gui/mass-remove.toolbar: compatibility with released default_pos; roll back the fancier positioning

Now that this overlay has been released (51.09-r1), it is important to
go back to a default_pos that matches the released value. This prevents
a "jump" in positioning when trying this code after having used the
mainline version.

If a overlay version change is done in the future, it would probably
make sense to reset the default position to a value that lets the
overlay be moved all the way to the left.

Beyond that, rollback the fancier "apply the same idea in all
directions" code to make the code easier to compare with the what is on
master.

That stuff is probably at least worth thinking about, but not as a part
of simply demonstrating how the "toolbar" library could be used for
toolbar-relative positioning.

Author: ChrisJohnsen

gui/mass-remove.lua

@@ -399,25 +399,33 @@ end
 -- MassRemoveToolbarOverlay
 --
 
--- The overlay is positioned so that (by default) its button is placed next to
--- the right-most button of the secondary toolbar displayed for the "erase" tool
+-- The overlay is positioned (by default) so that, no matter what size interface
+-- is being used, the overlay's button is placed one column to the right of the
+-- right-most button of the secondary toolbar displayed for the "erase" tool
 -- (used to remove designations).
 
 -- This would be straightforward in a full_interface overlay (just set its
--- l/r/t/b frame positioning fields). However, to preserve player-positioning,
--- we take a more circuitous route.
-
--- In a minimum-size interface area, the player is allowed to place the overlay
--- (a combination of the button and the tooltip) anywhere inside the interface
--- area. When the interface area is resized (usually through window resizes, but
--- also through interface percentage changes), placement is maintained relative
--- to the "ideal" position of the button (i.e. positions are relative to the
--- "ideal" position). When repositioning the overlay in a larger-than-minimum
--- interface area the overlays size is artificially inflated so that the overlay
--- can not be positioned (with respect to the "ideal" button position) farther
--- away than is possible in a minimum-size interface area. This limits the
--- positioning, but keeps the (relative) position consistent across all possible
--- resizes.
+-- l/r/t/b frame positioning fields based on the "erase" toolbar's position).
+-- However, to preserve player-positioning, we take a more circuitous route.
+
+-- Usually, the player-configured positions are relative to the edges of the DF
+-- interface area. But because the button of this overlay needs to "stick with"
+-- the rest of the toolbar buttons, the player-configured positioning is
+-- reinterpreted a bit.
+
+-- The offset between the overlay's default position and its player-configured
+-- position is used as the overlay's effective offset from its "ideal" position.
+-- This "effective offset" is realized by updating the overlay's width, not its
+-- position (which we leave in the hands of the overlay system, under player
+-- control). When combined with the player-configured position, this results in
+-- translating the overlay position to be relative to its "ideal" position so
+-- that the overlay "moves with" the rest of the toolbar buttons, but still
+-- allows for player customization.
+
+-- Note: This "position reinterpretation" currently only works when the overlay
+-- is anchored to the left and bottom edges of the interface area. If the
+-- overlay is player-reconfigured to be anchored to the right or top edges, it
+-- will result in normal edge-relative positioning.
 
 local tb = reqscript('internal/df-bottom-toolbars')
 
@@ -438,12 +446,17 @@ local function mass_remove_button_offsets(interface_rect)
     }
 end
 
-local MR_MIN_OFFSETS = mass_remove_button_offsets(tb.MINIMUM_INTERFACE_RECT)
+-- This value is compatible with the initial release of the overlay, but it not
+-- the actual left-offset of this overlay; if bumping overlay version, this
+-- could be changed to mass_remove_button_offsets(tb.MINIMUM_INTERFACE_RECT).l
+-- Adopting the calculated value would let the overlay be moved all the way to
+-- the left (in a minimum-size interface).
+local MR_DEFAULT_OFFSET = 41
 
 MassRemoveToolbarOverlay = defclass(MassRemoveToolbarOverlay, overlay.OverlayWidget)
 MassRemoveToolbarOverlay.ATTRS{
     desc='Adds a button to the erase toolbar to open the mass removal tool.',
-    default_pos={x=MR_MIN_OFFSETS.l+1, y=-(MR_MIN_OFFSETS.b+1)},
+    default_pos={x=MR_DEFAULT_OFFSET+1, y=-(tb.TOOLBAR_HEIGHT+1)},
     default_enabled=true,
     viewscreens='dwarfmode/Designate/ERASE',
     frame={w=MR_WIDTH, h=MR_HEIGHT},
@@ -458,57 +471,51 @@ function MassRemoveToolbarOverlay:init()
 
