Add braille & quarter-block canvas. Add scatter plot type. Re-write linechart + barchart.

20 files changed, 522 insertions, 371 deletions

diff --git a/pkg/jp/primitives/box.go b/pkg/draw/box.go
index 38474c6..769e2fd 100644
--- a/pkg/jp/primitives/box.go
+++ b/pkg/draw/box.go
@@ -1,4 +1,4 @@
-package primitives
+package draw
 
 type Box struct {
 	Width  int
diff --git a/pkg/draw/braille.go b/pkg/draw/braille.go
new file mode 100644
index 0000000..33b238e
--- /dev/null
+++ b/pkg/draw/braille.go
@@ -0,0 +1,42 @@
+package draw
+
+var _ Pixels = &Braille{}
+
+const (
+	brailleScaleX = 2
+	brailleScaleY = 4
+	brailleEmpty  = rune(0x2800)
+)
+
+type Braille struct{ *Buffer }
+
+func (b *Braille) Size() Box {
+	return Box{
+		Width:  b.Width * brailleScaleX,
+		Height: b.Height * brailleScaleY,
+	}
+}
+
+func (b *Braille) Clear() { b.Fill(brailleEmpty) }
+
+func (b *Braille) Set(y, x int) {
+	ry := y / brailleScaleY
+	rx := x / brailleScaleX
+	b.SetOr(ry, rx, braillePoint(y, x))
+}
+
+func braillePoint(y, x int) rune {
+	var cy, cx int
+	if y >= 0 {
+		cy = y % 4
+	} else {
+		cy = 3 + ((y + 1) % 4)
+	}
+	if x >= 0 {
+		cx = x % 2
+	} else {
+		cx = 1 + ((x + 1) % 2)
+	}
+	pixelMap := [4][2]rune{{1, 8}, {2, 16}, {4, 32}, {64, 128}}
+	return pixelMap[3-cy][cx]
+}
diff --git a/pkg/draw/buffer.go b/pkg/draw/buffer.go
new file mode 100644
index 0000000..9e18f58
--- /dev/null
+++ b/pkg/draw/buffer.go
@@ -0,0 +1,108 @@
+package draw
+
+import (
+	"io"
+)
+
+type Buffer struct {
+	Runes [][]rune
+	Box
+}
+
+func (b *Buffer) GetBuffer() *Buffer { return b }
+
+func NewBuffer(size Box) *Buffer {
+	r := make([][]rune, size.Height)
+	for i := range r {
+		r[i] = make([]rune, size.Width)
+	}
+	return &Buffer{
+		Runes: r,
+		Box:   size,
+	}
+}
+
+func (b *Buffer) Fill(r rune) {
+	for i := range b.Runes {
+		for j := range b.Runes[i] {
+			b.Runes[i][j] = r
+		}
+	}
+}
+
+func (b *Buffer) Get(y, x int) rune {
+	if y < 0 || y >= b.Height {
+		return 0
+	}
+	if x < 0 || x >= b.Width {
+		return 0
+	}
+	return b.Runes[y][x]
+}
+
+func (b *Buffer) Set(y, x int, r rune) {
+	if y < 0 || y >= b.Height {
+		return
+	}
+	if x < 0 || x >= b.Width {
+		return
+	}
+	b.Runes[y][x] = r
+}
+
+func (b *Buffer) SetRow(y, x1, x2 int, r rune) {
+	for i := x1; i < x2; i++ {
+		b.Set(y, i, r)
+	}
+}
+
+func (b *Buffer) SetColumn(y1, y2, x int, r rune) {
+	for i := y1; i < y2; i++ {
+		b.Set(i, x, r)
+	}
+}
+
+func (b *Buffer) SetOr(y, x int, r rune) {
+	if y < 0 || y >= b.Height {
+		return
+	}
+	if x < 0 || x >= b.Width {
+		return
+	}
+	b.Runes[y][x] |= r
+}
+
+func (b *Buffer) Write(y, x int, r []rune) {
+	if y < 0 || y >= b.Height {
+		return
+	}
+	for i := 0; i < len(r); i++ {
+		xi := x + i
+		if xi < 0 || xi >= b.Width {
+			continue
+		}
+		b.Runes[y][xi] = r[i]
+	}
+}
+
+func (b *Buffer) WriteLeft(y, x int, r []rune) {
