Fix problems with missing safety checks in Render::fillBuffer and pdfcomic

common/scroll_management.cpp

@@ -0,0 +1,61 @@
+#include "scroll_management.h"
+
+ScrollManagement::ScrollManagement()
+{
+    wheelTimer = new QTime();
+    wheelTimer->start();
+    wheelAccumulator = 0;
+}
+
+ScrollManagement::Movement ScrollManagement::getMovement(QWheelEvent *event)
+{
+    /*QLOG_DEBUG() << "WheelEvent angle delta : " << event->angleDelta();
+    QLOG_DEBUG() << "WheelEvent pixel delta : " << event->pixelDelta();*/
+
+    int tooFast = 1;
+    int timeThrottle = 16;
+    int minimumMove = 70;
+
+    //avoid any events overflood
+    if((wheelTimer->elapsed() < tooFast)){
+        event->setAccepted(true);
+        return None;
+    }
+
+    // Accumulate the delta
+    if(event->delta()<0 != wheelAccumulator<0 ) //different sign means change in direction
+        wheelAccumulator = 0;
+
+    wheelAccumulator += event->delta();
+
+    //Do not process events too fast
+    if((wheelTimer->elapsed() < timeThrottle)){
+        event->setAccepted(true);
+        return None;
+    }
+
+    //small intervals are ignored until with have enough acumulated delta
+    if((wheelAccumulator < minimumMove) && (wheelAccumulator > -minimumMove)){
+        event->setAccepted(true);
+        return None;
+    }
+
+    Movement m;
+    if(wheelAccumulator<0)
+            m = Forward;
+        else
+            m = Backward;
+
+    event->accept();
+    //Clean up
+    wheelAccumulator = 0;
+    wheelTimer->restart();
+
+    return m;
+}
+
+ScrollManagement::~ScrollManagement()
+{
+
+}
+