Added dialog with options for desaturation

Not sure if options for RGBA channels are really needed here, but I kept them from invert colors. We could remove them in the future if they are unneeded.

src/Autoload/DrawingAlgos.gd

@@ -310,17 +310,21 @@ func invert_image_colors(image : Image, pixels : Array, red := true, green := tr
 		image.set_pixelv(i, px_color)
 
 
-func desaturate_image(image : Image) -> void:
-	Global.canvas.handle_undo("Draw")
-	for xx in image.get_size().x:
-		for yy in image.get_size().y:
-			var px_color = image.get_pixel(xx, yy)
-			if px_color.a == 0:
-				continue
-			var gray = image.get_pixel(xx, yy).v
-			px_color = Color(gray, gray, gray, px_color.a)
-			image.set_pixel(xx, yy, px_color)
-	Global.canvas.handle_redo("Draw")
+func desaturate_image(image : Image, pixels : Array, red := true, green := true, blue := true, alpha := false) -> void:
+	image.lock()
+	for i in pixels:
+		var px_color := image.get_pixelv(i)
+		var gray = px_color.v
+		if red:
+			px_color.r = gray
+		if green:
+			px_color.g = gray
+		if blue:
+			px_color.b = gray
+		if alpha:
+			px_color.a = gray
+
+		image.set_pixelv(i, px_color)
 
 
 func generate_outline(image : Image, pixels : Array, outline_color : Color, thickness : int, diagonal : bool, inside_image : bool) -> void:

src/UI/Dialogs/ImageEffects/DesaturateDialog.gd

@@ -0,0 +1,112 @@
+extends ConfirmationDialog
+
+
+enum {CEL, FRAME, ALL_FRAMES, ALL_PROJECTS}
+
+var affect : int = CEL
+var pixels := []
+var current_cel : Image
+var preview_image : Image
+var preview_texture : ImageTexture
+
+var red := true
+var green := true
+var blue := true
+var alpha := false
+
+onready var preview : TextureRect = $VBoxContainer/Preview
+onready var selection_checkbox = $VBoxContainer/OptionsContainer/SelectionCheckBox
+
+
+func _ready() -> void:
+	current_cel = Image.new()
+	preview_image = Image.new()
+	preview_texture = ImageTexture.new()
+
+
+func _on_FlipImageDialog_about_to_show() -> void:
+	current_cel = Global.current_project.frames[Global.current_project.current_frame].cels[Global.current_project.current_layer].image
+	_on_SelectionCheckBox_toggled(selection_checkbox.pressed)
+
+
+func _on_FlipImageDialog_confirmed() -> void:
+	if affect == CEL:
+		Global.canvas.handle_undo("Draw")
+		DrawingAlgos.desaturate_image(current_cel, pixels, red, green, blue, alpha)
+		Global.canvas.handle_redo("Draw")
+	elif affect == FRAME:
+		Global.canvas.handle_undo("Draw", Global.current_project, -1)
+		for cel in Global.current_project.frames[Global.current_project.current_frame].cels:
+			DrawingAlgos.desaturate_image(cel.image, pixels, red, green, blue, alpha)
+		Global.canvas.handle_redo("Draw", Global.current_project, -1)
+
+	elif affect == ALL_FRAMES:
+		Global.canvas.handle_undo("Draw", Global.current_project, -1, -1)
+		for frame in Global.current_project.frames:
+			for cel in frame.cels:
+				DrawingAlgos.desaturate_image(cel.image, pixels, red, green, blue, alpha)
+		Global.canvas.handle_redo("Draw", Global.current_project, -1, -1)
+
+	elif affect == ALL_PROJECTS:
+		for project in Global.projects:
+			var _pixels := []
+			if selection_checkbox.pressed:
+				_pixels = project.selected_pixels.duplicate()
+			else:
+				for x in project.size.x:
+					for y in project.size.y:
+						_pixels.append(Vector2(x, y))
+
+			Global.canvas.handle_undo("Draw", project, -1, -1)
+			for frame in project.frames:
+				for cel in frame.cels:
+					DrawingAlgos.desaturate_image(cel.image, _pixels, red, green, blue, alpha)
+			Global.canvas.handle_redo("Draw", project, -1, -1)
+
+
+func _on_RButton_toggled(button_pressed : bool) -> void:
+	red = button_pressed
+	update_preview()
+
+
+func _on_GButton_toggled(button_pressed : bool) -> void:
+	green = button_pressed
+	update_preview()
+
+
+func _on_BButton_toggled(button_pressed : bool) -> void:
+	blue = button_pressed
+	update_preview()
+
+
+func _on_AButton_toggled(button_pressed : bool) -> void:
+	alpha = button_pressed
+	update_preview()
+
+
+func _on_SelectionCheckBox_toggled(button_pressed : bool) -> void:
+	pixels.clear()
+	if button_pressed:
+		pixels = Global.current_project.selected_pixels.duplicate()
+	else:
+		for x in Global.current_project.size.x:
+			for y in Global.current_project.size.y:
+				pixels.append(Vector2(x, y))
+
+	update_preview()
+
+
+func _on_AffectOptionButton_item_selected(index : int) -> void:
+	affect = index
+
+
+func update_preview() -> void:
+	preview_image.copy_from(current_cel)
+	DrawingAlgos.desaturate_image(preview_image, pixels, red, green, blue, alpha)
+	preview_image.unlock()
+	preview_texture.create_from_image(preview_image, 0)
+	preview.texture = preview_texture
+
+
+func _on_FlipImageDialog_popup_hide() -> void:
+	Global.dialog_open(false)