+	b.Write(y, x-len(r), r)
+}
+
+func (b *Buffer) WriteRight(y, x int, r []rune) {
+	b.Write(y, x, r)
+}
+
+func (b *Buffer) WriteCenter(y, x int, r []rune) {
+	b.Write(y, x-len(r)/2, r)
+}
+
+func (b *Buffer) Render(w io.Writer) {
+	for i := range b.Runes {
+		row := b.Runes[b.Height-i-1]
+		w.Write([]byte(string(row)))
+		if i < b.Height-1 {
+			w.Write([]byte{'\n'})
+		}
+	}
+}
diff --git a/pkg/draw/canvas.go b/pkg/draw/canvas.go
new file mode 100644
index 0000000..0235c66
--- /dev/null
+++ b/pkg/draw/canvas.go
@@ -0,0 +1,23 @@
+package draw
+
+type Pixels interface {
+	GetBuffer() *Buffer
+	Clear()
+	Set(y, x int)
+	Size() Box
+}
+
+type Canvas struct{ Pixels }
+
+func (c *Canvas) RuneSize() Box {
+	pixelBox := c.Size()
+	runeBox := c.GetBuffer().Box
+	return Box{
+		Width:  pixelBox.Width / runeBox.Width,
+		Height: pixelBox.Height / runeBox.Height,
+	}
+}
+
+func (c *Canvas) DrawLine(y0, x0, y1, x1 int) {
+	line(y0, x0, y1, x1, c.Set)
+}
diff --git a/pkg/draw/full.go b/pkg/draw/full.go
new file mode 100644
index 0000000..6f234b0
--- /dev/null
+++ b/pkg/draw/full.go
@@ -0,0 +1,11 @@
+package draw
+
+var _ Pixels = &Full{}
+
+type Full struct{ *Buffer }
+
+func (b *Full) Size() Box { return b.Box }
+
+func (b *Full) Set(y, x int) { b.Buffer.Set(y, x, '█') }
+
+func (b *Full) Clear() { b.Fill(' ') }
diff --git a/pkg/jp/primitives/line.go b/pkg/draw/line.go
index 4bcedca..c5a5ee5 100644
--- a/pkg/jp/primitives/line.go
+++ b/pkg/draw/line.go
@@ -1,4 +1,4 @@
-package primitives
+package draw
 
 // Adapted from https://github.com/buger/goterm under the MIT License.
 
@@ -27,8 +27,7 @@ SOFTWARE.
 
 */
 
-// http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
-func DrawLine(x0, y0, x1, y1 int, plot func(int, int)) {
+func line(y0, x0, y1, x1 int, plot func(y, x int)) {
 	dx := x1 - x0
 	if dx < 0 {
 		dx = -dx
@@ -51,7 +50,7 @@ func DrawLine(x0, y0, x1, y1 int, plot func(int, int)) {
 	err := dx - dy
 
 	for {
-		plot(x0, y0)
+		plot(y0, x0)
 		if x0 == x1 && y0 == y1 {
 			break
 		}
diff --git a/pkg/draw/quarter.go b/pkg/draw/quarter.go
new file mode 100644
index 0000000..b7748f4
--- /dev/null
+++ b/pkg/draw/quarter.go
@@ -0,0 +1,37 @@
+package draw
+
+var _ Pixels = &Quarter{}
+
+const (
+	quarterScaleX = 2
+	quarterScaleY = 2
+)
+
+type Quarter struct{ *Buffer }
+
+func (b *Quarter) Size() Box {
+	return Box{
+		Width:  b.Width * quarterScaleX,
+		Height: b.Height * quarterScaleY,
+	}
+}
+
+func (b *Quarter) Set(y, x int) {
+	ry, cy := y/2, 1-y%2
+	rx, cx := x/2, x%2
+	i := index(b.Get(ry, rx))
+	b.Buffer.Set(ry, rx, runes[i|(1<<uint(cx+2*cy))])
+}
+
+func (b *Quarter) Clear() { b.Fill(runes[0]) }
+
+var runes = []rune(" ▘▝▀▖▌▞▛▗▚▐▜▄▙▟█")
+
+func index(r rune) int {
+	for i := range runes {
+		if runes[i] == r {
+			return i
+		}
+	}
+	return 0
+}
diff --git a/pkg/draw/runes.go b/pkg/draw/runes.go
