package ui
import (
"fmt"
"math"
"sync"
"sync/atomic"
"github.com/gdamore/tcell"
)
type Grid struct {
Invalidatable
rows []GridSpec
rowLayout []gridLayout
columns []GridSpec
columnLayout []gridLayout
invalid bool
// Protected by mutex
cells []*GridCell
mutex sync.RWMutex
}
const (
SIZE_EXACT = iota
SIZE_WEIGHT = iota
)
// Specifies the layout of a single row or column
type GridSpec struct {
// One of SIZE_EXACT or SIZE_WEIGHT
Strategy int
// If Strategy = SIZE_EXACT, this function returns the number of cells
// this row/col shall occupy. If SIZE_WEIGHT, the space left after all
// exact rows/cols are measured is distributed amonst the remainder
// weighted by the value returned by this function.
Size func() int
}
// Used to cache layout of each row/column
type gridLayout struct {
Offset int
Size int
}
type GridCell struct {
Row int
Column int
RowSpan int
ColSpan int
Content Drawable
invalid atomic.Value // bool
}
func NewGrid() *Grid {
return &Grid{invalid: true}
}
// MakeGrid creates a grid with the specified number of columns and rows. Each
// cell has a size of 1.
func MakeGrid(numRows, numCols, rowStrategy, colStrategy int) *Grid {
rows := make([]GridSpec, numRows)
for i := 0; i < numRows; i++ {
rows[i] = GridSpec{rowStrategy, Const(1)}
}
cols := make([]GridSpec, numCols)
for i := 0; i < numCols; i++ {
cols[i] = GridSpec{colStrategy, Const(1)}
}
return NewGrid().Rows(rows).Columns(cols)
}
func (cell *GridCell) At(row, col int) *GridCell {
cell.Row = row
cell.Column = col
return cell
}
func (cell *GridCell) Span(rows, cols int) *GridCell {
cell.RowSpan = rows
cell.ColSpan = cols
return cell
}
func (grid *Grid) Rows(spec []GridSpec) *Grid {
grid.rows = spec
return grid
}
func (grid *Grid) Columns(spec []GridSpec) *Grid {
grid.columns = spec
return grid
}
func (grid *Grid) Children() []Drawable {
grid.mutex.RLock()
defer grid.mutex.RUnlock()
children := make([]Drawable, len(grid.cells))
for i, cell := range grid.cells {
children[i] = cell.Content
}
return children
}
func (grid *Grid) Draw(ctx *Context) {
invalid := grid.invalid
if invalid {
grid.reflow(ctx)
}
grid.mutex.RLock()
defer grid.mutex.RUnlock()
for _, cell := range grid.cells {
cellInvalid := cell.invalid.Load().(bool)
if !cellInvalid && !invalid {
continue
}
rows := grid.rowLayout[cell.Row : cell.Row+cell.RowSpan]
cols := grid.columnLayout[cell.Column : cell.Column+cell.ColSpan]
x := cols[0].Offset
y := rows[0].Offset
width := 0
height := 0
for _, col := range cols {
width += col.Size
}
for _, row := range rows {
height += row.Size
}
if x+width > ctx.Width() {
width = ctx.Width() - x
}
if y+height > ctx.Height() {
height = ctx.Height() - y
}
if width <= 0 || height <= 0 {
continue
}
subctx := ctx.Subcontext(x, y, width, height)
cell.Content.Draw(subctx)
}
}
func (grid *Grid) MouseEvent(localX int, localY int, event tcell.Event) {
switch event := event.(type) {
case *tcell.EventMouse:
invalid := grid.invalid
grid.mutex.RLock()
defer grid.mutex.RUnlock()
for _, cell := range grid.cells {
cellInvalid := cell.invalid.Load().(bool)
if !cellInvalid && !invalid {
continue
}
rows := grid.rowLayout[cell.Row : cell.Row+cell.RowSpan]
cols := grid.columnLayout[cell.Column : cell.Column+cell.ColSpan]
x := cols[0].Offset
y := rows[0].Offset
width := 0
height := 0
for _, col := range cols {
width += col.Size
}
for _, row := range rows {
height += row.Size
}
if x <= localX && localX < x+width && y <= localY && localY < y+height {
switch content := cell.Content.(type) {
case MouseableDrawableInteractive:
content.MouseEvent(localX-x, localY-y, event)
case Mouseable:
content.MouseEvent(localX-x, localY-y, event)
case MouseHandler:
content.MouseEvent(localX-x, localY-y, event)
}
}
}
}
}
func (grid *Grid) reflow(ctx *Context) {
grid.rowLayout = nil
grid.columnLayout = nil
flow := func(specs *[]GridSpec, layouts *[]gridLayout, extent int) {
exact := 0
weight := 0
nweights := 0
for _, spec := range *specs {
if spec.Strategy == SIZE_EXACT {
exact += spec.Size()
} else if spec.Strategy == SIZE_WEIGHT {
nweights += 1
weight += spec.Size()
}
}
offset := 0
remainingExact := 0
if weight > 0 {
remainingExact = (extent - exact) % weight
}
for _, spec := range *specs {
layout := gridLayout{Offset: offset}
if spec.Strategy == SIZE_EXACT {
layout.Size = spec.Size()
} else if spec.Strategy == SIZE_WEIGHT {
proportion := float64(spec.Size()) / float64(weight)
size := proportion * float64(extent-exact)
if remainingExact > 0 {
extraExact := int(math.Ceil(proportion * float64(remainingExact)))
layout.Size = int(math.Floor(size)) + extraExact
remainingExact -= extraExact
} else {
layout.Size = int(math.Floor(size))
}
}
offset += layout.Size
*layouts = append(*layouts, layout)
}
}
flow(&grid.rows, &grid.rowLayout, ctx.Height())
flow(&grid.columns, &grid.columnLayout, ctx.Width())
grid.invalid = false
}
func (grid *Grid) invalidateLayout() {
grid.invalid = true
grid.DoInvalidate(grid)
}
func (grid *Grid) Invalidate() {
grid.invalidateLayout()
grid.mutex.RLock()
for _, cell := range grid.cells {
cell.Content.Invalidate()
}
grid.mutex.RUnlock()
}
func (grid *Grid) AddChild(content Drawable) *GridCell {
cell := &GridCell{
RowSpan: 1,
ColSpan: 1,
Content: content,
}
grid.mutex.Lock()
grid.cells = append(grid.cells, cell)
grid.mutex.Unlock()
cell.Content.OnInvalidate(grid.cellInvalidated)
cell.invalid.Store(true)
grid.invalidateLayout()
return cell
}
func (grid *Grid) RemoveChild(content Drawable) {
grid.mutex.Lock()
for i, cell := range grid.cells {
if cell.Content == content {
grid.cells = append(grid.cells[:i], grid.cells[i+1:]...)
break
}
}
grid.mutex.Unlock()
grid.invalidateLayout()
}
func (grid *Grid) cellInvalidated(drawable Drawable) {
var cell *GridCell
grid.mutex.RLock()
for _, cell = range grid.cells {
if cell.Content == drawable {
break
}
cell = nil
}
grid.mutex.RUnlock()
if cell == nil {
panic(fmt.Errorf("Attempted to invalidate unknown cell"))
}
cell.invalid.Store(true)
grid.DoInvalidate(grid)
}
func Const(i int) func() int {
return func() int { return i }
}