package ui import ( "math" "sync" "github.com/gdamore/tcell/v2" ) type Grid struct { rows []GridSpec rowLayout []gridLayout columns []GridSpec columnLayout []gridLayout // 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 } func NewGrid() *Grid { return &Grid{} } // 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) Draw(ctx *Context) { grid.reflow(ctx) grid.mutex.RLock() defer grid.mutex.RUnlock() for _, cell := range grid.cells { 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 if x < 0 || y < 0 { continue } 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) if cell.Content != nil { cell.Content.Draw(subctx) } } } func (grid *Grid) MouseEvent(localX int, localY int, event tcell.Event) { if event, ok := event.(*tcell.EventMouse); ok { grid.mutex.RLock() defer grid.mutex.RUnlock() for _, cell := range grid.cells { 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()) } func (grid *Grid) Invalidate() { Invalidate() } 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() grid.Invalidate() 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.Invalidate() } func Const(i int) func() int { return func() int { return i } }