Fixes string count

Resolves #35

box.go

@@ -3,6 +3,7 @@ package goterm
 import (
 	"bytes"
 	"strings"
+	"unicode/utf8"
 )
 
 const DEFAULT_BORDER = "- │ ┌ ┐ └ ┘"
@@ -74,7 +75,6 @@ func (b *Box) String() (out string) {
 
 	// Content width without borders and padding
 	contentWidth := b.Width - (b.PaddingX+1)*2
-
 	for y := 0; y < b.Height; y++ {
 		var line string
 
@@ -99,20 +99,21 @@ func (b *Box) String() (out string) {
 				line = ""
 			}
 
-			if len(line) > contentWidth-1 {
+			r := []rune(line)
+			if len(r) > contentWidth-1 {
 				// If line is too large limit it
-				line = line[0:contentWidth]
+				line = string(r[0:contentWidth])
 			} else {
 				// If line is too small enlarge it by adding spaces
-				line = line + strings.Repeat(" ", contentWidth-len(line))
+				line += strings.Repeat(" ", contentWidth-utf8.RuneCountInString(line))
 			}
 
 			line = prefix + line + suffix
 		}
 
 		// Don't add newline for last element
 		if y != b.Height-1 {
-			line = line + "\n"
+			line += "\n"
 		}
 
 		out += line

box_test.go

@@ -22,3 +22,21 @@ func TestBox(t *testing.T) {
 		t.Error(boxSample)
 	}
 }
+
+func TestBox_WithUnicode(t *testing.T) {
+	boxSample := `
+┌--------┐
+│ hell☺  │
+│ w©rld  │
+│ test✓✓ │
+└--------┘`
+
+	box := NewBox(10, 5, 0)
+	fmt.Fprint(box, "hell☺\nw©rld\ntest✓✓")
+
+	if box.String() != boxSample[1:] {
+		t.Error("\n" + box.String())
+		t.Error("!=")
+		t.Error(boxSample)
+	}
+}

plot.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"math"
 	"strings"
+	"unicode/utf8"
 )
 
 const (
@@ -119,7 +120,7 @@ func (c *LineChart) DrawAxes(maxX, minX, maxY, minY float64, index int) {
 	c.writeText(ff(minX), c.paddingX, 0)
 
 	x_col := c.data.columns[0]
-	c.writeText(c.data.columns[0], c.Width/2-len(x_col)/2, 1)
+	c.writeText(c.data.columns[0], c.Width/2-utf8.RuneCountInString(x_col)/2, 1)
 
 	if c.Flags&DRAW_INDEPENDENT != 0 || len(c.data.columns) < 3 {
 		col := c.data.columns[index]

plot_test.go

@@ -34,7 +34,7 @@ func TestCreateDataTable(t *testing.T) {
 }
 
 func TestLineChartIndependent(t *testing.T) {
-	fmt.Println("Independent charts\n")
+	fmt.Print("Independent charts\n\n")
 
 	chart := NewLineChart(100, 20)
 	chart.Flags = DRAW_INDEPENDENT //| DRAW_RELATIVE
@@ -51,7 +51,7 @@ func TestLineChartIndependent(t *testing.T) {
 	dataReversed.AddColumn("Lat")
 	dataReversed.AddColumn("Count")
 
-	//data.AddColumn("x*x")
+	// data.AddColumn("x*x")
 
 	for i := 0; i < 60; i++ {
 		x := float64(i + 60)
@@ -62,13 +62,13 @@ func TestLineChartIndependent(t *testing.T) {
 		dataReversed.AddRow(x, y2, y1)
 	}
 
-	// The two charts should look the same, only with inversed axes and colors
+	// The two charts should look the same, only with inverse axes and colors
 	fmt.Println(chart.Draw(data))
 	fmt.Println(chartReversed.Draw(dataReversed))
 }
 
 func TestLineChartRelative(t *testing.T) {
-	fmt.Println("Relative chart\n")
+	fmt.Print("Relative chart\n\n")
 
 	chart := NewLineChart(100, 20)
 	chart.Flags = DRAW_RELATIVE
@@ -78,7 +78,7 @@ func TestLineChartRelative(t *testing.T) {
 	data.AddColumn("Sin(x)")
 	data.AddColumn("Cos(x+1)")
 
-	//data.AddColumn("x*x")
+	// data.AddColumn("x*x")
 
 	for i := 0.1; i < 10; i += 0.1 {
 		data.AddRow(i, math.Sin(i), math.Cos(i+1))
@@ -88,10 +88,10 @@ func TestLineChartRelative(t *testing.T) {
 }
 
 func TestLineChart(t *testing.T) {
-	fmt.Println("Simple chart\n")
+	fmt.Print("Simple chart\n\n")
 
 	chart := NewLineChart(100, 20)
-	//chart.Flags = /*DRAW_INDEPENDENT // | */// DRAW_RELATIVE
+	// chart.Flags = /*DRAW_INDEPENDENT // | */// DRAW_RELATIVE
 
 	data := new(DataTable)
 	data.AddColumn("x")