Add Tab/TabBar to widgets

docs/changelog.txt

@@ -52,7 +52,6 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 
 ## API
 - ``Gui::any_civzone_hotkey``, ``Gui::getAnyCivZone``, ``Gui::getSelectedCivZone``:  new functions to operate on the new zone system
-
 - Units module: added new predicates for:
   - ``isGeldable()``
   - ``isMarkedForGelding()``
@@ -60,8 +59,8 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 
 ## Lua
 - ``dfhack.gui.getSelectedCivZone``: returns the Zone that the user has selected currently
-
 - ``widgets.FilteredList``: Added ``edit_on_change`` optional parameter to allow a custom callback on filter edit change.
+- Added ``widgets.TabBar`` and ``widgets.Tab`` (migrated from control-panel.lua)
 
 ## Removed
 

docs/dev/Lua API.rst

@@ -5028,6 +5028,41 @@ The widget implements:
 
   Same as with an ordinary list.
 
+TabBar class
+------------
+
+This widget implements a set of one or more tabs to allow navigation between groups of content. Tabs automatically wrap on
+the width of the window and will continue rendering on the next line(s) if all tabs cannot fit on a single line.
+
+:key: Specifies a keybinding that can be used to switch to the next tab.
+:key_back: Specifies a keybinding that can be used to switch to the previous tab.
+:labels: A table of strings; entry representing the label text for a single tab. The order of the entries
+         determines the order the tabs will appear in.
+:get_cur_page: Returns the current "page". This function does not have a default implementation; you must provide
+               an implementation that returns the current value of whichever variable your script uses to keep track of the
+               current "page" (this does not need to relate to an actual Pages widget).
+:on_select: Callback executed when a tab is selected. It receives the selected tab index as an argument. Your implementation
+            should likely update the value of whichever variable your script uses to keep track of the current page.
+:active_tab_pens: A table of pens used to render active tabs. See the default implementation in widgets.lua for an example
+                  of how to construct the table. Leave unspecified to use the default pens.
+:inactive_tab_pens: A table of pens used to render inactive tabs. See the default implementation in widgets.lua for an example
+                    of how to construct the table. Leave unspecified to use the default pens.
+:get_pens: A function used to determine which pens should be used to render a tab. Receives the index of the tab as the first
+           argument and the TabBar widget itself as the second. The default implementation, which will handle most situations,
+           returns ``self.active_tab_pens``, if ``self.get_cur_page() == idx``, otherwise returns ``self.inactive_tab_pens``.
+
+Tab class
+---------
+
+This widget implements a single clickable tab and is the main component of the TabBar widget. Usage of the ``TabBar``
+widget does not require direct usage of ``Tab``.
+
+:id: The id of the tab.
+:label: The text displayed on the tab.
+:on_select: Callback executed when the tab is selected.
+:get_pens: A function that is used during ``Tab:onRenderBody`` to determine the pens that should be used for drawing. See the
+           usage of ``Tab`` in ``TabBar:init()`` for an example. See the default value of ``active_tab_pens`` or ``inactive_tab_pens``
+           in ``TabBar`` for an example of how to construct pens.
 
 .. _lua-plugins:
 

library/lua/gui/widgets.lua

@@ -2091,4 +2091,149 @@ function FilteredList:onFilterChar(char, text)
     return true
 end
 
