push button: Allow for animations when clicking

Which e.g. the Material 3 style does

skins/material3/QskMaterial3Skin.cpp

@@ -476,11 +476,16 @@ void Editor::setupPushButton()
 
     setGradient( Q::Panel | Q::Pressed, focusColor );
 
+    // we cannot use relative size here because the rect changes size during the animation:
+    setBoxShape( Q::Ripple, 15.5 );
+    setGradient( Q::Ripple, stateLayerColor( m_pal.onPrimary, m_pal.hoverOpacity ) );
+
     setColor( Q::Text, m_pal.onPrimary );
     setColor( Q::Text | Q::Disabled, m_pal.onSurface38 );
 
     setAnimation( Q::Panel | A::Color, qskDuration );
     setAnimation( Q::Panel | A::Metric, qskDuration );
+    setAnimation( Q::Ripple | A::Color, qskDuration );
     setAnimation( Q::Text | A::Color, qskDuration );
 }
 

src/controls/QskPushButton.cpp

@@ -4,6 +4,8 @@
  *****************************************************************************/
 
 #include "QskPushButton.h"
+#include "QskAnimationHint.h"
+#include "QskAnimator.h"
 #include "QskAspect.h"
 #include "QskBoxShapeMetrics.h"
 #include "QskGraphic.h"
@@ -16,9 +18,41 @@
 #include <qfontmetrics.h>
 
 QSK_SUBCONTROL( QskPushButton, Panel )
+QSK_SUBCONTROL( QskPushButton, Ripple )
 QSK_SUBCONTROL( QskPushButton, Text )
 QSK_SUBCONTROL( QskPushButton, Graphic )
 
+namespace
+{
+    class ClickAnimator : public QskAnimator
+    {
+      public:
+        ClickAnimator()
+            : QskAnimator()
+        {
+        }
+
+        void setButton( QskPushButton* button )
+        {
+            m_button = button;
+        }
+
+      protected:
+        void advance( qreal value ) override
+        {
+            m_button->setMetric( QskPushButton::Ripple | QskAspect::Size, value );
+        }
+
+        void done() override
+        {
+            m_button->setMetric( QskPushButton::Ripple | QskAspect::Size, 0.0 );
+        }
+
+      private:
+        QskPushButton* m_button;
+    };
+}
+
 class QskPushButton::PrivateData
 {
   public:
@@ -49,6 +83,9 @@ class QskPushButton::PrivateData
 
     QSizeF graphicSourceSize;
 
+    ClickAnimator clickAnimator;
+    qreal rippleSize = 0.0;
+
     bool isCheckable : 1;
     bool isGraphicSourceDirty : 1;
 };
@@ -273,6 +310,24 @@ void QskPushButton::changeEvent( QEvent* event )
     Inherited::changeEvent( event );
 }
 
+void QskPushButton::mousePressEvent( QMouseEvent* event )
+{
+    Inherited::mousePressEvent( event );
+
+    const auto hint = animationHint( Ripple | QskAspect::Color );
+
+    if( hint.isValid() )
+    {
+        setSkinHint( Ripple | QskAspect::Position, event->pos() );
+
+        m_data->clickAnimator.setWindow( window() );
+        m_data->clickAnimator.setButton( this );
+        m_data->clickAnimator.setDuration( hint.duration );
+        m_data->clickAnimator.setEasingCurve( hint.type );
+        m_data->clickAnimator.start();
+    }
+}
+
 QskGraphic QskPushButton::loadGraphic( const QUrl& url ) const
 {
     return Qsk::loadGraphic( url );

src/controls/QskPushButton.h

@@ -42,7 +42,7 @@ class QSK_EXPORT QskPushButton : public QskAbstractButton
     using Inherited = QskAbstractButton;
 
   public:
-    QSK_SUBCONTROLS( Panel, Text, Graphic )
+    QSK_SUBCONTROLS( Panel, Ripple, Text, Graphic )
 
     QskPushButton( QQuickItem* parent = nullptr );
     QskPushButton( const QString& text, QQuickItem* parent = nullptr );
@@ -90,6 +90,7 @@ class QSK_EXPORT QskPushButton : public QskAbstractButton
 
   protected:
     void changeEvent( QEvent* ) override;
+    void mousePressEvent( QMouseEvent* ) override;
 
     void updateResources() override;
     virtual QskGraphic loadGraphic( const QUrl& ) const;

src/controls/QskPushButtonSkinlet.cpp

@@ -6,6 +6,7 @@
 #include "QskPushButtonSkinlet.h"
 #include "QskPushButton.h"
 
+#include "QskAnimationHint.h"
 #include "QskGraphic.h"
 #include "QskTextOptions.h"
 #include "QskFunctions.h"
@@ -29,7 +30,7 @@ static inline Qt::Orientation qskOrientation( const QskPushButton* button )
 QskPushButtonSkinlet::QskPushButtonSkinlet( QskSkin* skin )
     : Inherited( skin )
 {
-    setNodeRoles( { PanelRole, GraphicRole, TextRole } );
+    setNodeRoles( { PanelRole, RippleRole, GraphicRole, TextRole } );
 }
 
 QskPushButtonSkinlet::~QskPushButtonSkinlet() = default;
@@ -51,6 +52,17 @@ QRectF QskPushButtonSkinlet::subControlRect( const QskSkinnable* skinnable,
     {
         return contentsRect;
     }
+    else if ( subControl == QskPushButton::Ripple )
+    {
+        const auto clickPos = button->effectiveSkinHint( QskPushButton::Ripple | QskAspect::Position ).toPointF();
+        const auto ratio = button->metric( QskPushButton::Ripple | QskAspect::Size );
+        const auto w = contentsRect.width() * ratio;
+        const auto h = contentsRect.height() * ratio;
+        const auto x = clickPos.x() - w;
+        const auto y = clickPos.y() - h;
+        const QRectF r( x, y, w * 2, h * 2 );
+        return r.intersected( contentsRect );
+    }
 
     return Inherited::subControlRect( skinnable, contentsRect, subControl );
 }
@@ -67,6 +79,19 @@ QSGNode* QskPushButtonSkinlet::updateSubNode(
             return updateBoxNode( button, node, QskPushButton::Panel );
         }
 
+        case RippleRole:
+        {
+            if( button->hasAnimationHint( QskPushButton::Ripple | QskAspect::Color )
+                    && button->metric( QskPushButton::Ripple | QskAspect::Size ) > 0.0 )
+            {
+                return updateBoxNode( button, node, QskPushButton::Ripple );
+            }
+            else
+            {
+                return nullptr;
+            }
+        }
+
         case TextRole:
         {
             return updateTextNode( button, node );

src/controls/QskPushButtonSkinlet.h

@@ -20,6 +20,7 @@ class QSK_EXPORT QskPushButtonSkinlet : public QskSkinlet
     enum NodeRole
     {
         PanelRole,
+        RippleRole,
         TextRole,
         GraphicRole,