Add on_click/on_rclick handlers to widgets.Label

Closes #919

NEWS.rst

@@ -33,6 +33,10 @@ Changelog
 DFHack future
 =============
 
+Lua
+---
+- Label widgets can now easily register handlers for mouse clicks
+
 New Features
 ------------
 - `gui/gm-editor` it's now possible to insert default types to containers. For primitive types leave the type entry empty, for references use ``*``.

docs/Lua API.rst

@@ -3051,10 +3051,13 @@ It has the following attributes:
 
 :text_pen: Specifies the pen for active text.
 :text_dpen: Specifies the pen for disabled text.
+:text_hpen: Specifies the pen for text hovered over by the mouse, if a click handler is registered.
 :disabled: Boolean or a callback; if true, the label is disabled.
 :enabled: Boolean or a callback; if false, the label is disabled.
 :auto_height: Sets self.frame.h from the text height.
 :auto_width: Sets self.frame.w from the text width.
+:on_click: A callback called when the label is clicked (optional)
+:on_rclick: A callback called when the label is right-clicked (optional)
 
 The text itself is represented as a complex structure, and passed
 to the object via the ``text`` argument of the constructor, or via

library/lua/gui/widgets.lua

@@ -330,15 +330,21 @@ Label = defclass(Label, Widget)
 
 Label.ATTRS{
     text_pen = COLOR_WHITE,
-    text_dpen = COLOR_DARKGREY,
+    text_dpen = COLOR_DARKGREY, -- disabled
+    text_hpen = DEFAULT_NIL, -- highlight - default is text_pen with reversed brightness
     disabled = DEFAULT_NIL,
     enabled = DEFAULT_NIL,
     auto_height = true,
     auto_width = false,
+    on_click = DEFAULT_NIL,
+    on_rclick = DEFAULT_NIL,
 }
 
 function Label:init(args)
     self:setText(args.text)
+    if not self.text_hpen then
+        self.text_hpen = ((tonumber(self.text_pen) or tonumber(self.text_pen.fg) or 0) + 8) % 16
+    end
 end
 
 function Label:setText(text)
@@ -374,11 +380,21 @@ function Label:getTextWidth()
 end
 
 function Label:onRenderBody(dc)
-    render_text(self,dc,0,0,self.text_pen,self.text_dpen,is_disabled(self))
+    local text_pen = self.text_pen
+    if self:getMousePos() and (self.on_click or self.on_rclick) then
+        text_pen = self.text_hpen
+    end
+    render_text(self,dc,0,0,text_pen,self.text_dpen,is_disabled(self))
 end
 
 function Label:onInput(keys)
     if not is_disabled(self) then
+        if keys._MOUSE_L_DOWN and self:getMousePos() and self.on_click then
+            self:on_click()
+        end
+        if keys._MOUSE_R_DOWN and self:getMousePos() and self.on_rclick then
+            self:on_rclick()
+        end
         return check_text_keys(self, keys)
     end
 end

scripts/gui/gm-editor.lua

@@ -136,7 +136,8 @@ function GmEditorUi:init(args)
         subviews={
             mainList,
             widgets.Label{text={{text="<no item>",id="name"},{gap=1,text="Help",key=keybindings.help.key,key_sep = '()'}}, view_id = 'lbl_current_item',frame = {l=1,t=1,yalign=0}},
-            widgets.Label{text={{text="Search",key=keybindings.start_filter.key,key_sep = '()'},{text=": "}},frame={l=1,t=2}},
+            widgets.Label{text={{text="Search",key=keybindings.start_filter.key,key_sep = '()'},{text=": "}},frame={l=1,t=2},
+                on_click=function() self:enable_input(true) end},
             widgets.EditField{frame={l=12,t=2},active=false,on_change=self:callback('text_input'),on_submit=self:callback("enable_input",false),view_id="filter_input"},
             --widgets.Label{text="BLAH2"}
                 }