Added basic gradient generation

A new option in the "Image" menu, gradient generation.

src/UI/Dialogs/GradientDialog.gd

@@ -0,0 +1,49 @@
+extends ConfirmationDialog
+
+
+var current_cel : Image
+var preview_image : Image
+var preview_texture : ImageTexture
+
+onready var preview : TextureRect = $VBoxContainer/Preview
+onready var color1 : ColorPickerButton = $VBoxContainer/ColorsContainer/ColorPickerButton
+onready var color2 : ColorPickerButton = $VBoxContainer/ColorsContainer/ColorPickerButton2
+onready var steps : SpinBox = $VBoxContainer/StepsContainer/StepSpinBox
+
+
+func _ready() -> void:
+	current_cel = Image.new()
+	preview_image = Image.new()
+	preview_texture = ImageTexture.new()
+	preview_texture.flags = 0
+
+
+func _on_GradientDialog_about_to_show() -> void:
+	current_cel = Global.current_project.frames[Global.current_project.current_frame].cels[Global.current_project.current_layer].image
+	update_preview()
+
+
+func update_preview() -> void:
+	preview_image.copy_from(current_cel)
+	DrawingAlgos.generate_gradient(preview_image, [color1.color, color2.color], steps.value)
+	preview_texture.create_from_image(preview_image, 0)
+	preview.texture = preview_texture
+
+
+func _on_ColorPickerButton_color_changed(_color : Color) -> void:
+	update_preview()
+
+
+func _on_ColorPickerButton2_color_changed(_color : Color) -> void:
+	update_preview()
+
+
+func _on_StepSpinBox_value_changed(_value : int) -> void:
+	update_preview()
+
+
+func _on_GradientDialog_confirmed() -> void:
+	Global.canvas.handle_undo("Draw")
+	DrawingAlgos.generate_gradient(current_cel, [color1.color, color2.color], steps.value)
+	Global.canvas.update_texture(Global.current_project.current_layer)
+	Global.canvas.handle_redo("Draw")

src/UI/Dialogs/GradientDialog.tscn

@@ -0,0 +1,83 @@
+[gd_scene load_steps=2 format=2]
+
+[ext_resource path="res://src/UI/Dialogs/GradientDialog.gd" type="Script" id=1]
+
+[node name="GradientDialog" type="ConfirmationDialog"]
+margin_right = 200.0
+margin_bottom = 196.0
+resizable = true
+script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[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="Preview" type="TextureRect" parent="VBoxContainer"]
+margin_right = 184.0
+margin_bottom = 100.0
+rect_min_size = Vector2( 0, 100 )
+expand = true
+stretch_mode = 6
+
+[node name="ColorsContainer" type="HBoxContainer" parent="VBoxContainer"]
+margin_top = 104.0
+margin_right = 184.0
+margin_bottom = 124.0
+
+[node name="Label" type="Label" parent="VBoxContainer/ColorsContainer"]
+margin_top = 3.0
+margin_right = 44.0
+margin_bottom = 17.0
+text = "Colors:"
+
+[node name="ColorPickerButton" type="ColorPickerButton" parent="VBoxContainer/ColorsContainer"]
+margin_left = 48.0
+margin_right = 68.0
+margin_bottom = 20.0
+rect_min_size = Vector2( 20, 0 )
+mouse_default_cursor_shape = 2
+
+[node name="ColorPickerButton2" type="ColorPickerButton" parent="VBoxContainer/ColorsContainer"]
+margin_left = 72.0
+margin_right = 92.0
+margin_bottom = 20.0
+rect_min_size = Vector2( 20, 0 )
+mouse_default_cursor_shape = 2
+color = Color( 1, 1, 1, 1 )
+
+[node name="StepsContainer" type="HBoxContainer" parent="VBoxContainer"]
+margin_top = 128.0
+margin_right = 184.0
+margin_bottom = 152.0
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="Label" type="Label" parent="VBoxContainer/StepsContainer"]
+margin_top = 5.0
+margin_right = 39.0
+margin_bottom = 19.0
+text = "Steps:"
+
+[node name="StepSpinBox" type="SpinBox" parent="VBoxContainer/StepsContainer"]
+margin_left = 43.0
+margin_right = 117.0
+margin_bottom = 24.0
+mouse_default_cursor_shape = 2
+min_value = 2.0
+value = 2.0
+[connection signal="about_to_show" from="." to="." method="_on_GradientDialog_about_to_show"]
+[connection signal="confirmed" from="." to="." method="_on_GradientDialog_confirmed"]
+[connection signal="color_changed" from="VBoxContainer/ColorsContainer/ColorPickerButton" to="." method="_on_ColorPickerButton_color_changed"]
+[connection signal="color_changed" from="VBoxContainer/ColorsContainer/ColorPickerButton2" to="." method="_on_ColorPickerButton2_color_changed"]
+[connection signal="value_changed" from="VBoxContainer/StepsContainer/StepSpinBox" to="." method="_on_StepSpinBox_value_changed"]

src/UI/Dialogs/HSVDialog.tscn

@@ -2,8 +2,6 @@
 
 [ext_resource path="res://src/UI/Dialogs/HSVDialog.gd" type="Script" id=1]
 
-
-
 [node name="HSVDialog" type="WindowDialog"]
 margin_left = 1.0
 margin_top = -1.0

src/UI/TopMenuContainer.gd

@@ -92,7 +92,8 @@ func setup_image_menu() -> void:
 		"Invert Colors" : 0,
 		"Desaturation" : 0,
 		"Outline" : 0,
-		"Adjust Hue/Saturation/Value" : 0
+		"Adjust Hue/Saturation/Value" : 0,
+		"Gradient" : 0
 		}
 	var image_menu : PopupMenu = Global.image_menu.get_popup()
 
@@ -321,6 +322,9 @@ func image_menu_id_pressed(id : int) -> void:
 
 		9: # HSV
 			show_hsv_configuration_popup()
+		10: # Gradient
+			Global.control.get_node("Dialogs/GradientDialog").popup_centered()
+			Global.dialog_open(true)
 
 
 func show_scale_image_popup() -> void: