Two rendering glitch fixes for time series charts

[simantics/platform.git] / bundles / org.simantics.g2d / src / org / simantics / g2d / utils / GridUtil.java

diff --git a/bundles/org.simantics.g2d/src/org/simantics/g2d/utils/GridUtil.java b/bundles/org.simantics.g2d/src/org/simantics/g2d/utils/GridUtil.java
index 8ee6c6a71e9a15a781498c0306ecc48f51e4d951..5114f1a660656771595a6a5375e1465d96c82e78 100644 (file)
--- a/bundles/org.simantics.g2d/src/org/simantics/g2d/utils/GridUtil.java
+++ b/bundles/org.simantics.g2d/src/org/simantics/g2d/utils/GridUtil.java
@@ -213,8 +213,7 @@ public class GridUtil {
         double x = startY / grid.pixelsPerSegment;
        return (int) Math.ceil( x );
     }
-    
-    
+
     /**
      * Estimate label width, by sampling values from xMin to xMax
      * using given font and format.
@@ -226,22 +225,36 @@ public class GridUtil {
      */
     public static double calcLabelWidth(double xMin, double xMax, Format format, GridSpacing grid)
     { 
-       double width = 0.0;     
-       double canvasDiff = GridUtils.distanceToNextGridCoord(xMin, grid.segment);
-       int c = 0;
-       for (double x=xMin + canvasDiff; x<xMax; x+=grid.segment) {
-               boolean nearZero = (x < 0.000000000001) && (x > -0.000000000001);
-               if (nearZero) x = 0.0;
-               String label = format.format(x);
-               if (label==null || label.equals("")) continue;
-               GlyphVector glyphVector;
-                       glyphVector = RULER_FONT.createGlyphVector(frc, label);
+        double width = 0.0;     
+        double canvasDiff = GridUtils.distanceToNextGridCoord(xMin, grid.segment);
+        int c = 0;
+        double canvasStart = xMin + canvasDiff;
+        for (double x=canvasStart; x<xMax; ) {
+            // This nearZero-logic causes a discrepancy between how the labels
+            // are rendered in paintVerticalRuler() and calculated in this method.
+            // Removing it doesn't seem to be causing any immediate adverse effects.
+            // However, this was introduced ages ago to "fix a glitch" so some kind
+            // of regressions might happen if rmeoved.
+//          boolean nearZero = (x < 0.000000000001) && (x > -0.000000000001);
+//          if (nearZero) x = 0.0;
+
+            String label = format.format(x);
+            if (label==null || label.equals("")) continue;
+            GlyphVector glyphVector;
+            glyphVector = RULER_FONT.createGlyphVector(frc, label);
             double labelWidth = glyphVector.getVisualBounds().getWidth();
+            //System.out.format("calcLabelWidth[%d](%s, %f, %f)%n", c, label, labelWidth, width);
             width = Math.max( width, labelWidth );
-            if (c++ > 100) break;            
-       }
-       return width * 1.05;
+            if (c++ > 100) break;
+
+            // It is floating-point-wise more precise to calculate x like this than
+            // accumulating x += grid.segment.
+            // Also, this is how paintVerticalRuler does it and we want to match that
+            // in order to calculate the label width from the exact same values that
+            // paintVerticalRuler will draw.
+            x = canvasStart + grid.segment * c;
+        }
+        return width * 1.05;
     }
-    
-       
+
 }