| 🛟 Updated. 28d5985 k33g 18h ago | 1 | package ui |
| 2 | |
| 3 | // The menu bar's types and its state. What it draws is in menu_draw.go, what it |
| 4 | // answers to is in menu_events.go, and the second-level panels are in |
| 5 | // submenu.go. |
| 6 | |
| 7 | // MenuItem is one line of a drop-down menu. |
| 8 | // |
| 9 | // Label may carry a hot key written with tildes, as in "~O~pen…". Shortcut is |
| 10 | // the key combination shown right-aligned; the menu only displays it, since |
| 11 | // the shortcut itself is handled wherever global keys are. |
| 12 | type MenuItem struct { |
| 13 | Label string |
| 14 | Shortcut string |
| 15 | Action func() |
| 16 | Enabled func() bool |
| 17 | Separator bool |
| 18 | |
| 19 | // Items makes this a submenu: choosing it opens a second drop-down beside |
| 20 | // the first rather than running anything, and Action is ignored. |
| 21 | // |
| 22 | // One level deep is all there is. The menus that need it — snippets |
| 23 | // grouped by kind — are exactly one level, and a general depth would mean |
| 24 | // replacing the bar's two indices with a path for a need nobody has. |
| 25 | Items []*MenuItem |
| 26 | } |
| 27 | |
| 28 | // hasSubmenu reports whether choosing this item opens another drop-down. |
| 29 | func (m *MenuItem) hasSubmenu() bool { return len(m.Items) > 0 } |
| 30 | |
| 31 | // enabled reports whether the item can be chosen right now. An item with no |
| 32 | // Enabled function is always available, which is the common case. |
| 33 | func (m *MenuItem) enabled() bool { |
| 34 | if m.Separator { |
| 35 | return false |
| 36 | } |
| 37 | if m.Action == nil && !m.hasSubmenu() { |
| 38 | return false |
| 39 | } |
| 40 | return m.Enabled == nil || m.Enabled() |
| 41 | } |
| 42 | |
| 43 | // width returns how many cells the item needs, shortcut or marker included. |
| 44 | func (m *MenuItem) width() int { |
| 45 | if m.Separator { |
| 46 | return 0 |
| 47 | } |
| 48 | |
| 49 | width := LabelWidth(m.Label) |
| 50 | switch { |
| 51 | case m.Shortcut != "": |
| 52 | width += len([]rune(m.Shortcut)) + 3 |
| 53 | case m.hasSubmenu(): |
| 54 | width += len([]rune(submenuMarker)) + 2 |
| 55 | } |
| 56 | return width |
| 57 | } |
| 58 | |
| 59 | // Menu is one drop-down: a title on the bar and the items under it. |
| 60 | type Menu struct { |
| 61 | Label string |
| 62 | Items []*MenuItem |
| 63 | |
| 64 | // OnOpen is called just before the menu drops down, so its owner can |
| 65 | // refill Items first. |
| 66 | // |
| 67 | // A menu built from a file, or from what the front window holds, cannot be |
| 68 | // decided once at start-up. This is the hook for that, and it runs at the |
| 69 | // only moment the contents are about to be seen. |
| 70 | OnOpen func() |
| 71 | } |
| 72 | |
| 73 | // MenuBar is the row of menu titles across the top of the screen, and the |
| 74 | // drop-down currently open under it. |
| 75 | // |
| 76 | // It is drawn last and offered events first, so an open menu takes precedence |
| 77 | // over everything behind it. |
| 78 | type MenuBar struct { |
| 79 | Box |
| 80 | menus []*Menu |
| 81 | |
| 82 | openMenu int // -1 when nothing is open |
| 83 | highlight int |
| 84 | |
| 85 | // openItem is the index of the drop-down item whose submenu is showing, or |
| 86 | // -1 when none is, and subHighlight is the highlighted line inside it. |
| 87 | openItem int |
| 88 | subHighlight int |
| 89 | } |
| 90 | |
| 91 | // NewMenuBar returns a closed menu bar holding the given menus. |
| 92 | func NewMenuBar(menus ...*Menu) *MenuBar { |
| 93 | return &MenuBar{menus: menus, openMenu: -1, openItem: -1} |
| 94 | } |
| 95 | |
| 96 | // Menus returns the menus on the bar. |
| 97 | func (b *MenuBar) Menus() []*Menu { return b.menus } |
| 98 | |
| 99 | // SetMenus replaces the menus on the bar, closing whatever was open. |
| 100 | // |
| 101 | // Menu.OnOpen refills one menu; this is for the rarer case where the *set* of |
| 102 | // menus changes — a project file that names menus of its own can add or remove |
| 103 | // one while the editor is running. Closing first matters: the open index refers |
| 104 | // to the old slice, and keeping it would drop down whichever menu happened to |
| 105 | // land at that position. |
| 106 | // |
| 107 | // bar.SetMenus(append(fixedMenus(), toolMenus()...)) |
| 108 | func (b *MenuBar) SetMenus(menus []*Menu) { |
| 109 | b.Close() |
| 110 | b.menus = menus |
| 111 | } |
| 112 | |
| 113 | // Open reports whether a drop-down is currently showing. |
| 114 | func (b *MenuBar) Open() bool { return b.openMenu >= 0 } |
| 115 | |
| 116 | // OpenMenu drops down menu i and highlights its first usable item. |
| 117 | // |
| 118 | // The menu's OnOpen runs first, so a menu whose contents come from elsewhere is |
| 119 | // filled in before anyone sees it. |
| 120 | func (b *MenuBar) OpenMenu(i int) { |
| 121 | if i < 0 || i >= len(b.menus) { |
| 122 | return |
| 123 | } |
| 124 | if b.menus[i].OnOpen != nil { |
| 125 | b.menus[i].OnOpen() |
| 126 | } |
| 127 | |
| 128 | b.openMenu = i |
| 129 | b.openItem = -1 |
| 130 | b.highlight = b.nextUsableIn(b.menus[i].Items, -1, +1) |
| 131 | } |
| 132 | |
| 133 | // Close puts the open drop-down away, and the submenu with it. |
| 134 | func (b *MenuBar) Close() { |
| 135 | b.openMenu = -1 |
| 136 | b.openItem = -1 |
| 137 | b.highlight = 0 |
| 138 | b.subHighlight = 0 |
| 139 | } |