From ba792163ba0ea5a013f7c6d7fe8530661e22721e 2013-03-21 08:05:30
From: Miikka Heikkinen <miikka.heikkinen@digia.com>
Date: 2013-03-21 08:05:30
Subject: [PATCH] Fix int-qreal rounding errors in axislayout calculations

Task-number: QTRD-1930
Reviewed-by: Mika Salmela

---

diff --git a/src/axis/barcategoryaxis/chartbarcategoryaxisx.cpp b/src/axis/barcategoryaxis/chartbarcategoryaxisx.cpp
index b4b296e..8d86b12 100644
--- a/src/axis/barcategoryaxis/chartbarcategoryaxisx.cpp
+++ b/src/axis/barcategoryaxis/chartbarcategoryaxisx.cpp
@@ -60,7 +60,7 @@ QVector<qreal> ChartBarCategoryAxisX::calculateLayout() const
     points.resize(count + 2);
 
     for (int i = 0; i < count + 2; ++i)
-        points[i] = offset + (i * delta) + gridRect.left();
+        points[i] = offset + (qreal(i) * delta) + gridRect.left();
 
     return points;
 }
diff --git a/src/axis/barcategoryaxis/chartbarcategoryaxisy.cpp b/src/axis/barcategoryaxis/chartbarcategoryaxisy.cpp
index e35aea6..0ca8116 100644
--- a/src/axis/barcategoryaxis/chartbarcategoryaxisy.cpp
+++ b/src/axis/barcategoryaxis/chartbarcategoryaxisy.cpp
@@ -60,7 +60,7 @@ QVector<qreal> ChartBarCategoryAxisY::calculateLayout() const
     points.resize(count + 2);
 
     for (int i = 0; i < count + 2; ++i)
-        points[i] =  gridRect.bottom() - (i * delta) - offset;
+        points[i] =  gridRect.bottom() - (qreal(i) * delta) - offset;
 
     return points;
 }
diff --git a/src/axis/datetimeaxis/chartdatetimeaxisx.cpp b/src/axis/datetimeaxis/chartdatetimeaxisx.cpp
index 591daf9..39fc3ba 100644
--- a/src/axis/datetimeaxis/chartdatetimeaxisx.cpp
+++ b/src/axis/datetimeaxis/chartdatetimeaxisx.cpp
@@ -50,11 +50,9 @@ QVector<qreal> ChartDateTimeAxisX::calculateLayout() const
     QVector<qreal> points;
     points.resize(tickCount);
     const QRectF &gridRect = gridGeometry();
-    const qreal deltaX = gridRect.width() / (tickCount - 1);
-    for (int i = 0; i < tickCount; ++i) {
-        int x = i * deltaX + gridRect.left();
-        points[i] = x;
-    }
+    const qreal deltaX = gridRect.width() / (qreal(tickCount) - 1.0);
+    for (int i = 0; i < tickCount; ++i)
+        points[i] =  qreal(i) * deltaX + gridRect.left();
     return points;
 }
 
diff --git a/src/axis/datetimeaxis/chartdatetimeaxisy.cpp b/src/axis/datetimeaxis/chartdatetimeaxisy.cpp
index 8b27d1c..a534617 100644
--- a/src/axis/datetimeaxis/chartdatetimeaxisy.cpp
+++ b/src/axis/datetimeaxis/chartdatetimeaxisy.cpp
@@ -50,11 +50,9 @@ QVector<qreal> ChartDateTimeAxisY::calculateLayout() const
     QVector<qreal> points;
     points.resize(tickCount);
     const QRectF &gridRect = gridGeometry();
-    const qreal deltaY = gridRect.height() / (tickCount - 1);
-    for (int i = 0; i < tickCount; ++i) {
-        int y = i * -deltaY + gridRect.bottom();
-        points[i] = y;
-    }
+    const qreal deltaY = gridRect.height() / (qreal(tickCount) - 1.0);
+    for (int i = 0; i < tickCount; ++i)
+        points[i] =  qreal(i) * -deltaY + gridRect.bottom();
 
     return points;
 }
diff --git a/src/axis/valueaxis/chartvalueaxisx.cpp b/src/axis/valueaxis/chartvalueaxisx.cpp
index ccf4925..a084ac3 100644
--- a/src/axis/valueaxis/chartvalueaxisx.cpp
+++ b/src/axis/valueaxis/chartvalueaxisx.cpp
@@ -53,10 +53,9 @@ QVector<qreal> ChartValueAxisX::calculateLayout() const
     points.resize(tickCount);
 
     const QRectF &gridRect = gridGeometry();
-    const qreal deltaX = gridRect.width() / (tickCount - 1);
-    for (int i = 0; i < tickCount; ++i) {
-        points[i] = i * deltaX + gridRect.left();
-    }
+    const qreal deltaX = gridRect.width() / (qreal(tickCount) - 1.0);
+    for (int i = 0; i < tickCount; ++i)
+        points[i] = qreal(i) * deltaX + gridRect.left();
     return points;
 }
 
diff --git a/src/axis/valueaxis/chartvalueaxisy.cpp b/src/axis/valueaxis/chartvalueaxisy.cpp
index 848d4ae..14b2d20 100644
--- a/src/axis/valueaxis/chartvalueaxisy.cpp
+++ b/src/axis/valueaxis/chartvalueaxisy.cpp
@@ -53,10 +53,9 @@ QVector<qreal> ChartValueAxisY::calculateLayout() const
 
     const QRectF &gridRect = gridGeometry();
 
-    const qreal deltaY = gridRect.height() / (tickCount - 1);
-    for (int i = 0; i < tickCount; ++i) {
-        points[i] = i * -deltaY + gridRect.bottom();
-    }
+    const qreal deltaY = gridRect.height() / (qreal(tickCount) - 1.0);
+    for (int i = 0; i < tickCount; ++i)
+        points[i] = qreal(i) * -deltaY + gridRect.bottom();
 
     return points;
 }