| 🛟 Updated. 28d5985 k33g 18h ago | 1 | package ui |
| 2 | |
| 3 | import ( |
| 4 | "github.com/gdamore/tcell/v2" |
| 5 | |
| 📦 Turbo Core f3ade8d k33g 11h ago | 6 | "rickub.com/turbo-editors/turbo-core/theme" |
| 🛟 Updated. 28d5985 k33g 18h ago | 7 | ) |
| 8 | |
| 9 | // ListBox is a scrolling list of strings with one selected line. |
| 10 | // |
| 11 | // It is what the Open File dialog, the theme picker and the window list are |
| 12 | // all made of, so it carries the scrolling and the keyboard handling those |
| 13 | // three would otherwise each repeat. |
| 14 | type ListBox struct { |
| 15 | FocusBox |
| 16 | items []string |
| 17 | selected int |
| 18 | top int |
| 19 | |
| 20 | // OnChoose is called when a line is picked with Enter or a double click. |
| 21 | OnChoose func(index int) |
| 22 | // OnSelect is called whenever the highlighted line changes. |
| 23 | OnSelect func(index int) |
| 24 | } |
| 25 | |
| 26 | // NewListBox returns a list showing items, with the first one selected. |
| 27 | func NewListBox(items []string) *ListBox { |
| 28 | return &ListBox{items: items} |
| 29 | } |
| 30 | |
| 31 | // Items returns the lines the list holds. |
| 32 | func (l *ListBox) Items() []string { return l.items } |
| 33 | |
| 34 | // SetItems replaces the lines and selects the first one. |
| 35 | func (l *ListBox) SetItems(items []string) { |
| 36 | l.items = items |
| 37 | l.top = 0 |
| 38 | l.setSelected(0) |
| 39 | } |
| 40 | |
| 41 | // Selected returns the index of the highlighted line, or -1 when the list is |
| 42 | // empty. |
| 43 | func (l *ListBox) Selected() int { |
| 44 | if len(l.items) == 0 { |
| 45 | return -1 |
| 46 | } |
| 47 | return l.selected |
| 48 | } |
| 49 | |
| 50 | // SelectedItem returns the highlighted line, or the empty string when the list |
| 51 | // is empty. |
| 52 | func (l *ListBox) SelectedItem() string { |
| 53 | if index := l.Selected(); index >= 0 { |
| 54 | return l.items[index] |
| 55 | } |
| 56 | return "" |
| 57 | } |
| 58 | |
| 59 | // Select highlights a line, clamping the index into the list. |
| 60 | func (l *ListBox) Select(index int) { l.setSelected(index) } |
| 61 | |
| 62 | // setSelected moves the highlight and tells the owner, if it changed. |
| 63 | func (l *ListBox) setSelected(index int) { |
| 64 | if len(l.items) == 0 { |
| 65 | l.selected = 0 |
| 66 | return |
| 67 | } |
| 68 | |
| 69 | index = min(max(index, 0), len(l.items)-1) |
| 70 | if index == l.selected { |
| 71 | return |
| 72 | } |
| 73 | l.selected = index |
| 74 | if l.OnSelect != nil { |
| 75 | l.OnSelect(index) |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | // Choose runs the OnChoose action for the highlighted line. |
| 80 | func (l *ListBox) Choose() { |
| 81 | if l.OnChoose != nil && l.Selected() >= 0 { |
| 82 | l.OnChoose(l.selected) |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | // visibleHeight is how many lines fit, one column being kept for the scroll |
| 87 | // bar down the right-hand edge. |
| 88 | func (l *ListBox) visibleHeight() int { return l.Bounds().H } |
| 89 | |
| 90 | // scrollToSelection slides the view so the highlighted line is inside it. |
| 91 | func (l *ListBox) scrollToSelection() { |