new file mode 100644
index 0000000..834681e
--- /dev/null
+++ b/pkg/draw/runes.go
@@ -0,0 +1,12 @@
+// +build !windows
+
+package draw
+
+// Box drawing characters
+var (
+	HorizontalLine     = '─'
+	VerticalLine       = '│'
+	CornerBottomLeft   = '└'
+	PointSymbolDefault = '•'
+	Cross              = '╳'
+)
diff --git a/pkg/draw/runes_windows.go b/pkg/draw/runes_windows.go
new file mode 100644
index 0000000..6132acb
--- /dev/null
+++ b/pkg/draw/runes_windows.go
@@ -0,0 +1,11 @@
+// +build windows
+
+package draw
+
+var (
+	HorizontalLine     = '-'
+	VerticalLine       = '|'
+	CornerBottomLeft   = '+'
+	PointSymbolDefault = '*'
+	Cross              = 'X'
+)
diff --git a/pkg/jp/barchart.go b/pkg/jp/barchart.go
deleted file mode 100644
index c561f98..0000000
--- a/pkg/jp/barchart.go
+++ /dev/null
@@ -1,124 +0,0 @@
-package jp
-
-import (
-	"math"
-	"strings"
-
-	"github.com/sgreben/jp/pkg/jp/primitives"
-)
-
-// BarChart is a bar chart
-type BarChart struct {
-	Buffer []string
-
-	data *DataTable
-
-	Width       int
-	Height      int
-	Symbol      string
-	BarPaddingX int
-
-	chartHeight int
-	chartWidth  int
-
-	paddingX int
-	paddingY int
-}
-
-// NewBarChart returns a new bar chart
-func NewBarChart(width, height int) *BarChart {
-	chart := new(BarChart)
-	chart.Width = width
-	chart.Height = height
-	chart.Buffer = primitives.Buffer(width * height)
-	chart.Symbol = primitives.FullBlock4
-	chart.paddingY = 3
-	chart.BarPaddingX = 1
-	return chart
-}
-
-func (c *BarChart) writeText(text string, x, y int) {
-	coord := y*c.Width + x
-
-	for idx, char := range strings.Split(text, "") {
-		if coord+idx >= 0 && coord+idx < len(c.Buffer) {
-			c.Buffer[coord+idx] = char
-		}
-	}
-}
-
-// Draw implements Chart
-func (c *BarChart) Draw(data *DataTable) (out string) {
-
-	c.data = data
-
-	minY := math.Inf(1)
-	maxY := math.Inf(-1)
-	for _, row := range data.Rows {
-		for _, y := range row {
-			if y < minY {
-				minY = y
-			}
-			if y > maxY {
-				maxY = y
-			}
-		}
-	}
-
-	c.paddingX = 1
-	c.chartHeight = c.Height - c.paddingY
-	c.chartWidth = c.Width - c.paddingX - 1
-	scaleY := float64(c.chartHeight) / maxY
-	barPaddedWidth := c.chartWidth / len(data.Columns)
-	barWidth := barPaddedWidth - c.BarPaddingX
-	if barPaddedWidth < 1 {
-		barPaddedWidth = 1
-	}
-	if barWidth < 1 {
-		barWidth = 1
-	}
-
-	scaleY = float64(c.chartHeight) / maxY
-
-	for i, group := range data.Columns {
-		barLeft := c.paddingX + barPaddedWidth*i
-		barRight := barLeft + barWidth
-		y := data.Rows[0][i]
-		barHeight := y * scaleY
-		barTop := c.paddingY - 1 + int(barHeight)
-		for x := barLeft; x < barRight; x++ {
-			for y := c.paddingY - 1; y < barTop; y++ {
-				c.set(x, y, c.Symbol)
-			}
-			if barHeight < 1 && y > 0 {
-				for x := barLeft; x < barRight; x++ {
-					c.set(x, barTop, "▁")
-				}
-			}
-		}
-
-		// Group label
