AbstractButton: add support for icons

This patch adds the following properties to AbstractButton:

- icon.name
- icon.source
- icon.width
- icon.height
- icon.color

Derived types implement the behavior behind these properties
using the new private IconImage type.

[ChangeLog][Controls][AbstractButton] Added support for icons. The
following properties are now available for derived types to use:
icon.name, icon.source, icon.width, icon.height, icon.color.

Task-number: QTBUG-49820
Change-Id: I3b5e4eaac390543deef60883e13539646a6bb060
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>

6 files changed, 99 insertions, 2 deletions

diff --git a/src/imports/controls/doc/src/includes/qquickicon.qdocinc b/src/imports/controls/doc/src/includes/qquickicon.qdocinc
new file mode 100644
index 00000000..1bfa0119
--- /dev/null
+++ b/src/imports/controls/doc/src/includes/qquickicon.qdocinc
@@ -0,0 +1,36 @@
+//! [grouped-properties]
+\table
+\header
+    \li Name
+    \li Description
+\row
+    \li name
+    \li This property holds the name of the icon to use.
+
+    The icon will be loaded from the platform theme. If the icon is found
+    in the theme, it will always be used; even if \l icon.source is also set.
+    If the icon is not found, \l icon.source will be used instead.
+
+    For more information on theme icons, see \l {QIcon::fromTheme()}.
+\row
+    \li source
+    \li This property holds the name of the icon to use.
+
+    The icon will be loaded as a regular image.
+
+    If \l icon.name is set and refers to a valid theme icon, it will always
+    be used instead of this property.
+\row
+    \li width
+    \li This property holds the width of the icon.
+
+        The icon's width will never exceed this value, though it will
+        shrink when necessary.
+\row
+    \li height
+    \li This property holds the height of the icon.
+
+        The icon's height will never exceed this value, though it will
+        shrink when necessary.
+\endtable
+//! [grouped-properties]
diff --git a/src/imports/controls/qtquickcontrols2plugin.cpp b/src/imports/controls/qtquickcontrols2plugin.cpp
index 3a131511..084a24ba 100644
--- a/src/imports/controls/qtquickcontrols2plugin.cpp
+++ b/src/imports/controls/qtquickcontrols2plugin.cpp
@@ -153,7 +153,7 @@ void QtQuickControls2Plugin::registerTypes(const char *uri)
     qmlRegisterType(selector.select(QStringLiteral("DelayButton.qml")), uri, 2, 2, "DelayButton");
     qmlRegisterType(selector.select(QStringLiteral("ScrollView.qml")), uri, 2, 2, "ScrollView");
 
-    // QtQuick.Templates 2.3 (new types and revisions in Qt 5.10)
+    // QtQuick.Controls 2.3 (new types in Qt 5.10)
     qmlRegisterType<QQuickIcon>();
 }
 
diff --git a/src/imports/templates/qtquicktemplates2plugin.cpp b/src/imports/templates/qtquicktemplates2plugin.cpp
index 6816df96..a37fa977 100644
--- a/src/imports/templates/qtquicktemplates2plugin.cpp
+++ b/src/imports/templates/qtquicktemplates2plugin.cpp
@@ -255,6 +255,7 @@ void QtQuickTemplates2Plugin::registerTypes(const char *uri)
 
     // QtQuick.Templates 2.3 (new types and revisions in Qt 5.10)
     qmlRegisterType<QQuickIcon>();
+    qmlRegisterType<QQuickAbstractButton, 3>(uri, 2, 3, "AbstractButton");
 }
 
 QT_END_NAMESPACE
diff --git a/src/quicktemplates2/qquickabstractbutton.cpp b/src/quicktemplates2/qquickabstractbutton.cpp
index 225ab9ab..0a2c7e6d 100644
--- a/src/quicktemplates2/qquickabstractbutton.cpp
+++ b/src/quicktemplates2/qquickabstractbutton.cpp
@@ -37,6 +37,7 @@
 #include "qquickabstractbutton_p.h"
 #include "qquickabstractbutton_p_p.h"
 #include "qquickbuttongroup_p.h"
+#include "qquickicon_p.h"
 
 #include <QtGui/qstylehints.h>
 #include <QtGui/qguiapplication.h>
@@ -63,6 +64,34 @@ static const int AUTO_REPEAT_INTERVAL = 100;
     radio buttons and check boxes. As an abstract control, it has no delegate
     implementations, leaving them to the types that derive from it.
 
