Draw a line from a data point to its label if the label is not

very near the point.  When a line is drawn, it also draws a
rounded rectangle around the label text.

CCMAIL: kde-edu@kde.org

svn path=/trunk/KDE/kdeedu/libkdeedu/; revision=600211

diff --git a/kdeeduplot/kplotwidget.cpp b/kdeeduplot/kplotwidget.cpp
index db63d00db889af9880f03bd4c1b0a8066967a26b..77474af01dcce4189adc3d6bce432d7294119d36 100644 (file)
--- a/kdeeduplot/kplotwidget.cpp
+++ b/kdeeduplot/kplotwidget.cpp
@@ -36,12 +36,7 @@
 #define YPADDING 20
 #define BIGTICKSIZE 10
 #define SMALLTICKSIZE 4
-
-//Different architectures seem to draw the tickmarks differently.
-#define TICKOFFSET 2
-#if defined DARWIN
 #define TICKOFFSET 0
-#endif
 
 KPlotWidget::KPlotWidget( QWidget *parent, double x1, double x2, double y1, double y2 )
  : QFrame( parent ), ShowGrid( false ), ShowObjectToolTips( true ), UseAntialias( false )
@@ -307,8 +302,9 @@ void KPlotWidget::maskAlongLine( const QPointF &p1, const QPointF &p2, float val
 }
 
 void KPlotWidget::placeLabel( QPainter *painter, KPlotPoint *pp ) {
-       int textFlags = Qt::TextSingleLine | Qt::AlignLeft | Qt::AlignTop;
+       int textFlags = Qt::TextSingleLine | Qt::AlignCenter;
 
+       float rbest = 100;
        float bestCost = 1.0e7;
        QPointF pos = toScreen( pp->position() );
        QRectF bestRect;
@@ -319,13 +315,16 @@ void KPlotWidget::placeLabel( QPainter *painter, KPlotPoint *pp ) {
                for ( int iy=iy0-20; iy<iy0+20; iy++ ) {
                        if ( ( ix >= 0 && ix < 100 ) && ( iy >= 0 && iy < 100 ) ) {
                                QRectF labelRect = painter->boundingRect( QRectF( px[ix], py[iy], 1, 1 ), textFlags, pp->label() );
-                                       
+                               //Add some padding to labelRect
+                               labelRect.adjust( -2, -2, 2, 2 );
+
                                float r = sqrt( (ix-ix0)*(ix-ix0) + (iy-iy0)*(iy-iy0) );
                                float cost = rectCost( labelRect ) + 0.1*r;
 
                                if ( cost < bestCost ) {
                                        bestRect = labelRect;
                                        bestCost = cost;
+                                       rbest = r;
                                }
                        }
                }
@@ -333,10 +332,35 @@ void KPlotWidget::placeLabel( QPainter *painter, KPlotPoint *pp ) {
 
        painter->drawText( bestRect, textFlags, pp->label() );
 
-       //DEBUG_LABEL_RECT
-       //painter->setBrush( QBrush() );
-       //painter->drawRect( bestRect );
-
+       //Is a line needed to connect the label to the point?
+       if ( rbest > 2.0 ) {
+               //Draw a rectangle around the label 
+               painter->setBrush( QBrush() );
+               //QPen pen = painter->pen();
+               //pen.setStyle( Qt::DotLine );
+               //painter->setPen( pen );
+               painter->drawRoundRect( bestRect );
+
+               //Now connect the label to the point with a line.
+               //The line is drawn from the center of the near edge of the rectangle
+               float xline = bestRect.center().x();
+               if ( bestRect.left() > pos.x() )
+                       xline = bestRect.left();
+               if ( bestRect.right() < pos.x() )
+                       xline = bestRect.right();
+
+               float yline = bestRect.center().y();
+               if ( bestRect.top() > pos.y() )
+                       yline = bestRect.top();
+               if ( bestRect.bottom() < pos.y() )
+                       yline = bestRect.bottom();
+
+               //DEBUG
+               kDebug() << pp->label() << ": ( " << xline << ", " << yline << " )  " << bestRect << endl;
+
+               painter->drawLine( QPointF( xline, yline ), pos );
+       }
+                                                                                        
        //Mask the label's rectangle so other labels won't overlap it.
        maskRect( bestRect );
 }