-		barMiddle := (barLeft + barRight) / 2
-		c.writeText(group, barMiddle-(len(group)/2), 0)
-
-		// Count label
-		countLabelY := barTop
-		if barHeight < 1 {
-			countLabelY = barTop + 1
-		}
-		c.writeText(primitives.Ff(y), barMiddle-(len(primitives.Ff(y))/2), countLabelY)
-	}
-
-	for row := c.Height - 1; row >= 0; row-- {
-		out += strings.Join(c.Buffer[row*c.Width:(row+1)*c.Width], "") + "\n"
-	}
-
-	return
-}
-
-func (c *BarChart) set(x, y int, s string) {
-	coord := y*c.Width + x
-	if coord > 0 && coord < len(c.Buffer) {
-		c.Buffer[coord] = s
-	}
-}
diff --git a/pkg/jp/linechart.go b/pkg/jp/linechart.go
deleted file mode 100644
index 1849a1e..0000000
--- a/pkg/jp/linechart.go
+++ /dev/null
@@ -1,205 +0,0 @@
-package jp
-
-import (
-	"math"
-	"strings"
-
-	"github.com/sgreben/jp/pkg/jp/primitives"
-)
-
-// Adapted from https://github.com/buger/goterm under the MIT License.
-
-/*
-MIT License
-
-Copyright (c) 2016 Leonid Bugaev
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-
-*/
-
-// LineChart is a line chart
-type LineChart struct {
-	Buffer      []string
-	Width       int
-	Height      int
-	Symbol      string
-	chartHeight int
-	chartWidth  int
-	paddingX    int
-	paddingY    int
-
-	data *DataTable
-}
-
-// NewLineChart returns a new line chart
-func NewLineChart(width, height int) *LineChart {
-	chart := new(LineChart)
-	chart.Width = width
-	chart.Height = height
-	chart.Buffer = primitives.Buffer(width * height)
-	chart.Symbol = primitives.PointSymbolDefault
-	chart.paddingY = 2
-	return chart
-}
-
-func (c *LineChart) drawAxes(maxX, minX, maxY, minY float64, index int) {
-	c.drawLine(c.paddingX-1, 1, c.Width-1, 1, primitives.HorizontalLine)
-	c.drawLine(c.paddingX-1, 1, c.paddingX-1, c.Height-1, primitives.VerticalLine)
-	c.set(c.paddingX-1, c.paddingY-1, primitives.CornerBottomLeft)
-
-	left := 0 // c.Width - c.paddingX + 1
-	c.writeText(primitives.Ff(minY), left, 1)
-
-	c.writeText(primitives.Ff(maxY), left, c.Height-1)
-
-	c.writeText(primitives.Ff(minX), c.paddingX, 0)
-
-	xCol := c.data.Columns[0]
-	c.writeText(c.data.Columns[0], c.Width/2-len(xCol)/2, 1)
-
-	if len(c.data.Columns) < 3 {
-		col := c.data.Columns[index]
-
-		for idx, char := range strings.Split(col, "") {
-			startFrom := c.Height/2 + len(col)/2 - idx
-
-			c.writeText(char, c.paddingX-1, startFrom)
-		}
-	}
-
-	c.writeText(primitives.Ff(maxX), c.Width-len(primitives.Ff(maxX)), 0)
-
-}
-
-func (c *LineChart) writeText(text string, x, y int) {
-	coord := y*c.Width + x
-
-	for idx, char := range strings.Split(text, "") {
-		c.Buffer[coord+idx] = char
-	}
-}
-
-// Draw implements Chart
-func (c *LineChart) Draw(data *DataTable) (out string) {
-	var scaleY, scaleX float64
-
-	c.data = data
-
-	charts := len(data.Columns) - 1
-
-	prevPoint := [2]int{-1, -1}
-
-	maxX, minX, maxY, minY := getBoundaryValues(data, -1)
-
