Add a transparent background for flip image dialog preview

Seems to be working fine, will do the same for the remaining dialogs.

src/UI/Dialogs/ImageEffects/FlipImageDialog.gd

@@ -24,6 +24,7 @@ func _ready() -> void:
 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)
+	update_transparent_background_size()
 
 
 func _on_FlipImageDialog_confirmed() -> void:
@@ -118,6 +119,19 @@ func flip_image(image : Image, _pixels : Array, project : Project = Global.curre
 		image.blit_rect_mask(selected_image, selected_image, Rect2(Vector2.ZERO, selected_image.get_size()), Vector2.ZERO)
 
 
+func update_transparent_background_size() -> void:
+	var image_size_y = preview.rect_size.y
+	var image_size_x = preview.rect_size.x
+	if preview_image.get_size().x > preview_image.get_size().y:
+		var scale_ratio = preview_image.get_size().x / image_size_x
+		image_size_y = preview_image.get_size().y / scale_ratio
+	else:
+		var scale_ratio = preview_image.get_size().y / image_size_y
+		image_size_x = preview_image.get_size().x / scale_ratio
+
+	preview.get_node("TransparentChecker").rect_size.x = image_size_x
+	preview.get_node("TransparentChecker").rect_size.y = image_size_y
+
+
 func _on_FlipImageDialog_popup_hide() -> void:
 	Global.dialog_open(false)
-

src/UI/Dialogs/ImageEffects/FlipImageDialog.tscn

@@ -1,11 +1,13 @@
-[gd_scene load_steps=2 format=2]
+[gd_scene load_steps=3 format=2]
 
 [ext_resource path="res://src/UI/Dialogs/ImageEffects/FlipImageDialog.gd" type="Script" id=1]
+[ext_resource path="res://src/UI/TransparentChecker.tscn" type="PackedScene" id=2]
 
 [node name="FlipImageDialog" type="ConfirmationDialog"]
-margin_right = 200.0
-margin_bottom = 70.0
+margin_right = 283.0
+margin_bottom = 300.0
 window_title = "Flip"
+resizable = true
 script = ExtResource( 1 )
 
 [node name="VBoxContainer" type="VBoxContainer" parent="."]
@@ -13,13 +15,21 @@ margin_left = 8.0
 margin_top = 8.0
 margin_right = 275.0
 margin_bottom = 264.0
+__meta__ = {
+"_edit_use_anchors_": false
+}
 
 [node name="Preview" type="TextureRect" parent="VBoxContainer"]
-margin_right = 267.0
+margin_left = 33.0
+margin_right = 233.0
 margin_bottom = 200.0
 rect_min_size = Vector2( 200, 200 )
+size_flags_horizontal = 4
 expand = true
-stretch_mode = 6
+stretch_mode = 5
+
+[node name="TransparentChecker" parent="VBoxContainer/Preview" instance=ExtResource( 2 )]
+show_behind_parent = true
 
 [node name="OptionsContainer" type="GridContainer" parent="VBoxContainer"]
 margin_top = 204.0

src/UI/Dialogs/ImageEffects/ImageEffects.tscn

@@ -27,8 +27,6 @@ margin_bottom = 392.0
 [node name="RotateImage" parent="." instance=ExtResource( 9 )]
 
 [node name="FlipImageDialog" parent="." instance=ExtResource( 1 )]
-margin_right = 283.0
-margin_bottom = 300.0
 
 [node name="InvertColorsDialog" parent="." instance=ExtResource( 2 )]
 

src/UI/Dialogs/ImageEffects/ResizeCanvas.gd

@@ -39,7 +39,6 @@ func _on_ResizeCanvas_about_to_show() -> void:
 		layer_i += 1
 	image.unlock()
 
-	preview_rect.get_node("TransparentChecker").rect_size = preview_rect.rect_size
 	update_preview()
 
 
@@ -80,6 +79,7 @@ func _on_CenterButton_pressed() -> void:
 
 
 func update_preview() -> void:
+	# preview_image is the same as image but offsetted
 	var preview_image := Image.new()
 	preview_image.create(width, height, false, Image.FORMAT_RGBA8)
 	preview_image.blend_rect(image, Rect2(Vector2.ZERO, Global.current_project.size), Vector2(offset_x, offset_y))

src/UI/Dialogs/ImageEffects/ResizeCanvas.tscn

@@ -111,6 +111,7 @@ suffix = "px"
 margin_top = 130.0
 margin_right = 54.0
 margin_bottom = 150.0
+mouse_default_cursor_shape = 2
 text = "Center"
 
 [node name="Preview" type="TextureRect" parent="VBoxContainer"]