To use the command channel, read command by command and switch on the
+// command type.
 package input
 
 import (
@@ -7,7 +11,10 @@ import (
 	"unicode"
 )
 
+// Move captures a motion command. The data are a unit vector.
 type Move image.Point
+
+// ShiftMove captures a motion command with the shift key pressed. The data are a unit vector.
 type ShiftMove image.Point
 
 // Channel returns a read channel for commands, distinguishable by type, and a