Implement ColorGradient for qml

Reimplementation of qml's Gradient type, which unfortunately cannot be
used by 3rd party modules, as the implementation classes are private.

Task-number: QTRD-2328
Change-Id: Ib984b07f6771d26a9e37fd5f78016b7ba0bd7ce0
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

11 files changed, 347 insertions, 54 deletions

diff --git a/examples/qmlsurface/qml/qmlsurface/main.qml b/examples/qmlsurface/qml/qmlsurface/main.qml
index 758b0346..2e192197 100644
--- a/examples/qmlsurface/qml/qmlsurface/main.qml
+++ b/examples/qmlsurface/qml/qmlsurface/main.qml
@@ -37,10 +37,11 @@ Item {
         height: mainview.height
         anchors.right: mainview.right;
 
-        Gradient {
+        ColorGradient {
             id: surfaceGradient
-            GradientStop { position: 0.0; color: "darkslategray" }
-            GradientStop { position: 1.0; color: "peru" }
+            ColorGradientStop { position: 0.0; color: "darkslategray" }
+            ColorGradientStop { id: middleGradient; position: 0.55; color: "peru" }
+            ColorGradientStop { position: 1.0; color: "red" }
         }
 
         Surface3D {
@@ -66,11 +67,7 @@ Item {
             axisY.segmentCount: 5
             axisY.subSegmentCount: 2
             axisY.labelFormat: "%i"
-            //gradient: surfaceGradient
-            Component.onCompleted: {
-                setGradientColorAt(0, "darkslategray");
-                setGradientColorAt(1, "peru");
-            }
+            gradient: surfaceGradient
         }
     }
 
@@ -147,10 +144,12 @@ Item {
             if (surfaceplot.dataProxy === surfaceData.heightProxy) {
                 surfaceplot.axisY.max = 500.0
                 surfaceplot.dataProxy = surfaceData.proxy
+                middleGradient.position = 0.25
                 text = "Switch to Height Map Proxy"
             } else {
                 surfaceplot.axisY.max = 250.0
                 surfaceplot.dataProxy = surfaceData.heightProxy
+                middleGradient.position = 0.55
                 text = "Switch to Item Model Proxy"
             }
         }
diff --git a/src/datavisualization/data/qsurfacedataproxy.cpp b/src/datavisualization/data/qsurfacedataproxy.cpp
index bd3688dc..1a2e29ce 100644
--- a/src/datavisualization/data/qsurfacedataproxy.cpp
+++ b/src/datavisualization/data/qsurfacedataproxy.cpp
@@ -42,6 +42,8 @@ const qreal defaultMaxValue = 10.0;
  * \note Surfaces with less than two rows or columns are not considered valid surfaces and will
  * not get rendered.
  *
+ * \note The way row and column values are handled is subject to change after technology preview.
+ *
  * QSurfaceDataProxy supports the following format tags for QAbstractDataProxy::setItemLabelFormat():
  * \table
  *   \row
@@ -86,6 +88,8 @@ const qreal defaultMaxValue = 10.0;
  *
  * The minimum value of the range in rows. For instance if function z value varies between -8.0
  * and 8.0 set this property to -8.0.
+ *
+ * \note The way row and column values are handled is subject to change after technology preview.
  */
 
 /*!
@@ -93,6 +97,8 @@ const qreal defaultMaxValue = 10.0;
  *
  * The maximum value of the range in rows. For instance if function z value varies between -8.0
  * and 8.0 set this property to 8.0.
+ *
+ * \note The way row and column values are handled is subject to change after technology preview.
  */
 
 /*!
@@ -100,6 +106,8 @@ const qreal defaultMaxValue = 10.0;
  *
  * The minimum value of the range in columns. For instance if function x value varies between -8.0
  * and 8.0 set this property to -8.0.
+ *
+ * \note The way row and column values are handled is subject to change after technology preview.
  */
 
