From a9ab31dedbc7cb10ed368ef3f56b50c7e8237185 Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@gmail.com>
Date: Fri, 21 Aug 2015 12:02:48 -0400
Subject: [PATCH] Allow NULL arguments in TrackPanel::GetTracksUsableArea()

---
 src/Menus.cpp         |  8 ++++----
 src/TrackPanel.cpp    | 16 +++++++++-------
 src/TrackPanel.h      |  1 +
 src/widgets/Ruler.cpp |  4 ++--
 4 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/src/Menus.cpp b/src/Menus.cpp
index 48a00426a..4a768e86e 100644
--- a/src/Menus.cpp
+++ b/src/Menus.cpp
@@ -4952,8 +4952,8 @@ void AudacityProject::OnZoomFit()
    if (len <= 0.0)
       return;
 
-   int w, h;
-   mTrackPanel->GetTracksUsableArea(&w, &h);
+   int w;
+   mTrackPanel->GetTracksUsableArea(&w, NULL);
    w -= 10;
 
    Zoom(w / len);
@@ -4962,9 +4962,9 @@ void AudacityProject::OnZoomFit()
 
 void AudacityProject::DoZoomFitV()
 {
-   int width, height, count;
+   int height, count;
 
-   mTrackPanel->GetTracksUsableArea(&width, &height);
+   mTrackPanel->GetTracksUsableArea(NULL, &height);
 
    height -= 28;
 
diff --git a/src/TrackPanel.cpp b/src/TrackPanel.cpp
index be1716227..a1472eb76 100644
--- a/src/TrackPanel.cpp
+++ b/src/TrackPanel.cpp
@@ -1074,9 +1074,11 @@ void TrackPanel::SelectTrackLength(Track *t)
 void TrackPanel::GetTracksUsableArea(int *width, int *height) const
 {
    GetSize(width, height);
-   *width -= GetLeftOffset();
-   *width -= kRightMargin;
-   *width = std::max(0, *width);
+   if (width) {
+      *width -= GetLeftOffset();
+      *width -= kRightMargin;
+      *width = std::max(0, *width);
+   }
 }
 
 /// Gets the pointer to the AudacityProject that
@@ -4150,8 +4152,8 @@ void TrackPanel::DoSlide(wxMouseEvent & event)
    if (mouseTrack == NULL) {
       // Allow sliding if the pointer is not over any track, but only if x is
       // within the bounds of the tracks area.
-      int width, height;
-      GetTracksUsableArea(&width, &height);
+      int width;
+      GetTracksUsableArea(&width, NULL);
       if (event.m_x >= GetLeftOffset() && event.m_x < GetLeftOffset() + width)
          mouseTrack = mCapturedTrack;
       else
@@ -8254,8 +8256,8 @@ void TrackPanel::ScrollIntoView(double pos)
 {
    const int screenWidth = rint(mViewInfo->GetScreenWidth());
 
-   int w, h;
-   GetTracksUsableArea( &w, &h );
+   int w;
+   GetTracksUsableArea( &w, NULL );
    // Or should we just set w = screenWidth ?
 
    int pixel = mViewInfo->TimeToPosition(pos);
diff --git a/src/TrackPanel.h b/src/TrackPanel.h
index d30165cdc..c823c39d6 100644
--- a/src/TrackPanel.h
+++ b/src/TrackPanel.h
@@ -166,6 +166,7 @@ class AUDACITY_DLL_API TrackPanel:public wxPanel {
    virtual int GetLeftOffset() const { return GetLabelWidth() + 1;}
 
    // Width and height, relative to upper left corner at (GetLeftOffset(), 0)
+   // Either argument may be NULL
    virtual void GetTracksUsableArea(int *width, int *height) const;
 
    virtual void SelectNone();
diff --git a/src/widgets/Ruler.cpp b/src/widgets/Ruler.cpp
index 9e19fd1b2..533c65a0b 100644
--- a/src/widgets/Ruler.cpp
+++ b/src/widgets/Ruler.cpp
@@ -1936,8 +1936,8 @@ void AdornedRulerPanel::OnMouseEvents(wxMouseEvent &evt)
 
    // Keep Quick-Play within usable track area.
    TrackPanel *tp = mProject->GetTrackPanel();
-   int mousePosX, width, height;
-   tp->GetTracksUsableArea(&width, &height);
+   int mousePosX, width;
+   tp->GetTracksUsableArea(&width, NULL);
    mousePosX = std::max(evt.GetX(), tp->GetLeftOffset());
    mousePosX = std::min(mousePosX, tp->GetLeftOffset() + width - 1);