ParameterInput: Use DragDropArea

Instead of using ParameterInput's own input events, add a DragDropArea
for each input component. This allows us to use _gui_input events so
events are correctly filtered based on z order and visibility.

Author: dylanmccall

addons/block_code/ui/blocks/utilities/parameter_input/parameter_input.gd

@@ -20,7 +20,6 @@ signal modified
 var default_value: Variant
 
 var _drag_start: Vector2 = Vector2.INF
-var _is_dragging: bool = false
 
 @onready var _panel := %Panel
 @onready var snap_point := %SnapPoint
@@ -156,6 +155,10 @@ func _ready():
 		set_raw_input(default_value)
 
 
+func _on_drag_drop_area_drag_started():
+	drag_started.emit()
+
+
 func get_snapped_block() -> Block:
 	return snap_point.get_snapped_block()
 
@@ -289,32 +292,3 @@ func _on_option_input_item_selected(index):
 
 func _on_snap_point_snapped_block_changed(block):
 	_update_visible_input()
-
-
-func _input(event: InputEvent) -> void:
-	if snap_point.has_snapped_block():
-		return
-
-	if event is InputEventMouseButton:
-		var button_event: InputEventMouseButton = event as InputEventMouseButton
-
-		if button_event.button_index != MOUSE_BUTTON_LEFT:
-			return
-
-		if button_event.double_click:
-			# Double click event (with the mouse released) has both pressed=true
-			# and double_click=true, so ignore it as a special case.
-			pass
-		elif button_event.pressed and get_global_rect().has_point(button_event.global_position):
-			# Keep track of where the mouse click originated, but allow this
-			# event to propagate to other nodes.
-			_drag_start = event.global_position
-		else:
-			_drag_start = Vector2.INF
-	elif _drag_start != Vector2.INF and event is InputEventMouseMotion:
-		var motion_event: InputEventMouseMotion = event as InputEventMouseMotion
-
-		if not get_global_rect().has_point(event.global_position) and _drag_start.distance_to(event.global_position) > Constants.MINIMUM_DRAG_THRESHOLD:
-			get_viewport().set_input_as_handled()
-			drag_started.emit()
-			_drag_start = Vector2.INF

addons/block_code/ui/blocks/utilities/parameter_input/parameter_input.tscn

@@ -1,6 +1,7 @@
-[gd_scene load_steps=10 format=3 uid="uid://cjvxs6euc6xbm"]
+[gd_scene load_steps=11 format=3 uid="uid://cjvxs6euc6xbm"]
 
 [ext_resource type="Script" path="res://addons/block_code/ui/blocks/utilities/parameter_input/parameter_input.gd" id="1_rgmxn"]
+[ext_resource type="PackedScene" uid="uid://c1l0mpkvmvwfd" path="res://addons/block_code/ui/blocks/utilities/drag_drop_area/drag_drop_area.tscn" id="2_05gck"]
 [ext_resource type="PackedScene" uid="uid://b1oge52xhjqnu" path="res://addons/block_code/ui/blocks/utilities/snap_point/snap_point.tscn" id="2_6esp3"]
 
 [sub_resource type="StyleBoxFlat" id="StyleBoxFlat_tn6h4"]
@@ -71,6 +72,10 @@ theme_override_styles/normal = SubResource("StyleBoxEmpty_6oowp")
 placeholder_text = "Parameter"
 expand_to_text_length = true
 
+[node name="DragDropArea" parent="InputSwitcher/TextInput/LineEdit" instance=ExtResource("2_05gck")]
+layout_mode = 1
+drag_outside = true
+
 [node name="ColorInput" type="ColorPickerButton" parent="InputSwitcher"]
 unique_name_in_owner = true
 visible = false
@@ -80,6 +85,10 @@ layout_mode = 2
 mouse_default_cursor_shape = 2
 theme_override_styles/normal = SubResource("StyleBoxEmpty_5hq7f")
 
+[node name="DragDropArea" parent="InputSwitcher/ColorInput" instance=ExtResource("2_05gck")]
+layout_mode = 1
+drag_outside = true
+
 [node name="OptionInput" type="OptionButton" parent="InputSwitcher"]
 unique_name_in_owner = true
 visible = false
@@ -90,6 +99,10 @@ theme_override_styles/normal = SubResource("StyleBoxEmpty_fjquj")
 action_mode = 1
 fit_to_longest_item = false
 
+[node name="DragDropArea" parent="InputSwitcher/OptionInput" instance=ExtResource("2_05gck")]
+layout_mode = 1
+drag_outside = true
+
 [node name="Vector2Input" type="MarginContainer" parent="InputSwitcher"]
 unique_name_in_owner = true
 visible = false
@@ -121,6 +134,10 @@ placeholder_text = "x"
 alignment = 1
 expand_to_text_length = true
 