-	c.paddingX = int(math.Max(float64(len(primitives.Ff(minY))), float64(len(primitives.Ff(maxY))))) + 1
-
-	c.chartHeight = c.Height - c.paddingY
-	c.chartWidth = c.Width - c.paddingX - 1
-
-	scaleX = float64(c.chartWidth) / (maxX - minX)
-
-	scaleY = float64(c.chartHeight) / (maxY - minY)
-
-	for i := 1; i < charts+1; i++ {
-		symbol := c.Symbol
-
-		chartData := getChartData(data, i)
-
-		for _, point := range chartData {
-			x := int((point[0]-minX)*scaleX) + c.paddingX
-			y := int((point[1])*scaleY) + c.paddingY
-			y = int((point[1]-minY)*scaleY) + c.paddingY
-
-			if prevPoint[0] == -1 {
-				prevPoint[0] = x
-				prevPoint[1] = y
-			}
-
-			if prevPoint[0] <= x {
-				c.drawLine(prevPoint[0], prevPoint[1], x, y, symbol)
-			}
-
-			prevPoint[0] = x
-			prevPoint[1] = y
-		}
-
-		c.drawAxes(maxX, minX, maxY, minY, i)
-	}
-
-	for row := c.Height - 1; row >= 0; row-- {
-		out += strings.Join(c.Buffer[row*c.Width:(row+1)*c.Width], "") + "\n"
-	}
-
-	return
-}
-
-func (c *LineChart) set(x, y int, s string) {
-	coord := y*c.Width + x
-	if coord > 0 && coord < len(c.Buffer) {
-		c.Buffer[coord] = s
-	}
-}
-
-func (c *LineChart) drawLine(x0, y0, x1, y1 int, symbol string) {
-	primitives.DrawLine(x0, y0, x1, y1, func(x, y int) { c.set(x, y, symbol) })
-}
-
-func getBoundaryValues(data *DataTable, index int) (maxX, minX, maxY, minY float64) {
-	maxX = math.Inf(-1)
-	minX = math.Inf(1)
-	maxY = math.Inf(-1)
-	minY = math.Inf(1)
-
-	for _, r := range data.Rows {
-		maxX = math.Max(maxX, r[0])
-		minX = math.Min(minX, r[0])
-
-		for idx, c := range r {
-			if idx > 0 {
-				if index == -1 || index == idx {
-					maxY = math.Max(maxY, c)
-					minY = math.Min(minY, c)
-				}
-			}
-		}
-	}
-
-	if maxY > 0 {
-		maxY = maxY * 1.1
-	} else {
-		maxY = maxY * 0.9
-	}
-
-	if minY > 0 {
-		minY = minY * 0.9
-	} else {
-		minY = minY * 1.1
-	}
-
-	return
-}
-
-func getChartData(data *DataTable, index int) (out [][]float64) {
-	for _, r := range data.Rows {
-		out = append(out, []float64{r[0], r[index]})
-	}
-
-	return
-}
diff --git a/pkg/jp/primitives/buffer.go b/pkg/jp/primitives/buffer.go
deleted file mode 100644
index 4102322..0000000
--- a/pkg/jp/primitives/buffer.go
+++ /dev/null
@@ -1,9 +0,0 @@
-package primitives
-
-func Buffer(size int) (out []string) {
-	out = make([]string, size)
-	for i := range out {
-		out[i] = " "
-	}
-	return
-}
diff --git a/pkg/jp/primitives/format.go b/pkg/jp/primitives/format.go
deleted file mode 100644
index 26df0e3..0000000
--- a/pkg/jp/primitives/format.go
+++ /dev/null
@@ -1,8 +0,0 @@
-package primitives
-
-import "fmt"
-
-// Format float
-func Ff(num interface{}) string {
-	return fmt.Sprintf("%.1f", num)
-}
diff --git a/pkg/jp/primitives/runes.go b/pkg/jp/primitives/runes.go
deleted file mode 100644
index 03c0845..0000000
--- a/pkg/jp/primitives/runes.go
+++ /dev/null
