From 3fdf1960a0ba975a93b0aeac59eb5ec1dbecc62a Mon Sep 17 00:00:00 2001
From: Jason Harris <kstars@30doradus.org>
Date: Sun, 29 Oct 2006 21:31:43 +0000
Subject: [PATCH] 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
---
 kdeeduplot/kplotwidget.cpp | 46 +++++++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 11 deletions(-)

diff --git a/kdeeduplot/kplotwidget.cpp b/kdeeduplot/kplotwidget.cpp
index db63d00..77474af 100644
--- 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 );
 }
-- 
2.47.3