 /*!
@@ -107,6 +115,8 @@ const qreal defaultMaxValue = 10.0;
  *
  * The maximum value of the range in columns. For instance if function x value varies between -8.0
  * and 8.0 set this property to 8.0.
+ *
+ * \note The way row and column values are handled is subject to change after technology preview.
  */
 
 /*!
diff --git a/src/datavisualization/doc/src/qtdatavisualization-qml-colorgradient.qdoc b/src/datavisualization/doc/src/qtdatavisualization-qml-colorgradient.qdoc
new file mode 100644
index 00000000..98b29c87
--- /dev/null
+++ b/src/datavisualization/doc/src/qtdatavisualization-qml-colorgradient.qdoc
@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc
+** All rights reserved.
+** For any questions to Digia, please use contact form at http://qt.digia.com
+**
+** This file is part of the QtDataVisualization module.
+**
+** Licensees holding valid Qt Enterprise licenses may use this file in
+** accordance with the Qt Enterprise License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.
+**
+** If you have questions regarding the use of this file, please use
+** contact form at http://qt.digia.com
+**
+****************************************************************************/
+
+/*!
+    \qmltype ColorGradientStop
+
+    Defines the color at a position in a ColorGradient.
+
+    \sa ColorGradient
+*/
+
+/*!
+    \qmlproperty real ColorGradientStop::position
+
+    The position property describes the position of this gradient stop.
+
+    The default position is 0.0.
+
+    \sa ColorGradient
+*/
+
+/*!
+    \qmlproperty color ColorGradientStop::color
+
+    The color property describes the color color of this gradient stop.
+
+    The default color is black.
+
+    \sa ColorGradient
+*/
+
+/*!
+    \qmltype ColorGradient
+
+    A gradient is defined by two or more colors, which will be blended seamlessly.
+
+    The colors are specified as a set of ColorGradientStop child items, each of
+    which defines a position on the gradient from 0.0 to 1.0 and a color.
+    The position of each ColorGradientStop is defined by setting its
+    \l{ColorGradientStop::}{position} property; its color is defined using its
+    \l{ColorGradientStop::}{color} property.
+
+    A gradient without any gradient stops falls back to QLinearGradient default,
+    which is black at 0.0 and white at 1.0.
+
+    \sa ColorGradientStop
+*/
+
+/*!
+    \qmlproperty list<ColorGradientStop> ColorGradient::stops
+    \default
+
+    This property holds the gradient stops describing the gradient.
+
+    By default, this property contains an empty list.
+
+    To set the gradient stops, define them as children of the ColorGradient.
+*/
diff --git a/src/datavisualization/doc/src/qtdatavisualization-qml-surface3d.qdoc b/src/datavisualization/doc/src/qtdatavisualization-qml-surface3d.qdoc
index 21c3f474..31d05844 100644
--- a/src/datavisualization/doc/src/qtdatavisualization-qml-surface3d.qdoc
+++ b/src/datavisualization/doc/src/qtdatavisualization-qml-surface3d.qdoc
@@ -82,6 +82,6 @@
  */
 
