Add a Gradient Map image effect, implements the second half of #595

The gradient edit code was taken and modified from Material Maker, MIT license.

project.godot

@@ -44,6 +44,11 @@ _global_script_classes=[ {
 "language": "GDScript",
 "path": "res://src/Classes/Frame.gd"
 }, {
+"base": "TextureRect",
+"class": "GradientEditNode",
+"language": "GDScript",
+"path": "res://src/UI/Nodes/GradientEdit.gd"
+}, {
 "base": "Line2D",
 "class": "Guide",
 "language": "GDScript",
@@ -127,6 +132,7 @@ _global_script_class_icons={
 "Cel": "",
 "Drawer": "",
 "Frame": "",
+"GradientEditNode": "",
 "Guide": "",
 "ImageEffect": "",
 "Layer": "",
@@ -830,6 +836,10 @@ about_pixelorama={
 "deadzone": 0.5,
 "events": [  ]
 }
+gradient_map={
+"deadzone": 0.5,
+"events": [  ]
+}
 
 [locale]
 

src/Autoload/Global.gd

@@ -33,6 +33,7 @@ enum ImageMenu {
 	DROP_SHADOW,
 	HSV,
 	GRADIENT,
+	GRADIENT_MAP,
 	SHADER
 }
 enum SelectMenu { SELECT_ALL, CLEAR_SELECTION, INVERT }
@@ -281,6 +282,8 @@ func _initialize_keychain() -> void:
 		Keychain.MenuInputAction.new("", "Image menu", true, "ImageMenu", ImageMenu.HSV),
 		"gradient":
 		Keychain.MenuInputAction.new("", "Image menu", true, "ImageMenu", ImageMenu.GRADIENT),
+		"gradient_map":
+		Keychain.MenuInputAction.new("", "Image menu", true, "ImageMenu", ImageMenu.GRADIENT_MAP),
 		"mirror_view":
 		Keychain.MenuInputAction.new("", "View menu", true, "ViewMenu", ViewMenu.MIRROR_VIEW),
 		"show_grid":

src/Shaders/GradientMap.gdshader

@@ -0,0 +1,16 @@
+shader_type canvas_item;
+
+uniform sampler2D map;  // GradientTexture
+uniform sampler2D selection;
+
+void fragment() {
+	vec4 original_color = texture(TEXTURE, UV);
+	vec4 selection_color = texture(selection, UV);
+	vec4 output = original_color;
+	float value = (0.2126 * original_color.r) + (0.7152 * original_color.g) + (0.0722 * original_color.b);
+	vec4 gradient_color = texture(map, vec2(value, 0.0));
+	output.rgb = gradient_color.rgb;
+	output.a *= gradient_color.a;
+
+	COLOR = mix(original_color, output, selection_color.a);
+}

src/UI/Dialogs/ImageEffects/GradientMapDialog.gd

@@ -0,0 +1,49 @@
+extends ImageEffect
+
+var shader: Shader = preload("res://src/Shaders/GradientMap.gdshader")
+var confirmed := false
+
+
+# Called when the node enters the scene tree for the first time.
+func _ready() -> void:
+	var sm := ShaderMaterial.new()
+	sm.shader = shader
+	preview.set_material(sm)
+
+
+func set_nodes() -> void:
+	preview = $VBoxContainer/AspectRatioContainer/Preview
+	selection_checkbox = $VBoxContainer/OptionsContainer/SelectionCheckBox
+	affect_option_button = $VBoxContainer/OptionsContainer/AffectOptionButton
+
+
+func _about_to_show() -> void:
+	confirmed = false
+	._about_to_show()
+
+
+func _confirmed() -> void:
+	confirmed = true
+	._confirmed()
+
+
+func commit_action(cel: Image, project: Project = Global.current_project) -> void:
+	var selection_tex := ImageTexture.new()
+	if selection_checkbox.pressed and project.has_selection:
+		var selection: Image = project.bitmap_to_image(project.selection_bitmap)
+		selection_tex.create_from_image(selection, 0)
+
+	var params := {"selection": selection_tex, "map": $VBoxContainer/GradientEdit.texture}
+
+	if !confirmed:
+		preview.material.shader = shader
+		for param in params:
+			preview.material.set_shader_param(param, params[param])
+	else:
+		var gen := ShaderImageEffect.new()
+		gen.generate_image(cel, shader, params, project.size)
+		yield(gen, "done")
+
+
+func _on_GradientEdit_updated(_gradient, _cc) -> void:
+	update_preview()

