gim: modify terminal to use a buffer, which will allow for much more complex behavior later

gim/box.go

@@ -9,24 +9,6 @@ import (
 	"github.com/mediocregopher/ginger/gim/terminal"
 )
 
-const (
-	boxBorderHoriz = iota
-	boxBorderVert
-	boxBorderTL
-	boxBorderTR
-	boxBorderBL
-	boxBorderBR
-)
-
-var boxDefault = []string{
-	"─",
-	"│",
-	"┌",
-	"┐",
-	"└",
-	"┘",
-}
-
 type box struct {
 	topLeft       geo.XY
 	flowDir       geo.XY
@@ -58,6 +40,7 @@ func (b box) bodyLines() []string {
 	return lines
 }
 
+// TODO this is utterly broken, the terminal.Buffer should be used for this
 func (b box) bodySize() geo.XY {
 	var size geo.XY
 	for _, line := range b.bodyLines() {
@@ -102,47 +85,14 @@ func (b box) bodyRect() geo.Rect {
 	return geo.Rect{Size: b.bodySize()}.Centered(center, rounder)
 }
 
-func (b box) draw(term *terminal.Terminal) {
-	chars := boxDefault
+func (b box) draw(buf *terminal.Buffer) {
+	bodyBuf := terminal.NewBuffer()
+	bodyBuf.WriteString(b.body)
+	bodyBufRect := geo.Rect{Size: bodyBuf.Size()}
+
 	rect := b.rect()
-	pos := rect.TopLeft
-	w, h := rect.Size[0], rect.Size[1]
+	buf.DrawRect(rect, terminal.SingleLine)
 
-	// draw top line
-	term.MoveCursorTo(pos)
-	term.Printf(chars[boxBorderTL])
-	for i := 0; i < w-2; i++ {
-		term.Printf(chars[boxBorderHoriz])
-	}
-	term.Printf(chars[boxBorderTR])
-	pos[1]++
-
-	// draw vertical lines
-	for i := 0; i < h-2; i++ {
-		term.MoveCursorTo(pos)
-		term.Printf(chars[boxBorderVert])
-		if b.transparent {
-			term.MoveCursorTo(pos.Add(geo.XY{w, 0}))
-		} else {
-			term.Printf(strings.Repeat(" ", w-2))
-		}
-		term.Printf(chars[boxBorderVert])
-		pos[1]++
-	}
-
-	// draw bottom line
-	term.MoveCursorTo(pos)
-	term.Printf(chars[boxBorderBL])
-	for i := 0; i < w-2; i++ {
-		term.Printf(chars[boxBorderHoriz])
-	}
-	term.Printf(chars[boxBorderBR])
-
-	// write out inner lines
-	pos = b.bodyRect().TopLeft
-	for _, line := range b.bodyLines() {
-		term.MoveCursorTo(pos)
-		term.Printf(line)
-		pos[1]++
-	}
+	center := rect.Center(rounder)
+	buf.DrawBuffer(bodyBufRect.Centered(center, rounder).TopLeft, bodyBuf)
 }

gim/line.go

@@ -5,38 +5,20 @@ import (
 	"github.com/mediocregopher/ginger/gim/terminal"
 )
 
-var lineSegments = func() map[[2]geo.XY]string {
-	m := map[[2]geo.XY]string{
-		{geo.Left, geo.Right}: "─",
-		{geo.Down, geo.Up}:    "│",
-		{geo.Right, geo.Down}: "┌",
-		{geo.Left, geo.Down}:  "┐",
-		{geo.Right, geo.Up}:   "└",
-		{geo.Left, geo.Up}:    "┘",
-	}
-
-	// the inverse segments use the same characters
-	for seg, str := range m {
-		seg[0], seg[1] = seg[1], seg[0]
-		m[seg] = str
-	}
-	return m
-}()
-
-var edgeSegments = map[geo.XY]string{
-	geo.Up:    "┴",
-	geo.Down:  "┬",
-	geo.Left:  "┤",
-	geo.Right: "├",
+var edgeSegments = map[geo.XY]rune{
+	geo.Up:    '┴',
+	geo.Down:  '┬',
+	geo.Left:  '┤',
+	geo.Right: '├',
 }
 
