Add flipHorizontalGrid property for surface

This property allows drawind the horizontal grid and axis labels on
top of the graph rather than on the bottom. This is useful when
surface graph is used for 2D spectrograms in orthographic mode, as
otherwise the grid is covered by the surface itself. Particularly
relevant for polar plots of the same.

Task-number: QTRD-3184
Change-Id: I9dbcdbfc754e13af52d2cf31a1d9991ef4b241f7
Reviewed-by: Mika Salmela <mika.salmela@digia.com>

1 files changed, 30 insertions, 11 deletions

diff --git a/src/datavisualization/engine/surface3drenderer.cpp b/src/datavisualization/engine/surface3drenderer.cpp
index 60e501f1..5fd59e5e 100644
--- a/src/datavisualization/engine/surface3drenderer.cpp
+++ b/src/datavisualization/engine/surface3drenderer.cpp
@@ -1050,6 +1050,17 @@ void Surface3DRenderer::drawScene(GLuint defaultFboHandle)
     else
         m_xFlipped = true;
 
+    if (m_flipHorizontalGrid) {
+        // Need to determine if camera is below graph top
+        float distanceToCenter = activeCamera->position().length()
+                / activeCamera->zoomLevel() / m_autoScaleAdjustment * 100.0f;
+        qreal cameraAngle = qreal(activeCamera->yRotation()) / 180.0 * M_PI;
+        float cameraYPos = float(qSin(cameraAngle)) * distanceToCenter;
+        m_yFlippedForGrid = cameraYPos < backgroundMargin;
+    } else {
+        m_yFlippedForGrid = m_yFlipped;
+    }
+
     // calculate background rotation based on view matrix rotation
     if (viewMatrix.row(0).x() > 0 && viewMatrix.row(0).z() <= 0)
         backgroundRotation = 270.0f;
@@ -1467,13 +1478,13 @@ void Surface3DRenderer::drawScene(GLuint defaultFboHandle)
         else
             lineYRotation = m_yRightAngleRotation;
 
-        if (m_yFlipped)
+        if (m_yFlippedForGrid)
             lineXRotation = m_xRightAngleRotation;
         else
             lineXRotation = m_xRightAngleRotationNeg;
 
         float yFloorLinePosition = -backgroundMargin + gridLineOffset;
-        if (m_yFlipped)
+        if (m_yFlipped != m_flipHorizontalGrid)
             yFloorLinePosition = -yFloorLinePosition;
 
         // Rows (= Z)
@@ -1844,7 +1855,7 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
     if (m_axisCacheZ.segmentCount() > 0) {
         int labelCount = m_axisCacheZ.labelCount();
         float labelXTrans = 0.0f;
-        float labelYTrans = -backgroundMargin;
+        float labelYTrans = m_flipHorizontalGrid ? backgroundMargin : -backgroundMargin;
         if (m_polarGraph) {
             // TODO optional placement of radial labels - YTrans up only if over background
             labelXTrans = m_scaleXWithBackground + labelMargin;
@@ -1861,7 +1872,7 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
         if (labelAutoAngle == 0.0f) {
             if (m_zFlipped)
                 labelRotation.setY(180.0f);
-            if (m_yFlipped) {
+            if (m_yFlippedForGrid) {
                 if (m_zFlipped)
                     labelRotation.setY(180.0f);
                 else
@@ -1873,7 +1884,7 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
         } else {
             if (m_zFlipped)
                 labelRotation.setY(180.0f);
-            if (m_yFlipped) {
+            if (m_yFlippedForGrid) {
                 if (m_zFlipped) {
                     if (m_xFlipped) {
                         labelRotation.setX(90.0f - (labelAutoAngle - fractionCamX)
@@ -1978,7 +1989,7 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
         int labelCount = m_axisCacheX.labelCount();
 
         GLfloat labelZTrans = 0.0f;
-        GLfloat labelYTrans = -backgroundMargin;
+        float labelYTrans = m_flipHorizontalGrid ? backgroundMargin : -backgroundMargin;
         if (m_polarGraph)
             labelYTrans += gridLineOffset + gridLineWidth;
         else
@@ -1994,7 +2005,7 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
             labelRotation = QVector3D(-90.0f, 90.0f, 0.0f);
             if (m_xFlipped)
                 labelRotation.setY(-90.0f);
-            if (m_yFlipped) {
+            if (m_yFlippedForGrid) {
                 if (m_xFlipped)
                     labelRotation.setY(-90.0f);
                 else
@@ -2006,7 +2017,7 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
                 labelRotation.setY(-90.0f);
             else
                 labelRotation.setY(90.0f);
-            if (m_yFlipped) {
+            if (m_yFlippedForGrid) {
                 if (m_zFlipped) {
                     if (m_xFlipped) {
                         labelRotation.setX(90.0f - (2.0f * labelAutoAngle - fractionCamX)
@@ -2055,10 +2066,12 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
 
         QQuaternion totalRotation = Utils::calculateRotation(labelRotation);
         if (m_polarGraph) {
-            if (m_zFlipped != m_xFlipped)
+            if (!m_yFlippedForGrid && (m_zFlipped != m_xFlipped)
+                    || m_yFlippedForGrid && (m_zFlipped == m_xFlipped)) {
                 totalRotation *= m_zRightAngleRotation;
-            else
+            } else {
                 totalRotation *= m_zRightAngleRotationNeg;
+            }
         }
 
         QVector3D labelTrans = QVector3D(0.0f,
@@ -2108,7 +2121,8 @@ void Surface3DRenderer::drawLabels(bool drawSelection, const Q3DCamera *activeCa
                     hAlignment = m_zFlipped ? Qt::AlignRight : Qt::AlignLeft;
                 else if (gridPosition < 1.0f - centerMargin && gridPosition > 0.5f + centerMargin)
                     hAlignment = m_zFlipped ? Qt::AlignLeft : Qt::AlignRight;
-
+                if (m_yFlippedForGrid && vAlignment != Qt::AlignCenter)
+                    vAlignment = (vAlignment == Qt::AlignTop) ? Qt::AlignBottom : Qt::AlignTop;
                 alignment = Qt::AlignmentFlag(vAlignment | hAlignment);
             } else {
                 labelTrans.setX(m_axisCacheX.labelPosition(label));
@@ -2417,6 +2431,11 @@ void Surface3DRenderer::updateSelectedPoint(const QPoint &position, QSurface3DSe
     m_selectionDirty = true;
 }
 
+void Surface3DRenderer::updateFlipHorizontalGrid(bool flip)
+{
+    m_flipHorizontalGrid = flip;
+}
+
 void Surface3DRenderer::resetClickedStatus()
 {
     m_clickedPosition = Surface3DController::invalidSelectionPosition();