qwt_plot_layout.cpp

  \param options Layout options
  \param canvasRect Geometry of the canvas ( IN/OUT )
  \param scaleRect Geometries of the scales ( IN/OUT )

  \sa Options
*/

void QwtPlotLayout::alignScales( Options options,
    QRectF &canvasRect, QRectF scaleRect[QwtPlot::axisCnt] ) const
{
    int backboneOffset[QwtPlot::axisCnt];
    for ( int axis = 0; axis < QwtPlot::axisCnt; axis++ )
    {
        backboneOffset[axis] = 0;

        if ( !d_data->alignCanvasToScales[axis] )
        {
            backboneOffset[axis] += d_data->canvasMargin[axis];
        }

        if ( !( options & IgnoreFrames ) )
        {
            backboneOffset[axis] += 
                d_data->layoutData.canvas.contentsMargins[axis];
        }
    }

    for ( int axis = 0; axis < QwtPlot::axisCnt; axis++ )
    {
        if ( !scaleRect[axis].isValid() )
            continue;

        const int startDist = d_data->layoutData.scale[axis].start;
        const int endDist = d_data->layoutData.scale[axis].end;

        QRectF &axisRect = scaleRect[axis];

        if ( axis == QwtPlot::xTop || axis == QwtPlot::xBottom )
        {
            const QRectF &leftScaleRect = scaleRect[QwtPlot::yLeft];
            const int leftOffset =
                backboneOffset[QwtPlot::yLeft] - startDist;

            if ( leftScaleRect.isValid() )
            {
                const double dx = leftOffset + leftScaleRect.width();
                if ( d_data->alignCanvasToScales[QwtPlot::yLeft] && dx < 0.0 )
                {
                    /*
                      The axis needs more space than the width
                      of the left scale.
                     */
                    const double cLeft = canvasRect.left(); // qreal -> double
                    canvasRect.setLeft( qMax( cLeft, axisRect.left() - dx ) );
                }
                else
                {
                    const double minLeft = leftScaleRect.left();
                    const double left = axisRect.left() + leftOffset;
                    axisRect.setLeft( qMax( left, minLeft ) );
                }
            }
            else
            {
                if ( d_data->alignCanvasToScales[QwtPlot::yLeft] && leftOffset < 0 )
                {
                    canvasRect.setLeft( qMax( canvasRect.left(),
                        axisRect.left() - leftOffset ) );
                }
                else
                {
                    if ( leftOffset > 0 )
                        axisRect.setLeft( axisRect.left() + leftOffset );
                }
            }

            const QRectF &rightScaleRect = scaleRect[QwtPlot::yRight];
            const int rightOffset =
                backboneOffset[QwtPlot::yRight] - endDist + 1;

            if ( rightScaleRect.isValid() )
            {
                const double dx = rightOffset + rightScaleRect.width();
                if ( d_data->alignCanvasToScales[QwtPlot::yRight] && dx < 0 )
                {
                    /*
                      The axis needs more space than the width
                      of the right scale.
                     */
                    const double cRight = canvasRect.right(); // qreal -> double
                    canvasRect.setRight( qMin( cRight, axisRect.right() + dx ) );
                }   

                const double maxRight = rightScaleRect.right();
                const double right = axisRect.right() - rightOffset;
                axisRect.setRight( qMin( right, maxRight ) );
            }
            else
            {
                if ( d_data->alignCanvasToScales[QwtPlot::yRight] && rightOffset < 0 )
                {
                    canvasRect.setRight( qMin( canvasRect.right(),
                        axisRect.right() + rightOffset ) );
                }
                else
                {
                    if ( rightOffset > 0 )
                        axisRect.setRight( axisRect.right() - rightOffset );
                }
            }
        }
        else // QwtPlot::yLeft, QwtPlot::yRight
        {
            const QRectF &bottomScaleRect = scaleRect[QwtPlot::xBottom];
            const int bottomOffset =
                backboneOffset[QwtPlot::xBottom] - endDist + 1;

            if ( bottomScaleRect.isValid() )
            {
                const double dy = bottomOffset + bottomScaleRect.height();
                if ( d_data->alignCanvasToScales[QwtPlot::xBottom] && dy < 0 )
                {
                    /*
                      The axis needs more space than the height
                      of the bottom scale.
                     */
                    const double cBottom = canvasRect.bottom(); // qreal -> double
                    canvasRect.setBottom( qMin( cBottom, axisRect.bottom() + dy ) );
                }
                else
                {
                    const double maxBottom = bottomScaleRect.top() +
                        d_data->layoutData.scale[QwtPlot::xBottom].tickOffset;
                    const double bottom = axisRect.bottom() - bottomOffset;
                    axisRect.setBottom( qMin( bottom, maxBottom ) );
                }
            }
            else
            {
                if ( d_data->alignCanvasToScales[QwtPlot::xBottom] && bottomOffset < 0 )
                {
                    canvasRect.setBottom( qMin( canvasRect.bottom(),
                        axisRect.bottom() + bottomOffset ) );
                }
                else
                {
                    if ( bottomOffset > 0 )
                        axisRect.setBottom( axisRect.bottom() - bottomOffset );
                }
            }

