Rectangular grid center snapping (#905)

* implement center snapping

* typo

* allow snap distance in center snapping

* better description of snapping distance

* Update Translations.pot

Translations/Translations.pot

@@ -1274,7 +1274,7 @@ msgid "Snapping distance:"
 msgstr ""
 
 #. Found in the Preferences, in the Canvas tab. Refers to grid and guide snapping. Hint tooltip of the snapping distance slider.
-msgid "This is the distance in pixels where guide and grid snapping gets activated."
+msgid "This is the distance in screen pixels where guide and grid snapping gets activated."
 msgstr ""
 
 msgid "Grid"

src/Autoload/Global.gd

@@ -142,7 +142,8 @@ var draw_pixel_grid := false
 var show_rulers := true
 var show_guides := true
 var show_mouse_guides := false
-var snap_to_rectangular_grid := false
+var snap_to_rectangular_grid_boundary := false
+var snap_to_rectangular_grid_center := false
 var snap_to_guides := false
 var snap_to_perspective_guides := false
 

src/Preferences/PreferencesDialog.tscn

@@ -518,7 +518,7 @@ columns = 3
 margin_right = 161.0
 margin_bottom = 14.0
 rect_min_size = Vector2( 110, 0 )
-hint_tooltip = "This is the distance in pixels where guide and grid snapping gets activated."
+hint_tooltip = "This is the distance in screen pixels where guide and grid snapping gets activated."
 mouse_filter = 0
 size_flags_horizontal = 3
 text = "Snapping distance:"

src/Tools/BaseTool.gd

@@ -123,7 +123,7 @@ func draw_preview() -> void:
 
 func snap_position(position: Vector2) -> Vector2:
 	var snapping_distance := Global.snapping_distance * Global.camera.zoom.x
-	if Global.snap_to_rectangular_grid:
+	if Global.snap_to_rectangular_grid_boundary:
 		var grid_pos := position.snapped(Global.grid_size)
 		grid_pos += Global.grid_offset
 		# keeping grid_pos as is would have been fine but this adds extra accuracy as to
@@ -146,6 +146,27 @@ func snap_position(position: Vector2) -> Vector2:
 		if grid_point != Vector2.INF:
 			position = grid_point.floor()
 
+	if Global.snap_to_rectangular_grid_center:
+		var grid_center := position.snapped(Global.grid_size) + (Global.grid_size / 2)
+		grid_center += Global.grid_offset
+		# keeping grid_center as is would have been fine but this adds extra accuracy as to
+		# which snap point (from the list below) is closest to mouse and occupy THAT point
+		var t_l := grid_center + Vector2(-Global.grid_size.x, -Global.grid_size.y)
+		var t_c := grid_center + Vector2(0, -Global.grid_size.y)  # t_c is for "top centre" and so on
+		var t_r := grid_center + Vector2(Global.grid_size.x, -Global.grid_size.y)
+		var m_l := grid_center + Vector2(-Global.grid_size.x, 0)
+		var m_c := grid_center
+		var m_r := grid_center + Vector2(Global.grid_size.x, 0)
+		var b_l := grid_center + Vector2(-Global.grid_size.x, Global.grid_size.y)
+		var b_c := grid_center + Vector2(0, Global.grid_size.y)
+		var b_r := grid_center + Global.grid_size
+		var vec_arr := [t_l, t_c, t_r, m_l, m_c, m_r, b_l, b_c, b_r]
+		for vec in vec_arr:
+			if vec.distance_to(position) < grid_center.distance_to(position):
+				grid_center = vec
+		if grid_center.distance_to(position) <= snapping_distance:
+			position = grid_center.floor()
+
 	var snap_to := Vector2.INF
 	if Global.snap_to_guides:
 		for guide in Global.current_project.guides:

src/UI/TopMenuContainer/TopMenuContainer.gd

@@ -186,7 +186,8 @@ func _setup_tile_mode_submenu(item: String) -> void:
 
 func _setup_snap_to_submenu(item: String) -> void:
 	snap_to_submenu.set_name("snap_to_submenu")
-	snap_to_submenu.add_check_item("Snap to Rectangular Grid")
+	snap_to_submenu.add_check_item("Snap to Rectangular Grid Boundary")
+	snap_to_submenu.add_check_item("Snap to Rectangular Grid Center")
 	snap_to_submenu.add_check_item("Snap to Guides")
 	snap_to_submenu.add_check_item("Snap to Perspective Guides")
 	snap_to_submenu.connect("id_pressed", self, "_snap_to_submenu_id_pressed")
@@ -506,12 +507,15 @@ func _tile_mode_submenu_id_pressed(id: int) -> void:
 
 func _snap_to_submenu_id_pressed(id: int) -> void:
 	if id == 0:
-		Global.snap_to_rectangular_grid = !Global.snap_to_rectangular_grid
+		Global.snap_to_rectangular_grid_boundary = !Global.snap_to_rectangular_grid_boundary
-		snap_to_submenu.set_item_checked(id, Global.snap_to_rectangular_grid)
+		snap_to_submenu.set_item_checked(id, Global.snap_to_rectangular_grid_boundary)
-	elif id == 1:
+	if id == 1:
+		Global.snap_to_rectangular_grid_center = !Global.snap_to_rectangular_grid_center
+		snap_to_submenu.set_item_checked(id, Global.snap_to_rectangular_grid_center)
+	elif id == 2:
 		Global.snap_to_guides = !Global.snap_to_guides
 		snap_to_submenu.set_item_checked(id, Global.snap_to_guides)
-	elif id == 2:
+	elif id == 3:
 		Global.snap_to_perspective_guides = !Global.snap_to_perspective_guides
 		snap_to_submenu.set_item_checked(id, Global.snap_to_perspective_guides)