forked from bmmcginty/barnard
/
tree.go
185 lines (164 loc) · 3.59 KB
/
tree.go
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package uiterm
import (
"strings"
"github.com/nsf/termbox-go"
)
type TreeItem interface {
TreeItemStyle(fg, bg Attribute, active bool) (Attribute, Attribute)
String() string
}
type renderedTreeItem struct {
//String string
Level int
Item TreeItem
}
type Tree struct {
Fg, Bg Attribute
Generator func(item TreeItem) []TreeItem
KeyListener func(ui *Ui, tree *Tree, item TreeItem, key Key)
CharacterListener func(ui *Ui, tree *Tree, item TreeItem, chr rune)
lines []renderedTreeItem
activeLine int
ui *Ui
active bool
x0, y0, x1, y1 int
}
func bounded(i, lower, upper int) int {
if i < lower {
return lower
}
if i > upper {
return upper
}
return i
}
func (t *Tree) uiInitialize(ui *Ui) {
t.ui = ui
}
func (t *Tree) uiSetActive(active bool) {
t.active = active
t.uiDraw()
}
func (t *Tree) uiSetBounds(x0, y0, x1, y1 int) {
t.x0 = x0
t.y0 = y0
t.x1 = x1
t.y1 = y1
t.uiDraw()
}
func (t *Tree) Rebuild() {
if t.Generator == nil {
t.lines = []renderedTreeItem{}
return
}
lines := []renderedTreeItem{}
for _, item := range t.Generator(nil) {
children := t.rebuild_rec(item, 0)
if children != nil {
lines = append(lines, children...)
}
}
t.lines = lines
t.SetActiveLine(0, true)
t.uiDraw()
}
func (t *Tree) rebuild_rec(parent TreeItem, level int) []renderedTreeItem {
if parent == nil {
return nil
}
lines := []renderedTreeItem{
renderedTreeItem{
Level: level,
Item: parent,
},
}
for _, item := range t.Generator(parent) {
children := t.rebuild_rec(item, level+1)
if children != nil {
lines = append(lines, children...)
}
}
return lines
}
func (t *Tree) uiDraw() {
t.ui.beginDraw()
defer t.ui.endDraw()
if t.lines == nil {
t.Rebuild()
}
if t.y1-t.y0 <= 0 {
return
}
var line = t.activeLine
var height = t.y1 - t.y0
var startline = 0
//var total = len(t.lines)
//I'd welcome a better algorithm for this; for that matter, I'd love a book or reference for all sorts of GUI algorithms.
//if (startline+height) < line {
for startline = 0; (startline + height) <= line; startline += height {
}
//}
//if startline+height >= total {
//var rem=(startline+height)-total
//startline-=rem
//}
if startline < 0 {
startline = 0
}
line = startline
for y := t.y0; y < t.y1; y++ {
var reader *strings.Reader
var item TreeItem
level := 0
if line < len(t.lines) {
item = t.lines[line].Item
level = t.lines[line].Level
reader = strings.NewReader(item.String())
}
for x := t.x0; x < t.x1; x++ {
var chr rune = ' '
fg := t.Fg
bg := t.Bg
dx := x - t.x0
dy := y - t.y0
if reader != nil && level*2 <= dx {
if ch, _, err := reader.ReadRune(); err == nil {
chr = ch
fg, bg = item.TreeItemStyle(fg, bg, t.active && t.activeLine == dy)
}
}
termbox.SetCell(x, y, chr, termbox.Attribute(fg), termbox.Attribute(bg))
}
if t.activeLine == (line) {
termbox.SetCursor(t.x0, y)
}
line++
}
}
func (t *Tree) SetActiveLine(num int, relative bool) {
if relative {
t.activeLine = bounded(t.activeLine+num, 0, len(t.lines)-1)
} else {
t.activeLine = bounded(num, 0, len(t.lines)-1)
}
}
func (t *Tree) uiKeyEvent(key Key) {
var runHandler = true
switch key {
case KeyArrowUp:
t.SetActiveLine(-1, true)
runHandler = false
case KeyArrowDown:
t.SetActiveLine(1, true)
runHandler = false
}
if runHandler == true && t.KeyListener != nil {
t.KeyListener(t.ui, t, t.lines[t.activeLine].Item, key)
}
t.uiDraw()
}
func (t *Tree) uiCharacterEvent(ch rune) {
if t.CharacterListener != nil {
t.CharacterListener(t.ui, t, t.lines[t.activeLine].Item, ch)
}
}