src/UI/Dialogs/ImageEffects/GradientMapDialog.tscn

@@ -0,0 +1,77 @@
+[gd_scene load_steps=4 format=2]
+
+[ext_resource path="res://src/UI/TransparentChecker.tscn" type="PackedScene" id=1]
+[ext_resource path="res://src/UI/Nodes/GradientEdit.tscn" type="PackedScene" id=2]
+[ext_resource path="res://src/UI/Dialogs/ImageEffects/GradientMapDialog.gd" type="Script" id=3]
+
+[node name="GradientMapDialog" type="ConfirmationDialog"]
+margin_right = 200.0
+margin_bottom = 70.0
+window_title = "Gradient Map"
+resizable = true
+script = ExtResource( 3 )
+
+[node name="VBoxContainer" type="VBoxContainer" parent="."]
+anchor_right = 1.0
+anchor_bottom = 1.0
+margin_left = 8.0
+margin_top = 8.0
+margin_right = -8.0
+margin_bottom = -36.0
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="AspectRatioContainer" type="AspectRatioContainer" parent="VBoxContainer"]
+margin_right = 278.0
+margin_bottom = 200.0
+size_flags_vertical = 3
+
+[node name="Preview" type="TextureRect" parent="VBoxContainer/AspectRatioContainer"]
+margin_left = 39.0
+margin_right = 239.0
+margin_bottom = 200.0
+rect_min_size = Vector2( 200, 200 )
+size_flags_horizontal = 5
+size_flags_vertical = 3
+expand = true
+stretch_mode = 5
+
+[node name="TransparentChecker" parent="VBoxContainer/AspectRatioContainer/Preview" instance=ExtResource( 1 )]
+show_behind_parent = true
+anchor_right = 1.0
+anchor_bottom = 1.0
+margin_right = 0.0
+margin_bottom = 0.0
+
+[node name="GradientEdit" parent="VBoxContainer" instance=ExtResource( 2 )]
+anchor_right = 0.0
+anchor_bottom = 0.0
+margin_top = 204.0
+margin_right = 278.0
+margin_bottom = 234.0
+rect_min_size = Vector2( 0, 30 )
+
+[node name="OptionsContainer" type="GridContainer" parent="VBoxContainer"]
+margin_top = 238.0
+margin_right = 278.0
+margin_bottom = 262.0
+columns = 2
+
+[node name="SelectionCheckBox" type="CheckBox" parent="VBoxContainer/OptionsContainer" groups=["gradient_common"]]
+margin_right = 160.0
+margin_bottom = 24.0
+mouse_default_cursor_shape = 2
+pressed = true
+text = "Only affect selection"
+
+[node name="AffectOptionButton" type="OptionButton" parent="VBoxContainer/OptionsContainer" groups=["gradient_common"]]
+margin_left = 164.0
+margin_right = 278.0
+margin_bottom = 24.0
+mouse_default_cursor_shape = 2
+text = "Selected cels"
+items = [ "Selected cels", null, false, 0, null, "Current frame", null, false, 1, null, "All frames", null, false, 2, null, "All projects", null, false, 3, null ]
+selected = 0
+
+[connection signal="updated" from="VBoxContainer/GradientEdit" to="." method="_on_GradientEdit_updated"]

src/UI/Dialogs/ImageEffects/ImageEffects.tscn

@@ -1,9 +1,10 @@
-[gd_scene load_steps=12 format=2]
+[gd_scene load_steps=13 format=2]
 
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/FlipImageDialog.tscn" type="PackedScene" id=1]
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/InvertColorsDialog.tscn" type="PackedScene" id=2]
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/DesaturateDialog.tscn" type="PackedScene" id=3]
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/DropShadowDialog.tscn" type="PackedScene" id=4]
+[ext_resource path="res://src/UI/Dialogs/ImageEffects/GradientMapDialog.tscn" type="PackedScene" id=5]
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/ResizeCanvas.tscn" type="PackedScene" id=8]
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/RotateImage.tscn" type="PackedScene" id=9]
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/ShaderEffect.tscn" type="PackedScene" id=10]
@@ -14,9 +15,6 @@
 
 [node name="ImageEffects" type="Control"]
 mouse_filter = 2
-__meta__ = {
-"_edit_use_anchors_": false
-}
 
 [node name="ScaleImage" parent="." instance=ExtResource( 14 )]
 margin_bottom = 127.0
@@ -44,4 +42,6 @@ margin_bottom = 106.0
 [node name="GradientDialog" parent="." instance=ExtResource( 12 )]
 margin_bottom = 214.0
 
