From 825c77a81d317141591f83089bc2edba6660214a 2013-03-20 13:42:51
From: Miikka Heikkinen <miikka.heikkinen@digia.com>
Date: 2013-03-20 13:42:51
Subject: [PATCH] Compensate for rounding errors when determining label visibility

If the label bordered exactly the axis boundary, there was a
chance it would not be shown because of half pixel rounding error
somewhere down the line.

Task-number: QTRD-1932
Reviewed-by: Mika Salmela

---

diff --git a/src/axis/horizontalaxis.cpp b/src/axis/horizontalaxis.cpp
index d09cb5f..5d2bfbd 100644
--- a/src/axis/horizontalaxis.cpp
+++ b/src/axis/horizontalaxis.cpp
@@ -142,10 +142,10 @@ void HorizontalAxis::updateGeometry()
             labelItem->setPos(layout[i] + delta - center.x(), labelItem->pos().y());
         }
 
-        //label overlap detection
+        //label overlap detection - compensate one pixel for rounding errors
         if(labelItem->pos().x() < width ||
-            labelItem->pos().x() < axisRect.left()  ||
-            labelItem->pos().x() + boundingRect.width() -1 > axisRect.right()){
+            labelItem->pos().x() < (axisRect.left() - 1.0) ||
+            (labelItem->pos().x() + boundingRect.width() - 1.0) > axisRect.right()){
             labelItem->setVisible(false);
         } else {
             labelItem->setVisible(true);
diff --git a/src/axis/verticalaxis.cpp b/src/axis/verticalaxis.cpp
index 0c6ecac..9c9d462 100644
--- a/src/axis/verticalaxis.cpp
+++ b/src/axis/verticalaxis.cpp
@@ -152,10 +152,10 @@ void VerticalAxis::updateGeometry()
             labelItem->setPos(labelItem->pos().x() , layout[i] + delta - center.y());
         }
 
-        //label overlap detection
-        if(labelItem->pos().y() + boundingRect.height() > height ||
-            labelItem->pos().y() + boundingRect.height()/2 > axisRect.bottom() ||
-            labelItem->pos().y() + boundingRect.height()/2 < axisRect.top()) {
+        //label overlap detection - compensate one pixel for rounding errors
+        if (labelItem->pos().y() + boundingRect.height() > height ||
+            (labelItem->pos().y() + (boundingRect.height() / 2.0) - 1.0) > axisRect.bottom() ||
+            labelItem->pos().y() + (boundingRect.height() / 2.0) < (axisRect.top() - 1.0)) {
             labelItem->setVisible(false);
         }
         else {