From b176f98f0e9d10e1849cb29dda9281fbc4967dd9 Mon Sep 17 00:00:00 2001
From: Luis Lucas <luisfrlucas@gmail.com>
Date: Sun, 22 Feb 2015 22:50:03 +0000
Subject: [PATCH] Use integer precision for zoom percentage value. This fixes
 alignment of zoommed pixels between two tiled images.

---
 app/ViewArea.cpp    | 24 +++++++++++++++---------
 app/plaYUVerApp.cpp |  1 +
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/app/ViewArea.cpp b/app/ViewArea.cpp
index 478b13e..0322c08 100644
--- a/app/ViewArea.cpp
+++ b/app/ViewArea.cpp
@@ -114,7 +114,18 @@ Double ViewArea::scaleZoomFactor( Double scale, QPoint center, QSize minimumSize
   Double maxZoom = 100.0;
   Double minZoom = 0.01;  //( 1.0 / m_pixmap.width() );
   Double new_scale = 1.0;
-  Double zoomFactor = m_zoomFactor * scale;
+
+  if( ( m_zoomFactor == minZoom ) && ( scale < 1 ) )
+    return new_scale;
+
+  if( ( m_zoomFactor == maxZoom ) && ( scale > 1 ) )
+    return new_scale;
+
+  Double zoomFactor = m_zoomFactor * scale * 100.0;
+  zoomFactor=round(zoomFactor);
+  zoomFactor=zoomFactor/100.0;
+  scale = zoomFactor/m_zoomFactor;
+
 
   if(!minimumSize.isNull())
   {
@@ -140,18 +151,13 @@ Double ViewArea::scaleZoomFactor( Double scale, QPoint center, QSize minimumSize
       else
         scale = hfactor;
 
-      zoomFactor = zoomFactor * scale;
+      zoomFactor = zoomFactor * scale * 100.0;
+      zoomFactor=round(zoomFactor);
+      zoomFactor=zoomFactor/100.0;
       scale = zoomFactor/m_zoomFactor;
     }
   }
 
-  if( ( m_zoomFactor == minZoom ) && ( scale < 1 ) )
-    return new_scale;
-
-  if( ( m_zoomFactor == maxZoom ) && ( scale > 1 ) )
-    return new_scale;
-
-
   new_scale = scale;
 
   if( zoomFactor < minZoom )
diff --git a/app/plaYUVerApp.cpp b/app/plaYUVerApp.cpp
index 2e003bf..c958294 100644
--- a/app/plaYUVerApp.cpp
+++ b/app/plaYUVerApp.cpp
@@ -779,6 +779,7 @@ Void plaYUVerApp::createToolBars()
   m_arrayToolBars[VIEW_TOOLBAR] = new QToolBar( tr( "View" ) );
   m_pcZoomFactorSBox = new QDoubleSpinBox;
   m_pcZoomFactorSBox->setRange( 1.0, 10000.0 );
+  m_pcZoomFactorSBox->setDecimals(0);
   m_pcZoomFactorSBox->setSingleStep( 10.0 );
   m_pcZoomFactorSBox->setValue( 100.0 );
   m_pcZoomFactorSBox->setSuffix( "%" );