New Widget: Slider

docs/dev/Lua API.rst

@@ -6440,10 +6440,24 @@ 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/slider.lua

@@ -0,0 +1,132 @@
+local Widget = require('gui.widgets.widget')
+
+local to_pen = dfhack.pen.parse
+
+--------------------------------
+-- Slider
+--------------------------------
+
+---@class widgets.Slider.attrs: widgets.Widget.attrs
+---@field num_stops integer
+---@field get_idx_fn? function
+---@field on_change? fun(index: integer)
+
+---@class widgets.Slider.attrs.partial: widgets.Slider.attrs
+
+---@class widgets.Slider.initTable: widgets.Slider.attrs
+---@field num_stops integer
+
+---@class widgets.Slider: widgets.Widget, widgets.Slider.attrs
+---@field super widgets.Widget
+---@field ATTRS widgets.Slider.attrs|fun(attributes: widgets.Slider.attrs.partial)
+---@overload fun(init_table: widgets.Slider.initTable): self
+Slider = defclass(Slider, Widget)
+Slider.ATTRS{
+    num_stops=DEFAULT_NIL,
+    get_idx_fn=DEFAULT_NIL,
+    on_change=DEFAULT_NIL,
+}
+
+function Slider:preinit(init_table)
+    init_table.frame = init_table.frame or {}
+    init_table.frame.h = init_table.frame.h or 1
+end
+
+function Slider:init()
+    if self.num_stops < 2 then error('too few Slider stops') end
+    self.is_dragging_target = nil -- 'left', 'right', or 'both'
+    self.is_dragging_idx = nil -- offset from leftmost dragged tile
+end
+
+local function Slider_get_width_per_idx(self)
+    return math.max(3, (self.frame_body.width-7) // (self.num_stops-1))
+end
+
+function Slider:onInput(keys)
+    if not keys._MOUSE_L then return false end
+    local x = self:getMousePos()
+    if not x then return false end
+    local left_idx = self.get_idx_fn()
+    local width_per_idx = Slider_get_width_per_idx(self)
+    local left_pos = width_per_idx*(left_idx-1)
+    local right_pos = width_per_idx*(left_idx-1) + 4
+    if x < left_pos then
+        self.on_change(self.get_idx_fn() - 1)
+    else
+        self.is_dragging_target = 'both'
+        self.is_dragging_idx = x - right_pos
+    end
+    return true
+end
+
+local function Slider_do_drag(self, width_per_idx)
+    local x = self.frame_body:localXY(dfhack.screen.getMousePos())
+    local cur_pos = x - self.is_dragging_idx
+    cur_pos = math.max(0, cur_pos)
+    cur_pos = math.min(width_per_idx*(self.num_stops-1)+7, cur_pos)
+    local offset = 1
+    local new_idx = math.max(0, cur_pos+offset)//width_per_idx + 1
+    if self.is_dragging_target == 'both' then
+        if new_idx > self.num_stops then
+            return
+        end
+    end
+    if new_idx and new_idx ~= self.get_idx_fn() then
+        self.on_change(new_idx)
+    end
+end
+
+local SLIDER_LEFT_END = to_pen{ch=198, fg=COLOR_GREY, bg=COLOR_BLACK}
+local SLIDER_TRACK = to_pen{ch=205, fg=COLOR_GREY, bg=COLOR_BLACK}
+local SLIDER_TRACK_SELECTED = to_pen{ch=205, fg=COLOR_LIGHTGREEN, bg=COLOR_BLACK}
+local SLIDER_TRACK_STOP = to_pen{ch=216, fg=COLOR_GREY, bg=COLOR_BLACK}
+local SLIDER_TRACK_STOP_SELECTED = to_pen{ch=216, fg=COLOR_LIGHTGREEN, bg=COLOR_BLACK}
+local SLIDER_RIGHT_END = to_pen{ch=181, fg=COLOR_GREY, bg=COLOR_BLACK}
+local SLIDER_TAB_LEFT = to_pen{ch=60, fg=COLOR_BLACK, bg=COLOR_YELLOW}
+local SLIDER_TAB_CENTER = to_pen{ch=9, fg=COLOR_BLACK, bg=COLOR_YELLOW}
+local SLIDER_TAB_RIGHT = to_pen{ch=62, fg=COLOR_BLACK, bg=COLOR_YELLOW}
+
+function Slider:onRenderBody(dc, rect)
+    local left_idx = self.get_idx_fn()
+    local width_per_idx = Slider_get_width_per_idx(self)
+    -- draw track
+    dc:seek(1,0)
+    dc:char(nil, SLIDER_LEFT_END)
+    dc:char(nil, SLIDER_TRACK)
+    for stop_idx=1,self.num_stops-1 do
+        local track_stop_pen = SLIDER_TRACK_STOP_SELECTED
+        local track_pen = SLIDER_TRACK_SELECTED
+        if left_idx ~= stop_idx then
+            track_stop_pen = SLIDER_TRACK_STOP
+            track_pen = SLIDER_TRACK
+        elseif left_idx == stop_idx then
+            track_pen = SLIDER_TRACK
+        end
+        dc:char(nil, track_stop_pen)
+        for i=2,width_per_idx do
+            dc:char(nil, track_pen)
+        end
+    end
+    if left_idx >= self.num_stops then
+        dc:char(nil, SLIDER_TRACK_STOP_SELECTED)
+    else
+        dc:char(nil, SLIDER_TRACK_STOP)
+    end
+    dc:char(nil, SLIDER_TRACK)
+    dc:char(nil, SLIDER_RIGHT_END)
+    -- draw tab
+    dc:seek(width_per_idx*(left_idx-1)+2)
+    dc:char(nil, SLIDER_TAB_LEFT)
+    dc:char(nil, SLIDER_TAB_CENTER)
+    dc:char(nil, SLIDER_TAB_RIGHT)
+    -- manage dragging
+    if self.is_dragging_target then
+        Slider_do_drag(self, width_per_idx)
+    end
+    if df.global.enabler.mouse_lbut_down == 0 then
+        self.is_dragging_target = nil
+        self.is_dragging_idx = nil
+    end
+end
+
+return Slider