Fix #290

_examples/horizontal_stacked_barchart.go

@@ -0,0 +1,44 @@
+// Copyright 2017 Zack Guo <zack.y.guo@gmail.com>. All rights reserved.
+// Use of this source code is governed by a MIT license that can
+// be found in the LICENSE file.
+
+// +build ignore
+
+package main
+
+import (
+	"log"
+
+	ui "github.com/gizak/termui/v3"
+	"github.com/gizak/termui/v3/widgets"
+)
+
+func main() {
+	if err := ui.Init(); err != nil {
+		log.Fatalf("failed to initialize termui: %v", err)
+	}
+	defer ui.Close()
+
+	hsbc := widgets.NewHorizontalStackedBar()
+	hsbc.Title = "Student's Marks: X-Axis=Grade% (Math, English, Science, Computer Science), Y-Axis=Name"
+	hsbc.Labels = []string{"Ken", "Rob", "Dennis", "Linus"}
+
+	hsbc.Data = make([][]float64, 4)
+	hsbc.Data[0] = []float64{90, 85, 90, 80}
+	hsbc.Data[1] = []float64{70, 85, 75, 60}
+	hsbc.Data[2] = []float64{75, 60, 80, 85}
+	hsbc.Data[3] = []float64{100, 100, 100, 100}
+	hsbc.SetRect(5, 5, 100, 30)
+	hsbc.BarHeight = 3
+
+	ui.Render(hsbc)
+
+	uiEvents := ui.PollEvents()
+	for {
+		e := <-uiEvents
+		switch e.ID {
+		case "q", "<C-c>":
+			return
+		}
+	}
+}

widgets/horizontal_stacked_barchart.go

@@ -0,0 +1,94 @@
+// Copyright 2017 Zack Guo <zack.y.guo@gmail.com>. All rights reserved.
+// Use of this source code is governed by a MIT license that can
+// be found in the LICENSE file.
+
+package widgets
+
+import (
+	"fmt"
+	"image"
+
+	rw "github.com/mattn/go-runewidth"
+
+	. "github.com/gizak/termui/v3"
+)
+
+type HorizontalStackedBar struct {
+	Block
+	BarColors    []Color
+	LabelStyles  []Style
+	NumStyles    []Style // only Fg and Modifier are used
+	NumFormatter func(float64) string
+	Data         [][]float64
+	Labels       []string
+	BarHeight    int
+	BarGap       int
+	MaxVal       float64
+}
+
+func NewHorizontalStackedBar() *HorizontalStackedBar {
+	return &HorizontalStackedBar{
+		Block:        *NewBlock(),
+		BarColors:    Theme.StackedBarChart.Bars,
+		LabelStyles:  Theme.StackedBarChart.Labels,
+		NumStyles:    Theme.StackedBarChart.Nums,
+		NumFormatter: func(n float64) string { return fmt.Sprint(n) },
+		BarGap:       2,
+		BarHeight:    3,
+	}
+}
+
+func (self *HorizontalStackedBar) Draw(buf *Buffer) {
+	self.Block.Draw(buf)
+
+	maxVal := self.MaxVal
+	if maxVal == 0 {
+		for _, data := range self.Data {
+			maxVal = MaxFloat64(maxVal, SumFloat64Slice(data))
+		}
+	}
+
+	barYCoordinate := self.Inner.Min.Y+1
+
+	labelWidth := 10
+
+	for i, bar := range self.Data {
+		stackX := labelWidth
+
+		for j, data := range bar {
+			width := int((data / maxVal) * float64(self.Inner.Dx()-labelWidth-1))
+
+			for y := barYCoordinate; y < MinInt(barYCoordinate+self.BarHeight, self.Inner.Max.Y); y++ {
+				for x := self.Inner.Min.X + stackX; x < MinInt(self.Inner.Min.X+stackX+width, self.Inner.Max.X); x++ {
+					c := NewCell(' ', NewStyle(ColorClear, SelectColor(self.BarColors, j)))
+					buf.SetCell(c, image.Pt(x, y))
+				}
+			}
+
+			textX := self.Inner.Min.X + stackX + width/2 - rw.StringWidth(self.NumFormatter(data))/2
+			textY := barYCoordinate+self.BarHeight/2
+			buf.SetString(
+				self.NumFormatter(data),
+				NewStyle(
+					SelectStyle(self.NumStyles, j+1).Fg,
+					ColorClear,
+					SelectStyle(self.NumStyles, j+1).Modifier,
+				),
+				image.Pt(textX, textY),
+			)
+
+			stackX += width
+		}
+
+		if i < len(self.Labels) {
+			labelY := barYCoordinate+self.BarHeight/2
+			buf.SetString(
+				TrimString(self.Labels[i], labelWidth-2),
+				SelectStyle(self.LabelStyles, i),
+				image.Pt(self.Inner.Min.X+1, labelY),
+			)
+		}
+
+		barYCoordinate += (self.BarHeight + self.BarGap)
+	}
+}