+    \section1 Button Icons
+
+    AbstractButton provides the following properties through which icons can
+    be set:
+
+    \list
+    \li \l icon.name
+    \li \l icon.source
+    \li \l icon.width
+    \li \l icon.height
+    \li \l icon.color
+    \endlist
+
+    For applications that target platforms that support both
+    \l {QIcon::fromTheme()}{theme icons} and regular icons,
+    both \l icon.name and \l icon.source can be set to ensure that an icon will
+    always be found. If the icon is found in the theme, it will always be used;
+    even if \l icon.source is also set. If the icon is not found,
+    \l icon.source will be used instead.
+
+    Each \l {Styling Qt Quick Controls 2}{style} sets a default size for
+    icons, but it is possible to override this by setting the \l icon.width and
+    \l icon.height properties. The image that is loaded by an icon whose
+    \c width and \c height are not set depends on the type of icon in use. For
+    theme icons, the closest available size will be chosen. For regular icons,
+    the behavior is the same as the \l {Image::}{sourceSize} property of
+    \l Image.
+
     \sa ButtonGroup, {Button Controls}
 */
 
@@ -127,7 +156,8 @@ QQuickAbstractButtonPrivate::QQuickAbstractButtonPrivate()
       repeatTimer(0),
       repeatButton(Qt::NoButton),
       indicator(nullptr),
-      group(nullptr)
+      group(nullptr),
+      icon(nullptr)
 {
 }
 
@@ -559,6 +589,29 @@ void QQuickAbstractButton::setIndicator(QQuickItem *indicator)
 }
 
 /*!
+    \qmlpropertygroup QtQuick.Controls::AbstractButton::icon
+    \qmlproperty string QtQuick.Controls::AbstractButton::icon.name
+    \qmlproperty string QtQuick.Controls::AbstractButton::icon.source
+    \qmlproperty int QtQuick.Controls::AbstractButton::icon.width
+    \qmlproperty int QtQuick.Controls::AbstractButton::icon.height
+    \qmlproperty color QtQuick.Controls::AbstractButton::icon.color
+
+    This property group was added in QtQuick.Controls 2.3.
+
+    \include qquickicon.qdocinc grouped-properties
+
+    \sa {Control::}{contentItem}
+*/
+
+QQuickIcon *QQuickAbstractButton::icon() const
+{
+    QQuickAbstractButtonPrivate *d = const_cast<QQuickAbstractButtonPrivate*>(d_func());
+    if (!d->icon)
+        d->icon = new QQuickIcon(const_cast<QQuickAbstractButton*>(this));
+    return d->icon;
+}
+
+/*!
     \qmlmethod void QtQuick.Controls::AbstractButton::toggle()
 
     Toggles the checked state of the button.
diff --git a/src/quicktemplates2/qquickabstractbutton_p.h b/src/quicktemplates2/qquickabstractbutton_p.h
index 28a59c00..42af6650 100644
--- a/src/quicktemplates2/qquickabstractbutton_p.h
+++ b/src/quicktemplates2/qquickabstractbutton_p.h
@@ -52,6 +52,8 @@
 
 QT_BEGIN_NAMESPACE
 
+class QQuickIcon;
+
 class QQuickAbstractButtonPrivate;
 
 class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickAbstractButton : public QQuickControl
@@ -64,6 +66,7 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickAbstractButton : public QQuickContr
     Q_PROPERTY(bool checkable READ isCheckable WRITE setCheckable NOTIFY checkableChanged FINAL)
     Q_PROPERTY(bool autoExclusive READ autoExclusive WRITE setAutoExclusive NOTIFY autoExclusiveChanged FINAL)
     Q_PROPERTY(QQuickItem *indicator READ indicator WRITE setIndicator NOTIFY indicatorChanged FINAL)
+    Q_PROPERTY(QQuickIcon *icon READ icon CONSTANT FINAL REVISION 3)
 
 public:
     explicit QQuickAbstractButton(QQuickItem *parent = nullptr);
@@ -94,6 +97,8 @@ public:
     QQuickItem *indicator() const;
     void setIndicator(QQuickItem *indicator);
 
+    QQuickIcon *icon() const;
+
 public Q_SLOTS:
     void toggle();
 
diff --git a/src/quicktemplates2/qquickabstractbutton_p_p.h b/src/quicktemplates2/qquickabstractbutton_p_p.h
index e27f5c82..388e5517 100644
--- a/src/quicktemplates2/qquickabstractbutton_p_p.h
+++ b/src/quicktemplates2/qquickabstractbutton_p_p.h
@@ -54,6 +54,7 @@
 QT_BEGIN_NAMESPACE
 
 class QQuickButtonGroup;
+class QQuickIcon;
 
 class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickAbstractButtonPrivate : public QQuickControlPrivate
 {
@@ -103,6 +104,7 @@ public:
     Qt::MouseButton repeatButton;
     QQuickItem *indicator;
     QQuickButtonGroup *group;
+    QQuickIcon *icon;
 };
 
 QT_END_NAMESPACE