 // actual unicode arrows were fucking up my terminal, and they didn't even
 // connect properly with the line segments anyway
-var arrows = map[geo.XY]string{
-	geo.Up:    "^",
-	geo.Down:  "v",
-	geo.Left:  "<",
-	geo.Right: ">",
+var arrows = map[geo.XY]rune{
+	geo.Up:    '^',
+	geo.Down:  'v',
+	geo.Left:  '<',
+	geo.Right: '>',
 }
 
 type line struct {
@@ -54,7 +36,7 @@ func secondaryDir(flowDir, start, end geo.XY) geo.XY {
 	return end.Sub(start).Mul(perpDir.Abs()).Unit()
 }
 
-func (l line) draw(term *terminal.Terminal, flowDir, secFlowDir geo.XY) {
+func (l line) draw(buf *terminal.Buffer, flowDir, secFlowDir geo.XY) {
 	from, to := *(l.from), *(l.to)
 
 	start := from.rect().Edge(flowDir, secFlowDir)[0].Add(secFlowDir.Scale(l.fromI*2 + 1))
@@ -86,28 +68,24 @@ func (l line) draw(term *terminal.Terminal, flowDir, secFlowDir geo.XY) {
 
 	// draw each point
 	for i, pt := range pts {
-		var str string
+		var r rune
 		switch {
 		case i == 0:
-			str = edgeSegments[flowDir]
+			r = edgeSegments[flowDir]
 		case i == len(pts)-1:
-			str = arrows[flowDir]
+			r = arrows[flowDir]
 		default:
 			prev, next := pts[i-1], pts[i+1]
-			seg := [2]geo.XY{
-				prev.Sub(pt),
-				next.Sub(pt),
-			}
-			str = lineSegments[seg]
+			r = terminal.SingleLine.Segment(prev.Sub(pt), next.Sub(pt))
 		}
-		term.MoveCursorTo(pt)
-		term.Printf(str)
+		buf.SetPos(pt)
+		buf.WriteRune(r)
 	}
 
 	// draw the body
 	if l.body != "" {
 		bodyPos := mid.Add(geo.Left.Scale(len(l.body) / 2))
-		term.MoveCursorTo(bodyPos)
-		term.Printf(l.body)
+		buf.SetPos(bodyPos)
+		buf.WriteString(l.body)
 	}
 }

gim/main.go

@@ -80,8 +80,7 @@ func mkGraph() (*gg.Graph, gg.Value) {
 func main() {
 	rand.Seed(time.Now().UnixNano())
 	term := terminal.New()
-	//term.Reset()
-	//term.HideCursor()
+	wSize := term.WindowSize()
 
 	g, start := mkGraph()
 	v := view{
@@ -89,13 +88,11 @@ func main() {
 		primFlowDir: geo.Right,
 		secFlowDir:  geo.Down,
 		start:       start,
-		center:      geo.Zero.Midpoint(term.WindowSize(), rounder),
+		center:      geo.Zero.Midpoint(wSize, rounder),
 	}
 
-	//for range time.Tick(frameperiod) {
-	term.Reset()
+	term.Clear()
 	v.draw(term)
-	term.Flush()
-	//}
-	time.Sleep(1 * time.Hour)
+	term.SetPos(wSize.Add(geo.XY{0, -1}))
+	term.Draw()
 }

