From 2e795e8db50a9f83549a0b28dfb4c2b58c242ea2 Mon Sep 17 00:00:00 2001
From: Emmanouil Papadeas <manoschool@yahoo.gr>
Date: Tue, 13 Sep 2022 00:49:22 +0300
Subject: [PATCH] Fix onion skinning not working with mirror view

Addresses the 3rd issue in #717.
---
 src/UI/Canvas/OnionSkinning.gd | 48 ++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 23 deletions(-)

diff --git a/src/UI/Canvas/OnionSkinning.gd b/src/UI/Canvas/OnionSkinning.gd
index 6121cd42b..c100386ea 100644
--- a/src/UI/Canvas/OnionSkinning.gd
+++ b/src/UI/Canvas/OnionSkinning.gd
@@ -10,27 +10,29 @@ var rate := Global.onion_skinning_past_rate
 func _draw() -> void:
 	if !Global.onion_skinning:
 		return
-
 	rate = Global.onion_skinning_past_rate if type == PAST else Global.onion_skinning_future_rate
-	if rate > 0:
-		var color: Color
-		if Global.onion_skinning_blue_red:
-			color = blue_red_color
-		else:
-			color = Color.white
-		for i in range(1, rate + 1):
-			var change: int = Global.current_project.current_frame
-			if type == PAST:
-				change -= i
-			else:
-				change += i
-			if change == clamp(change, 0, Global.current_project.frames.size() - 1):
-				var layer_i := 0
-				for cel in Global.current_project.frames[change].cels:
-					var layer: Layer = Global.current_project.layers[layer_i]
-					if layer.visible:
-						# Ignore layer if it has the "_io" suffix in its name (case in-sensitive)
-						if not (layer.name.to_lower().ends_with("_io")):
-							color.a = 0.6 / i
-							draw_texture(cel.image_texture, Vector2.ZERO, color)
-					layer_i += 1
+	if rate <= 0:
+		return
+
+	var color := blue_red_color if Global.onion_skinning_blue_red else Color.white
+	var position_tmp := position
+	var scale_tmp := scale
+	if Global.mirror_view:
+		position_tmp.x += Global.current_project.size.x
+		scale_tmp.x = -1
+	draw_set_transform(position_tmp, rotation, scale_tmp)
+
+	for i in range(1, rate + 1):
+		var change: int = Global.current_project.current_frame
+		change += i if type == FUTURE else -i
+		if change == clamp(change, 0, Global.current_project.frames.size() - 1):
+			var layer_i := 0
+			for cel in Global.current_project.frames[change].cels:
+				var layer: Layer = Global.current_project.layers[layer_i]
+				if layer.visible:
+					# Ignore layer if it has the "_io" suffix in its name (case in-sensitive)
+					if not (layer.name.to_lower().ends_with("_io")):
+						color.a = 0.6 / i
+						draw_texture(cel.image_texture, Vector2.ZERO, color)
+				layer_i += 1
+	draw_set_transform(position, rotation, scale)