Implement view's buffer and draw

_demos/demo2.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"log"
 
 	"github.com/jroimartin/gocui"
@@ -20,6 +21,29 @@ func layout(g *gocui.Gui) error {
 	return nil
 }
 
+func start(g *gocui.Gui) error {
+	if err := keybindings(g); err != nil {
+		return err
+	}
+	if err := g.SetCurrentView("main"); err != nil {
+		return err
+	}
+	if v := g.GetView("main"); v != nil {
+		fmt.Fprintln(v, "This is a test")
+	}
+	if v := g.GetView("side"); v != nil {
+		fmt.Fprintln(v, "Item 1")
+		fmt.Fprintln(v, "Item 2")
+		fmt.Fprintln(v, "Item 3")
+		fmt.Fprintln(v, "Item 4")
+	}
+	if v := g.GetView("cmdline"); v != nil {
+		fmt.Fprintln(v, "Buffer test")
+	}
+	g.ShowCursor = true
+	return nil
+}
+
 func focusMain(g *gocui.Gui, v *gocui.View) error {
 	return g.SetCurrentView("main")
 }
@@ -103,17 +127,6 @@ func keybindings(g *gocui.Gui) error {
 	return nil
 }
 
-func start(g *gocui.Gui) error {
-	if err := keybindings(g); err != nil {
-		return err
-	}
-	if err := g.SetCurrentView("main"); err != nil {
-		return err
-	}
-	g.ShowCursor = true
-	return nil
-}
-
 func quit(g *gocui.Gui, v *gocui.View) error {
 	return gocui.ErrorQuit
 }

gui.go

@@ -198,17 +198,13 @@ func (g *Gui) draw() (err error) {
 	}
 
 	for _, v := range g.views {
-		if err := g.drawView(v); err != nil {
+		if err := v.Draw(); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-func (g *Gui) drawView(v *View) (err error) {
-	return nil
-}
-
 func (g *Gui) resize() (err error) {
 	if g.Layout == nil {
 		return errors.New("Null layout")

view.go

@@ -1,12 +1,17 @@
 package gocui
 
 import (
+	"bufio"
+	"bytes"
 	"errors"
+	"io"
+
 	"github.com/nsf/termbox-go"
 )
 
 type View struct {
 	Name                   string
+	buffer                 []rune
 	X0, Y0, X1, Y1         int
 	CX, CY                 int
 	BgColor, FgColor       termbox.Attribute
@@ -28,8 +33,32 @@ func NewView(name string, x0, y0, x1, y1 int) (v *View) {
 	return v
 }
 
+func (v *View) Size() (x, y int) {
+	return v.X1 - v.X0 - 1, v.Y1 - v.Y0 - 1
+}
+
+func (v *View) SetRune(x, y int, ch rune) (err error) {
+	maxX, maxY := v.Size()
+	if x < 0 || x >= maxX || y < 0 || y >= maxY {
+		return errors.New("invalid point")
+	}
+	termbox.SetCell(v.X0+x+1, v.Y0+y+1, ch, v.FgColor, v.BgColor)
+	return nil
+}
+
+func (v *View) GetRune(x, y int) (ch rune, err error) {
+	maxX, maxY := v.Size()
+	if x < 0 || x >= maxX || y < 0 || y >= maxY {
+		return 0, errors.New("invalid point")
+	}
+	h := v.Y1 - v.Y0 - 1
+	c := v.buffer[y*h+x]
+	return c, nil
+}
+
 func (v *View) SetCursor(x, y int) (err error) {
-	if x < 0 || v.X0+x+1 >= v.X1 || y < 0 || v.Y0+y+1 >= v.Y1 {
+	maxX, maxY := v.Size()
+	if x < 0 || x >= maxX || y < 0 || y >= maxY {
 		return errors.New("invalid point")
 	}
 	v.CX = x
@@ -38,5 +67,29 @@ func (v *View) SetCursor(x, y int) (err error) {
 }
 
 func (v *View) Write(p []byte) (n int, err error) {
-	return 0, nil
+	pr := bytes.Runes(p)
+	v.buffer = append(v.buffer, pr...)
+	return len(pr), nil
+}
+
+func (v *View) Draw() (err error) {
+	maxX, maxY := v.Size()
+	buf := bytes.NewBufferString(string(v.buffer))
+	br := bufio.NewReader(buf)
+	for nl := 0; ; nl++ {
+		line, _, err := br.ReadLine()
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return err
+		}
+		for i, ch := range bytes.Runes(line) {
+			if i >= 0 && i < maxX && nl >= 0 && nl < maxY {
+				if err := v.SetRune(i, nl, ch); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
 }