Implement a spacing option for the pencil tool (#813)

* Added Code for cursor snapping

* Added the Snap option

* typo

* Fix snapvector not updating properly

* formatting

* better snapping system

This makes the stroke snapping more accurate by preferring the snap point nearest to the cursor

* changed Snap mode to spacing

* Code Improvements

* more changes

* Update Pencil.gd

* formatting

* fix max line length

---------

Co-authored-by: Emmanouil Papadeas <35376950+OverloadedOrama@users.noreply.github.com>

src/Tools/BaseTool.gd

@@ -10,6 +10,12 @@ var _cursor := Vector2.INF
 var _draw_cache: PoolVector2Array = []  # for storing already drawn pixels
 var _for_frame := 0  # cache for which frame?
 
+# Only use "_spacing_mode" and "_spacing" variables (the others are set automatically)
+# The _spacing_mode and _spacing values are to be CHANGED only in the tool scripts (e.g Pencil.gd)
+var _spacing_mode := false  # Enables spacing (continuos gaps between two strokes)
+var _spacing := Vector2.ZERO  # Spacing between two strokes
+var _stroke_dimensions := Vector2.ONE  # 2d vector containing _brush_size from Draw.gd
+var _spacing_offset := Vector2.ZERO  # The "INITIAL" error between position and position.snapped()
 onready var color_rect: ColorRect = $ColorRect
 
 
@@ -47,10 +53,11 @@ func update_config() -> void:
 	pass
 
 
-func draw_start(_position: Vector2) -> void:
+func draw_start(position: Vector2) -> void:
 	_draw_cache = []
 	is_moving = true
 	Global.current_project.can_undo = false
+	_spacing_offset = _get_spacing_offset(position)
 
 
 func draw_move(position: Vector2) -> void:
@@ -68,6 +75,40 @@ func draw_end(_position: Vector2) -> void:
 
 func cursor_move(position: Vector2) -> void:
 	_cursor = position
+	if _spacing_mode and is_moving:
+		_cursor = get_spacing_position(position)
+
+
+func get_spacing_position(position: Vector2) -> Vector2:
+	# spacing_factor is the distance the mouse needs to get snapped by in order
+	# to keep a space "_spacing" between two strokes of dimensions "_stroke_dimensions"
+	var spacing_factor = _stroke_dimensions + _spacing
+	var snap_position = position.snapped(spacing_factor) + _spacing_offset
+
+	# keeping snap_position 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_c = snap_position + Vector2(0, -spacing_factor.y)  # t_c is for "top centre" and so on...
+	var t_r = snap_position + Vector2(spacing_factor.x, -spacing_factor.y)
+	var t_r_r = snap_position + Vector2(2 * spacing_factor.x, -spacing_factor.y)
+	var m_c = snap_position
+	var m_r = snap_position + Vector2(spacing_factor.x, 0)
+	var m_r_r = snap_position + Vector2(2 * spacing_factor.x, 0)
+	var b_c = snap_position + Vector2(0, spacing_factor.y)
+	var b_r = snap_position + Vector2(spacing_factor.x, spacing_factor.y)
+	var b_r_r = snap_position + Vector2(2 * spacing_factor.x, spacing_factor.y)
+	var vec_arr := [t_c, t_r, t_r_r, m_c, m_r, m_r_r, b_c, b_r, b_r_r]
+	for vec in vec_arr:
+		if vec.distance_to(position) < snap_position.distance_to(position):
+			snap_position = vec
+
+	return snap_position
+
+
+func _get_spacing_offset(position: Vector2) -> Vector2:
+	var spacing_factor = _stroke_dimensions + _spacing  # spacing_factor is explained above
+	# since we just started drawing, the "position" is our intended location so the error
+	# (_spacing_offset) is measured by subtracting both quantities
+	return position - position.snapped(spacing_factor)
 
 
 func draw_indicator(left: bool) -> void:

src/Tools/BaseTool.tscn

@@ -1,6 +1,7 @@
-[gd_scene load_steps=2 format=2]
+[gd_scene load_steps=3 format=2]
 
 [ext_resource path="res://src/Tools/BaseTool.gd" type="Script" id=1]
+[ext_resource path="res://src/UI/Nodes/ValueSlider.tscn" type="PackedScene" id=2]
 