+local DEFAULT_ACTIVE_TAB_PENS = {
+    text_mode_tab_pen=to_pen{fg=COLOR_YELLOW},
+    text_mode_label_pen=to_pen{fg=COLOR_WHITE},
+    lt=to_pen{tile=1005, write_to_lower=true},
+    lt2=to_pen{tile=1006, write_to_lower=true},
+    t=to_pen{tile=1007, fg=COLOR_BLACK, write_to_lower=true, top_of_text=true},
+    rt2=to_pen{tile=1008, write_to_lower=true},
+    rt=to_pen{tile=1009, write_to_lower=true},
+    lb=to_pen{tile=1015, write_to_lower=true},
+    lb2=to_pen{tile=1016, write_to_lower=true},
+    b=to_pen{tile=1017, fg=COLOR_BLACK, write_to_lower=true, bottom_of_text=true},
+    rb2=to_pen{tile=1018, write_to_lower=true},
+    rb=to_pen{tile=1019, write_to_lower=true},
+}
+
+local DEFAULT_INACTIVE_TAB_PENS = {
+    text_mode_tab_pen=to_pen{fg=COLOR_BROWN},
+    text_mode_label_pen=to_pen{fg=COLOR_DARKGREY},
+    lt=to_pen{tile=1000, write_to_lower=true},
+    lt2=to_pen{tile=1001, write_to_lower=true},
+    t=to_pen{tile=1002, fg=COLOR_WHITE, write_to_lower=true, top_of_text=true},
+    rt2=to_pen{tile=1003, write_to_lower=true},
+    rt=to_pen{tile=1004, write_to_lower=true},
+    lb=to_pen{tile=1010, write_to_lower=true},
+    lb2=to_pen{tile=1011, write_to_lower=true},
+    b=to_pen{tile=1012, fg=COLOR_WHITE, write_to_lower=true, bottom_of_text=true},
+    rb2=to_pen{tile=1013, write_to_lower=true},
+    rb=to_pen{tile=1014, write_to_lower=true},
+}
+
+---------
+-- Tab --
+---------
+
+Tab = defclass(Tabs, Widget)
+Tab.ATTRS{
+    id=DEFAULT_NIL,
+    label=DEFAULT_NIL,
+    on_select=DEFAULT_NIL,
+    get_pens=DEFAULT_NIL,
+}
+
+function Tab:preinit(init_table)
+    init_table.frame = init_table.frame or {}
+    init_table.frame.w = #init_table.label + 4
+    init_table.frame.h = 2
+end
+
+function Tab:onRenderBody(dc)
+    local pens = self.get_pens()
+    dc:seek(0, 0)
+    if dfhack.screen.inGraphicsMode() then
+        dc:char(nil, pens.lt):char(nil, pens.lt2)
+        for i=1,#self.label do
+            dc:char(self.label:sub(i,i), pens.t)
+        end
+        dc:char(nil, pens.rt2):char(nil, pens.rt)
+        dc:seek(0, 1)
+        dc:char(nil, pens.lb):char(nil, pens.lb2)
+        for i=1,#self.label do
+            dc:char(self.label:sub(i,i), pens.b)
+        end
+        dc:char(nil, pens.rb2):char(nil, pens.rb)
+    else
+        local tp = pens.text_mode_tab_pen
+        dc:char(' ', tp):char('/', tp)
+        for i=1,#self.label do
+            dc:char('-', tp)
+        end
+        dc:char('\\', tp):char(' ', tp)
+        dc:seek(0, 1)
+        dc:char('/', tp):char('-', tp)
+        dc:string(self.label, pens.text_mode_label_pen)
+        dc:char('-', tp):char('\\', tp)
+    end
+end
+
+function Tab:onInput(keys)
+    if Tab.super.onInput(self, keys) then return true end
+    if keys._MOUSE_L_DOWN and self:getMousePos() then
+        self.on_select(self.id)
+        return true
+    end
+end
+
+-------------
+-- Tab Bar --
+-------------
+
+TabBar = defclass(TabBar, ResizingPanel)
+TabBar.ATTRS{
+    labels=DEFAULT_NIL,
+    on_select=DEFAULT_NIL,
+    get_cur_page=DEFAULT_NIL,
+    active_tab_pens=DEFAULT_ACTIVE_TAB_PENS,
+    inactive_tab_pens=DEFAULT_INACTIVE_TAB_PENS,
+    get_pens=DEFAULT_NIL,
+    switch_tab_key=DEFAULT_NIL,
+}
+
+function TabBar:init()
+    for idx,label in ipairs(self.labels) do
+        self:addviews{
+            Tab{
+                frame={t=0, l=0},
+                id=idx,
+                label=label,
+                on_select=self.on_select,
+                get_pens=self.get_pens and function()
+                    return self.get_pens(idx, self)
+                end or function()
+                    if self.get_cur_page() == idx then
+                        return self.active_tab_pens
+                    end
+
+                    return self.inactive_tab_pens
+                end,
+            }
+        }
+    end
+end
+
+function TabBar:postComputeFrame(body)
+    local t, l, width = 0, 0, body.width
+    for _,tab in ipairs(self.subviews) do
+        if l > 0 and l + tab.frame.w > width then
+            t = t + 2
+            l = 0
+        end
+        tab.frame.t = t
+        tab.frame.l = l
+        l = l + tab.frame.w
+    end
+end
+
+function TabBar:onInput(keys)
+    if TabBar.super.onInput(self, keys) then return true end
+    if self.switch_tab_key and keys[self.switch_tab_key] then
+        local zero_idx = self.get_cur_page() - 1
+        local next_zero_idx = (zero_idx + 1) % #self.labels
+        self.on_select(next_zero_idx + 1)
+        return true
+    end
+end
+
 return _ENV