qwt_plot_panner.cpp

/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include "qwt_plot_panner.h"
#include "qwt_scale_div.h"
#include "qwt_plot.h"
#include "qwt_painter.h"
#include <qbitmap.h>
#include <qstyle.h>
#include <qstyleoption.h>

static QBitmap qwtBorderMask( const QWidget *canvas, const QSize &size )
{
    const QRect r( 0, 0, size.width(), size.height() );

    QPainterPath borderPath;

    ( void )QMetaObject::invokeMethod( 
        const_cast< QWidget *>( canvas ), "borderPath", Qt::DirectConnection,
        Q_RETURN_ARG( QPainterPath, borderPath ), Q_ARG( QRect, r ) );

    if ( borderPath.isEmpty() )
    {
        if ( canvas->contentsRect() == canvas->rect() )
            return QBitmap();

        QBitmap mask( size );
        mask.fill( Qt::color0 );

        QPainter painter( &mask );
        painter.fillRect( canvas->contentsRect(), Qt::color1 );

        return mask;
    }

    QImage image( size, QImage::Format_ARGB32_Premultiplied );
    image.fill( Qt::color0 );

    QPainter painter( &image );
    painter.setClipPath( borderPath );
    painter.fillRect( r, Qt::color1 );

    // now erase the frame

    painter.setCompositionMode( QPainter::CompositionMode_DestinationOut );

    if ( canvas->testAttribute(Qt::WA_StyledBackground ) )
    {
        QStyleOptionFrame opt;
        opt.initFrom(canvas);
        opt.rect = r;
        canvas->style()->drawPrimitive( QStyle::PE_Frame, &opt, &painter, canvas );
    }
    else
    {
        const QVariant borderRadius = canvas->property( "borderRadius" );
        const QVariant frameWidth = canvas->property( "frameWidth" );

        if ( borderRadius.type() == QVariant::Double 
            && frameWidth.type() == QVariant::Int )
        {
            const double br = borderRadius.toDouble();
            const int fw = frameWidth.toInt();
        
            if ( br > 0.0 && fw > 0 )
            {
                painter.setPen( QPen( Qt::color1, fw ) );
                painter.setBrush( Qt::NoBrush );
                painter.setRenderHint( QPainter::Antialiasing, true );

                painter.drawPath( borderPath );
            }
        }
    }

    painter.end();

    const QImage mask = image.createMaskFromColor(
        QColor( Qt::color1 ).rgb(), Qt::MaskOutColor );

    return QBitmap::fromImage( mask );
}

class QwtPlotPanner::PrivateData
{
public:
    PrivateData()
    {