@@ -1,18 +0,0 @@
-package primitives
-
-// Block elements
-const (
-	FullBlock1 = "░"
-	FullBlock2 = "▒"
-	FullBlock3 = "▓"
-	FullBlock4 = "█"
-)
-
-// Box drawing characters
-var (
-	HorizontalLine     = "─"
-	VerticalLine       = "│"
-	CornerBottomLeft   = "└"
-	PointSymbolDefault = "•"
-	Cross              = "╳"
-)
diff --git a/pkg/plot/barchart.go b/pkg/plot/barchart.go
new file mode 100644
index 0000000..cb6c95c
--- /dev/null
+++ b/pkg/plot/barchart.go
@@ -0,0 +1,87 @@
+package plot
+
+import (
+	"bytes"
+	"math"
+
+	"github.com/sgreben/jp/pkg/draw"
+)
+
+// BarChart is a bar chart
+type BarChart struct {
+	draw.Canvas
+	BarPaddingX int
+}
+
+// NewBarChart returns a new bar chart
+func NewBarChart(canvas draw.Canvas) *BarChart {
+	chart := new(BarChart)
+	chart.Canvas = canvas
+	chart.BarPaddingX = 1
+	return chart
+}
+
+// Draw implements Chart
+func (c *BarChart) Draw(data *DataTable) string {
+	minY := math.Inf(1)
+	maxY := math.Inf(-1)
+	for _, row := range data.Rows {
+		for _, y := range row {
+			if y < minY {
+				minY = y
+			}
+			if y > maxY {
+				maxY = y
+			}
+		}
+	}
+	paddingX := 4
+	paddingY := 3
+	chartHeight := c.Size().Height - paddingY*c.RuneSize().Height
+	chartWidth := c.Size().Width - 2*paddingX*c.RuneSize().Width
+	scaleY := float64(chartHeight) / maxY
+	barPaddedWidth := chartWidth / len(data.Columns)
+	barWidth := barPaddedWidth - (c.BarPaddingX * c.RuneSize().Width)
+	if barPaddedWidth < c.RuneSize().Width {
+		barPaddedWidth = c.RuneSize().Width
+	}
+	if barWidth < c.RuneSize().Width {
+		barWidth = c.RuneSize().Width
+	}
+
+	scaleY = float64(chartHeight) / maxY
+
+	for i, group := range data.Columns {
+		barLeft := paddingX*c.RuneSize().Width + barPaddedWidth*i
+		barRight := barLeft + barWidth
+
+		y := data.Rows[0][i]
+		barHeight := y * scaleY
+		barBottom := (paddingY - 1) * c.RuneSize().Height
+		barTop := barBottom + int(barHeight)
+
+		for x := barLeft; x < barRight; x++ {
+			for y := barBottom; y < barTop; y++ {
+				c.Set(y, x)
+			}
+		}
+
+		// Group label
+		barMiddle := (barLeft + barRight) / 2
+		c.GetBuffer().WriteCenter(0, barMiddle/c.RuneSize().Width, []rune(group))
+
+		// Count label
+		countLabelY := int(math.Ceil(float64(barTop)/float64(c.RuneSize().Height))) * c.RuneSize().Height
+
+		if countLabelY <= barBottom && y > 0 {
+			c.GetBuffer().SetRow(barTop/c.RuneSize().Height, barLeft/c.RuneSize().Width, barRight/c.RuneSize().Width, '▁')
+			countLabelY = 3 * c.RuneSize().Height
+		}
+
+		c.GetBuffer().WriteCenter(countLabelY/c.RuneSize().Height, barMiddle/c.RuneSize().Width, Ff(y))
+	}
+
+	b := bytes.NewBuffer(nil)
+	c.GetBuffer().Render(b)
+	return b.String()
+}
diff --git a/pkg/jp/datatable.go b/pkg/plot/datatable.go
index f1a682e..15cbff4 100644
--- a/pkg/jp/datatable.go
+++ b/pkg/plot/datatable.go
@@ -1,4 +1,4 @@
-package jp
+package plot
 
