JasperReport scales images when exporting to PDF, thus losing quality
I have a report designed with iReport 1.3.0. This report includes several images, which are loaded dynamically. Then I use JasperRunManager.runReportToPdfFile to create the PDF. Everything in the PDF looks fine except for the images, which appear scaled.
Can anyone tell me what am I doing wrong?
Thanks.
Answer
About Images
If you save the report as HTML, you will notice that the logo appears correctly.
Image files such as PNG are raster images: stored as individual pixels.
Whereas PDF files are primarily vectorized: the elements inside are stored as descriptions of how to draw them. This allows PDFs to scale and be legible at any size.
Using a raster image in a vector format will likely result in a pixelated effect.
Possible Solutions
You have a few options to make the images match the quality of the text, in order of ease:
- Create a version of the logo at 1200 dpi, scaled 400% larger.
- Create an SVG version of the logo.
- Convert the image to a vector format.
- Scale image 300% and change resolution to 288 dpi.
1200 DPI Version
The image will look sharp until around 400% zoom.
SVG Version
The image will look sharp at every resolution. Replace the normal <image...> XML with the following code (be sure to adjust the width and height accordingly):
<image hAlign="Center" vAlign="Middle">
<reportElement x="0" y="0" width="179" height="66"/>
<imageExpression class="net.sf.jasperreports.engine.JRRenderable"><![CDATA[net.sf.jasperreports.renderers.BatikRenderer.getInstance(new java.io.File("/path/to/logo.svg"))]]></imageExpression>
</image>
Convert GIF to SVG
To convert a GIF to SVG, first try a quick web-based tool, such as: http://vectormagic.com
Once converted to SVG, you will have to use the code listed above to display the logo.
Resolution and Scale
See: