From 51e25cdfa0bb598e5c6ff126b55a82e08ef53cdf Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@audacityteam.org>
Date: Sun, 25 Jun 2017 18:15:54 -0400
Subject: [PATCH] Highlighting of Track Control Panel sliders

---
 src/TrackPanel.cpp             | 11 ++++++-----
 src/TrackPanel.h               |  3 ++-
 src/tracks/ui/SliderHandle.cpp |  4 +++-
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/TrackPanel.cpp b/src/TrackPanel.cpp
index a50eb04b0..2e394df24 100644
--- a/src/TrackPanel.cpp
+++ b/src/TrackPanel.cpp
@@ -2076,12 +2076,13 @@ template<typename TrackClass>
 void TrackInfo::SliderDrawFunction
 ( LWSlider *(*Selector)
     (const wxRect &sliderRect, const TrackClass *t, bool captured, wxWindow*),
-  wxDC *dc, const wxRect &rect, const Track *pTrack, bool captured )
+  wxDC *dc, const wxRect &rect, const Track *pTrack,
+  bool captured, bool highlight )
 {
    wxRect sliderRect = rect;
    TrackInfo::GetSliderHorizontalBounds( rect.GetTopLeft(), sliderRect );
    auto wt = static_cast<const TrackClass*>( pTrack );
-   Selector( sliderRect, wt, captured, nullptr )->OnPaint(*dc, false);
+   Selector( sliderRect, wt, captured, nullptr )->OnPaint(*dc, highlight);
 }
 
 #include "tracks/playabletrack/wavetrack/ui/WaveTrackSliderHandles.h"
@@ -2094,7 +2095,7 @@ void TrackInfo::PanSliderDrawFunction
    bool hit = target && target->GetTrack().get() == pTrack;
    bool captured = hit && target->IsClicked();
    SliderDrawFunction<WaveTrack>
-      ( &TrackInfo::PanSlider, dc, rect, pTrack, captured);
+      ( &TrackInfo::PanSlider, dc, rect, pTrack, captured, hit);
 }
 
 void TrackInfo::GainSliderDrawFunction
@@ -2106,7 +2107,7 @@ void TrackInfo::GainSliderDrawFunction
    bool hit = target && target->GetTrack().get() == pTrack;
    bool captured = hit && target->IsClicked();
    SliderDrawFunction<WaveTrack>
-      ( &TrackInfo::GainSlider, dc, rect, pTrack, captured);
+      ( &TrackInfo::GainSlider, dc, rect, pTrack, captured, hit);
 }
 
 #ifdef EXPERIMENTAL_MIDI_OUT
@@ -2120,7 +2121,7 @@ void TrackInfo::VelocitySliderDrawFunction
    bool hit = target && target->GetTrack().get() == pTrack;
    bool captured = hit && target->IsClicked();
    SliderDrawFunction<NoteTrack>
-      ( &TrackInfo::VelocitySlider, dc, rect, pTrack, captured);
+      ( &TrackInfo::VelocitySlider, dc, rect, pTrack, captured, hit);
 }
 #endif
 
diff --git a/src/TrackPanel.h b/src/TrackPanel.h
index 943aeb540..8e11c1e89 100644
--- a/src/TrackPanel.h
+++ b/src/TrackPanel.h
@@ -121,7 +121,8 @@ public:
       ( LWSlider *(*Selector)
            (const wxRect &sliderRect, const TrackClass *t, bool captured,
             wxWindow*),
-        wxDC *dc, const wxRect &rect, const Track *pTrack, bool captured );
+        wxDC *dc, const wxRect &rect, const Track *pTrack,
+        bool captured, bool highlight );
 
    static void PanSliderDrawFunction
       ( TrackPanelDrawingContext &context,
diff --git a/src/tracks/ui/SliderHandle.cpp b/src/tracks/ui/SliderHandle.cpp
index d422d820f..6bae9d82e 100644
--- a/src/tracks/ui/SliderHandle.cpp
+++ b/src/tracks/ui/SliderHandle.cpp
@@ -21,7 +21,9 @@ SliderHandle::SliderHandle
    : mSliderFn{ sliderFn }
    , mRect{ rect }
    , mpTrack{ pTrack }
-{}
+{
+   mChangeHighlight = RefreshCode::RefreshCell;
+}
 
 SliderHandle::~SliderHandle()
 {