gim/terminal/buffer.go

@@ -0,0 +1,210 @@
+package terminal
+
+import (
+	"fmt"
+	"strconv"
+	"unicode"
+
+	"github.com/mediocregopher/ginger/gim/geo"
+)
+
+// Reset all custom styles
+const ansiReset = "\033[0m"
+
+// Color describes the foreground or background color of text
+type Color int
+
+// Available Color values
+const (
+	// whatever the terminal's default color scheme is
+	Default = iota
+
+	Black
+	Red
+	Green
+	Yellow
+	Blue
+	Magenta
+	Cyan
+	White
+)
+
+type bufStyle struct {
+	fgColor Color
+	bgColor Color
+}
+
+// returns foreground and background ansi codes
+func (bf bufStyle) ansi() (string, string) {
+	var fg, bg string
+	if bf.fgColor != Default {
+		fg = "\033[0;3" + strconv.Itoa(int(bf.fgColor)-1) + "m"
+	}
+	if bf.bgColor != Default {
+		bg = "\033[0;4" + strconv.Itoa(int(bf.bgColor)-1) + "m"
+	}
+	return fg, bg
+}
+
+// returns the ansi sequence which would modify the style to the given one
+func (bf bufStyle) diffTo(bf2 bufStyle) string {
+	// this implementation is naive, but whatever
+	if bf == bf2 {
+		return ""
+	}
+
+	fg, bg := bf2.ansi()
+	if (bf == bufStyle{}) {
+		return fg + bg
+	}
+	return ansiReset + fg + bg
+}
+
+type bufPoint struct {
+	r rune
+	bufStyle
+}
+
+// Buffer describes an infinitely sized terminal buffer to which anything may be
+// drawn, and which will efficiently generate strings representing the drawn
+// text.
+type Buffer struct {
+	currStyle bufStyle
+	currPos   geo.XY
+	m         *mat
+	max       geo.XY
+}
+
+// NewBuffer initializes and returns a new empty buffer. The proper way to clear
+// a buffer is to toss the old one and generate a new one.
+func NewBuffer() *Buffer {
+	return &Buffer{
+		m:   newMat(),
+		max: geo.XY{-1, -1},
+	}
+}
+
+// Copy creates a new identical instance of this Buffer and returns it.
+func (b *Buffer) Copy() *Buffer {
+	b2 := NewBuffer()
+	b.m.iter(func(x, y int, v interface{}) bool {
+		b2.setRune(geo.XY{x, y}, v.(bufPoint))
+		return true
+	})
+	b2.currStyle = b.currStyle
+	b2.currPos = b.currPos
+	return b2
+}
+
+func (b *Buffer) setRune(at geo.XY, p bufPoint) {
+	b.m.set(at[0], at[1], p)
+	b.max = b.max.Max(at)
+}
+
+// WriteRune writes the given rune to the Buffer at whatever the current
+// position is, with whatever the current styling is.
+func (b *Buffer) WriteRune(r rune) {
+	if r == '\n' {
+		b.currPos[0], b.currPos[1] = 0, b.currPos[1]+1
+		return
+	} else if r == '\r' {
+		b.currPos[0] = 0
+	} else if !unicode.IsPrint(r) {
+		panic(fmt.Sprintf("character %q is not supported by terminal.Buffer", r))
+	}
+
+	b.setRune(b.currPos, bufPoint{
+		r:        r,
+		bufStyle: b.currStyle,
+	})
+	b.currPos[0]++
+}
+
+// WriteString writes the given string to the Buffer at whatever the current
+// position is, with whatever the current styling is.
+func (b *Buffer) WriteString(s string) {
+	for _, r := range s {
+		b.WriteRune(r)
+	}
+}
+
+// SetPos sets the cursor position in the Buffer, so Print operations will begin
+// at that point. Remember that the origin is at point (0, 0).
+func (b *Buffer) SetPos(xy geo.XY) {
+	b.currPos = xy
+}
+
+// SetFGColor sets subsequent text's foreground color.
+func (b *Buffer) SetFGColor(c Color) {
+	b.currStyle.fgColor = c
+}
+
+// SetBGColor sets subsequent text's background color.
+func (b *Buffer) SetBGColor(c Color) {
+	b.currStyle.bgColor = c
+}
+
+// ResetStyle unsets all text styling options which have been set.
+func (b *Buffer) ResetStyle() {
+	b.currStyle = bufStyle{}
+}
+
+// String renders and returns a string which, when printed to a terminal, will
+// print the Buffer's contents at the terminal's current cursor position.
+func (b *Buffer) String() string {
+	s := ansiReset // always start with a reset
+	var style bufStyle
+	var pos geo.XY
+	move := func(to geo.XY) {
+		diff := to.Sub(pos)
+		if diff[0] > 0 {
+			s += "\033[" + strconv.Itoa(diff[0]) + "C"
+		} else if diff[0] < 0 {
+			s += "\033[" + strconv.Itoa(-diff[0]) + "D"
+		}
+		if diff[1] > 0 {
+			s += "\033[" + strconv.Itoa(diff[1]) + "B"
+		} else if diff[1] < 0 {
+			s += "\033[" + strconv.Itoa(-diff[1]) + "A"
+		}
+		pos = to
+	}
+
+	b.m.iter(func(x, y int, v interface{}) bool {
+		p := v.(bufPoint)
+		move(geo.XY{x, y})
+		s += style.diffTo(p.bufStyle)
+		style = p.bufStyle
+		s += string(p.r)
+		pos[0]++
+		return true
+	})
+	return s
+}
+
+// DrawBuffer copies the given Buffer onto this one, with the given's top-left
+// corner being at the given position. The given buffer may be the same as this
+// one.
+//
+// Calling this method does not affect this Buffer's current cursor position or
+// style.
+func (b *Buffer) DrawBuffer(at geo.XY, b2 *Buffer) {
+	if b == b2 {
+		b2 = b2.Copy()
+	}
+	b2.m.iter(func(x, y int, v interface{}) bool {
+		x += at[0]
+		y += at[1]
+		if x < 0 || y < 0 {
+			return true
+		}
+		b.setRune(geo.XY{x, y}, v.(bufPoint))
+		return true
+	})
+}
+
+// Size returns the dimensions of the Buffer's current area which has been
+// written to.
+func (b *Buffer) Size() geo.XY {
+	return b.max.Add(geo.XY{1, 1})
+}

