Switch to go in order to use tcell

view.go

@@ -0,0 +1,164 @@
+package main
+
+import (
+	"github.com/gdamore/tcell"
+	"strings"
+)
+
+type View struct {
+	cursor  Cursor
+	topline int
+	linesN  int
+	colsN   int
+
+	buf           *Buffer
+	mouseReleased bool
+
+	s tcell.Screen
+}
+
+func newViewFromBuffer(buf *Buffer, s tcell.Screen) *View {
+	v := new(View)
+
+	v.buf = buf
+	v.s = s
+	w, h := s.Size()
+
+	v.topline = 0
+	v.linesN = h
+	v.colsN = w
+	v.cursor = Cursor{
+		x:   0,
+		y:   0,
+		loc: 0,
+		v:   v,
+	}
+
+	return v
+}
+
+// Returns an int describing how the screen needs to be redrawn
+// 0: Screen does not need to be redrawn
+// 1: Only the cursor needs to be redrawn
+// 2: Everything needs to be redrawn
+func (v *View) handleEvent(event tcell.Event) int {
+	var ret int
+	switch e := event.(type) {
+	case *tcell.EventKey:
+		switch e.Key() {
+		case tcell.KeyUp:
+			v.cursor.up()
+			ret = 1
+		case tcell.KeyDown:
+			v.cursor.down()
+			ret = 1
+		case tcell.KeyLeft:
+			v.cursor.left()
+			ret = 1
+		case tcell.KeyRight:
+			v.cursor.right()
+			ret = 1
+		case tcell.KeyEnter:
+			v.buf.insert(v.cursor.loc, "\n")
+			v.cursor.right()
+			ret = 2
+		case tcell.KeyBackspace2:
+			if v.cursor.loc > 0 {
+				v.cursor.left()
+				v.buf.remove(v.cursor.loc, v.cursor.loc+1)
+				ret = 2
+			}
+		case tcell.KeyTab:
+			v.buf.insert(v.cursor.loc, "\t")
+			v.cursor.right()
+			ret = 2
+		case tcell.KeyRune:
+			v.buf.insert(v.cursor.loc, string(e.Rune()))
+			v.cursor.right()
+			ret = 2
+		}
+	case *tcell.EventMouse:
+		x, y := e.Position()
+		y += v.topline
+		// Position always seems to be off by one
+		x--
+		y--
+
+		button := e.Buttons()
+
+		switch button {
+		case tcell.Button1:
+			if y-v.topline > v.linesN-1 {
+				y = v.linesN + v.topline - 1
+			}
+			if y > len(v.buf.lines) {
+				y = len(v.buf.lines) - 1
+			}
+			if x > count(v.buf.lines[y]) {
+				x = count(v.buf.lines[y])
+			}
+
+			x = v.cursor.getCharPos(y, x)
+			d := v.cursor.distance(x, y)
+			v.cursor.loc += d
+			v.cursor.x = x
+			v.cursor.y = y
+
+			if v.mouseReleased {
+				v.cursor.selectionStart = v.cursor.loc
+			}
+			v.cursor.selectionEnd = v.cursor.loc
+			v.mouseReleased = false
+			ret = 2
+		case tcell.ButtonNone:
+			v.mouseReleased = true
+		case tcell.WheelUp:
+			if v.topline > 0 {
+				v.topline--
+				return 2
+			} else {
+				return 0
+			}
+		case tcell.WheelDown:
+			if v.topline < len(v.buf.lines)-v.linesN {
+				v.topline++
+				return 2
+			} else {
+				return 0
+			}
+		}
+	}
+
+	cy := v.cursor.y
+	if cy < v.topline {
+		v.topline = cy
+		ret = 2
+	}
+	if cy > v.topline+v.linesN-1 {
+		v.topline = cy - v.linesN + 1
+		ret = 2
+	}
+
+	return ret
+}
+
+func (v *View) display() {
+
+	var charNum int
+	for lineN := 0; lineN < v.linesN; lineN++ {
+		if lineN+v.topline >= len(v.buf.lines) {
+			break
+		}
+		line := strings.Replace(v.buf.lines[lineN+v.topline], "\t", emptyString(tabSize), -1)
+		for colN, ch := range line {
+			st := tcell.StyleDefault
+			if v.cursor.hasSelection() && charNum >= v.cursor.selectionStart && charNum <= v.cursor.selectionEnd {
+				st = st.Reverse(true)
+			}
+
+			v.s.SetContent(colN, lineN, ch, nil, st)
+			charNum++
+		}
+		charNum++
+	}
+}