Move some numbers out of ViewInfo.h ...

... Move them to new header TrackPanelConstants.h, to be used only by TrackPanel
and some closely cooperating classes, but not known to the track view, controls,
vertical ruler, or affordance classes.

Also distinguish track from channel separator thickness though these remain
equal.

src/CMakeLists.txt

@@ -276,6 +276,7 @@ list( APPEND SOURCES
       TrackPanelAx.h
       TrackPanelCell.cpp
       TrackPanelCell.h
+      TrackPanelConstants.h
       TrackPanelDrawable.cpp
       TrackPanelDrawable.h
       TrackPanelDrawingContext.h

src/TrackPanel.cpp

@@ -45,6 +45,7 @@ is time to refresh some aspect of the screen.
 
 
 #include "TrackPanel.h"
+#include "TrackPanelConstants.h"
 
 #include <wx/app.h>
 #include <wx/setup.h> // for wxUSE_* macros
@@ -90,6 +91,8 @@ is time to refresh some aspect of the screen.
 #include <wx/dcclient.h>
 #include <wx/graphics.h>
 
+static_assert( kVerticalPadding == kTopMargin + kBottomMargin );
+
 /**
 
 \class TrackPanel
@@ -1363,7 +1366,7 @@ struct ChannelGroup final : TrackPanelGroup {
 
          auto height = view.GetHeight();
          rect.SetTop( yy );
-         rect.SetHeight( height - kSeparatorThickness );
+         rect.SetHeight( height - kChannelSeparatorThickness );
          refinement.emplace_back( yy,
             std::make_shared< VRulersAndChannels >(
                channel->shared_from_this(),
@@ -1372,7 +1375,7 @@ struct ChannelGroup final : TrackPanelGroup {
          if ( channel != pLast ) {
             yy += height;
             refinement.emplace_back(
-               yy - kSeparatorThickness,
+               yy - kChannelSeparatorThickness,
                TrackPanelResizerCell::Get( *channel ).shared_from_this() );
          }
       }
@@ -1400,7 +1403,7 @@ struct ChannelGroup final : TrackPanelGroup {
                mLeftOffset,
                yy,
                rect.GetRight() - mLeftOffset,
-               height - kSeparatorThickness);
+               height - kChannelSeparatorThickness);
             TrackArt::DrawCursor(context, trackRect, mpTrack.get());
             yy += height;
          }
@@ -1520,7 +1523,7 @@ struct ResizingChannelGroup final : TrackPanelGroup {
    { return { Axis::Y, Refinement{
       { rect.GetTop(),
          std::make_shared< LabeledChannelGroup >( mpTrack, mLeftOffset ) },
-      { rect.GetTop() + rect.GetHeight() - kSeparatorThickness,
+      { rect.GetTop() + rect.GetHeight() - kTrackSeparatorThickness,
          TrackPanelResizerCell::Get(
             **TrackList::Channels( mpTrack.get() ).rbegin() ).shared_from_this()
       }

src/TrackPanelConstants.h

@@ -0,0 +1,27 @@
+/*!********************************************************************
+ 
+ Audacity: A Digital Audio Editor
+ 
+ TrackPanelConstants.h
+ 
+ Paul Licameli split from ViewInfo.h
+ 
+ **********************************************************************/
+
+#ifndef  __AUDACITY_TRACK_PANEL_CONSTANTS__
+#define  __AUDACITY_TRACK_PANEL_CONSTANTS__
+
+#include "ZoomInfo.h"
+
+// See big pictorial comment in TrackPanel.cpp for explanation of these numbers
+//! constants related to y coordinates in the track panel
+enum : int {
+   kAffordancesAreaHeight = 20,
+   kTopInset = 4,
+   kTopMargin = kTopInset + kBorderThickness,
+   kBottomMargin = kShadowThickness + kBorderThickness,
+   kTrackSeparatorThickness = kBottomMargin + kTopMargin,
+   kChannelSeparatorThickness = kTrackSeparatorThickness,
+};
+
+#endif

src/ViewInfo.h

@@ -98,19 +98,10 @@ private:
    SelectedRegion mRegion;
 };
 
-// See big pictorial comment in TrackPanel.cpp for explanation of these numbers
-//! constants related to y coordinates in the track panel
 enum : int {
    kVerticalPadding = 7, /*!< Width of padding below each channel group */
-   kAffordancesAreaHeight = 20,
-   kTopInset = 4,
-   kTopMargin = kTopInset + kBorderThickness,
-   kBottomMargin = kShadowThickness + kBorderThickness,
-   kSeparatorThickness = kBottomMargin + kTopMargin,
 };
 
-static_assert( kVerticalPadding == kTopMargin + kBottomMargin );
-
 enum : int {
    kTrackInfoBtnSize = 18, // widely used dimension, usually height
    kTrackInfoSliderHeight = 25,

src/tracks/ui/BackgroundCell.cpp

@@ -19,6 +19,7 @@ Paul Licameli split from TrackPanel.cpp
 #include "../../Track.h"
 #include "../../TrackArtist.h"
 #include "../../TrackPanel.h"
+#include "../../TrackPanelConstants.h"
 #include "../../TrackPanelDrawingContext.h"
 #include "../../TrackPanelMouseEvent.h"
 #include "../../UIHandle.h"