gim/terminal/example/main.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"log"
+	"time"
+
+	"github.com/mediocregopher/ginger/gim/geo"
+	"github.com/mediocregopher/ginger/gim/terminal"
+)
+
+func main() {
+	b := terminal.NewBuffer()
+	b.WriteString("this is fun")
+
+	b.SetFGColor(terminal.Blue)
+	b.SetBGColor(terminal.Green)
+	b.SetPos(geo.XY{18, 0})
+	b.WriteString("blue and green")
+
+	b.ResetStyle()
+	b.SetFGColor(terminal.Red)
+	b.SetPos(geo.XY{3, 3})
+	b.WriteString("red!!!")
+
+	b.ResetStyle()
+	b.SetFGColor(terminal.Blue)
+	b.SetPos(geo.XY{20, 0})
+	b.WriteString("boo")
+
+	bcp := b.Copy()
+	b.DrawBuffer(geo.XY{2, 2}, bcp)
+	b.DrawBuffer(geo.XY{-1, 1}, bcp)
+
+	brect := terminal.NewBuffer()
+	brect.DrawRect(geo.Rect{Size: b.Size().Add(geo.XY{2, 2})}, terminal.SingleLine)
+	log.Printf("b.Size:%v", b.Size())
+	brect.DrawBuffer(geo.XY{1, 1}, b)
+
+	t := terminal.New()
+	p := geo.XY{0, 0}
+	dirH, dirV := geo.Right, geo.Down
+	wsize := t.WindowSize()
+	for range time.Tick(time.Second / 15) {
+		t.Clear()
+		t.WriteBuffer(p, brect)
+		t.Draw()
+
+		brectSize := brect.Size()
+		p = p.Add(dirH).Add(dirV)
+		if p[0] < 0 || p[0]+brectSize[0] > wsize[0] {
+			dirH = dirH.Scale(-1)
+			p = p.Add(dirH.Scale(2))
+		}
+		if p[1] < 0 || p[1]+brectSize[1] > wsize[1] {
+			dirV = dirV.Scale(-1)
+			p = p.Add(dirV.Scale(2))
+		}
+	}
+}

