From c26620643cd86cf84e9f1672b61109fcd9d98b4f Mon Sep 17 00:00:00 2001
From: Thomas Holder <thomas.holder@schrodinger.com>
Date: Fri, 14 Sep 2018 10:54:56 +0200
Subject: fix 3D boxes with inverted y-axis (follow-up)

The initial fix was only correct for parallel/infinite Y direction
---
 src/object/persp3d.cpp | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

(limited to 'src/object/persp3d.cpp')

diff --git a/src/object/persp3d.cpp b/src/object/persp3d.cpp
index 05ba5898b..5c6835e28 100644
--- a/src/object/persp3d.cpp
+++ b/src/object/persp3d.cpp
@@ -96,8 +96,11 @@ static Proj::Pt2 legacy_transform_forward(Proj::Pt2 pt, SPDocument const *doc) {
     }
 
     // <inkscape:perspective> stores inverted y-axis coordinates
-    if (pt[2] && SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
-        pt[1] = doc->getHeight().value("px") - pt[1];
+    if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+        pt[1] *= -1;
+        if (pt[2]) {
+            pt[1] += doc->getHeight().value("px");
+        }
     }
 
     return pt;
@@ -108,8 +111,11 @@ static Proj::Pt2 legacy_transform_forward(Proj::Pt2 pt, SPDocument const *doc) {
  */
 static Proj::Pt2 legacy_transform_backward(Proj::Pt2 pt, SPDocument const *doc) {
     // <inkscape:perspective> stores inverted y-axis coordinates
-    if (pt[2] && SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
-        pt[1] = doc->getHeight().value("px") - pt[1];
+    if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+        pt[1] *= -1;
+        if (pt[2]) {
+            pt[1] += doc->getHeight().value("px");
+        }
     }
 
     // Written values are in 'user units'.
-- 
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