src/UI/Dialogs/ImageEffects/DesaturateDialog.tscn

@@ -0,0 +1,101 @@
+[gd_scene load_steps=2 format=2]
+
+[ext_resource path="res://src/UI/Dialogs/ImageEffects/DesaturateDialog.gd" type="Script" id=1]
+
+[node name="DesaturateDialog" type="ConfirmationDialog"]
+margin_right = 200.0
+margin_bottom = 70.0
+window_title = "Desaturation"
+resizable = true
+script = ExtResource( 1 )
+
+[node name="VBoxContainer" type="VBoxContainer" parent="."]
+margin_left = 8.0
+margin_top = 8.0
+margin_right = 271.0
+margin_bottom = 260.0
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="Preview" type="TextureRect" parent="VBoxContainer"]
+margin_right = 263.0
+margin_bottom = 200.0
+rect_min_size = Vector2( 200, 200 )
+expand = true
+stretch_mode = 6
+
+[node name="RGBAContainer" type="HBoxContainer" parent="VBoxContainer"]
+margin_top = 204.0
+margin_right = 263.0
+margin_bottom = 224.0
+alignment = 1
+
+[node name="RButton" type="Button" parent="VBoxContainer/RGBAContainer"]
+margin_left = 83.0
+margin_right = 103.0
+margin_bottom = 20.0
+hint_tooltip = "Modify Red Channel"
+mouse_default_cursor_shape = 2
+toggle_mode = true
+pressed = true
+text = "R"
+
+[node name="GButton" type="Button" parent="VBoxContainer/RGBAContainer"]
+margin_left = 107.0
+margin_right = 129.0
+margin_bottom = 20.0
+hint_tooltip = "Modify Green Channel"
+mouse_default_cursor_shape = 2
+toggle_mode = true
+pressed = true
+text = "G"
+
+[node name="BButton" type="Button" parent="VBoxContainer/RGBAContainer"]
+margin_left = 133.0
+margin_right = 154.0
+margin_bottom = 20.0
+hint_tooltip = "Modify Blue Channel"
+mouse_default_cursor_shape = 2
+toggle_mode = true
+pressed = true
+text = "B"
+
+[node name="AButton" type="Button" parent="VBoxContainer/RGBAContainer"]
+margin_left = 158.0
+margin_right = 179.0
+margin_bottom = 20.0
+hint_tooltip = "Modify Alpha Channel"
+mouse_default_cursor_shape = 2
+toggle_mode = true
+text = "A"
+
+[node name="OptionsContainer" type="HBoxContainer" parent="VBoxContainer"]
+margin_top = 228.0
+margin_right = 263.0
+margin_bottom = 252.0
+
+[node name="SelectionCheckBox" type="CheckBox" parent="VBoxContainer/OptionsContainer"]
+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"]
+margin_left = 164.0
+margin_right = 263.0
+margin_bottom = 24.0
+mouse_default_cursor_shape = 2
+text = "Current cel"
+items = [ "Current cel", 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="about_to_show" from="." to="." method="_on_FlipImageDialog_about_to_show"]
+[connection signal="confirmed" from="." to="." method="_on_FlipImageDialog_confirmed"]
+[connection signal="popup_hide" from="." to="." method="_on_FlipImageDialog_popup_hide"]
+[connection signal="toggled" from="VBoxContainer/RGBAContainer/RButton" to="." method="_on_RButton_toggled"]
+[connection signal="toggled" from="VBoxContainer/RGBAContainer/GButton" to="." method="_on_GButton_toggled"]
+[connection signal="toggled" from="VBoxContainer/RGBAContainer/BButton" to="." method="_on_BButton_toggled"]
+[connection signal="toggled" from="VBoxContainer/RGBAContainer/AButton" to="." method="_on_AButton_toggled"]
+[connection signal="toggled" from="VBoxContainer/OptionsContainer/SelectionCheckBox" to="." method="_on_SelectionCheckBox_toggled"]
+[connection signal="item_selected" from="VBoxContainer/OptionsContainer/AffectOptionButton" to="." method="_on_AffectOptionButton_item_selected"]

src/UI/Dialogs/ImageEffects/ImageEffects.tscn

@@ -1,7 +1,8 @@
-[gd_scene load_steps=10 format=2]
+[gd_scene load_steps=11 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/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]
@@ -31,6 +32,8 @@ margin_bottom = 300.0
 
 [node name="InvertColorsDialog" parent="." instance=ExtResource( 2 )]
 
+[node name="DesaturateDialog" parent="." instance=ExtResource( 3 )]
+
 [node name="OutlineDialog" parent="." instance=ExtResource( 13 )]
 margin_right = 217.0
 margin_bottom = 106.0

src/UI/Dialogs/ImageEffects/InvertColorsDialog.tscn

@@ -5,6 +5,8 @@
 [node name="InvertColorsDialog" type="ConfirmationDialog"]
 margin_right = 200.0
 margin_bottom = 70.0
+window_title = "Invert Colors"
+resizable = true
 script = ExtResource( 1 )
 
 [node name="VBoxContainer" type="VBoxContainer" parent="."]

src/UI/TopMenuContainer.gd

@@ -322,7 +322,8 @@ func image_menu_id_pressed(id : int) -> void:
 			Global.dialog_open(true)
 
 		6: # Desaturation
-			DrawingAlgos.desaturate_image(image)
+			Global.control.get_node("Dialogs/ImageEffects/DesaturateDialog").popup_centered()
+			Global.dialog_open(true)
 
 		7: # Outline
 			show_add_outline_popup()