+[node name="GradientMapDialog" parent="." instance=ExtResource( 5 )]
+
 [node name="ShaderEffect" parent="." instance=ExtResource( 10 )]

src/UI/Nodes/GradientEdit.gd

@@ -0,0 +1,162 @@
+# Code taken and modified from Material Maker, licensed under MIT
+# gdlint: ignore=max-line-length
+# https://github.com/RodZill4/material-maker/blob/master/material_maker/widgets/gradient_editor/gradient_editor.gd
+class_name GradientEditNode
+extends TextureRect
+
+signal updated(gradient, cc)
+
+var continuous_change := true
+var active_cursor: GradientCursor  # Showing a color picker popup to change a cursor's color
+
+onready var x_offset: float = rect_size.x - GradientCursor.WIDTH
+onready var gradient: Gradient = texture.gradient
+
+
+class GradientCursor:
+	extends Control
+
+	const WIDTH := 10
+	var color: Color
+	var sliding := false
+	onready var label: Label = get_parent().get_node("Value")
+
+	func _ready() -> void:
+		rect_position = Vector2(0, 15)
+		rect_size = Vector2(WIDTH, 15)
+
+	func _draw() -> void:
+# warning-ignore:integer_division
+		var polygon := PoolVector2Array(
+			[
+				Vector2(0, 5),
+				Vector2(WIDTH / 2, 0),
+				Vector2(WIDTH, 5),
+				Vector2(WIDTH, 15),
+				Vector2(0, 15),
+				Vector2(0, 5)
+			]
+		)
+		var c := color
+		c.a = 1.0
+		draw_colored_polygon(polygon, c)
+		draw_polyline(polygon, Color(0.0, 0.0, 0.0) if color.v > 0.5 else Color(1.0, 1.0, 1.0))
+
+	func _gui_input(ev: InputEvent) -> void:
+		if ev is InputEventMouseButton:
+			if ev.button_index == BUTTON_LEFT:
+				if ev.doubleclick:
+					get_parent().select_color(self, ev.global_position)
+				elif ev.pressed:
+					get_parent().continuous_change = false
+					sliding = true
+					label.visible = true
+					label.text = "%.03f" % get_cursor_position()
+				else:
+					sliding = false
+					label.visible = false
+			elif ev.button_index == BUTTON_RIGHT and get_parent().get_sorted_cursors().size() > 2:
+				var parent = get_parent()
+				parent.remove_child(self)
+				parent.continuous_change = false
+				parent.update_from_value()
+				queue_free()
+		elif ev is InputEventMouseMotion and (ev.button_mask & BUTTON_MASK_LEFT) != 0 and sliding:
+			rect_position.x += get_local_mouse_position().x
+			if ev.control:
+				rect_position.x = (
+					round(get_cursor_position() * 20.0)
+					* 0.05
+					* (get_parent().rect_size.x - WIDTH)
+				)
+			rect_position.x = min(max(0, rect_position.x), get_parent().rect_size.x - rect_size.x)
+			get_parent().update_from_value()
+			label.text = "%.03f" % get_cursor_position()
+
+	func get_cursor_position() -> float:
+		return rect_position.x / (get_parent().rect_size.x - WIDTH)
+
+	func set_color(c: Color) -> void:
+		color = c
+		get_parent().update_from_value()
+		update()
+
+	static func sort(a, b) -> bool:
+		return a.get_position() < b.get_position()
+
+	func can_drop_data(_position, data) -> bool:
+		return typeof(data) == TYPE_COLOR
+
+	func drop_data(_position, data) -> void:
+		set_color(data)
+
+
+func _ready() -> void:
+	create_cursors()
+
+
+func create_cursors() -> void:
+	for c in get_children():
+		if c is GradientCursor:
+			remove_child(c)
+			c.queue_free()
+	for i in gradient.get_point_count():
+		var p: float = gradient.get_offset(i)
+		add_cursor(p * x_offset, gradient.get_color(i))
+
+
+func _gui_input(ev: InputEvent) -> void:
+	if ev.is_action_pressed("left_mouse"):
+		var p = clamp(ev.position.x, 0, x_offset)
+		add_cursor(p, get_gradient_color(p))
+		continuous_change = false
+		update_from_value()
+
+
+func update_from_value() -> void:
+	gradient.offsets = []
+	for c in get_children():
+		if c is GradientCursor:
+			var point: float = c.rect_position.x / x_offset
+			gradient.add_point(point, c.color)
+	emit_signal("updated", gradient, continuous_change)
+	continuous_change = true
+
+
+func add_cursor(x: float, color: Color) -> void:
+	var cursor := GradientCursor.new()
+	add_child(cursor)
+	cursor.rect_position.x = x
+	cursor.color = color
+
+
+func select_color(cursor: GradientCursor, position: Vector2) -> void:
+	active_cursor = cursor
+	var color_picker = $Popup.get_node("ColorPicker")
+	color_picker.color = cursor.color
+	$Popup.rect_position = position
+	$Popup.popup()
+
+
+func get_sorted_cursors() -> Array:
+	var array := []
+	for c in get_children():
+		if c is GradientCursor:
+			array.append(c)
+	array.sort_custom(GradientCursor, "sort")
+	return array
+
+
+func get_gradient_color(x: float) -> Color:
+	return gradient.interpolate(x / x_offset)
+
+
+func _on_ColorPicker_color_changed(color: Color) -> void:
+	active_cursor.set_color(color)
+
+
+func _on_GradientEdit_resized() -> void:
+	if not gradient:
+		return
+	x_offset = rect_size.x - GradientCursor.WIDTH
+	create_cursors()