Add Drop Shadow (#674)

src/Shaders/DropShadow.tres

@@ -0,0 +1,20 @@
+[gd_resource type="Shader" format=2]
+
+[resource]
+code = "shader_type canvas_item;
+
+uniform vec2 shadow_offset; // Offset, in pixel coordinate [0, 1, 2, and so on]
+uniform vec4 shadow_color;
+uniform sampler2D selection;
+
+
+void fragment() {
+	vec2 offset = shadow_offset * TEXTURE_PIXEL_SIZE; // Normalize shadow_offset to [0..1]
+	vec4 original = texture(TEXTURE, UV); // Original texture
+	float shadow = texture(TEXTURE, UV - offset).a; // Shadow, alpha only
+	shadow *= shadow_color.a; // Multiply this mask by shadow alpha
+	shadow = mix(0.0, shadow, texture(selection, UV).a); // Clip shadow by selection mask
+	
+	COLOR.rgb = mix(shadow_color.rgb, original.rgb, original.a); // Set background color
+	COLOR.a = mix(original.a, 1.0, shadow); // Combine alpha
+}"

src/UI/Dialogs/ImageEffects/DropShadowDialog.gd

@@ -0,0 +1,73 @@
+extends ImageEffect
+
+var offset := Vector2(5, 5)
+var color := Color.black
+var confirmed := false
+var shader: Shader = load("res://src/Shaders/DropShadow.tres")
+
+onready var x_spinbox: SpinBox = $VBoxContainer/OptionsContainer/XSpinBox
+onready var y_spinbox: SpinBox = $VBoxContainer/OptionsContainer/YSpinBox
+onready var shadow_color = $VBoxContainer/OptionsContainer/ShadowColor
+
+
+func _ready() -> void:
+	shadow_color.get_picker().presets_visible = false
+	color = shadow_color.color
+
+
+func _about_to_show() -> void:
+	confirmed = false
+	var sm := ShaderMaterial.new()
+	sm.shader = shader
+	preview.set_material(sm)
+	._about_to_show()
+
+
+func _confirmed() -> void:
+	confirmed = true
+	._confirmed()
+
+
+func set_nodes() -> void:
+	preview = $VBoxContainer/AspectRatioContainer/Preview
+	selection_checkbox = $VBoxContainer/OptionsContainer/SelectionCheckBox
+
+
+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)
+
+	if !confirmed:
+		preview.material.set_shader_param("shadow_offset", offset)
+		preview.material.set_shader_param("shadow_color", color)
+		preview.material.set_shader_param("selection", selection_tex)
+	else:
+		var params := {
+			"shadow_offset": offset,
+			"shadow_color": color,
+			"selection": selection_tex,
+		}
+		var gen := ShaderImageEffect.new()
+		gen.generate_image(cel, shader, params, project.size)
+		yield(gen, "done")
+
+
+func _on_XSpinBox_value_changed(value) -> void:
+	x_spinbox.max_value = value + 1
+	x_spinbox.min_value = value - 1
+	offset.x = value
+	update_preview()
+
+
+func _on_YSpinBox_value_changed(value) -> void:
+	y_spinbox.max_value = value + 1
+	y_spinbox.min_value = value - 1
+	offset.y = value
+	update_preview()
+
+
+func _on_OutlineColor_color_changed(_color: Color) -> void:
+	color = _color
+	update_preview()

