Gradient to highlight series

Added a gradient to highlight series on textured surface example.

Change-Id: I2fc17dfa79f986cf5b651d964eb3bcf5d65f1c80
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

8 files changed, 114 insertions, 28 deletions

diff --git a/examples/datavisualization/texturesurface/custominputhandler.cpp b/examples/datavisualization/texturesurface/custominputhandler.cpp
index 0f79feef..2510df54 100644
--- a/examples/datavisualization/texturesurface/custominputhandler.cpp
+++ b/examples/datavisualization/texturesurface/custominputhandler.cpp
@@ -21,8 +21,6 @@
 #include <QtDataVisualization/Q3DCamera>
 #include <QtCore/qmath.h>
 
-#include <QDebug>
-
 CustomInputHandler::CustomInputHandler(QAbstract3DGraph *graph, QObject *parent) :
     Q3DInputHandler(parent),
     m_highlight(0),
diff --git a/examples/datavisualization/texturesurface/custominputhandler.h b/examples/datavisualization/texturesurface/custominputhandler.h
index 5307a6be..8bef990e 100644
--- a/examples/datavisualization/texturesurface/custominputhandler.h
+++ b/examples/datavisualization/texturesurface/custominputhandler.h
@@ -40,15 +40,15 @@ class CustomInputHandler : public Q3DInputHandler
 public:
     explicit CustomInputHandler(QAbstract3DGraph *graph, QObject *parent = 0);
 
-    inline void setLimits(float min, float max) {
+    inline void setLimits(float min, float max, float minRange) {
         m_areaMinValue = min;
         m_areaMaxValue = max;
         m_axisXMinValue = m_areaMinValue;
         m_axisXMaxValue = m_areaMaxValue;
         m_axisZMinValue = m_areaMinValue;
         m_axisZMaxValue = m_areaMaxValue;
-        m_axisXMinRange = (m_areaMaxValue - m_areaMinValue) * 0.49f;
-        m_axisZMinRange = (m_areaMaxValue - m_areaMinValue) * 0.49f;
+        m_axisXMinRange = minRange;
+        m_axisZMinRange = minRange;
     }
     inline void setAxes(QValue3DAxis *axisX, QValue3DAxis *axisY, QValue3DAxis *axisZ) {
         m_axisX = axisX;
diff --git a/examples/datavisualization/texturesurface/doc/src/texturesurface.qdoc b/examples/datavisualization/texturesurface/doc/src/texturesurface.qdoc
index a4aa219e..483b8110 100644
--- a/examples/datavisualization/texturesurface/doc/src/texturesurface.qdoc
+++ b/examples/datavisualization/texturesurface/doc/src/texturesurface.qdoc
@@ -21,14 +21,15 @@
     \title Textured Surface Example
     \ingroup qtdatavisualization_examples
     \brief Using texture with Q3DSurface.
+    \since QtDataVisualization 1.2
 
     The textured surface example shows how to add an image as a texture for a surface. The example
     shows also how to:
 
     \list
         \li Create a surface series from an image
-        \li Highlight an area of the surface
         \li Use custom input handler to enable zooming and panning
+        \li Highlight an area of the surface
     \endlist
 
     \image texturesurface-example.png
@@ -64,6 +65,28 @@
     And then the actual decoding.
     \snippet texturesurface/topographicseries.cpp 1
 
+    \section1 Use custom input handler to enable zooming and panning
+
+    For the panning the implementation is similar to the \l{Axis Range Dragging With Labels Example}.
+    The difference is that in this example we follow only dragging of X and Z axis and we don't
+    allow dragging the surface outside the graph. The control for this is very simple and done as
+    on the following example for the X axis.
+
+    \snippet texturesurface/custominputhandler.cpp 0
+
+    For the zooming we catch the \c wheelEvent and adjust the X and Y axis ranges according to delta
+    value on QWheelEvent. The Y axis is also adjusted so that the aspect ratio between Y axis and
+    XZ plane stays the same, and we don't get silly looking graph with height exaggerated too much.
+
+    \snippet texturesurface/custominputhandler.cpp 1
+
+    In this case we want to control the zoom level so that it won't get too near to or far from the
+    surface. For instance, if the value for the X axis gets below the allowed, i.e. zooming gets too
+    far, the value is set to the minimum allowed value. If the range is going to below the range
+    minimum, both ends of the axis are adjusted so that the range stays at the limit.
+
+    \snippet texturesurface/custominputhandler.cpp 2
+
     \section1 Highlight an area of the surface
 
     The main idea on creating a highlight on the surface is to create a copy of the series and add
@@ -81,25 +104,23 @@
 
     \snippet texturesurface/highlightseries.cpp 1
 
-    \section1 Use custom input handler to enable zooming and panning
+    \section1 A gradient to the highlight series
 
-    For the panning the implementation is similar to the \l{Axis Range Dragging With Labels Example}.
-    The difference is that in this example we follow only dragging of X and Z axis and we don't
-    allow dragging the surface outside the graph. The control for this is very simple and done as
-    on the following example for the X axis.
+    Since the \c HighlightSeries is QSurface3DSeries, we can use all the decoration methods series can
+    have. In this example we added a gradient to emphasize the elevation. Because the suitable gradient
+    style depends on the range of the Y axis and we change the range when zooming, we need to adjust
+    the gradient color positions as the range change.
 
