termui/grid.go
2016-11-10 23:25:53 -05:00

280 lines
5.3 KiB
Go

// Copyright 2016 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 termui
// GridBufferer introduces a Bufferer that can be manipulated by Grid.
type GridBufferer interface {
Bufferer
GetHeight() int
SetWidth(int)
SetX(int)
SetY(int)
}
// Row builds a layout tree
type Row struct {
Cols []*Row //children
Widget GridBufferer // root
X int
Y int
Width int
Height int
Span int
Offset int
}
// calculate and set the underlying layout tree's x, y, height and width.
func (r *Row) calcLayout() {
r.assignWidth(r.Width)
r.Height = r.solveHeight()
r.assignX(r.X)
r.assignY(r.Y)
}
// tell if the node is leaf in the tree.
func (r *Row) isLeaf() bool {
return r.Cols == nil || len(r.Cols) == 0
}
func (r *Row) isRenderableLeaf() bool {
return r.isLeaf() && r.Widget != nil
}
// assign widgets' (and their parent rows') width recursively.
func (r *Row) assignWidth(w int) {
r.SetWidth(w)
accW := 0 // acc span and offset
calcW := make([]int, len(r.Cols)) // calculated width
calcOftX := make([]int, len(r.Cols)) // computated start position of x
for i, c := range r.Cols {
accW += c.Span + c.Offset
cw := int(float64(c.Span*r.Width) / 12.0)
if i >= 1 {
calcOftX[i] = calcOftX[i-1] +
calcW[i-1] +
int(float64(r.Cols[i-1].Offset*r.Width)/12.0)
}
// use up the space if it is the last col
if i == len(r.Cols)-1 && accW == 12 {
cw = r.Width - calcOftX[i]
}
calcW[i] = cw
r.Cols[i].assignWidth(cw)
}
}
// bottom up calc and set rows' (and their widgets') height,
// return r's total height.
func (r *Row) solveHeight() int {
if r.isRenderableLeaf() {
r.Height = r.Widget.GetHeight()
return r.Widget.GetHeight()
}
maxh := 0
if !r.isLeaf() {
for _, c := range r.Cols {
nh := c.solveHeight()
// when embed rows in Cols, row widgets stack up
if r.Widget != nil {
nh += r.Widget.GetHeight()
}
if nh > maxh {
maxh = nh
}
}
}
r.Height = maxh
return maxh
}
// recursively assign x position for r tree.
func (r *Row) assignX(x int) {
r.SetX(x)
if !r.isLeaf() {
acc := 0
for i, c := range r.Cols {
if c.Offset != 0 {
acc += int(float64(c.Offset*r.Width) / 12.0)
}
r.Cols[i].assignX(x + acc)
acc += c.Width
}
}
}
// recursively assign y position to r.
func (r *Row) assignY(y int) {
r.SetY(y)
if r.isLeaf() {
return
}
for i := range r.Cols {
acc := 0
if r.Widget != nil {
acc = r.Widget.GetHeight()
}
r.Cols[i].assignY(y + acc)
}
}
// GetHeight implements GridBufferer interface.
func (r Row) GetHeight() int {
return r.Height
}
// SetX implements GridBufferer interface.
func (r *Row) SetX(x int) {
r.X = x
if r.Widget != nil {
r.Widget.SetX(x)
}
}
// SetY implements GridBufferer interface.
func (r *Row) SetY(y int) {
r.Y = y
if r.Widget != nil {
r.Widget.SetY(y)
}
}
// SetWidth implements GridBufferer interface.
func (r *Row) SetWidth(w int) {
r.Width = w
if r.Widget != nil {
r.Widget.SetWidth(w)
}
}
// Buffer implements Bufferer interface,
// recursively merge all widgets buffer
func (r *Row) Buffer() Buffer {
merged := NewBuffer()
if r.isRenderableLeaf() {
return r.Widget.Buffer()
}
// for those are not leaves but have a renderable widget
if r.Widget != nil {
merged.Merge(r.Widget.Buffer())
}
// collect buffer from children
if !r.isLeaf() {
for _, c := range r.Cols {
merged.Merge(c.Buffer())
}
}
return merged
}
// Grid implements 12 columns system.
// A simple example:
/*
import ui "github.com/gizak/termui"
// init and create widgets...
// build
ui.Body.AddRows(
ui.NewRow(
ui.NewCol(6, 0, widget0),
ui.NewCol(6, 0, widget1)),
ui.NewRow(
ui.NewCol(3, 0, widget2),
ui.NewCol(3, 0, widget30, widget31, widget32),
ui.NewCol(6, 0, widget4)))
// calculate layout
ui.Body.Align()
ui.Render(ui.Body)
*/
type Grid struct {
Rows []*Row
Width int
X int
Y int
BgColor Attribute
}
// NewGrid returns *Grid with given rows.
func NewGrid(rows ...*Row) *Grid {
return &Grid{Rows: rows}
}
// AddRows appends given rows to Grid.
func (g *Grid) AddRows(rs ...*Row) {
g.Rows = append(g.Rows, rs...)
}
// NewRow creates a new row out of given columns.
func NewRow(cols ...*Row) *Row {
rs := &Row{Span: 12, Cols: cols}
return rs
}
// NewCol accepts: widgets are LayoutBufferer or widgets is A NewRow.
// Note that if multiple widgets are provided, they will stack up in the col.
func NewCol(span, offset int, widgets ...GridBufferer) *Row {
r := &Row{Span: span, Offset: offset}
if widgets != nil && len(widgets) == 1 {
wgt := widgets[0]
nw, isRow := wgt.(*Row)
if isRow {
r.Cols = nw.Cols
} else {
r.Widget = wgt
}
return r
}
r.Cols = []*Row{}
ir := r
for _, w := range widgets {
nr := &Row{Span: 12, Widget: w}
ir.Cols = []*Row{nr}
ir = nr
}
return r
}
// Align calculate each rows' layout.
func (g *Grid) Align() {
h := 0
for _, r := range g.Rows {
r.SetWidth(g.Width)
r.SetX(g.X)
r.SetY(g.Y + h)
r.calcLayout()
h += r.GetHeight()
}
}
// Buffer implments Bufferer interface.
func (g Grid) Buffer() Buffer {
buf := NewBuffer()
for _, r := range g.Rows {
buf.Merge(r.Buffer())
}
return buf
}
var Body *Grid