 /*!
-  \qmlproperty var Surface3D::gradient
+  \qmlproperty ColorGradient Surface3D::gradient
   The current surface gradient. Setting this property replaces the previous gradient.
  */
diff --git a/src/datavisualizationqml2/colorgradient.cpp b/src/datavisualizationqml2/colorgradient.cpp
new file mode 100644
index 00000000..43efbd1c
--- /dev/null
+++ b/src/datavisualizationqml2/colorgradient.cpp
@@ -0,0 +1,75 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc
+** All rights reserved.
+** For any questions to Digia, please use contact form at http://qt.digia.com
+**
+** This file is part of the QtDataVisualization module.
+**
+** Licensees holding valid Qt Enterprise licenses may use this file in
+** accordance with the Qt Enterprise License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.
+**
+** If you have questions regarding the use of this file, please use
+** contact form at http://qt.digia.com
+**
+****************************************************************************/
+
+#include "colorgradient_p.h"
+
+QT_DATAVISUALIZATION_BEGIN_NAMESPACE
+
+ColorGradientStop::ColorGradientStop(QObject *parent)
+    : QObject(parent)
+{
+}
+
+qreal ColorGradientStop::position() const
+{
+    return m_position;
+}
+
+void ColorGradientStop::setPosition(qreal position)
+{
+    m_position = position;
+    updateGradient();
+}
+
+QColor ColorGradientStop::color() const
+{
+    return m_color;
+}
+
+void ColorGradientStop::setColor(const QColor &color)
+{
+    m_color = color;
+    updateGradient();
+}
+
+void ColorGradientStop::updateGradient()
+{
+    if (ColorGradient *grad = qobject_cast<ColorGradient*>(parent()))
+        grad->doUpdate();
+}
+
+ColorGradient::ColorGradient(QObject *parent)
+: QObject(parent)
+{
+}
+
+ColorGradient::~ColorGradient()
+{
+}
+
+QQmlListProperty<ColorGradientStop> ColorGradient::stops()
+{
+    return QQmlListProperty<ColorGradientStop>(this, m_stops);
+}
+
+void ColorGradient::doUpdate()
+{
+    emit updated();
+}
+
+QT_DATAVISUALIZATION_END_NAMESPACE
diff --git a/src/datavisualizationqml2/colorgradient_p.h b/src/datavisualizationqml2/colorgradient_p.h
new file mode 100644
index 00000000..37d3e407
--- /dev/null
+++ b/src/datavisualizationqml2/colorgradient_p.h
@@ -0,0 +1,90 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc
+** All rights reserved.
+** For any questions to Digia, please use contact form at http://qt.digia.com
+**
+** This file is part of the QtDataVisualization module.
+**
+** Licensees holding valid Qt Enterprise licenses may use this file in
+** accordance with the Qt Enterprise License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.
+**
+** If you have questions regarding the use of this file, please use
+** contact form at http://qt.digia.com
+**
+****************************************************************************/
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the QtDataVisualization API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+
+#ifndef COLORGRADIENT_P_H
+#define COLORGRADIENT_P_H
+
+#include "datavisualizationglobal_p.h"
+#include <QColor>
+#include <QQmlListProperty>
+
+QT_DATAVISUALIZATION_BEGIN_NAMESPACE
+
+class ColorGradientStop : public QObject
+{
+    Q_OBJECT
+
+    Q_PROPERTY(qreal position READ position WRITE setPosition)
+    Q_PROPERTY(QColor color READ color WRITE setColor)
+
+public:
+    ColorGradientStop(QObject *parent = 0);
+
+    qreal position() const;
+    void setPosition(qreal position);
+
+    QColor color() const;
+    void setColor(const QColor &color);
+
+private:
+    void updateGradient();
+
+private:
+    qreal m_position;
+    QColor m_color;
+};
+
+class ColorGradient : public QObject
+{
+    Q_OBJECT
+
+    Q_PROPERTY(QQmlListProperty<ColorGradientStop> stops READ stops)
+    Q_CLASSINFO("DefaultProperty", "stops")
+
+public:
+    ColorGradient(QObject *parent = 0);
+    ~ColorGradient();
+
+    QQmlListProperty<ColorGradientStop> stops();
+
+Q_SIGNALS:
+    void updated();
+
+private:
+    void doUpdate();
+
+private:
+    QList<ColorGradientStop *> m_stops;
+
+    friend class ColorGradientStop;
+    friend class DeclarativeSurface;
+};
+
+QT_DATAVISUALIZATION_END_NAMESPACE
+
+#endif
diff --git a/src/datavisualizationqml2/datavisualizationqml2.pro b/src/datavisualizationqml2/datavisualizationqml2.pro
index 68e267ed..d5191c62 100644
--- a/src/datavisualizationqml2/datavisualizationqml2.pro
+++ b/src/datavisualizationqml2/datavisualizationqml2.pro
@@ -24,7 +24,8 @@ SOURCES += \
     declarativescatterrenderer.cpp \
     declarativesurface.cpp \
     declarativesurfacerenderer.cpp \
-    abstractdeclarative.cpp
+    abstractdeclarative.cpp \
+    colorgradient.cpp
 