src/UI/Dialogs/ImageEffects/DropShadowDialog.tscn

@@ -0,0 +1,120 @@
+[gd_scene load_steps=3 format=2]
+
+[ext_resource path="res://src/UI/TransparentChecker.tscn" type="PackedScene" id=1]
+[ext_resource path="res://src/UI/Dialogs/ImageEffects/DropShadowDialog.gd" type="Script" id=2]
+
+[node name="DropShadowDialog" type="ConfirmationDialog"]
+margin_right = 294.0
+margin_bottom = 352.0
+rect_min_size = Vector2( 172, 60.2 )
+window_title = "Drop Shadow"
+resizable = true
+script = ExtResource( 2 )
+
+[node name="VBoxContainer" type="VBoxContainer" parent="."]
+margin_left = 8.0
+margin_top = 8.0
+margin_right = 286.0
+margin_bottom = 316.0
+
+[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 )
+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="OptionsContainer" type="GridContainer" parent="VBoxContainer"]
+margin_top = 204.0
+margin_right = 278.0
+margin_bottom = 308.0
+custom_constants/vseparation = 4
+custom_constants/hseparation = 4
+columns = 2
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="XLabel" type="Label" parent="VBoxContainer/OptionsContainer"]
+margin_top = 5.0
+margin_right = 160.0
+margin_bottom = 19.0
+text = "Offset X:"
+
+[node name="XSpinBox" type="SpinBox" parent="VBoxContainer/OptionsContainer"]
+margin_left = 164.0
+margin_right = 278.0
+margin_bottom = 24.0
+mouse_default_cursor_shape = 2
+max_value = 5.0
+value = 5.0
+allow_greater = true
+allow_lesser = true
+suffix = "px"
+
+[node name="YLabel" type="Label" parent="VBoxContainer/OptionsContainer"]
+margin_top = 33.0
+margin_right = 160.0
+margin_bottom = 47.0
+text = "Offset Y:"
+
+[node name="YSpinBox" type="SpinBox" parent="VBoxContainer/OptionsContainer"]
+margin_left = 164.0
+margin_top = 28.0
+margin_right = 278.0
+margin_bottom = 52.0
+mouse_default_cursor_shape = 2
+max_value = 5.0
+value = 5.0
+allow_greater = true
+allow_lesser = true
+suffix = "px"
+
+[node name="ShadowColorLabel" type="Label" parent="VBoxContainer/OptionsContainer"]
+margin_top = 59.0
+margin_right = 160.0
+margin_bottom = 73.0
+text = "Shadow Color"
+
+[node name="ShadowColor" type="ColorPickerButton" parent="VBoxContainer/OptionsContainer"]
+margin_left = 164.0
+margin_top = 56.0
+margin_right = 278.0
+margin_bottom = 76.0
+rect_min_size = Vector2( 64, 20 )
+color = Color( 0.0823529, 0.0823529, 0.0823529, 0.627451 )
+
+[node name="SelectionCheckBox" type="CheckBox" parent="VBoxContainer/OptionsContainer"]
+margin_top = 80.0
+margin_right = 160.0
+margin_bottom = 104.0
+mouse_default_cursor_shape = 2
+pressed = true
+text = "Only affect selection"
+
+[node name="AffectOptionButton" type="OptionButton" parent="VBoxContainer/OptionsContainer"]
+margin_left = 164.0
+margin_top = 80.0
+margin_right = 278.0
+margin_bottom = 104.0
+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="value_changed" from="VBoxContainer/OptionsContainer/XSpinBox" to="." method="_on_XSpinBox_value_changed"]
+[connection signal="value_changed" from="VBoxContainer/OptionsContainer/YSpinBox" to="." method="_on_YSpinBox_value_changed"]
+[connection signal="color_changed" from="VBoxContainer/OptionsContainer/ShadowColor" to="." method="_on_OutlineColor_color_changed"]

src/UI/Dialogs/ImageEffects/ImageEffects.tscn

@@ -1,8 +1,9 @@
-[gd_scene load_steps=11 format=2]
+[gd_scene load_steps=12 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/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]
@@ -33,9 +34,12 @@ margin_bottom = 392.0
 [node name="DesaturateDialog" parent="." instance=ExtResource( 3 )]
 
 [node name="OutlineDialog" parent="." instance=ExtResource( 13 )]
+visible = false
 margin_right = 217.0
 margin_bottom = 106.0
 
+[node name="DropShadowDialog" parent="." instance=ExtResource( 4 )]
+
 [node name="HSVDialog" parent="." instance=ExtResource( 11 )]
 
 [node name="GradientDialog" parent="." instance=ExtResource( 12 )]

src/UI/TopMenuContainer.gd

@@ -22,6 +22,7 @@ enum ImageMenuId {
 	INVERT_COLORS,
 	DESATURATION,
 	OUTLINE,
+	DROP_SHADOW,
 	HSV,
 	GRADIENT,
 	SHADER
@@ -273,6 +274,7 @@ func _setup_image_menu() -> void:
 		"Invert Colors": 0,
 		"Desaturation": 0,
 		"Outline": 0,
+		"Drop Shadow": 0,
 		"Adjust Hue/Saturation/Value": 0,
 		"Gradient": 0,
 		# "Shader": 0
@@ -636,6 +638,9 @@ func image_menu_id_pressed(id: int) -> void:
 		ImageMenuId.OUTLINE:
 			_show_add_outline_popup()
 
+		ImageMenuId.DROP_SHADOW:
+			_show_drop_shadow_popup()
+
 		ImageMenuId.HSV:
 			_show_hsv_configuration_popup()
 
@@ -671,6 +676,11 @@ func _show_add_outline_popup() -> void:
 	Global.dialog_open(true)
 
 
+func _show_drop_shadow_popup() -> void:
+	Global.control.get_node("Dialogs/ImageEffects/DropShadowDialog").popup_centered()
+	Global.dialog_open(true)
+
+
 func _show_hsv_configuration_popup() -> void:
 	Global.control.get_node("Dialogs/ImageEffects/HSVDialog").popup_centered()
 	Global.dialog_open(true)