gim/terminal/mat.go

@@ -0,0 +1,117 @@
+package terminal
+
+import (
+	"container/list"
+)
+
+type matEl struct {
+	x int
+	v interface{}
+}
+
+type matRow struct {
+	y int
+	l *list.List
+}
+
+// a 2-d sparse matrix
+type mat struct {
+	rows *list.List
+
+	currY     int
+	currRowEl *list.Element
+	currEl    *list.Element
+}
+
+func newMat() *mat {
+	return &mat{
+		rows: list.New(),
+	}
+}
+
+func (m *mat) getRow(y int) *list.List {
+	m.currY = y             // this will end up being true no matter what
+	if m.currRowEl == nil { // first call
+		l := list.New()
+		m.currRowEl = m.rows.PushFront(matRow{y: y, l: l})
+		return l
+
+	} else if m.currRowEl.Value.(matRow).y > y {
+		m.currRowEl = m.rows.Front()
+	}
+
+	for {
+		currRow := m.currRowEl.Value.(matRow)
+		switch {
+		case currRow.y == y:
+			return currRow.l
+		case currRow.y < y:
+			if m.currRowEl = m.currRowEl.Next(); m.currRowEl == nil {
+				l := list.New()
+				m.currRowEl = m.rows.PushBack(matRow{y: y, l: l})
+				return l
+			}
+		default: // currRow.y > y
+			l := list.New()
+			m.currRowEl = m.rows.InsertBefore(matRow{y: y, l: l}, m.currRowEl)
+			return l
+		}
+	}
+}
+
+func (m *mat) getEl(x, y int) *matEl {
+	var rowL *list.List
+	if m.currRowEl == nil || m.currY != y {
+		rowL = m.getRow(y)
+		m.currEl = rowL.Front()
+	} else {
+		rowL = m.currRowEl.Value.(matRow).l
+	}
+
+	if m.currEl == nil || m.currEl.Value.(*matEl).x > x {
+		if m.currEl = rowL.Front(); m.currEl == nil {
+			// row is empty
+			mel := &matEl{x: x}
+			m.currEl = rowL.PushFront(mel)
+			return mel
+		}
+	}
+
+	for {
+		currEl := m.currEl.Value.(*matEl)
+		switch {
+		case currEl.x == x:
+			return currEl
+		case currEl.x < x:
+			if m.currEl = m.currEl.Next(); m.currEl == nil {
+				mel := &matEl{x: x}
+				m.currEl = rowL.PushBack(mel)
+				return mel
+			}
+		default: // currEl.x > x
+			mel := &matEl{x: x}
+			m.currEl = rowL.InsertBefore(mel, m.currEl)
+			return mel
+		}
+	}
+}
+
+func (m *mat) get(x, y int) interface{} {
+	return m.getEl(x, y).v
+}
+
+func (m *mat) set(x, y int, v interface{}) {
+	m.getEl(x, y).v = v
+}
+
+func (m *mat) iter(f func(x, y int, v interface{}) bool) {
+	for rowEl := m.rows.Front(); rowEl != nil; rowEl = rowEl.Next() {
+		row := rowEl.Value.(matRow)
+		for el := row.l.Front(); el != nil; el = el.Next() {
+			mel := el.Value.(*matEl)
+			if !f(mel.x, row.y, mel.v) {
+				return
+			}
+		}
+	}
+}

gim/terminal/mat_test.go

@@ -0,0 +1,59 @@
+package terminal
+
+import (
+	"fmt"
+	"math/rand"
+	"strings"
+	. "testing"
+	"time"
+)
+
+func TestMat(t *T) {
+	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+
+	type xy struct {
+		x, y int
+	}
+
+	type action struct {
+		xy
+		set int
+	}
+
+	run := func(aa []action) {
+		aaStr := func(i int) string {
+			s := fmt.Sprintf("%#v", aa[:i+1])
+			return strings.Replace(s, "terminal.", "", -1)
+		}
+
+		m := newMat()
+		mm := map[xy]int{}
+		for i, a := range aa {
+			if a.set > 0 {
+				mm[a.xy] = a.set
+				m.set(a.xy.x, a.xy.y, a.set)
+				continue
+			}
+
+			expI, expOk := mm[a.xy]
+			gotI, gotOk := m.get(a.xy.x, a.xy.y).(int)
+			if expOk != gotOk {
+				t.Fatalf("get failed: expOk:%v gotOk:%v actions:%#v", expOk, gotOk, aaStr(i))
+			} else if expI != gotI {
+				t.Fatalf("get failed: expI:%v gotI:%v actions:%#v", expI, gotI, aaStr(i))
+			}
+		}
+	}
+
+	for i := 0; i < 10000; i++ {
+		var actions []action
+		for j := r.Intn(1000); j > 0; j-- {
+			a := action{xy: xy{x: r.Intn(5), y: r.Intn(5)}}
+			if r.Intn(3) == 0 {
+				a.set = r.Intn(10000) + 1
+			}
+			actions = append(actions, a)
+		}
+		run(actions)
+	}
+}