 HEADERS += \
     datavisualizationqml2_plugin.h \
@@ -34,7 +35,8 @@ HEADERS += \
     declarativescatterrenderer_p.h \
     declarativesurface_p.h \
     declarativesurfacerenderer_p.h \
-    abstractdeclarative_p.h
+    abstractdeclarative_p.h \
+    colorgradient_p.h
 
 OTHER_FILES = qmldir
 
diff --git a/src/datavisualizationqml2/datavisualizationqml2_plugin.cpp b/src/datavisualizationqml2/datavisualizationqml2_plugin.cpp
index f5642831..10fc7f4c 100644
--- a/src/datavisualizationqml2/datavisualizationqml2_plugin.cpp
+++ b/src/datavisualizationqml2/datavisualizationqml2_plugin.cpp
@@ -25,8 +25,6 @@ QT_DATAVISUALIZATION_BEGIN_NAMESPACE
 void Datavis3Dqml2Plugin::registerTypes(const char *uri)
 {
     // @uri com.digia.QtDataVisualization
-    qmlRegisterUncreatableType<QLinearGradient>(uri, 1, 0, "LinearGradient",
-                                                QLatin1String("Trying to create uncreatable: LinearGradient."));
     qmlRegisterUncreatableType<const QAbstractItemModel>(uri, 1, 0, "AbstractItemModel",
                                                          QLatin1String("Trying to create uncreatable: AbstractItemModel."));
     qmlRegisterUncreatableType<QDataVis>(uri, 1, 0, "DataVis",
@@ -59,6 +57,10 @@ void Datavis3Dqml2Plugin::registerTypes(const char *uri)
     qmlRegisterType<QItemModelScatterDataProxy>(uri, 1, 0, "ItemModelScatterDataProxy");
     qmlRegisterType<QItemModelSurfaceDataProxy>(uri, 1, 0, "ItemModelSurfaceDataProxy");
     qmlRegisterType<QHeightMapSurfaceDataProxy>(uri, 1, 0, "HeightMapSurfaceDataProxy");
+
+    qmlRegisterType<ColorGradientStop>(uri, 1, 0, "ColorGradientStop");
+    qmlRegisterType<ColorGradient>(uri, 1, 0, "ColorGradient");
+
 }
 
 QT_DATAVISUALIZATION_END_NAMESPACE
diff --git a/src/datavisualizationqml2/datavisualizationqml2_plugin.h b/src/datavisualizationqml2/datavisualizationqml2_plugin.h
index 31066c47..66b5cb61 100644
--- a/src/datavisualizationqml2/datavisualizationqml2_plugin.h
+++ b/src/datavisualizationqml2/datavisualizationqml2_plugin.h
@@ -37,32 +37,33 @@
 