 type DataTable struct {
 	Columns []string
diff --git a/pkg/plot/format.go b/pkg/plot/format.go
new file mode 100644
index 0000000..f1175dd
--- /dev/null
+++ b/pkg/plot/format.go
@@ -0,0 +1,15 @@
+package plot
+
+import "strconv"
+
+const maxDigits = 7
+
+// Ff formats a float
+func Ff(x float64) []rune {
+	minExact := strconv.FormatFloat(x, 'g', -1, 64)
+	fixed := strconv.FormatFloat(x, 'g', maxDigits, 64)
+	if len(minExact) < len(fixed) {
+		return []rune(minExact)
+	}
+	return []rune(fixed)
+}
diff --git a/pkg/plot/linechart.go b/pkg/plot/linechart.go
new file mode 100644
index 0000000..f3c47f1
--- /dev/null
+++ b/pkg/plot/linechart.go
@@ -0,0 +1,107 @@
+package plot
+
+import (
+	"bytes"
+	"math"
+
+	"github.com/sgreben/jp/pkg/draw"
+)
+
+// LineChart is a line chart
+type LineChart struct{ draw.Canvas }
+
+// NewLineChart returns a new line chart
+func NewLineChart(canvas draw.Canvas) *LineChart { return &LineChart{canvas} }
+
+func (c *LineChart) drawAxes(paddingX, paddingY int, minX, maxX, minY, maxY float64) {
+	buffer := c.GetBuffer()
+	// X axis
+	buffer.SetRow(1, paddingX, buffer.Width, draw.HorizontalLine)
+	// Y axis
+	buffer.SetColumn(1, buffer.Height, paddingX, draw.VerticalLine)
+	// Corner
+	buffer.Set(1, paddingX, draw.CornerBottomLeft)
+	// Labels
+	buffer.WriteRight(1, 1, Ff(minY))
+	buffer.WriteLeft(buffer.Height-1, paddingX, Ff(maxY))
+	buffer.WriteRight(0, paddingX, Ff(minX))
+	buffer.WriteLeft(0, buffer.Width, Ff(maxX))
+}
+
+// Draw implements Chart
+func (c *LineChart) Draw(data *DataTable) string {
+	var scaleY, scaleX float64
+	var prevX, prevY int
+
+	minX, maxX, minY, maxY := minMax(data)
+	minLabelWidth := len(Ff(minY))
+	maxLabelWidth := len(Ff(maxY))
+
+	paddingX := minLabelWidth + 1
+	paddingY := 2
+	if minLabelWidth < maxLabelWidth {
+		paddingX = maxLabelWidth + 1
+	}
+	chartWidth := c.Size().Width - (paddingX+1)*c.RuneSize().Width
+	chartHeight := c.Size().Height - paddingY*c.RuneSize().Height
+	scaleX = float64(chartWidth) / (maxX - minX)
+	scaleY = float64(chartHeight) / (maxY - minY)
+
+	first := true
+	for _, point := range data.Rows {
+		if len(point) < 2 {
+			continue
+		}
+		x := int((point[0]-minX)*scaleX + float64((paddingX+1)*c.RuneSize().Width))
+		y := int((point[1]-minY)*scaleY + float64(paddingY*c.RuneSize().Height))
+
+		if first {
+			first = false
+			prevX = x
+			prevY = y
+		}
+
+		if prevX <= x {
+			c.DrawLine(prevY, prevX, y, x)
+		}
+
+		prevX = x
+		prevY = y
+	}
+	c.drawAxes(paddingX, paddingY, minX, maxX, minY, maxY)
+
+	b := bytes.NewBuffer(nil)
+	c.GetBuffer().Render(b)
+	return b.String()
+}
+
+func roundDownToPercentOfRange(x, d float64) float64 {
+	return math.Floor((x*(100-math.Copysign(5, x)))/d) * d / 100
+}
+
+func roundUpToPercentOfRange(x, d float64) float64 {
+	return math.Ceil((x*105)/d) * d / 100
+}
+
