From 9460f8c0b9c2058ed357aa63a6b7e748e5496d46 Mon Sep 17 00:00:00 2001
From: kgv <kgv@opencascade.com>
Date: Fri, 26 Jul 2019 05:59:39 +0300
Subject: [PATCH] 0030853: Visualization, AIS_ViewController - fix 1 pixel Y
 shift while zooming

Fixed error in math converting Y-down mouse coordinates into Y-up within AIS_ViewController::handleZoom().
Added flags ToStickToRayOnZoom()/ToStickToRayOnRotation() enabled by default,
which will project picked point onto ray at mouse cursor to preserve focus on zoom out.
---
 src/AIS/AIS_ViewController.cxx | 15 +++++++--------
 src/AIS/AIS_ViewController.hxx | 14 ++++++++++++++
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/AIS/AIS_ViewController.cxx b/src/AIS/AIS_ViewController.cxx
index 8d8f199ed3..61aaac54c5 100644
--- a/src/AIS/AIS_ViewController.cxx
+++ b/src/AIS/AIS_ViewController.cxx
@@ -48,6 +48,8 @@ AIS_ViewController::AIS_ViewController()
   myToAllowZFocus        (true),
   myToAllowHighlight     (true),
   myToAllowDragging      (true),
+  myToStickToRayOnZoom   (true),
+  myToStickToRayOnRotation (true),
   //
   myWalkSpeedAbsolute (1.5f),
   myWalkSpeedRelative (0.1f),
@@ -1393,9 +1395,9 @@ void AIS_ViewController::handleZoom (const Handle(V3d_View)& theView,
     Graphic3d_Vec2i aWinSize;
     theView->Window()->Size (aWinSize.x(), aWinSize.y());
     const Graphic3d_Vec2d aPanFromCenterPx (double(theParams.Point.x()) - 0.5 * double(aWinSize.x()),
-                                            double(theParams.Point.y()) - 0.5 * double(aWinSize.y()));
+                                            double(aWinSize.y() - theParams.Point.y() - 1) - 0.5 * double(aWinSize.y()));
     aDxy.x() += -aViewDims1.X() * aPanFromCenterPx.x() / double(aWinSize.x());
-    aDxy.y() +=  aViewDims1.X() * aPanFromCenterPx.y() / double(aWinSize.x());
+    aDxy.y() += -aViewDims1.Y() * aPanFromCenterPx.y() / double(aWinSize.y());
   }
 
   //theView->Translate (aCam, aDxy.x(), aDxy.y());
@@ -1661,7 +1663,7 @@ gp_Pnt AIS_ViewController::GravityPoint (const Handle(AIS_InteractiveContext)& t
       }
 
       gp_Pnt aPnt;
-      if (PickPoint (aPnt, theCtx, theView, aCursor, false))
+      if (PickPoint (aPnt, theCtx, theView, aCursor, myToStickToRayOnRotation))
       {
         return aPnt;
       }
@@ -1882,12 +1884,9 @@ void AIS_ViewController::handleCameraActions (const Handle(AIS_InteractiveContex
 
       if (!theView->Camera()->IsOrthographic())
       {
-        // what is more natural to user - point on ray or point exactly on geometry in corner cases?
-        const bool toStickToRay = false; // true;
-
         gp_Pnt aPnt;
         if (aZoomParams.HasPoint()
-         && PickPoint (aPnt, theCtx, theView, aZoomParams.Point, toStickToRay))
+         && PickPoint (aPnt, theCtx, theView, aZoomParams.Point, myToStickToRayOnZoom))
         {
           handleZoom (theView, aZoomParams, &aPnt);
           continue;
@@ -1895,7 +1894,7 @@ void AIS_ViewController::handleCameraActions (const Handle(AIS_InteractiveContex
 
         Graphic3d_Vec2i aWinSize;
         theView->Window()->Size (aWinSize.x(), aWinSize.y());
-        if (PickPoint (aPnt, theCtx, theView, aWinSize / 2, toStickToRay))
+        if (PickPoint (aPnt, theCtx, theView, aWinSize / 2, myToStickToRayOnZoom))
         {
           aZoomParams.ResetPoint(); // do not pretend to zoom at 'nothing'
           handleZoom (theView, aZoomParams, &aPnt);
diff --git a/src/AIS/AIS_ViewController.hxx b/src/AIS/AIS_ViewController.hxx
index 7cec4ce390..01e1f517be 100644
--- a/src/AIS/AIS_ViewController.hxx
+++ b/src/AIS/AIS_ViewController.hxx
@@ -152,6 +152,18 @@ public: //! @name global parameters
   //! Set if dynamic highlight on mouse move is allowed.
   void SetAllowDragging (bool theToEnable) { myToAllowDragging = theToEnable; }
 
+  //! Return TRUE if picked point should be projected to picking ray on zooming at point; TRUE by default.
+  bool ToStickToRayOnZoom() const { return myToStickToRayOnZoom; }
+
+  //! Set if picked point should be projected to picking ray on zooming at point.
+  void SetStickToRayOnZoom (bool theToEnable) { myToStickToRayOnZoom = theToEnable; }
+
+  //! Return TRUE if picked point should be projected to picking ray on rotating around point; TRUE by default.
+  bool ToStickToRayOnRotation() const { return myToStickToRayOnRotation; }
+
+  //! Set if picked point should be projected to picking ray on rotating around point.
+  void SetStickToRayOnRotation (bool theToEnable) { myToStickToRayOnRotation = theToEnable; }
+
   //! Return TRUE if pitch direction should be inverted while processing Aspect_VKey_NavLookUp/Aspect_VKey_NavLookDown; FALSE by default.
   bool ToInvertPitch() const { return myToInvertPitch; }
 
@@ -600,6 +612,8 @@ protected:
   Standard_Boolean    myToAllowZFocus;            //!< enable ZFocus change; TRUE by default
   Standard_Boolean    myToAllowHighlight;         //!< enable dynamic highlight on mouse move; TRUE by default
   Standard_Boolean    myToAllowDragging;          //!< enable dragging object; TRUE by default
+  Standard_Boolean    myToStickToRayOnZoom;       //!< project picked point to ray while zooming at point, TRUE by default
+  Standard_Boolean    myToStickToRayOnRotation;   //!< project picked point to ray while rotating around point; TRUE by default
 
   Standard_ShortReal  myWalkSpeedAbsolute;        //!< normal walking speed, in m/s; 1.5 by default
   Standard_ShortReal  myWalkSpeedRelative;        //!< walking speed relative to scene bounding box; 0.1 by default