[Kst] [Bug 123698] bar graph bars widths are not correctly calculated for unevenly spaced data

[Andrew Walker]

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http://bugs.kde.org/show_bug.cgi?id=123698         




------- Additional Comments From arwalker sumusltd com  2006-03-17 21:14 -------
SVN commit 519650 by arwalker:

CCBUG:123698 Make bar width the smallest difference between data points on the x-axis in the case where x-data is monotonically increasing. The x-error bar, if set,  already defines the bar width.

 M  +26 -8     kstvcurve.cpp  


--- trunk/extragear/graphics/kst/src/libkstmath/kstvcurve.cpp #519649:519650
 @ -843,7 +843,7  @
   bool _xLog = context._xLog, _yLog = context._yLog;
   int penWidth = context.penWidth;
   double maxY = 0.0, minY = 0.0;
-  double rX, rY, rEX, rEY;
+  double rX = 0.0, rY, rEX, rEY;
   double X1 = 0.0, Y1 = 0.0;
   double X2 = 0.0, Y2 = 0.0;
   double last_x1, last_y1;
 @ -1145,10 +1145,12  @
       // we might have some overlapping points still unplotted...
       if (overlap) {
         if (X2 >= Lx && X2 <= Hx) {
-          if (maxY > Hy && minY <= Hy)
+          if (maxY > Hy && minY <= Hy) {
             maxY = Hy;
-          if (minY < Ly && maxY >= Ly)
+          }
+          if (minY < Ly && maxY >= Ly) {
             minY = Ly;
+          }
           if (minY >= Ly && minY <= Hy && maxY >= Ly && maxY <= Hy) {
             p->drawLine(d2i(X2), d2i(minY), d2i(X2), d2i(maxY));
           }
 @ -1174,7 +1176,7  @
       bool has_right = true;
       bool visible = true;
       double rX2 = 0.0;
-      double drX;
+      double drX = 0.0;
 
       if (barStyle() == 1) { // filled
         p->setPen(QPen(_foregroundColor, width, style));
 @ -1182,13 +1184,29  @
         p->setPen(QPen(color(), width, style));
       }
 
-      drX = (maxX() - minX())/double(sampleCount());
+      if (!exv) {        
+        // determine the bar position width. NOTE: This is done
+        //  only if xv->isRising() as in this case the calculation
+        //  is simple...
+        drX = (maxX() - minX())/double(sampleCount());
+        if (xv->isRising()) {       
+          double oldX = 0.0;
+
+          for (i_pt = i0; i_pt <= iN; i_pt++) {
+            rX = xv->interpolate(i_pt, NS);
+            if (i_pt > i0) {                      
+              if (rX - oldX < drX) {
+                drX = rX - oldX;                      
+              }
+            }
+            oldX = rX; 
+          }
+        }
+      }
+      
       for (i_pt = i0; i_pt <= iN; i_pt++) {
         visible = has_bot = has_top = has_left = has_right = true;
 
-        // determine the bar position width.
-        // NOTE: this assumes even X spacing if XError is not defined
-        // There may a better way...
         if (exv) {
           drX = exv->interpolate(i_pt, NS);
         }