 QT_DATAVISUALIZATION_USE_NAMESPACE
 
-Q_DECLARE_METATYPE(AbstractDeclarative *)
-Q_DECLARE_METATYPE(DeclarativeBars *)
-Q_DECLARE_METATYPE(DeclarativeScatter *)
-Q_DECLARE_METATYPE(DeclarativeSurface *)
-
-Q_DECLARE_METATYPE(QItemModelBarDataMapping *)
-Q_DECLARE_METATYPE(QItemModelScatterDataMapping *)
-Q_DECLARE_METATYPE(QItemModelSurfaceDataMapping *)
-
-Q_DECLARE_METATYPE(const QAbstractItemModel *)
-Q_DECLARE_METATYPE(QLinearGradient)
-
-Q_DECLARE_METATYPE(QDataVis *)
-
-Q_DECLARE_METATYPE(Q3DAbstractAxis *)
-Q_DECLARE_METATYPE(Q3DCategoryAxis *)
-Q_DECLARE_METATYPE(Q3DValueAxis *)
-
-Q_DECLARE_METATYPE(QAbstractDataProxy *)
-Q_DECLARE_METATYPE(QBarDataProxy *)
-Q_DECLARE_METATYPE(QItemModelBarDataProxy *)
-Q_DECLARE_METATYPE(QScatterDataProxy *)
-Q_DECLARE_METATYPE(QItemModelScatterDataProxy *)
-Q_DECLARE_METATYPE(QSurfaceDataProxy *)
-Q_DECLARE_METATYPE(QItemModelSurfaceDataProxy *)
-Q_DECLARE_METATYPE(QHeightMapSurfaceDataProxy *)
+QML_DECLARE_TYPE(AbstractDeclarative)
+QML_DECLARE_TYPE(DeclarativeBars)
+QML_DECLARE_TYPE(DeclarativeScatter)
+QML_DECLARE_TYPE(DeclarativeSurface)
+
+QML_DECLARE_TYPE(QItemModelBarDataMapping)
+QML_DECLARE_TYPE(QItemModelScatterDataMapping)
+QML_DECLARE_TYPE(QItemModelSurfaceDataMapping)
+
+QML_DECLARE_TYPE(const QAbstractItemModel)
+QML_DECLARE_TYPE(QDataVis)
+
+QML_DECLARE_TYPE(Q3DAbstractAxis)
+QML_DECLARE_TYPE(Q3DCategoryAxis)
+QML_DECLARE_TYPE(Q3DValueAxis)
+
+QML_DECLARE_TYPE(QAbstractDataProxy)
+QML_DECLARE_TYPE(QBarDataProxy)
+QML_DECLARE_TYPE(QItemModelBarDataProxy)
+QML_DECLARE_TYPE(QScatterDataProxy)
+QML_DECLARE_TYPE(QItemModelScatterDataProxy)
+QML_DECLARE_TYPE(QSurfaceDataProxy)
+QML_DECLARE_TYPE(QItemModelSurfaceDataProxy)
+QML_DECLARE_TYPE(QHeightMapSurfaceDataProxy)
+
+QML_DECLARE_TYPE(ColorGradientStop)
+QML_DECLARE_TYPE(ColorGradient)
 
 QT_DATAVISUALIZATION_BEGIN_NAMESPACE
 
diff --git a/src/datavisualizationqml2/declarativesurface.cpp b/src/datavisualizationqml2/declarativesurface.cpp
index f74472f5..8375fa53 100644
--- a/src/datavisualizationqml2/declarativesurface.cpp
+++ b/src/datavisualizationqml2/declarativesurface.cpp
@@ -27,7 +27,8 @@ QT_DATAVISUALIZATION_BEGIN_NAMESPACE
 DeclarativeSurface::DeclarativeSurface(QQuickItem *parent)
     : AbstractDeclarative(parent),
       m_shared(0),
-      m_initialisedSize(0, 0)
+      m_initialisedSize(0, 0),
+      m_gradient(0)
 {
     setFlags(QQuickItem::ItemHasContents);
     setAcceptedMouseButtons(Qt::AllButtons);
@@ -49,6 +50,12 @@ DeclarativeSurface::~DeclarativeSurface()
     delete m_shared;
 }
 
+void DeclarativeSurface::handleGradientUpdate()
+{
+    if (m_gradient)
+        setControllerGradient(*m_gradient);
+}
+
 QSGNode *DeclarativeSurface::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
 {
     // If old node exists and has right size, reuse it.
@@ -72,11 +79,6 @@ QSGNode *DeclarativeSurface::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeDa
     return node;
 }
 
-void DeclarativeSurface::setGradientColorAt(qreal pos, const QColor &color)
-{
-    m_shared->setGradientColorAt(pos, color);
-}
-
 void DeclarativeSurface::setDataProxy(QSurfaceDataProxy *dataProxy)
 {
     m_shared->setActiveDataProxy(dataProxy);
@@ -137,14 +139,47 @@ bool DeclarativeSurface::isSurfaceGridEnabled() const
     return m_shared->surfaceGrid();
 }
 
