doc/html/chart-chartform_canvas-cpp.html


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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>chart/chartform_canvas.cpp Example File</h1>

 
<pre>#include "canvastext.h"
#include "chartform.h"

#include &lt;<a href="qbrush-h.html">qbrush.h</a>&gt;
#include &lt;<a href="qcanvas-h.html">qcanvas.h</a>&gt;

#include &lt;math.h&gt; // sin, cos

#ifndef M_PI
#define M_PI 3.1415
#endif

void <a name="f167"></a>ChartForm::drawElements()
{
    <a href="qcanvasitemlist.html">QCanvasItemList</a> list = m_canvas-&gt;allItems();
    for ( QCanvasItemList::iterator it = list.<a href="qvaluelist.html#begin">begin</a>(); it != list.<a href="qvaluelist.html#end">end</a>(); ++it )
        delete *it;

        // 360 * 16 for pies; Qt works with 16ths of degrees
    int scaleFactor = m_chartType == PIE ? 5760 :
                        m_chartType == VERTICAL_BAR ? m_canvas-&gt;height() :
                            m_canvas-&gt;width();
    double biggest = 0.0;
    int count = 0;
    double total = 0.0;
    static double scales[MAX_ELEMENTS];

    for ( int i = 0; i &lt; MAX_ELEMENTS; ++i ) {
        if ( m_elements[i].isValid() ) {
            double value = m_elements[i].value();
            count++;
            total += value;
            if ( value &gt; biggest )
                biggest = value;
            scales[i] = m_elements[i].value() * scaleFactor;
        }
    }

    if ( count ) {
            // 2nd loop because of total and biggest
        for ( int i = 0; i &lt; MAX_ELEMENTS; ++i )
            if ( m_elements[i].isValid() )
                if ( m_chartType == PIE )
                    scales[i] = (m_elements[i].value() * scaleFactor) / total;
                else
                    scales[i] = (m_elements[i].value() * scaleFactor) / biggest;

        switch ( m_chartType ) {
            case PIE:
                drawPieChart( scales, total, count );
                break;
            case VERTICAL_BAR:
                drawVerticalBarChart( scales, total, count );
                break;
            case HORIZONTAL_BAR:
                drawHorizontalBarChart( scales, total, count );
                break;
        }
    }

    m_canvas-&gt;update();
}


void <a name="f168"></a>ChartForm::drawPieChart( const double scales[], double total, int )
{
    double width = m_canvas-&gt;width();
    double height = m_canvas-&gt;height();
    int size = int(width &gt; height ? height : width);
    int x = int(width / 2);
    int y = int(height / 2);
    int angle = 0;

    for ( int i = 0; i &lt; MAX_ELEMENTS; ++i ) {
        if ( m_elements[i].isValid() ) {
            int extent = int(scales[i]);
            <a href="qcanvasellipse.html">QCanvasEllipse</a> *arc = new <a href="qcanvasellipse.html">QCanvasEllipse</a>(
                                            size, size, angle, extent, m_canvas );
            arc-&gt;<a href="qcanvasitem.html#setX">setX</a>( x );
            arc-&gt;<a href="qcanvasitem.html#setY">setY</a>( y );
            arc-&gt;<a href="qcanvasitem.html#setZ">setZ</a>( 0 );
            arc-&gt;<a href="qcanvaspolygonalitem.html#setBrush">setBrush</a>( QBrush( m_elements[i].valueColor(),
                                   BrushStyle(m_elements[i].valuePattern()) ) );
            arc-&gt;<a href="qcanvasitem.html#show">show</a>();
            angle += extent;
            <a href="qstring.html">QString</a> label = m_elements[i].label();
            if ( !label.<a href="qstring.html#isEmpty">isEmpty</a>() || m_addValues != NO ) {
                label = valueLabel( label, m_elements[i].value(), total );
                CanvasText *text = new CanvasText( i, label, m_font, m_canvas );
                double proX = m_elements[i].proX( PIE );
                double proY = m_elements[i].proY( PIE );
                if ( proX &lt; 0 || proY &lt; 0 ) {
                    // Find the centre of the pie segment
                    <a href="qrect.html">QRect</a> rect = arc-&gt;<a href="qcanvaspolygonalitem.html#boundingRect">boundingRect</a>();
                    proX = ( rect.<a href="qcanvasrectangle.html#width">width</a>() / 2 ) + rect.<a href="qcanvasitem.html#x">x</a>();
                    proY = ( rect.<a href="qcanvasrectangle.html#height">height</a>() / 2 ) + rect.<a href="qcanvasitem.html#y">y</a>();
                    // Centre text over the centre of the pie segment
                    rect = text-&gt;<a href="qcanvastext.html#boundingRect">boundingRect</a>();
                    proX -= ( rect.<a href="qcanvasrectangle.html#width">width</a>() / 2 );
                    proY -= ( rect.<a href="qcanvasrectangle.html#height">height</a>() / 2 );
                    // Make proportional
                    proX /= width;
                    proY /= height;
                }
                text-&gt;<a href="qcanvastext.html#setColor">setColor</a>( m_elements[i].labelColor() );
                text-&gt;<a href="qcanvasitem.html#setX">setX</a>( proX * width );
                text-&gt;<a href="qcanvasitem.html#setY">setY</a>( proY * height );
                text-&gt;<a href="qcanvasitem.html#setZ">setZ</a>( 1 );
                text-&gt;<a href="qcanvasitem.html#show">show</a>();
                m_elements[i].setProX( PIE, proX );
                m_elements[i].setProY( PIE, proY );
            }
        }
    }
}


