# HG changeset patch
# User Chris Cannam
# Date 1540908020 0
# Node ID bbeffb29bf0927f7befa24f2fa4ca715251258e5
# Parent  d79e21855aef46b7aa8501bc3c11db004048f9c4
Fix inconsistency between centre frame actually set and centre frame notified as set, which caused the start frame location to creep out of place gradually as you page through

diff -r d79e21855aef -r bbeffb29bf09 view/Pane.cpp
--- a/view/Pane.cpp	Thu Oct 18 13:21:56 2018 +0100
+++ b/view/Pane.cpp	Tue Oct 30 14:00:20 2018 +0000
@@ -62,9 +62,6 @@
 
 //#define DEBUG_PANE
 
-
-
-
 QCursor *Pane::m_measureCursor1 = 0;
 QCursor *Pane::m_measureCursor2 = 0;
 
diff -r d79e21855aef -r bbeffb29bf09 view/View.cpp
--- a/view/View.cpp	Thu Oct 18 13:21:56 2018 +0100
+++ b/view/View.cpp	Tue Oct 30 14:00:20 2018 +0000
@@ -340,7 +340,7 @@
         
         if (m_zoomLevel.zone == ZoomLevel::PixelsPerFrame) {
 
-#ifdef DEBUG_VIEW_WIDGET_PAINT
+#ifdef DEBUG_VIEW
             SVCERR << "View(" << this << ")::setCentreFrame: in PixelsPerFrame zone, so change must be visible" << endl;
 #endif
             update();
@@ -353,11 +353,18 @@
         
             if (newPixel != formerPixel) {
 
-#ifdef DEBUG_VIEW_WIDGET_PAINT
+#ifdef DEBUG_VIEW
                 SVCERR << "View(" << this << ")::setCentreFrame: newPixel " << newPixel << ", formerPixel " << formerPixel << endl;
 #endif
                 // ensure the centre frame is a multiple of the zoom level
                 m_centreFrame = sv_frame_t(newPixel) * m_zoomLevel.level;
+
+#ifdef DEBUG_VIEW
+                SVCERR << "View(" << this
+                       << ")::setCentreFrame: centre frame rounded to "
+                       << m_centreFrame << " (zoom level is "
+                       << m_zoomLevel.level << ")" << endl;
+#endif
                 
                 update();
                 changeVisible = true;
@@ -365,11 +372,12 @@
         }
 
         if (e) {
-            sv_frame_t rf = alignToReference(f);
+            sv_frame_t rf = alignToReference(m_centreFrame);
 #ifdef DEBUG_VIEW
             cerr << "View[" << this << "]::setCentreFrame(" << f
-                      << "): emitting centreFrameChanged("
-                      << rf << ")" << endl;
+                 << "): m_centreFrame = " << m_centreFrame
+                 << ", emitting centreFrameChanged with aligned frame "
+                 << rf << endl;
 #endif
             emit centreFrameChanged(rf, m_followPan, m_followPlay);
         }
@@ -427,7 +435,7 @@
         result = fdiff + m_centreFrame;
     }
 
-#ifdef DEBUG_VIEW
+#ifdef DEBUG_VIEW_WIDGET_PAINT
     if (x == 0) {
         SVCERR << "getFrameForX(" << x << "): diff = " << diff << ", fdiff = "
                << fdiff << ", m_centreFrame = " << m_centreFrame
@@ -1604,6 +1612,12 @@
     }
     if (right) delta = -delta;
 
+#ifdef DEBUG_VIEW
+    SVCERR << "View::scroll(" << right << ", " << lots << ", " << e << "): "
+           << "delta = " << delta << ", m_centreFrame = " << m_centreFrame
+           << endl;
+#endif
+    
     if (m_centreFrame < delta) {
         setCentreFrame(0, e);
     } else if (m_centreFrame - delta >= getModelsEndFrame()) {