+[node name="DragDropArea" parent="InputSwitcher/Vector2Input/HBoxContainer/XLineEdit" instance=ExtResource("2_05gck")]
+layout_mode = 1
+drag_outside = true
+
 [node name="Control3" type="Control" parent="InputSwitcher/Vector2Input/HBoxContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
@@ -135,6 +152,10 @@ layout_mode = 2
 size_flags_horizontal = 4
 color = Color(0.804743, 0.804743, 0.804743, 1)
 
+[node name="DragDropArea" parent="InputSwitcher/Vector2Input/HBoxContainer/CenterContainer/ColorRect" instance=ExtResource("2_05gck")]
+layout_mode = 1
+drag_outside = true
+
 [node name="Control4" type="Control" parent="InputSwitcher/Vector2Input/HBoxContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
@@ -154,6 +175,10 @@ placeholder_text = "y"
 alignment = 1
 expand_to_text_length = true
 
+[node name="DragDropArea" parent="InputSwitcher/Vector2Input/HBoxContainer/YLineEdit" instance=ExtResource("2_05gck")]
+layout_mode = 1
+drag_outside = true
+
 [node name="Control2" type="Control" parent="InputSwitcher/Vector2Input/HBoxContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
@@ -179,6 +204,10 @@ popup/item_0/text = "false"
 popup/item_1/text = "true"
 popup/item_1/id = 1
 
+[node name="DragDropArea" parent="InputSwitcher/BoolInput/BoolInputOption" instance=ExtResource("2_05gck")]
+layout_mode = 1
+drag_outside = true
+
 [node name="SnapPoint" parent="." instance=ExtResource("2_6esp3")]
 unique_name_in_owner = true
 layout_mode = 2
@@ -187,11 +216,18 @@ variant_type = 4
 
 [connection signal="focus_exited" from="InputSwitcher/TextInput/LineEdit" to="." method="_on_line_edit_focus_exited"]
 [connection signal="text_submitted" from="InputSwitcher/TextInput/LineEdit" to="." method="_on_line_edit_text_submitted"]
+[connection signal="drag_started" from="InputSwitcher/TextInput/LineEdit/DragDropArea" to="." method="_on_drag_drop_area_drag_started"]
 [connection signal="color_changed" from="InputSwitcher/ColorInput" to="." method="_on_color_input_color_changed"]
+[connection signal="drag_started" from="InputSwitcher/ColorInput/DragDropArea" to="." method="_on_drag_drop_area_drag_started"]
 [connection signal="item_selected" from="InputSwitcher/OptionInput" to="." method="_on_option_input_item_selected"]
+[connection signal="drag_started" from="InputSwitcher/OptionInput/DragDropArea" to="." method="_on_drag_drop_area_drag_started"]
 [connection signal="focus_exited" from="InputSwitcher/Vector2Input/HBoxContainer/XLineEdit" to="." method="_on_x_line_edit_focus_exited"]
 [connection signal="text_submitted" from="InputSwitcher/Vector2Input/HBoxContainer/XLineEdit" to="." method="_on_x_line_edit_text_submitted"]
+[connection signal="drag_started" from="InputSwitcher/Vector2Input/HBoxContainer/XLineEdit/DragDropArea" to="." method="_on_drag_drop_area_drag_started"]
+[connection signal="drag_started" from="InputSwitcher/Vector2Input/HBoxContainer/CenterContainer/ColorRect/DragDropArea" to="." method="_on_drag_drop_area_drag_started"]
 [connection signal="focus_exited" from="InputSwitcher/Vector2Input/HBoxContainer/YLineEdit" to="." method="_on_y_line_edit_focus_exited"]
 [connection signal="text_submitted" from="InputSwitcher/Vector2Input/HBoxContainer/YLineEdit" to="." method="_on_y_line_edit_text_submitted"]
+[connection signal="drag_started" from="InputSwitcher/Vector2Input/HBoxContainer/YLineEdit/DragDropArea" to="." method="_on_drag_drop_area_drag_started"]
 [connection signal="item_selected" from="InputSwitcher/BoolInput/BoolInputOption" to="." method="_on_option_input_item_selected"]
+[connection signal="drag_started" from="InputSwitcher/BoolInput/BoolInputOption/DragDropArea" to="." method="_on_drag_drop_area_drag_started"]
 [connection signal="snapped_block_changed" from="SnapPoint" to="." method="_on_snap_point_snapped_block_changed"]