     self:addviews{
         widgets.Panel{
-            view_id='tt_and_icon',
-            frame={ r=0, t=0, w=MR_WIDTH, h=MR_HEIGHT },
-                subviews={
-                widgets.Panel{
-                    frame={t=0, l=0, w=MR_WIDTH, h=MR_TOOLTIP_HEIGHT},
-                    frame_style=gui.FRAME_PANEL,
-                    frame_background=gui.CLEAR_PEN,
-                    frame_inset={l=1, r=1},
-                    visible=function() return self.subviews.icon:getMousePos() end,
-                    subviews={
-                        widgets.Label{
-                            text={
-                                'Open mass removal', NEWLINE,
-                                'interface.', NEWLINE,
-                                NEWLINE,
-                                {text='Hotkey: ', pen=COLOR_GRAY}, {key='CUSTOM_M'},
-                            },
-                        },
+            frame={t=0, r=0, w=MR_WIDTH, h=MR_TOOLTIP_HEIGHT},
+            frame_style=gui.FRAME_PANEL,
+            frame_background=gui.CLEAR_PEN,
+            frame_inset={l=1, r=1},
+            visible=function() return self.subviews.icon:getMousePos() end,
+            subviews={
+                widgets.Label{
+                    text={
+                        'Open mass removal', NEWLINE,
+                        'interface.', NEWLINE,
+                        NEWLINE,
+                        {text='Hotkey: ', pen=COLOR_GRAY}, {key='CUSTOM_M'},
                     },
                 },
-                widgets.Panel{
-                    view_id='icon',
-                    frame={b=0, l=0, w=MR_BUTTON_WIDTH, h=tb.SECONDARY_TOOLBAR_HEIGHT},
-                    subviews={
-                        widgets.Label{
-                            text=widgets.makeButtonLabelText{
-                                chars=button_chars,
-                                pens=COLOR_GRAY,
-                                tileset=toolbar_textures,
-                                tileset_offset=1,
-                                tileset_stride=8,
-                            },
-                            on_click=launch_mass_remove,
-                            visible=function () return not self.subviews.icon:getMousePos() end,
-                        },
-                        widgets.Label{
-                            text=widgets.makeButtonLabelText{
-                                chars=button_chars,
-                                pens={
-                                    {COLOR_WHITE, COLOR_WHITE, COLOR_WHITE, COLOR_WHITE},
-                                    {COLOR_WHITE, COLOR_GRAY,  COLOR_GRAY,  COLOR_WHITE},
-                                    {COLOR_WHITE, COLOR_WHITE, COLOR_WHITE, COLOR_WHITE},
-                                },
-                                tileset=toolbar_textures,
-                                tileset_offset=5,
-                                tileset_stride=8,
-                            },
-                            on_click=launch_mass_remove,
-                            visible=function() return self.subviews.icon:getMousePos() end,
+            },
+        },
+        widgets.Panel{
+            view_id='icon',
+            frame={b=0, r=0, w=MR_WIDTH, h=tb.SECONDARY_TOOLBAR_HEIGHT},
+            subviews={
+                widgets.Label{
+                    text=widgets.makeButtonLabelText{
+                        chars=button_chars,
+                        pens=COLOR_GRAY,
+                        tileset=toolbar_textures,
+                        tileset_offset=1,
+                        tileset_stride=8,
+                    },
+                    on_click=launch_mass_remove,
+                    visible=function () return not self.subviews.icon:getMousePos() end,
+                },
+                widgets.Label{
+                    text=widgets.makeButtonLabelText{
+                        chars=button_chars,
+                        pens={
+                            {COLOR_WHITE, COLOR_WHITE, COLOR_WHITE, COLOR_WHITE},
+                            {COLOR_WHITE, COLOR_GRAY,  COLOR_GRAY,  COLOR_WHITE},
+                            {COLOR_WHITE, COLOR_WHITE, COLOR_WHITE, COLOR_WHITE},
                         },
+                        tileset=toolbar_textures,
+                        tileset_offset=5,
+                        tileset_stride=8,
                     },
+                    on_click=launch_mass_remove,
+                    visible=function() return self.subviews.icon:getMousePos() end,
                 },
             },
         },
@@ -517,16 +524,7 @@ end
 
 function MassRemoveToolbarOverlay:preUpdateLayout(parent_rect)
     local offsets = mass_remove_button_offsets(parent_rect)
-    local r = offsets.r - MR_MIN_OFFSETS.r
-    local l = offsets.l - MR_MIN_OFFSETS.l
-    local t = offsets.t - MR_MIN_OFFSETS.t
-    local b = offsets.b - MR_MIN_OFFSETS.b
-    self.frame.w = MR_WIDTH + l + r
-    self.frame.h = MR_HEIGHT + t + b
-    self.subviews.tt_and_icon.frame.l = l
-    self.subviews.tt_and_icon.frame.r = r
-    self.subviews.tt_and_icon.frame.t = t
-    self.subviews.tt_and_icon.frame.b = b
+    self.frame.w = MR_WIDTH + offsets.l - MR_DEFAULT_OFFSET
 end
 
 function MassRemoveToolbarOverlay:onInput(keys)