void <a name="f169"></a>ChartForm::drawVerticalBarChart(
        const double scales[], double total, int count )
{
    double width = m_canvas-&gt;width();
    double height = m_canvas-&gt;height();
    int prowidth = int(width / count);
    int x = 0;
    <a href="qpen.html">QPen</a> pen;
    pen.<a href="qpen.html#setStyle">setStyle</a>( NoPen );

    for ( int i = 0; i &lt; MAX_ELEMENTS; ++i ) {
        if ( m_elements[i].isValid() ) {
            int extent = int(scales[i]);
            int y = int(height - extent);
            <a href="qcanvasrectangle.html">QCanvasRectangle</a> *rect = new <a href="qcanvasrectangle.html">QCanvasRectangle</a>(
                                            x, y, prowidth, extent, m_canvas );
            rect-&gt;<a href="qcanvaspolygonalitem.html#setBrush">setBrush</a>( QBrush( m_elements[i].valueColor(),
                                    BrushStyle(m_elements[i].valuePattern()) ) );
            rect-&gt;<a href="qcanvaspolygonalitem.html#setPen">setPen</a>( pen );
            rect-&gt;<a href="qcanvasitem.html#setZ">setZ</a>( 0 );
            rect-&gt;<a href="qcanvasitem.html#show">show</a>();
            <a href="qstring.html">QString</a> label = m_elements[i].label();
            if ( !label.<a href="qstring.html#isEmpty">isEmpty</a>() || m_addValues != NO ) {
                double proX = m_elements[i].proX( VERTICAL_BAR );
                double proY = m_elements[i].proY( VERTICAL_BAR );
                if ( proX &lt; 0 || proY &lt; 0 ) {
                    proX = x / width;
                    proY = y / height;
                }
                label = valueLabel( label, m_elements[i].value(), total );
                CanvasText *text = new CanvasText( i, label, m_font, m_canvas );
                text-&gt;<a href="qcanvastext.html#setColor">setColor</a>( m_elements[i].labelColor() );
                text-&gt;<a href="qcanvasitem.html#setX">setX</a>( proX * width );
                text-&gt;<a href="qcanvasitem.html#setY">setY</a>( proY * height );
                text-&gt;<a href="qcanvasitem.html#setZ">setZ</a>( 1 );
                text-&gt;<a href="qcanvasitem.html#show">show</a>();
                m_elements[i].setProX( VERTICAL_BAR, proX );
                m_elements[i].setProY( VERTICAL_BAR, proY );
            }
            x += prowidth;
        }
    }
}


void <a name="f170"></a>ChartForm::drawHorizontalBarChart(
        const double scales[], double total, int count )
{
    double width = m_canvas-&gt;width();
    double height = m_canvas-&gt;height();
    int proheight = int(height / count);
    int y = 0;
    <a href="qpen.html">QPen</a> pen;
    pen.<a href="qpen.html#setStyle">setStyle</a>( NoPen );

    for ( int i = 0; i &lt; MAX_ELEMENTS; ++i ) {
        if ( m_elements[i].isValid() ) {
            int extent = int(scales[i]);
            <a href="qcanvasrectangle.html">QCanvasRectangle</a> *rect = new <a href="qcanvasrectangle.html">QCanvasRectangle</a>(
                                            0, y, extent, proheight, m_canvas );
            rect-&gt;<a href="qcanvaspolygonalitem.html#setBrush">setBrush</a>( QBrush( m_elements[i].valueColor(),
                                    BrushStyle(m_elements[i].valuePattern()) ) );
            rect-&gt;<a href="qcanvaspolygonalitem.html#setPen">setPen</a>( pen );
            rect-&gt;<a href="qcanvasitem.html#setZ">setZ</a>( 0 );
            rect-&gt;<a href="qcanvasitem.html#show">show</a>();
            <a href="qstring.html">QString</a> label = m_elements[i].label();
            if ( !label.<a href="qstring.html#isEmpty">isEmpty</a>() || m_addValues != NO ) {
                double proX = m_elements[i].proX( HORIZONTAL_BAR );
                double proY = m_elements[i].proY( HORIZONTAL_BAR );
                if ( proX &lt; 0 || proY &lt; 0 ) {
                    proX = 0;
                    proY = y / height;
                }
                label = valueLabel( label, m_elements[i].value(), total );
                CanvasText *text = new CanvasText( i, label, m_font, m_canvas );
                text-&gt;<a href="qcanvastext.html#setColor">setColor</a>( m_elements[i].labelColor() );
                text-&gt;<a href="qcanvasitem.html#setX">setX</a>( proX * width );
                text-&gt;<a href="qcanvasitem.html#setY">setY</a>( proY * height );
                text-&gt;<a href="qcanvasitem.html#setZ">setZ</a>( 1 );
                text-&gt;<a href="qcanvasitem.html#show">show</a>();
                m_elements[i].setProX( HORIZONTAL_BAR, proX );
                m_elements[i].setProY( HORIZONTAL_BAR, proY );
            }
            y += proheight;
        }
    }
}


QString <a name="f171"></a>ChartForm::valueLabel(
            const <a href="qstring.html">QString</a>&amp; label, double value, double total )
{
    if ( m_addValues == NO )
        return label;

    <a href="qstring.html">QString</a> newLabel = label;
    if ( !label.<a href="qstring.html#isEmpty">isEmpty</a>() )
        if ( m_chartType == VERTICAL_BAR )
            newLabel += '\n';
        else
            newLabel += ' ';
    if ( m_addValues == YES )
        newLabel += QString::<a href="qstring.html#number">number</a>( value, 'f', m_decimalPlaces );
    else if ( m_addValues == AS_PERCENTAGE )
        newLabel += QString::<a href="qstring.html#number">number</a>( (value / total) * 100, 'f', m_decimalPlaces )
                    + '%';
    return newLabel;
}

</pre><!-- eof -->
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