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playground/rescaler/Plot.cpp

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+/*****************************************************************************
+ * Qwt Examples - Copyright (C) 2002 Uwe Rathmann
+ * This file may be used under the terms of the 3-clause BSD License
+ *****************************************************************************/
+
+#include "Plot.h"
+
+#include <QwtPlotGrid>
+#include <QwtPlotItem>
+#include <QwtScaleMap>
+#include <QwtPlotLayout>
+#include <QwtInterval>
+#include <QwtPainter>
+#include <QwtMath>
+
+#include <QPainter>
+
+class TextItem : public QwtPlotItem
+{
+  public:
+    void setText( const QString& text )
+    {
+        m_text = text;
+    }
+
+    virtual void draw( QPainter* painter,
+        const QwtScaleMap&, const QwtScaleMap&,
+        const QRectF& canvasRect ) const QWT_OVERRIDE
+    {
+        const int margin = 5;
+        const QRectF textRect =
+            canvasRect.adjusted( margin, margin, -margin, -margin );
+
+        painter->setPen( Qt::white );
+        painter->drawText( textRect,
+            Qt::AlignBottom | Qt::AlignRight, m_text );
+    }
+
+  private:
+    QString m_text;
+};
+
+// RectItem shows how to implement a simple plot item,
+// what wouldn't be necessary as QwtPlotShapeItem
+// would do the same
+
+class RectItem : public QwtPlotItem
+{
+  public:
+    enum Type
+    {
+        Rect,
+        Ellipse
+    };
+
+    explicit RectItem( Type type )
+        : m_type( type )
+    {
+    }
+
+    void setPen( const QPen& pen )
+    {
+        if ( pen != m_pen )
+        {
+            m_pen = pen;
+            itemChanged();
+        }
+    }
+
+    void setBrush( const QBrush& brush )
+    {
+        if ( brush != m_brush )
+        {
+            m_brush = brush;
+            itemChanged();
+        }
+    }
+    void setRect( const QRectF& rect )
+    {
+        if ( m_rect != rect )
+        {
+            m_rect = rect;
+            itemChanged();
+        }
+    }
+
+    virtual QRectF boundingRect() const QWT_OVERRIDE
+    {
+        return m_rect;
+    }
+
+    virtual void draw( QPainter* painter,
+        const QwtScaleMap& xMap, const QwtScaleMap& yMap,
+        const QRectF& ) const QWT_OVERRIDE
+    {
+        if ( m_rect.isValid() )
+        {
+            const QRectF rect = QwtScaleMap::transform(
+                xMap, yMap, m_rect );
+
+            painter->setPen( m_pen );
+            painter->setBrush( m_brush );
+
+            if ( m_type == Ellipse )
+                QwtPainter::drawEllipse( painter, rect );
+            else
+                QwtPainter::drawRect( painter, rect );
+        }
+    }
+
+  private:
+    QPen m_pen;
+    QBrush m_brush;
+    QRectF m_rect;
+    Type m_type;
+};
+
+Plot::Plot( QWidget* parent, const QwtInterval& interval )
+    : QwtPlot( parent )
+{
+    for ( int axisPos = 0; axisPos < QwtAxis::AxisPositions; axisPos++ )
+        setAxisScale( axisPos, interval.minValue(), interval.maxValue() );
+
+    setCanvasBackground( QColor( Qt::darkBlue ) );
+    plotLayout()->setAlignCanvasToScales( true );
+
+    // grid
+    QwtPlotGrid* grid = new QwtPlotGrid;
+    //grid->enableXMin(true);
+    grid->setMajorPen( Qt::white, 0, Qt::DotLine );
+    grid->setMinorPen( Qt::gray, 0, Qt::DotLine );
+    grid->attach( this );
+
+    const int numEllipses = 10;
+
+    for ( int i = 0; i < numEllipses; i++ )
+    {
+        const double x = interval.minValue() +
+            qwtRand() % qRound( interval.width() );
+        const double y = interval.minValue() +
+            qwtRand() % qRound( interval.width() );
+        const double r = interval.minValue() +
+            qwtRand() % qRound( interval.width() / 6 );
+
+        const QRectF area( x - r, y - r, 2 * r, 2 * r );
+
+        RectItem* item = new RectItem( RectItem::Ellipse );
+        item->setRenderHint( QwtPlotItem::RenderAntialiased, true );
+        item->setRect( area );
+        item->setPen( QPen( Qt::yellow ) );
+        item->attach( this );
+    }
+
+    TextItem* textItem = new TextItem();
+    textItem->setText( "Navigation Example" );
+    textItem->attach( this );
+
+    m_rectItem = new RectItem( RectItem::Rect );
+    m_rectItem->setPen( Qt::NoPen );
+    QColor c = Qt::gray;
+    c.setAlpha( 100 );
+    m_rectItem->setBrush( QBrush( c ) );
+    m_rectItem->attach( this );
+}
+
+void Plot::updateLayout()
+{
+    QwtPlot::updateLayout();
+
+    const QwtScaleMap xMap = canvasMap( QwtAxis::XBottom );
+    const QwtScaleMap yMap = canvasMap( QwtAxis::YLeft );
+
+    const QRect cr = canvas()->contentsRect();
+    const double x1 = xMap.invTransform( cr.left() );
+    const double x2 = xMap.invTransform( cr.right() );
+    const double y1 = yMap.invTransform( cr.bottom() );
+    const double y2 = yMap.invTransform( cr.top() );
+
+    const double xRatio = ( x2 - x1 ) / cr.width();
+    const double yRatio = ( y2 - y1 ) / cr.height();
+
+    Q_EMIT resized( xRatio, yRatio );
+}
+
+void Plot::setRectOfInterest( const QRectF& rect )
+{
+    m_rectItem->setRect( rect );
+}
+
+#include "moc_Plot.cpp"