| 92 | height := l.visibleHeight() |
| 93 | if height <= 0 { |
| 94 | return |
| 95 | } |
| 96 | |
| 97 | l.top = min(l.top, l.selected) |
| 98 | if l.selected >= l.top+height { |
| 99 | l.top = l.selected - height + 1 |
| 100 | } |
| 101 | l.top = min(max(l.top, 0), max(len(l.items)-height, 0)) |
| 102 | } |
| 103 | |
| 104 | // Draw paints the visible lines and the scroll bar. |
| 105 | func (l *ListBox) Draw(p *Painter, th *theme.Theme) { |
| 106 | area := p.Sub(l.Bounds()) |
| 107 | normal := th.Style(theme.KeyList) |
| 108 | area.Clear(normal) |
| 109 | |
| 110 | l.scrollToSelection() |
| 111 | width := max(area.Size().W-1, 0) |
| 112 | |
| 113 | for row := range area.Size().H { |
| 114 | index := l.top + row |
| 115 | if index >= len(l.items) { |
| 116 | break |
| 117 | } |
| 118 | |
| 119 | style := normal |
| 120 | if index == l.selected { |
| 121 | style = l.selectionStyle(th) |
| 122 | area.HLine(0, row, width, ' ', style) |
| 123 | } |
| 124 | area.TextLimited(0, row, width, l.items[index], style) |
| 125 | } |
| 126 | |
| 127 | DrawVScrollBar(area, area.Size().W-1, 0, area.Size().H, |
| 128 | l.top, area.Size().H, len(l.items), |
| 129 | th.Style(theme.KeyScrollBar), th.Style(theme.KeyScrollBarThumb)) |
| 130 | } |
| 131 | |
| 132 | // selectionStyle is the highlight, dimmed when the list does not have the |
| 133 | // focus so that a dialog shows where the keyboard actually is. |
| 134 | func (l *ListBox) selectionStyle(th *theme.Theme) tcell.Style { |
| 135 | if l.Focused() { |
| 136 | return th.Style(theme.KeyListSelected) |
| 137 | } |
| 138 | return th.Style(theme.KeyListUnfocused) |
| 139 | } |
| 140 | |
| 141 | // HandleKey walks the list. |
| 142 | func (l *ListBox) HandleKey(ev *tcell.EventKey) bool { |
| 143 | if !l.Focused() { |
| 144 | return false |
| 145 | } |
| 146 | |
| 147 | height := max(l.visibleHeight(), 1) |
| 148 | switch ev.Key() { |
| 149 | case tcell.KeyUp: |
| 150 | l.setSelected(l.selected - 1) |
| 151 | case tcell.KeyDown: |
| 152 | l.setSelected(l.selected + 1) |
| 153 | case tcell.KeyPgUp: |
| 154 | l.setSelected(l.selected - height) |
| 155 | case tcell.KeyPgDn: |
| 156 | l.setSelected(l.selected + height) |
| 157 | case tcell.KeyHome: |
| 158 | l.setSelected(0) |
| 159 | case tcell.KeyEnd: |
| 160 | l.setSelected(len(l.items) - 1) |
| 161 | case tcell.KeyEnter: |
| 162 | l.Choose() |
| 163 | default: |
| 164 | return false |
| 165 | } |
| 166 | return true |
| 167 | } |
| 168 | |
| 169 | // HandleMouse selects the clicked line, and chooses it on a second click or a |
| 170 | // wheel-free double click. |
| 171 | func (l *ListBox) HandleMouse(ev *tcell.EventMouse) bool { |
| 172 | if !l.hit(ev) { |
| 173 | return false |
| 174 | } |
| 175 | |
| 176 | switch ev.Buttons() { |
| 177 | case tcell.WheelUp: |
| 178 | l.setSelected(l.selected - 1) |
| 179 | case tcell.WheelDown: |
| 180 | l.setSelected(l.selected + 1) |
| 181 | case tcell.Button1: |
| 182 | _, y := ev.Position() |
| 183 | index := l.top + y - l.Bounds().Y |
| 184 | if index == l.selected { |
| 185 | l.Choose() // clicking the already-selected line opens it |
| 186 | } |
| 187 | l.setSelected(index) |
| 188 | } |
| 189 | return true |
| 190 | } |