 [node name="ToolOptions" type="VBoxContainer"]
 margin_left = 7.0
@@ -23,3 +24,34 @@ theme_type_variation = "Header"
 text = "Tool Name"
 align = 1
 autowrap = true
+
+[node name="SpacingMode" type="CheckBox" parent="."]
+visible = false
+margin_top = 26.0
+margin_right = 116.0
+margin_bottom = 50.0
+text = "Spacing"
+
+[node name="StrokeGap" type="VBoxContainer" parent="."]
+visible = false
+margin_top = 26.0
+margin_right = 116.0
+margin_bottom = 78.0
+
+[node name="SpacingX" parent="StrokeGap" instance=ExtResource( 2 )]
+margin_right = 116.0
+__meta__ = {
+"_editor_description_": ""
+}
+prefix = "Gap X:"
+suffix = "px"
+
+[node name="SpacingY" parent="StrokeGap" instance=ExtResource( 2 )]
+margin_top = 28.0
+margin_right = 116.0
+margin_bottom = 52.0
+__meta__ = {
+"_editor_description_": ""
+}
+prefix = "Gap Y:"
+suffix = "px"

src/Tools/Draw.gd

@@ -112,10 +112,13 @@ func update_brush() -> void:
 	match _brush.type:
 		Brushes.PIXEL:
 			_brush_texture.create_from_image(load("res://assets/graphics/pixel_image.png"), 0)
+			_stroke_dimensions = Vector2.ONE * _brush_size
 		Brushes.CIRCLE:
 			_brush_texture.create_from_image(load("res://assets/graphics/circle_9x9.png"), 0)
+			_stroke_dimensions = Vector2.ONE * _brush_size
 		Brushes.FILLED_CIRCLE:
 			_brush_texture.create_from_image(load("res://assets/graphics/circle_filled_9x9.png"), 0)
+			_stroke_dimensions = Vector2.ONE * _brush_size
 		Brushes.FILE, Brushes.RANDOM_FILE, Brushes.CUSTOM:
 			$Brush/BrushSize.suffix = "00 %"  # Use a different size convention on images
 			if _brush.random.size() <= 1:
@@ -125,6 +128,7 @@ func update_brush() -> void:
 				_brush_image = _create_blended_brush_image(_brush.random[random])
 			_brush_texture.create_from_image(_brush_image, 0)
 			update_mirror_brush()
+			_stroke_dimensions = _brush_image.get_size()
 	_indicator = _create_brush_indicator()
 	_polylines = _create_polylines(_indicator)
 	$Brush/Type/Texture.texture = _brush_texture
@@ -277,7 +281,10 @@ func draw_fill_gap(start: Vector2, end: Vector2) -> void:
 			err += dx
 			y += sy
 		#coords_to_draw.append_array(_draw_tool(Vector2(x, y)))
-		for coord in _draw_tool(Vector2(x, y)):
+		var current_pixel_coord = Vector2(x, y)
+		if _spacing_mode:
+			current_pixel_coord = get_spacing_position(current_pixel_coord)
+		for coord in _draw_tool(current_pixel_coord):
 			coords_to_draw[coord] = 0
 	for c in coords_to_draw.keys():
 		_set_pixel_no_cache(c)

src/Tools/Pencil.gd

@@ -6,6 +6,7 @@ var _changed := false
 var _overwrite := false
 var _fill_inside := false
 var _draw_points := Array()
+var _old_spacing_mode := false  # needed to reset spacing mode in case we change it
 
 
 class PencilOp:
@@ -37,6 +38,23 @@ func _on_FillInside_toggled(button_pressed):
 	save_config()
 
 
+func _on_SpacingMode_toggled(button_pressed):
+	# This acts as an interface to access the intrinsic spacing_mode feature
+	# BaseTool holds the spacing system but for a tool to access them i recommend we do it in
+	# their own script
+	_spacing_mode = button_pressed
+	update_config()
+	save_config()
+
+
+func _on_SpacingX_value_changed(value):
+	_spacing.x = value
+
+
+func _on_SpacingY_value_changed(value):
+	_spacing.y = value
+
+
 func _input(event: InputEvent) -> void:
 	var overwrite_button: CheckBox = $Overwrite
 
