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svgchartsvaadin7

Vaadin SVGConversor date format

I am using Vaadin charts from vaadin 7.7.6. When I create a chart where I have several values obtained in different dates, the chart is created correctly. Here I put an image of the obtained result where each value is a pair to be represented.

Correct chart with dates

The issue comes, when I want to convert this chart to a PDF file or create a web service that returns this chart as an image to be included elsewhere.

For creating an image from the chart, I use the SVGGenerator as recommended in the documentation. In general, it works really fine and I am able to create PDFs with charts inside. But with this chart I have an issue if the X axis is using dates. Here I copy the chart after converted to SVG:

Incorrect chart with dates

(I have removed some chart controls as the Navigation and the Range selector because are useless in an image or PDF).

At the image we can observe that now in the X axis the dates are not showed correctly. I have checked for several hours the issue, and I am pretty sure that the issue is related to the SVGConversor.

Reading the SVGConversor code, I found a withLang(String lang) method. My thought was that maybe, if I set the language, the date is showed correctly (something similar to localization). I am not able to found any documentation of the value needed to this function and therefore, I have tried some values such as en, en_EN, en-EN, English, .... But does not matter the value I put there, always this error is launched:

java.lang.RuntimeException: SVG generation failed: ReferenceError: Can't find variable: en

Still, I am not sure that the withLang(String lang) method is the solution to my issue.

The question is: How can I show the correct dates in the X axis of my chart when converted to SVG?

Solution

  • Seems that the solution at the end was really easy. The issue is that I have not set the xAxis type. It is not a problem when using the chart in a Vaadin view, but it is mandatory for the SVGConverter to know the axis. Then adding this line of code:

            chart.getConfiguration().getxAxis().setType(AxisType.DATETIME);

    Fix the issue with the SVGConverter. Now the chart is represented correctly in my PDF documents.