From 5d19887da6ce97d4d49e34856fe90f900ea47e6e Mon Sep 17 00:00:00 2001
From: Paul-Licameli <paul.licameli@gmail.com>
Date: Thu, 9 Apr 2015 20:20:51 -0400
Subject: [PATCH] Bug812 - Vertical scrollbar position should be persistent
 too, as is horizontal

Effective but perhaps inelegant fix.
---
 src/Project.cpp | 46 +++++++++++++++++++++++++++++++---------------
 src/Project.h   |  4 +++-
 2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/src/Project.cpp b/src/Project.cpp
index 85d88e4f7..5d0e1fa49 100644
--- a/src/Project.cpp
+++ b/src/Project.cpp
@@ -773,6 +773,7 @@ AudacityProject::AudacityProject(wxWindow * parent, wxWindowID id,
      mLastEffectType(0),
      mTimerRecordCanceled(false),
      mMenuClose(false)
+     , mbInitializingScrollbar(false)
 {
    int widths[] = {-2, -1};
    mStatusBar = CreateStatusBar(2);
@@ -1508,7 +1509,16 @@ void AudacityProject::FixScrollbars()
    mViewInfo.sbarH = (wxInt64) (mViewInfo.h * mViewInfo.zoom);
 
    int lastv = mViewInfo.vpos;
-   mViewInfo.vpos = mVsbar->GetThumbPosition() * mViewInfo.scrollStep;
+   // PRL:  Can someone else find a more elegant solution to bug 812, than
+   // introducing this boolean member variable?
+   // Setting mVSbar earlier, int HandlXMLTag, didn't succeed in restoring
+   // the vertical scrollbar to its saved position.  So defer that till now.
+   // mbInitializingScrollbar should be true only at the start of the life
+   // of an AudacityProject reopened from disk.
+   if (!mbInitializingScrollbar) {
+      mViewInfo.vpos = mVsbar->GetThumbPosition() * mViewInfo.scrollStep;
+   }
+   mbInitializingScrollbar = false;
 
    if (mViewInfo.vpos >= totalHeight)
       mViewInfo.vpos = totalHeight - 1;
@@ -2808,6 +2818,7 @@ bool AudacityProject::HandleXMLTag(const wxChar *tag, const wxChar **attrs)
    wxString fileVersion = _("<unrecognized version -- possibly corrupt project file>");
    wxString audacityVersion = _("<unrecognized version -- possibly corrupt project file>");
    int requiredTags = 0;
+   long longVpos = 0;
 
    // loop through attrs, which is a null-terminated list of
    // attribute-value pairs
@@ -2834,19 +2845,19 @@ bool AudacityProject::HandleXMLTag(const wxChar *tag, const wxChar **attrs)
          }
       }
 
-      if (!wxStrcmp(attr, wxT("version")))
+      else if (!wxStrcmp(attr, wxT("version")))
       {
          fileVersion = value;
          bFileVersionFound = true;
          requiredTags++;
       }
 
-      if (!wxStrcmp(attr, wxT("audacityversion"))) {
+      else if (!wxStrcmp(attr, wxT("audacityversion"))) {
          audacityVersion = value;
          requiredTags++;
       }
 
-      if (!wxStrcmp(attr, wxT("projname"))) {
+      else if (!wxStrcmp(attr, wxT("projname"))) {
          wxString projName;
          wxString projPath;
 
@@ -2911,13 +2922,13 @@ bool AudacityProject::HandleXMLTag(const wxChar *tag, const wxChar **attrs)
          requiredTags++;
       }
 
-      if (!wxStrcmp(attr, wxT("sel0"))) {
+      else if (!wxStrcmp(attr, wxT("sel0"))) {
          double t0;
          Internat::CompatibleToDouble(value, &t0);
          mViewInfo.selectedRegion.setT0(t0, false);
       }
 
-      if (!wxStrcmp(attr, wxT("sel1"))) {
+      else if (!wxStrcmp(attr, wxT("sel1"))) {
          double t1;
          Internat::CompatibleToDouble(value, &t1);
          mViewInfo.selectedRegion.setT1(t1, false);
@@ -2925,32 +2936,37 @@ bool AudacityProject::HandleXMLTag(const wxChar *tag, const wxChar **attrs)
 
       // PRL: to do: persistence of other fields of the selection
 
-      long longVpos = 0;
-      if (!wxStrcmp(attr, wxT("vpos")))
+      else if (!wxStrcmp(attr, wxT("vpos")))
+         // Just assign a variable, put the value in its place later 
          wxString(value).ToLong(&longVpos);
-      mViewInfo.track = NULL;
-      mViewInfo.vpos = longVpos;
 
-      if (!wxStrcmp(attr, wxT("h")))
+      else if (!wxStrcmp(attr, wxT("h")))
          Internat::CompatibleToDouble(value, &mViewInfo.h);
 
-      if (!wxStrcmp(attr, wxT("zoom")))
+      else if (!wxStrcmp(attr, wxT("zoom")))
          Internat::CompatibleToDouble(value, &mViewInfo.zoom);
 
-      if (!wxStrcmp(attr, wxT("rate"))) {
+      else if (!wxStrcmp(attr, wxT("rate"))) {
          Internat::CompatibleToDouble(value, &mRate);
          GetSelectionBar()->SetRate(mRate);
       }
 
-      if (!wxStrcmp(attr, wxT("snapto"))) {
+      else if (!wxStrcmp(attr, wxT("snapto"))) {
          SetSnapTo(wxString(value) == wxT("on") ? true : false);
       }
 
-      if (!wxStrcmp(attr, wxT("selectionformat"))) {
+      else if (!wxStrcmp(attr, wxT("selectionformat"))) {
          SetSelectionFormat(value);
       }
    } // while
 
+   if (longVpos != 0) {
+      // PRL: It seems this must happen after SetSnapTo
+       mViewInfo.track = NULL;
+       mViewInfo.vpos = longVpos;
+       mbInitializingScrollbar = true;
+   }
+
    // Specifically detect newer versions of Audacity
    // WARNING: This will need review/revision if we ever have a version string
    // such as 1.5.10, i.e. with 2 digit numbers.
diff --git a/src/Project.h b/src/Project.h
index e36d60671..e171b2dab 100644
--- a/src/Project.h
+++ b/src/Project.h
@@ -618,7 +618,9 @@ class AUDACITY_DLL_API AudacityProject:  public wxFrame,
    // Are we currently closing as the result of a menu command?
    bool mMenuClose;
 
-    DECLARE_EVENT_TABLE()
+   bool mbInitializingScrollbar;
+
+   DECLARE_EVENT_TABLE()
 };
 
 typedef void (AudacityProject::*audCommandFunction)();