gim/terminal/shape.go

@@ -0,0 +1,86 @@
+package terminal
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/mediocregopher/ginger/gim/geo"
+)
+
+// SingleLine is a set of single-pixel-width lines.
+var SingleLine = LineStyle{
+	Horiz:       '─',
+	Vert:        '│',
+	TopLeft:     '┌',
+	TopRight:    '┐',
+	BottomLeft:  '└',
+	BottomRight: '┘',
+}
+
+// LineStyle defines a set of characters to use together when drawing lines and
+// corners.
+type LineStyle struct {
+	Horiz, Vert rune
+	// Corner characters, identified as corners of a rectangle
+	TopLeft, TopRight, BottomLeft, BottomRight rune
+}
+
+// Segment takes two different directions (i.e. geo.Up/Down/Left/Right) and
+// returns the line character which points in both of those directions.
+//
+// For example, SingleLine.Segment(geo.Up, geo.Left) returns '┘'.
+func (ls LineStyle) Segment(a, b geo.XY) rune {
+	inner := func(a, b geo.XY) rune {
+		type c struct{ a, b geo.XY }
+		switch (c{a, b}) {
+		case c{geo.Up, geo.Down}:
+			return ls.Vert
+		case c{geo.Left, geo.Right}:
+			return ls.Horiz
+		case c{geo.Down, geo.Right}:
+			return ls.TopLeft
+		case c{geo.Down, geo.Left}:
+			return ls.TopRight
+		case c{geo.Up, geo.Right}:
+			return ls.BottomLeft
+		case c{geo.Up, geo.Left}:
+			return ls.BottomRight
+		default:
+			return 0
+		}
+	}
+	if r := inner(a, b); r != 0 {
+		return r
+	} else if r = inner(b, a); r != 0 {
+		return r
+	}
+	panic(fmt.Sprintf("invalid LineStyle.Segment directions: %v, %v", a, b))
+}
+
+// DrawRect draws the given Rect to the Buffer with the given LineStyle. The
+// Rect's TopLeft field is used for its position.
+//
+// If Rect's Size is not at least 2x2 this does nothing.
+func (b *Buffer) DrawRect(r geo.Rect, ls LineStyle) {
+	if r.Size[0] < 2 || r.Size[1] < 2 {
+		return
+	}
+	horiz := strings.Repeat(string(ls.Horiz), r.Size[0]-2)
+
+	b.SetPos(r.TopLeft)
+	b.WriteRune(ls.TopLeft)
+	b.WriteString(horiz)
+	b.WriteRune(ls.TopRight)
+
+	for i := 0; i < r.Size[1]-2; i++ {
+		b.SetPos(r.TopLeft.Add(geo.XY{0, i + 1}))
+		b.WriteRune(ls.Vert)
+		b.SetPos(r.TopLeft.Add(geo.XY{r.Size[0] - 1, i + 1}))
+		b.WriteRune(ls.Vert)
+	}
+
+	b.SetPos(r.TopLeft.Add(geo.XY{0, r.Size[1] - 1}))
+	b.WriteRune(ls.BottomLeft)
+	b.WriteString(horiz)
+	b.WriteRune(ls.BottomRight)
+}

gim/terminal/terminal.go

@@ -8,7 +8,6 @@ import (
 	"io"
 	"os"
 	"syscall"
-	"unicode/utf8"
 	"unsafe"
 
 	"github.com/mediocregopher/ginger/gim/geo"
@@ -34,7 +33,6 @@ import (
 //
 type Terminal struct {
 	buf *bytes.Buffer
-	pos geo.XY
 
 	// When initialized this will be set to os.Stdout, but can be set to
 	// anything
@@ -70,17 +68,10 @@ func (t *Terminal) WindowSize() geo.XY {
 	return geo.XY{int(sz.cols), int(sz.rows)}
 }
 