+func minMax(data *DataTable) (minX, maxX, minY, maxY float64) {
+	minX, minY = math.Inf(1), math.Inf(1)
+	maxX, maxY = math.Inf(-1), math.Inf(-1)
+
+	for _, r := range data.Rows {
+		if len(r) < 2 {
+			continue
+		}
+		maxX = math.Max(maxX, r[0])
+		minX = math.Min(minX, r[0])
+		maxY = math.Max(maxY, r[1])
+		minY = math.Min(minY, r[1])
+	}
+
+	xRange := maxX - minX
+	yRange := maxY - minY
+	minX = roundDownToPercentOfRange(minX, xRange)
+	minY = roundDownToPercentOfRange(minY, yRange)
+	maxX = roundUpToPercentOfRange(maxX, xRange)
+	maxY = roundUpToPercentOfRange(maxY, yRange)
+	return
+}
diff --git a/pkg/plot/scatterchart.go b/pkg/plot/scatterchart.go
new file mode 100644
index 0000000..85de1f3
--- /dev/null
+++ b/pkg/plot/scatterchart.go
@@ -0,0 +1,63 @@
+package plot
+
+import (
+	"bytes"
+
+	"github.com/sgreben/jp/pkg/draw"
+)
+
+// ScatterChart is a scatter plot
+type ScatterChart struct{ draw.Canvas }
+
+// NewScatterChart returns a new line chart
+func NewScatterChart(canvas draw.Canvas) *ScatterChart { return &ScatterChart{canvas} }
+
+func (c *ScatterChart) drawAxes(paddingX, paddingY int, minX, maxX, minY, maxY float64) {
+	buffer := c.GetBuffer()
+	// X axis
+	buffer.SetRow(1, paddingX, buffer.Width, draw.HorizontalLine)
+	// Y axis
+	buffer.SetColumn(1, buffer.Height, paddingX, draw.VerticalLine)
+	// Corner
+	buffer.Set(1, paddingX, draw.CornerBottomLeft)
+	// Labels
+	buffer.WriteRight(1, 1, Ff(minY))
+	buffer.WriteLeft(buffer.Height-1, paddingX, Ff(maxY))
+	buffer.WriteRight(0, paddingX, Ff(minX))
+	buffer.WriteLeft(0, buffer.Width, Ff(maxX))
+}
+
+// Draw implements Chart
+func (c *ScatterChart) Draw(data *DataTable) string {
+	var scaleY, scaleX float64
+
+	minX, maxX, minY, maxY := minMax(data)
+	minLabelWidth := len(Ff(minY))
+	maxLabelWidth := len(Ff(maxY))
+
+	paddingX := minLabelWidth + 1
+	paddingY := 2
+	if minLabelWidth < maxLabelWidth {
+		paddingX = maxLabelWidth + 1
+	}
+	chartWidth := c.Size().Width - (paddingX+1)*c.RuneSize().Width
+	chartHeight := c.Size().Height - paddingY*c.RuneSize().Height
+	scaleX = float64(chartWidth) / (maxX - minX)
+	scaleY = float64(chartHeight) / (maxY - minY)
+
+	for _, point := range data.Rows {
+		if len(point) < 2 {
+			continue
+		}
+		x := int((point[0]-minX)*scaleX + float64((paddingX+1)*c.RuneSize().Width))
+		y := int((point[1]-minY)*scaleY + float64(paddingY*c.RuneSize().Height))
+
+		c.Set(y, x)
+
+	}
+	c.drawAxes(paddingX, paddingY, minX, maxX, minY, maxY)
+
+	b := bytes.NewBuffer(nil)
+	c.GetBuffer().Render(b)
+	return b.String()
+}
diff --git a/pkg/terminal/terminal_nosysioctl.go b/pkg/terminal/terminal_nosysioctl.go
index 0190499..2ec899d 100644
--- a/pkg/terminal/terminal_nosysioctl.go
+++ b/pkg/terminal/terminal_nosysioctl.go
@@ -3,5 +3,5 @@
 package terminal
 
 func getWinsize() (int, int, error) {
-	return 80, 24, nil
+	return 79, 24, nil
 }