gradientModified() signal emitted by GradientWidget every time the gradient value changes.

Widgets/GradientWidget.cpp

@@ -26,8 +26,8 @@ GradientWidget::GradientWidget( QWidget *parent ) : QWidget(parent)
 
 GradientWidget::GradientWidget( const QColor& start, const QColor& end, QWidget *parent ) : GradientWidget(parent)
 {
-    m_Stops.push_back( Stop(start, 0.0f) );
-    m_Stops.push_back( Stop(end  , 1.0f) );
+    addStop( start, 0.0f );
+    addStop( end  , 1.0f );
 }
 
 
@@ -214,6 +214,7 @@ void GradientWidget::addStop( const QColor& color, float value )
 
     m_Stops.insert( getInterval(value), stop );
 
+    emit gradientModified();
     update();
 }
 
@@ -237,7 +238,7 @@ void GradientWidget::setStops( const QList<QColor>& colors, const QList<float>&
 }
 
 
-QString GradientWidget::getShaderFunctionBodyGLSL( int beg, int end, const QString& indent )
+QString GradientWidget::getShaderFunctionBodyGLSL( int beg, int end, const QString& indent ) const
 {
     QString res;
     if( end != beg )
@@ -280,7 +281,7 @@ QString GradientWidget::getShaderFunctionBodyGLSL( int beg, int end, const QStri
 }
 
 
-QString GradientWidget::getShaderFunctionGLSL( const QString& funcName )
+QString GradientWidget::getShaderFunctionGLSL( const QString& funcName ) const
 {
     QString func =
         "vec3 " + funcName + "( float value )\n"
@@ -298,9 +299,10 @@ void GradientWidget::mouseDoubleClickEvent( QMouseEvent *evt )
     {
         Stop &stop = m_Stops[m_SelectedStop];
         QColor color = QColorDialog::getColor( stop.color(), this, "Select gradient stop color" );
-        if( color.isValid() )
+        if( color.isValid()  &&  color != stop.color() )
         {
             stop.setColor( color );
+            emit gradientModified();
             update();
         }
     }
@@ -313,6 +315,7 @@ void GradientWidget::mouseDoubleClickEvent( QMouseEvent *evt )
         stop.updateX( width()-1 );
         m_Stops.insert( interval, stop );
 
+        emit gradientModified();
         update();
     }
 }
@@ -330,11 +333,13 @@ void GradientWidget::mouseMoveEvent( QMouseEvent *evt )
     if( (evt->buttons() & Qt::LeftButton)  &&  m_SelectedStop >= 0 )
     {
         float value = clampValueToStopInterval( m_SelectedStop, float(evt->x()) / (width()-1) );
-
-        m_Stops[m_SelectedStop].setValue( value );
-        m_Stops[m_SelectedStop].updateX( width()-1 );
-
-        update();
+        if( value != m_Stops[m_SelectedStop].value() )
+        {
+            m_Stops[m_SelectedStop].setValue( value );
+            m_Stops[m_SelectedStop].updateX( width()-1 );
+            emit gradientModified();
+            update();
+        }
     }
     else
     {
@@ -403,6 +408,7 @@ void GradientWidget::keyPressEvent( QKeyEvent *evt )
                 m_Stops.remove( m_SelectedStop );
                 m_SelectedStop = -1;
                 m_KeyboardInputValue = QString();
+                emit gradientModified();
                 update();
             }
             break;
@@ -413,11 +419,15 @@ void GradientWidget::keyPressEvent( QKeyEvent *evt )
             if( m_KeyboardInputValue.isEmpty() )
                 break;
 
-            float value = m_KeyboardInputValue.toFloat();
+            float value = clampValueToStopInterval( m_SelectedStop, m_KeyboardInputValue.toFloat() );
             m_KeyboardInputValue = QString();
 
-            m_Stops[m_SelectedStop].setValue( clampValueToStopInterval( m_SelectedStop, value ) );
-            m_Stops[m_SelectedStop].updateX( width()-1 );
+            if( value != m_Stops[m_SelectedStop].value() )
+            {
+                m_Stops[m_SelectedStop].setValue( value );
+                m_Stops[m_SelectedStop].updateX( width()-1 );
+                emit gradientModified();
+            }
 
             update();
             break;

Widgets/GradientWidget.h

@@ -47,7 +47,7 @@ private:
     int             getInterval( float value ) const;
     QColor          getColor( int interval, float value ) const;
     float           clampValueToStopInterval( int n, float value ) const;
-    QString         getShaderFunctionBodyGLSL( int beg, int end, const QString& indent );
+    QString         getShaderFunctionBodyGLSL( int beg, int end, const QString& indent ) const;
 
 protected:
     void            resizeEvent( QResizeEvent *evt );
@@ -70,7 +70,10 @@ public:
     void            setStops( const QList<QColor>& colors, const QList<float>& values );
     inline QColor   getColor( float v ) const                   { return getColor( getInterval(v), v ); }
 
-    QString         getShaderFunctionGLSL( const QString& funcName );
+    QString         getShaderFunctionGLSL( const QString& funcName ) const;
+
+signals:
+    void            gradientModified();
 };