New Widget: Slider

docs/changelog.txt

@@ -79,6 +79,7 @@ Template for new versions:
 - ``dfhack.units.setAutomaticProfessions``: sets unit labors according to current work detail settings
 - ``dfhack.military.removeFromSquad``: Lua API for ``Military::removeFromSquad``
 - ``gui.dwarfmode``: adventure mode cursor now supported in ``getCursorPos``, ``setCursorPos``, and ``clearCursorPos`` funcitons
+- ``widgets.Slider``: new mouse-controlled single-headed slider widget
 
 ## Removed
 

docs/dev/Lua API.rst

@@ -6452,10 +6452,24 @@ change, the ``RangeSlider`` appearance will adjust automatically.
 :get_left_idx_fn: The function used by the RangeSlider to get the notch index on which
                   to display the left handle.
 :get_right_idx_fn: The function used by the RangeSlider to get the notch index on which
-                   to display the right handle.
+                  to display the right handle.
 :on_left_change: Callback executed when moving the left handle.
 :on_right_change: Callback executed when moving the right handle.
 
+Slider class
+-----------------
+
+This widget implements a mouse-interactable slider. The player can move the handle to
+set the value of the slider. The parent widget owns the slider value, and can control
+it independently (e.g., with ``CycleHotkeyLabels``). If the value changes, the ``Slider``
+appearance will adjust automatically.
+
+:num_stops: Used to specify the number of "notches" in the slider, the places
+            where the handle can stop. (This should match the parents' number of options.)
+:get_idx_fn: The function used by the Slider to get the notch index on which
+                  to display the handle.
+:on_change: Callback executed when moving the handle.
+
 DimensionsTooltip class
 -----------------------
 

library/lua/gui/widgets.lua

@@ -27,6 +27,7 @@ List = require('gui.widgets.list')
 FilteredList = require('gui.widgets.filtered_list')
 TabBar = require('gui.widgets.tab_bar')
 RangeSlider = require('gui.widgets.range_slider')
+Slider = require('gui.widgets.slider')
 DimensionsTooltip = require('gui.widgets.dimensions_tooltip')
 TextArea = require('gui.widgets.text_area')
 

library/lua/gui/widgets/range_slider.lua

@@ -29,6 +29,7 @@ RangeSlider.ATTRS{
     get_right_idx_fn=DEFAULT_NIL,
     on_left_change=DEFAULT_NIL,
     on_right_change=DEFAULT_NIL,
+    is_single=DEFAULT_NIL
 }
 
 function RangeSlider:preinit(init_table)
@@ -43,7 +44,8 @@ function RangeSlider:init()
 end
 
 local function rangeslider_get_width_per_idx(self)
-    return math.max(5, (self.frame_body.width-7) // (self.num_stops-1))
+    local min_value = (self.is_single) and 3 or 5  -- Single slider = 3, else 5
+    return math.max(min_value, (self.frame_body.width-7) // (self.num_stops-1))
 end
 
 function RangeSlider:onInput(keys)
@@ -142,16 +144,27 @@ function RangeSlider:onRenderBody(dc, rect)
     end
     dc:char(nil, SLIDER_TRACK)
     dc:char(nil, SLIDER_RIGHT_END)
-    -- draw tabs
-    dc:seek(width_per_idx*(left_idx-1))
-    dc:char(nil, SLIDER_TAB_LEFT)
-    dc:char(nil, SLIDER_TAB_CENTER)
-    dc:char(nil, SLIDER_TAB_RIGHT)
-    dc:seek(width_per_idx*(right_idx-1)+4)
-    dc:char(nil, SLIDER_TAB_LEFT)
-    dc:char(nil, SLIDER_TAB_CENTER)
-    dc:char(nil, SLIDER_TAB_RIGHT)
-    -- manage dragging
+
+    -- Draw tab(s)
+    if self.is_single then
+        -- Single slider: Draw one centered tab
+        dc:seek(width_per_idx * (left_idx-1) + 2)  -- Center the tab
+        dc:char(nil, SLIDER_TAB_LEFT)
+        dc:char(nil, SLIDER_TAB_CENTER)
+        dc:char(nil, SLIDER_TAB_RIGHT)
+    else
+        -- Dual slider: Draw left and right tabs separately
+        dc:seek(width_per_idx * (left_idx-1))
+        dc:char(nil, SLIDER_TAB_LEFT)
+        dc:char(nil, SLIDER_TAB_CENTER)
+        dc:char(nil, SLIDER_TAB_RIGHT)
+        dc:seek(width_per_idx*(right_idx-1)+4)
+        dc:char(nil, SLIDER_TAB_LEFT)
+        dc:char(nil, SLIDER_TAB_CENTER)
+        dc:char(nil, SLIDER_TAB_RIGHT)
+    end
+
+    -- Manage dragging
     if self.is_dragging_target then
         rangeslider_do_drag(self, width_per_idx)
     end

library/lua/gui/widgets/slider.lua

@@ -0,0 +1,22 @@
+-- slider.lua
+local RangeSlider = require('gui.widgets.range_slider')
+
+local Slider = defclass(Slider, RangeSlider)
+Slider.ATTRS {
+    get_idx_fn = DEFAULT_NIL, -- Function to get the current index
+    on_change = DEFAULT_NIL, -- Function to handle index change
+    is_single = true
+}
+
+function Slider:init()
+    self.get_left_idx_fn = self.get_idx_fn
+    self.get_right_idx_fn = self.get_idx_fn
+    self.on_left_change = function(index)
+        if self.on_change then self.on_change(index) end
+    end
+    self.on_right_change = function(index)
+        if self.on_change then self.on_change(index) end
+    end
+end
+
+return Slider