-// MoveCursorTo moves the cursor to the given position
-func (t *Terminal) MoveCursorTo(to geo.XY) {
+// SetPos sets the terminal's actual cursor position to the given coordinates.
+func (t *Terminal) SetPos(to geo.XY) {
 	// actual terminal uses 1,1 as top-left, because 1-indexing is a great idea
 	fmt.Fprintf(t.buf, "\033[%d;%dH", to[1]+1, to[0]+1)
-	t.pos = to
-}
-
-// MoveCursor moves the cursor relative to its current position by the given
-// vector
-func (t *Terminal) MoveCursor(by geo.XY) {
-	t.MoveCursorTo(t.pos.Add(by))
 }
 
 // HideCursor causes the cursor to not actually be shown
@@ -93,64 +84,25 @@ func (t *Terminal) ShowCursor() {
 	fmt.Fprintf(t.buf, "\033[?25h")
 }
 
-// Reset completely clears all drawn characters on the screen and returns the
-// cursor to the origin
-func (t *Terminal) Reset() {
+// Clear completely clears all drawn characters on the screen and returns the
+// cursor to the origin. This implicitly calls Draw.
+func (t *Terminal) Clear() {
+	t.buf.Reset()
 	fmt.Fprintf(t.buf, "\033[2J")
+	t.Draw()
 }
 
-// Printf prints the given formatted string to the terminal, updating the
-// internal cursor position accordingly
-func (t *Terminal) Printf(format string, args ...interface{}) {
-	str := fmt.Sprintf(format, args...)
-	t.buf.WriteString(str)
-	t.pos[0] += utf8.RuneCountInString(str)
+// WriteBuffer writes the contents to the Buffer to the Terminal's buffer,
+// starting at the given coordinate.
+func (t *Terminal) WriteBuffer(at geo.XY, b *Buffer) {
+	t.SetPos(at)
+	t.buf.WriteString(b.String())
 }
 
-// Flush writes all buffered changes to the screen
-func (t *Terminal) Flush() {
+// Draw writes all buffered changes to the screen
+func (t *Terminal) Draw() {
 	if _, err := io.Copy(t.Out, t.buf); err != nil {
 		panic(err)
 	}
-}
-
-// TODO deal with these
-
-const (
-	// Reset all custom styles
-	ansiReset = "\033[0m"
-
-	// Reset to default color
-	ansiResetColor = "\033[32m"
-
-	// Return curor to start of line and clean it
-	ansiResetLine = "\r\033[K"
-)
-
-// List of possible colors
-const (
-	black = iota
-	red
-	green
-	yellow
-	blue
-	magenta
-	cyan
-	white
-)
-
-func getFgColor(code int) string {
-	return fmt.Sprintf("\033[3%dm", code)
-}
-
-func getBgColor(code int) string {
-	return fmt.Sprintf("\033[4%dm", code)
-}
-
-func fgColor(str string, color int) string {
-	return fmt.Sprintf("%s%s%s", getFgColor(color), str, ansiReset)
-}
-
-func bgColor(str string, color int) string {
-	return fmt.Sprintf("%s%s%s", getBgColor(color), str, ansiReset)
+	t.buf.Reset()
 }

gim/view.go

@@ -104,7 +104,7 @@ type view struct {
 	g                       *gg.Graph
 	primFlowDir, secFlowDir geo.XY
 	start                   gg.Value
-	center                  geo.XY
+	center                  geo.XY // TODO this shouldnt be needed
 }
 
 func (view *view) draw(term *terminal.Terminal) {
@@ -190,10 +190,12 @@ func (view *view) draw(term *terminal.Terminal) {
 	centerBoxes(boxes, view.center)
 
 	// actually draw the boxes and lines
+	buf := terminal.NewBuffer()
 	for _, b := range boxes {
-		b.draw(term)
+		b.draw(buf)
 	}
 	for _, line := range lines {
-		line.draw(term, view.primFlowDir, view.secFlowDir)
+		line.draw(buf, view.primFlowDir, view.secFlowDir)
 	}
+	term.WriteBuffer(geo.Zero, buf)
 }