-    \snippet texturesurface/custominputhandler.cpp 0
+    For the gradient color positions we define proportional values.
 
-    For the zooming we catch the \c wheelEvent and adjust the X and Y axis ranges according to delta
-    value on QWheelEvent. The Y axis is also adjusted so that the aspect ratio between Y axis and
-    XZ plane stays the same, and we don't get silly looking graph with height exaggerated too much.
+    \snippet texturesurface/highlightseries.cpp 2
 
-    \snippet texturesurface/custominputhandler.cpp 1
+    The gradient modification is done on \c handleGradientChange method and we connect it to react to
+    changes on Y axis.
 
-    In this case we want to control the zoom level so that it won't get too near to or far from the
-    surface. For instance, if the value for the X axis gets below the allowed, i.e. zooming gets too
-    far, the value is set to the minimum allowed value. If the range is going to below the range
-    minimum, both ends of the axis are adjusted so that the range stays at the limit.
+    \snippet texturesurface/surfacegraph.cpp 1
 
-    \snippet texturesurface/custominputhandler.cpp 2
+    When a change on Y axis max value happens, we calculate the gradient color positions.
+
+    \snippet texturesurface/highlightseries.cpp 3
 */
diff --git a/examples/datavisualization/texturesurface/highlightseries.cpp b/examples/datavisualization/texturesurface/highlightseries.cpp
index 7e5f7efb..13d1fba3 100644
--- a/examples/datavisualization/texturesurface/highlightseries.cpp
+++ b/examples/datavisualization/texturesurface/highlightseries.cpp
@@ -18,10 +18,16 @@
 
 #include "highlightseries.h"
 
-#include <QDebug>
-
 using namespace QtDataVisualization;
 
+//! [2]
+const float darkRedPos = 1.0f;
+const float redPos = 0.8f;
+const float yellowPos = 0.6f;
+const float greenPos = 0.4f;
+const float darkGreenPos = 0.2f;
+//! [2]
+
 HighlightSeries::HighlightSeries()
     : m_width(100),
       m_height(100)
@@ -93,3 +99,21 @@ void HighlightSeries::handlePositionChange(const QPoint &position)
     setVisible(true);
 }
 //! [1]
+
+//! [3]
+void HighlightSeries::handleGradientChange(float value)
+{
+    float ratio = m_minHeight / value;
+
+    QLinearGradient gr;
+    gr.setColorAt(0.0f, Qt::black);
+    gr.setColorAt(darkGreenPos * ratio, Qt::darkGreen);
+    gr.setColorAt(greenPos * ratio, Qt::green);
+    gr.setColorAt(yellowPos * ratio, Qt::yellow);
+    gr.setColorAt(redPos * ratio, Qt::red);
+    gr.setColorAt(darkRedPos * ratio, Qt::darkRed);
+
+    setBaseGradient(gr);
+    setColorStyle(Q3DTheme::ColorStyleRangeGradient);
+}
+//! [3]
diff --git a/examples/datavisualization/texturesurface/highlightseries.h b/examples/datavisualization/texturesurface/highlightseries.h
index 36361fbc..aa1590e5 100644
--- a/examples/datavisualization/texturesurface/highlightseries.h
+++ b/examples/datavisualization/texturesurface/highlightseries.h
@@ -33,9 +33,11 @@ public:
     ~HighlightSeries();
 
     void setTopographicSeries(TopographicSeries *series);
+    inline void setMinHeight(float height) { m_minHeight = height; }
 
 public slots:
     void handlePositionChange(const QPoint &position);
+    void handleGradientChange(float value);
 
 private:
     int m_width;
@@ -44,6 +46,7 @@ private:
     int m_srcHeight;
     QPoint m_position;
     TopographicSeries *m_topographicSeries;
+    float m_minHeight;
 };
 
 #endif // HIGHLIGHTSERIES_H
diff --git a/examples/datavisualization/texturesurface/main.cpp b/examples/datavisualization/texturesurface/main.cpp
index e73dc864..ed1a9be4 100644
--- a/examples/datavisualization/texturesurface/main.cpp
+++ b/examples/datavisualization/texturesurface/main.cpp
@@ -22,8 +22,11 @@
 #include <QtWidgets/QWidget>
 #include <QtWidgets/QHBoxLayout>
 #include <QtWidgets/QVBoxLayout>
+#include <QtWidgets/QGroupBox>
 #include <QtWidgets/QCheckBox>
+#include <QtWidgets/QLabel>
 #include <QtGui/QScreen>
+#include <QtGui/QPainter>
 
 int main(int argc, char **argv)
 {
@@ -49,7 +52,41 @@ int main(int argc, char **argv)
     QCheckBox *enableTexture = new QCheckBox(widget);
     enableTexture->setText(QStringLiteral("Surface texture"));
 