@@ -54,6 +72,8 @@ func get_config() -> Dictionary:
 	var config := .get_config()
 	config["overwrite"] = _overwrite
 	config["fill_inside"] = _fill_inside
+	config["spacing_mode"] = _spacing_mode
+	config["spacing"] = _spacing
 	return config
 
 
@@ -61,15 +81,22 @@ func set_config(config: Dictionary) -> void:
 	.set_config(config)
 	_overwrite = config.get("overwrite", _overwrite)
 	_fill_inside = config.get("fill_inside", _fill_inside)
+	_spacing_mode = config.get("spacing_mode", _spacing_mode)
+	_spacing = config.get("spacing", _spacing)
 
 
 func update_config() -> void:
 	.update_config()
 	$Overwrite.pressed = _overwrite
 	$FillInside.pressed = _fill_inside
+	$SpacingMode.pressed = _spacing_mode
+	$StrokeGap.visible = _spacing_mode
+	$StrokeGap/SpacingX.value = _spacing.x
+	$StrokeGap/SpacingY.value = _spacing.y
 
 
 func draw_start(position: Vector2) -> void:
+	_old_spacing_mode = _spacing_mode
 	position = snap_position(position)
 	.draw_start(position)
 	if Input.is_action_pressed("draw_color_picker"):
@@ -93,6 +120,7 @@ func draw_start(position: Vector2) -> void:
 
 	_draw_line = Input.is_action_pressed("draw_create_line")
 	if _draw_line:
+		_spacing_mode = false  # spacing mode is disabled during line mode
 		_line_start = position
 		_line_end = position
 		update_line_polylines(_line_start, _line_end)
@@ -114,6 +142,7 @@ func draw_move(position: Vector2) -> void:
 		return
 
 	if _draw_line:
+		_spacing_mode = false  # spacing mode is disabled during line mode
 		var d := _line_angle_constraint(_line_start, position)
 		_line_end = d.position
 		cursor_text = d.text
@@ -134,6 +163,7 @@ func draw_end(position: Vector2) -> void:
 		return
 
 	if _draw_line:
+		_spacing_mode = false  # spacing mode is disabled during line mode
 		draw_tool(_line_start)
 		draw_fill_gap(_line_start, _line_end)
 		_draw_line = false
@@ -148,11 +178,16 @@ func draw_end(position: Vector2) -> void:
 					for y in image_size.y:
 						v.y = y
 						if Geometry.is_point_in_polygon(v, _draw_points):
+							if _spacing_mode:
+								# use of get_spacing_position() in Pencil.gd is a rare case
+								# (you would ONLY need _spacing_mode and _spacing in most cases)
+								v = get_spacing_position(v)
 							draw_tool(v)
 
 	commit_undo()
 	cursor_text = ""
 	update_random_image()
+	_spacing_mode = _old_spacing_mode
 
 
 func _draw_brush_image(image: Image, src_rect: Rect2, dst: Vector2) -> void:

src/Tools/Pencil.tscn

@@ -9,6 +9,9 @@ script = ExtResource( 3 )
 [node name="ColorRect" parent="." index="0"]
 margin_right = 128.0
 
+[node name="Label" parent="." index="1"]
+margin_right = 128.0
+
 [node name="Brush" parent="." index="2"]
 margin_right = 128.0
 
@@ -36,10 +39,24 @@ margin_top = 90.0
 margin_right = 128.0
 margin_bottom = 114.0
 mouse_default_cursor_shape = 2
-text = "Fill inside"
+text = "Fill Inside"
 __meta__ = {
 "_editor_description_": ""
 }
 
+[node name="SpacingMode" parent="." index="6"]
+visible = true
+margin_top = 118.0
+margin_right = 128.0
+margin_bottom = 142.0
+
+[node name="StrokeGap" parent="." index="7"]
+margin_top = 146.0
+margin_right = 128.0
+margin_bottom = 198.0
+
 [connection signal="toggled" from="Overwrite" to="." method="_on_Overwrite_toggled"]
 [connection signal="toggled" from="FillInside" to="." method="_on_FillInside_toggled"]
+[connection signal="toggled" from="SpacingMode" to="." method="_on_SpacingMode_toggled"]
+[connection signal="value_changed" from="StrokeGap/SpacingX" to="." method="_on_SpacingX_value_changed"]
+[connection signal="value_changed" from="StrokeGap/SpacingY" to="." method="_on_SpacingY_value_changed"]