147 lines
3 KiB
Go
147 lines
3 KiB
Go
/**
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* UI package.
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*/
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package main
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import "github.com/nsf/termbox-go"
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// ==========================================================================
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// UI event.
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/**
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* The types of events.
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*/
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type EventType int
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const (
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EventKeyPress EventType = iota
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)
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/**
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* An event callback
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*/
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type UiEvent struct {
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eventType EventType
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eventPar int
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}
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// ==========================================================================
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// UI component.
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type UiComponent interface {
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/**
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* Request to redraw this component.
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*/
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Redraw(x int, y int, w int, h int)
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/**
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* Request the minimum dimensions of the component (width, height). If
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* either dimension is -1, no minimum is imposed.
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*/
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RequestDims() (int, int)
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}
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// ==========================================================================
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// UI context.
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/**
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* Ui context type.
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*/
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type Ui struct {
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statusBar UiComponent
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}
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/**
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* Creates a new UI context. This also initializes the UI state.
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* Returns the context and an error.
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*/
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func NewUI() (*Ui, error) {
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termboxError := termbox.Init()
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if termboxError != nil {
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return nil, termboxError
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} else {
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uiCtx := &Ui{&UiStatusBar{"Hello", "World"}}
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return uiCtx, nil
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}
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}
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/**
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* Closes the UI context.
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*/
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func (ui *Ui) Close() {
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termbox.Close()
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}
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/**
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* Redraws the UI.
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*/
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func (ui *Ui) Redraw() {
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var width, height int = termbox.Size()
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ui.redrawInternal(width, height)
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}
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/**
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* Internal redraw function which does not query the terminal size.
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*/
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func (ui *Ui) redrawInternal(width, height int) {
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termbox.Clear(termbox.ColorDefault, termbox.ColorDefault)
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// TODO: This will eventually offload to UI "components"
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// Draws the status bar
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ui.statusBar.Redraw(0, height - 2, width, 2)
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termbox.Flush()
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}
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/**
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* Waits for a UI event. Returns the event (if it's relevant to the user).
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*/
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func (ui *Ui) NextEvent() UiEvent {
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for {
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event := termbox.PollEvent()
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if event.Type == termbox.EventResize {
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ui.redrawInternal(event.Width, event.Height)
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} else {
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return UiEvent{EventKeyPress, 0}
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}
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}
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}
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// ==========================================================================
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// Status bar component
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type UiStatusBar struct {
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left string // Left aligned string
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right string // Right aligned string
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}
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// Minimum dimensions
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func (sbar *UiStatusBar) RequestDims() (int, int) {
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return -1, 2
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}
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// Status bar redraw
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func (sbar *UiStatusBar) Redraw(x int, y int, w int, h int) {
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leftLen := len(sbar.left)
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rightLen := len(sbar.right)
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rightPos := w - rightLen
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for x1 := 0; x1 < w; x1++ {
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var runeToPrint rune = ' '
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if x1 < leftLen {
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runeToPrint = rune(sbar.left[x1])
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} else if x1 >= rightPos {
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runeToPrint = rune(sbar.right[x1 - rightPos])
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}
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termbox.SetCell(x1, y, runeToPrint, termbox.AttrReverse, termbox.AttrReverse)
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}
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}
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