问题
I'm trying to export jasper report to pdf using partially opaque SVGs, but in the pdf the opaque are solid white-ish.
The image expression is:
<imageExpression><![CDATA[net.sf.jasperreports.renderers.SimpleRenderToImageAwareDataRenderer.getInstance(byte[] data)]]></imageExpression>
In the background it seems jasper is using Apache BatikRenderer and XML Graphics. Here are even examples of transparency support:
https://xmlgraphics.apache.org/fop/trunk/graphics.html#svg
According to this link, transparency should be supported: https://xmlgraphics.apache.org/fop/dev/svg.html
There is even a pdf-example which works with transparency.
回答1:
After looking at how the SVG in the example defined transparency, I noticed my SVGs differed:
In the example "fill-opacity" is used, while my SVGs used simply "opacity".
By changing opacity to fill-opacity in the SVG, the transparency also worked in the pdf generated by jasper. (Related thread svg opacity vs fill-opacity)
Now I faced 2 options: One solution would be to write a script that modifies the svg xml and replaces opacity with fill-opacity. Another option was to see if the source of the SVGs could be changed so that I would get SVGs using fill-opacity in the first place. The source outputting SVGs in my case was matplotlib, and the next question was how to get matplotlib to output SVG with fill-opacity instead of opacity:
来源：https://stackoverflow.com/questions/60545570/how-to-use-transparent-svgs-in-jasper-report-and-export-to-pdf