+    int height = 400;
+    int width = 100;
+    int border = 10;
+    QLinearGradient gr(0, 0, 1, height - 2 * border);
+    gr.setColorAt(1.0f, Qt::black);
+    gr.setColorAt(0.8f, Qt::darkGreen);
+    gr.setColorAt(0.6f, Qt::green);
+    gr.setColorAt(0.4f, Qt::yellow);
+    gr.setColorAt(0.2f, Qt::red);
+    gr.setColorAt(0.0f, Qt::darkRed);
+
+    QPixmap pm(width, height);
+    pm.fill(Qt::transparent);
+    QPainter pmp(&pm);
+    pmp.setBrush(QBrush(gr));
+    pmp.setPen(Qt::NoPen);
+    pmp.drawRect(border, border, 35, height - 2 * border);
+    pmp.setPen(Qt::black);
+    int step = (height - 2 * border) / 5;
+    for (int i = 0; i < 6; i++) {
+        int yPos = i * step + border;
+        pmp.drawLine(border, yPos, 55, yPos);
+        pmp.drawText(60, yPos + 2, QString("%1 m").arg(550 - (i * 110)));
+    }
+
+    QLabel *label = new QLabel(widget);
+    label->setPixmap(pm);
+
+    QGroupBox *heightMapGroupBox = new QGroupBox(QStringLiteral("Height color map"));
+    QVBoxLayout *colorMapVBox = new QVBoxLayout;
+    colorMapVBox->addWidget(label);
+    heightMapGroupBox->setLayout(colorMapVBox);
+
     vLayout->addWidget(enableTexture);
+    vLayout->addWidget(heightMapGroupBox);
 
     widget->show();
 
diff --git a/examples/datavisualization/texturesurface/surfacegraph.cpp b/examples/datavisualization/texturesurface/surfacegraph.cpp
index f85ef5c8..785cf576 100644
--- a/examples/datavisualization/texturesurface/surfacegraph.cpp
+++ b/examples/datavisualization/texturesurface/surfacegraph.cpp
@@ -22,13 +22,12 @@
 #include <QtDataVisualization/QValue3DAxis>
 #include <QtDataVisualization/Q3DTheme>
 
-#include <QDebug>
-
 using namespace QtDataVisualization;
 
 const float areaWidth = 8000.0f;
 const float areaHeight = 8000.0f;
 const float aspectRatio = 0.1389f;
+const float minRange = areaWidth * 0.49f;
 
 SurfaceGraph::SurfaceGraph(Q3DSurface *surface)
     : m_graph(surface)
@@ -56,6 +55,12 @@ SurfaceGraph::SurfaceGraph(Q3DSurface *surface)
 
     m_highlight = new HighlightSeries();
     m_highlight->setTopographicSeries(m_topography);
+    m_highlight->setMinHeight(minRange * aspectRatio);
+    m_highlight->handleGradientChange(areaWidth * aspectRatio);
+//! [1]
+    QObject::connect(m_graph->axisY(), &QValue3DAxis::maxChanged,
+                     m_highlight, &HighlightSeries::handleGradientChange);
+//! [1]
 
     m_graph->addSeries(m_topography);
     m_graph->addSeries(m_highlight);
@@ -63,7 +68,7 @@ SurfaceGraph::SurfaceGraph(Q3DSurface *surface)
     m_inputHandler = new CustomInputHandler(m_graph);
     m_inputHandler->setHighlightSeries(m_highlight);
     m_inputHandler->setAxes(m_graph->axisX(), m_graph->axisY(), m_graph->axisZ());
-    m_inputHandler->setLimits(0.0f, areaWidth);
+    m_inputHandler->setLimits(0.0f, areaWidth, minRange);
     m_inputHandler->setAspectRatio(aspectRatio);
 
     m_graph->setActiveInputHandler(m_inputHandler);
diff --git a/examples/datavisualization/texturesurface/topographicseries.cpp b/examples/datavisualization/texturesurface/topographicseries.cpp
index a1c61f56..2fa29d35 100644
--- a/examples/datavisualization/texturesurface/topographicseries.cpp
+++ b/examples/datavisualization/texturesurface/topographicseries.cpp
@@ -18,8 +18,6 @@
 
 #include "topographicseries.h"
 
-#include <QDebug>
-
 using namespace QtDataVisualization;
 
 //! [0]