-void DeclarativeSurface::setGradient(const QLinearGradient &gradient)
+void DeclarativeSurface::setGradient(ColorGradient *gradient)
 {
-    m_shared->setGradient(gradient);
+    // connect new / disconnect old
+    if (gradient != m_gradient) {
+        if (m_gradient)
+            QObject::disconnect(m_gradient, 0, this, 0);
+
+        m_gradient = gradient;
+
+        if (m_gradient) {
+            QObject::connect(m_gradient, &ColorGradient::updated, this,
+                             &DeclarativeSurface::handleGradientUpdate);
+        }
+    }
+
+    if (m_gradient)
+        setControllerGradient(*m_gradient);
+}
+
+ColorGradient *DeclarativeSurface::gradient() const
+{
+
+    return m_gradient;
 }
 
-QLinearGradient DeclarativeSurface::gradient() const
+void DeclarativeSurface::setControllerGradient(const ColorGradient &gradient)
 {
-    return m_shared->gradient();
+    QLinearGradient newGradient;
+    QGradientStops stops;
+    QList<ColorGradientStop *> qmlstops = gradient.m_stops;
+
+    // Get sorted gradient stops
+    for (int i = 0; i < qmlstops.size(); i++) {
+        int j = 0;
+        while (j < stops.size() && stops.at(j).first < qmlstops[i]->position())
+            j++;
+        stops.insert(j, QGradientStop(qmlstops.at(i)->position(), qmlstops.at(i)->color()));
+    }
+
+    newGradient.setStops(stops);
+    m_shared->setGradient(newGradient);
 }
 
 QT_DATAVISUALIZATION_END_NAMESPACE
diff --git a/src/datavisualizationqml2/declarativesurface_p.h b/src/datavisualizationqml2/declarativesurface_p.h
index 29db1a44..6ba52146 100644
--- a/src/datavisualizationqml2/declarativesurface_p.h
+++ b/src/datavisualizationqml2/declarativesurface_p.h
@@ -35,6 +35,7 @@
 #include "declarativesurface_p.h"
 #include "q3dvalueaxis.h"
 #include "qsurfacedataproxy.h"
+#include "colorgradient_p.h"
 
 #include <QAbstractItemModel>
 #include <QQuickItem>
@@ -52,14 +53,12 @@ class DeclarativeSurface : public AbstractDeclarative
     Q_PROPERTY(Q3DValueAxis *axisZ READ axisZ WRITE setAxisZ)
     Q_PROPERTY(bool smoothSurfaceEnabled READ isSmoothSurfaceEnabled WRITE setSmoothSurfaceEnabled)
     Q_PROPERTY(bool surfaceGridEnabled READ isSurfaceGridEnabled WRITE setSurfaceGridEnabled)
-    Q_PROPERTY(QLinearGradient gradient READ gradient WRITE setGradient)
+    Q_PROPERTY(ColorGradient *gradient READ gradient WRITE setGradient)
 
 public:
     explicit DeclarativeSurface(QQuickItem *parent = 0);
     ~DeclarativeSurface();
 
-    Q_INVOKABLE void setGradientColorAt(qreal pos, const QColor &color);
-
     QSurfaceDataProxy *dataProxy() const;
     void setDataProxy(QSurfaceDataProxy *dataProxy);
 
@@ -76,14 +75,21 @@ public:
     void setSurfaceGridEnabled(bool enabled);
     bool isSurfaceGridEnabled() const;
 
-    void setGradient(const QLinearGradient &gradient);
-    QLinearGradient gradient() const;
+    void setGradient(ColorGradient *gradient);
+    ColorGradient *gradient() const;
+
 protected:
+    void handleGradientUpdate();
+
     QSGNode *updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *);
 
 private:
     Surface3DController *m_shared;
+
+    void setControllerGradient(const ColorGradient &gradient);
+
     QSize m_initialisedSize;
+    ColorGradient *m_gradient; // Not owned
 };
 
 QT_DATAVISUALIZATION_END_NAMESPACE