Vision Chart - possible to show minor tick labels on logarithmic axis?

Ignition
, ,
1

I’m creating a Classic Chart in Vision (8.1.26) and noticed that when I use the logarithmic axis, the tick labels show only the major ticks labels. It would be nice to show the minor tick labels as well. I did some looking, and am I correct that the jFreeChart in Vision is version 1.0 and doesn’t support minor tick mark control? Anyway around this?

image
image174×361 5.83 KB

2

That does look to be correct. I am on version 8.1.48, and the jar is still jfreechart-min-1.0.0.jar

1 Like
3

I was able to build a custom Logarithmic Axis that includes labels for all the ticks

Result:

image
image228×396 7.86 KB

Configure Chart extension function script:

#def configureChart(self, chart):
	from java.lang import Math
	from java.util import ArrayList
	from org.jfree.chart.axis import LogarithmicAxis, NumberTick
	from org.jfree.ui import TextAnchor
	
	class LabelAllLogTicksAxis(LogarithmicAxis):
		def refreshTicksVertical(self, g2, dataArea, edge):
			lowerBound = self.range.lowerBound
			upperBound = self.range.upperBound
			
			ticks = ArrayList()

			# lowerGuard variable added by rpavlicek to cover cases where the lower bound is less than or equal to zero			
			lowerGuard = lowerBound if lowerBound > 0 else 1e-10
			startingDecade = int(Math.floor(Math.log10(lowerGuard)))
			endingDecade = int(Math.ceil(Math.log10(upperBound)))
		
			for decade in xrange(startingDecade, endingDecade):
				base = 10.0 ** decade
				for multiplier in xrange(1, 10):
					value = multiplier * base
					
					# Added to remove a negative label that was appearing below the lower bound
					if value < lowerBound or value > upperBound:
						continue
					
					# https://www.jfree.org/jfreechart/api/javadoc/org/jfree/chart/axis/NumberTick.html
					# NumberTick(Number number, String label, TextAnchor textAnchor, TextAnchor rotationAnchor, double angle)
					ticks.add(NumberTick(value, unicode(value), TextAnchor.CENTER_RIGHT, TextAnchor.CENTER_RIGHT, 0.0))
		
			return ticks
	
	plot = chart.plot
	oldLogAxis = plot.rangeAxis
	newLogAxis = LabelAllLogTicksAxis(oldLogAxis.label)
	newLogAxis.range = oldLogAxis.range
	plot.rangeAxis = newLogAxis

Edit: Added lower guard variable developed by @rpavlicek that covers cases where the lower bound of the chart is less than or equal to zero

3 Likes
4

Thank you for providing this, I do however get an error: “Error Drawing Chart” - “OverflowError: cannot convert float infinity to long” on these lines:

  startingDecade = int(Math.floor(Math.log10(lowerBound)))
  endingDecade = int(Math.ceil(Math.log10(upperBound)))

If I change the two int to float, I get the same error on a different line:

for decade in xrange(startingDecade, endingDecade):

I’m trying to work through this now to resolve. Might be a None type or negative that’s messing with it.

1 Like
5

You cannot have a lower bound of zero on a logarithmic scale. That makes negative infinity. (Nor any negative lower bound.)

The error is intrinsic--it's fundamental math.

2 Likes
6

Yes, I put a safe guard in place and works great. Thanks to @justinedwards.jle !

            lowerGuard = lowerBound if lowerBound > 0 else 1e-10 
            startingDecade = int(Math.floor(Math.log10(lowerGuard)))
            endingDecade = int(Math.ceil(Math.log10(upperBound)))
2 Likes