            const QRectF &topScaleRect = scaleRect[QwtPlot::xTop];
            const int topOffset = backboneOffset[QwtPlot::xTop] - startDist;

            if ( topScaleRect.isValid() )
            {
                const double dy = topOffset + topScaleRect.height();
                if ( d_data->alignCanvasToScales[QwtPlot::xTop] && dy < 0 )
                {
                    /*
                      The axis needs more space than the height
                      of the top scale.
                     */
                    const double cTop = canvasRect.top(); // qreal -> double
                    canvasRect.setTop( qMax( cTop, axisRect.top() - dy ) );
                }
                else
                {
                    const double minTop = topScaleRect.bottom() -
                        d_data->layoutData.scale[QwtPlot::xTop].tickOffset;
                    const double top = axisRect.top() + topOffset;
                    axisRect.setTop( qMax( top, minTop ) );
                }
            }
            else
            {
                if ( d_data->alignCanvasToScales[QwtPlot::xTop] && topOffset < 0 )
                {
                    canvasRect.setTop( qMax( canvasRect.top(),
                        axisRect.top() - topOffset ) );
                }
                else
                {
                    if ( topOffset > 0 )
                        axisRect.setTop( axisRect.top() + topOffset );
                }
            }
        }
    }

    /*
      The canvas has been aligned to the scale with largest
      border distances. Now we have to realign the other scale.
     */


    for ( int axis = 0; axis < QwtPlot::axisCnt; axis++ )
    {
        QRectF &sRect = scaleRect[axis];

        if ( !sRect.isValid() )
            continue;

        if ( axis == QwtPlot::xBottom || axis == QwtPlot::xTop )
        {
            if ( d_data->alignCanvasToScales[QwtPlot::yLeft] )
            {
                double y = canvasRect.left() - d_data->layoutData.scale[axis].start;
                if ( !( options & IgnoreFrames ) )
                    y += d_data->layoutData.canvas.contentsMargins[ QwtPlot::yLeft ];

                sRect.setLeft( y );
            }
            if ( d_data->alignCanvasToScales[QwtPlot::yRight] )
            {
                double y = canvasRect.right() - 1 + d_data->layoutData.scale[axis].end;
                if ( !( options & IgnoreFrames ) )
                    y -= d_data->layoutData.canvas.contentsMargins[ QwtPlot::yRight ];

                sRect.setRight( y );
            }

            if ( d_data->alignCanvasToScales[ axis ] )
            {
                if ( axis == QwtPlot::xTop )
                    sRect.setBottom( canvasRect.top() );
                else
                    sRect.setTop( canvasRect.bottom() );
            }
        }
        else
        {
            if ( d_data->alignCanvasToScales[QwtPlot::xTop] )
            {
                double x = canvasRect.top() - d_data->layoutData.scale[axis].start;
                if ( !( options & IgnoreFrames ) )
                    x += d_data->layoutData.canvas.contentsMargins[ QwtPlot::xTop ];

                sRect.setTop( x );
            }
            if ( d_data->alignCanvasToScales[QwtPlot::xBottom] )
            {
                double x = canvasRect.bottom() - 1 + d_data->layoutData.scale[axis].end;
                if ( !( options & IgnoreFrames ) )
                    x -= d_data->layoutData.canvas.contentsMargins[ QwtPlot::xBottom ];

                sRect.setBottom( x );
            }

            if ( d_data->alignCanvasToScales[ axis ] )
            {
                if ( axis == QwtPlot::yLeft )
                    sRect.setRight( canvasRect.left() );
                else
                    sRect.setLeft( canvasRect.right() );
            }
        }
    }
}

/*!
  \brief Recalculate the geometry of all components.

  \param plot Plot to be layout
  \param plotRect Rectangle where to place the components
  \param options Layout options

  \sa invalidate(), titleRect(), footerRect()
      legendRect(), scaleRect(), canvasRect()
*/
void QwtPlotLayout::activate( const QwtPlot *plot,
    const QRectF &plotRect, Options options )
{
    invalidate();

    QRectF rect( plotRect );  // undistributed rest of the plot rect

    // We extract all layout relevant parameters from the widgets,
    // and save them to d_data->layoutData.

    d_data->layoutData.init( plot, rect );

    if ( !( options & IgnoreLegend )
        && plot->legend() && !plot->legend()->isEmpty() )
    {
        d_data->legendRect = layoutLegend( options, rect );

        // subtract d_data->legendRect from rect

        const QRegion region( rect.toRect() );
        rect = region.subtracted( d_data->legendRect.toRect() ).boundingRect();

        switch ( d_data->legendPos )
        {
            case QwtPlot::LeftLegend:
                rect.setLeft( rect.left() + d_data->spacing );
                break;
            case QwtPlot::RightLegend:
                rect.setRight( rect.right() - d_data->spacing );
                break;
            case QwtPlot::TopLegend:
                rect.setTop( rect.top() + d_data->spacing );
                break;
            case QwtPlot::BottomLegend:
                rect.setBottom( rect.bottom() - d_data->spacing );
                break;
        }
    }

    /*
     +---+-----------+---+
     |       Title       |
     +---+-----------+---+
     |   |   Axis    |   |
     +---+-----------+---+
     | A |           | A |
     | x |  Canvas   | x |
     | i |           | i |
     | s |           | s |
     +---+-----------+---+
     |   |   Axis    |   |
     +---+-----------+---+
     |      Footer       |
     +---+-----------+---+
    */

    // title, footer and axes include text labels. The height of each
    // label depends on its line breaks, that depend on the width
    // for the label. A line break in a horizontal text will reduce
    // the available width for vertical texts and vice versa.
    // expandLineBreaks finds the height/width for title, footer and axes
    // including all line breaks.

    int dimTitle, dimFooter, dimAxes[QwtPlot::axisCnt];
    expandLineBreaks( options, rect, dimTitle, dimFooter, dimAxes );

    if ( dimTitle > 0 )
    {
        d_data->titleRect.setRect(
            rect.left(), rect.top(), rect.width(), dimTitle );

        rect.setTop( d_data->titleRect.bottom() + d_data->spacing );

        if ( d_data->layoutData.scale[QwtPlot::yLeft].isEnabled !=
            d_data->layoutData.scale[QwtPlot::yRight].isEnabled )
        {
            // if only one of the y axes is missing we align
            // the title centered to the canvas

            d_data->titleRect.setX( rect.left() + dimAxes[QwtPlot::yLeft] );
            d_data->titleRect.setWidth( rect.width()
                - dimAxes[QwtPlot::yLeft] - dimAxes[QwtPlot::yRight] );
        }
    }

    if ( dimFooter > 0 )
    {
        d_data->footerRect.setRect(
            rect.left(), rect.bottom() - dimFooter, rect.width(), dimFooter );

        rect.setBottom( d_data->footerRect.top() - d_data->spacing );

        if ( d_data->layoutData.scale[QwtPlot::yLeft].isEnabled !=
            d_data->layoutData.scale[QwtPlot::yRight].isEnabled )
        {
            // if only one of the y axes is missing we align
            // the footer centered to the canvas

            d_data->footerRect.setX( rect.left() + dimAxes[QwtPlot::yLeft] );
            d_data->footerRect.setWidth( rect.width()
                - dimAxes[QwtPlot::yLeft] - dimAxes[QwtPlot::yRight] );
        }
    }

    d_data->canvasRect.setRect(
        rect.x() + dimAxes[QwtPlot::yLeft],
        rect.y() + dimAxes[QwtPlot::xTop],
        rect.width() - dimAxes[QwtPlot::yRight] - dimAxes[QwtPlot::yLeft],
        rect.height() - dimAxes[QwtPlot::xBottom] - dimAxes[QwtPlot::xTop] );

    for ( int axis = 0; axis < QwtPlot::axisCnt; axis++ )
    {
        // set the rects for the axes

        if ( dimAxes[axis] )
        {
            int dim = dimAxes[axis];
            QRectF &scaleRect = d_data->scaleRect[axis];

            scaleRect = d_data->canvasRect;
            switch ( axis )
            {
                case QwtPlot::yLeft:
                    scaleRect.setX( d_data->canvasRect.left() - dim );
                    scaleRect.setWidth( dim );
                    break;
                case QwtPlot::yRight:
                    scaleRect.setX( d_data->canvasRect.right() );
                    scaleRect.setWidth( dim );
                    break;
                case QwtPlot::xBottom:
                    scaleRect.setY( d_data->canvasRect.bottom() );
                    scaleRect.setHeight( dim );
                    break;
                case QwtPlot::xTop:
                    scaleRect.setY( d_data->canvasRect.top() - dim );
                    scaleRect.setHeight( dim );
                    break;
            }
            scaleRect = scaleRect.normalized();
        }
    }

    // +---+-----------+---+
    // |  <-   Axis   ->   |
    // +-^-+-----------+-^-+
    // | | |           | | |
    // |   |           |   |
    // | A |           | A |
    // | x |  Canvas   | x |
    // | i |           | i |
    // | s |           | s |
    // |   |           |   |
    // | | |           | | |
    // +-V-+-----------+-V-+
    // |   <-  Axis   ->   |
    // +---+-----------+---+

    // The ticks of the axes - not the labels above - should
    // be aligned to the canvas. So we try to use the empty
    // corners to extend the axes, so that the label texts
    // left/right of the min/max ticks are moved into them.

    alignScales( options, d_data->canvasRect, d_data->scaleRect );

    if ( !d_data->legendRect.isEmpty() )
    {
        // We prefer to align the legend to the canvas - not to
        // the complete plot - if possible.

        d_data->legendRect = alignLegend( d_data->canvasRect, d_data->legendRect );
    }
}