How to access image generated via velocity template? (Confluence)

[diego diego]

Hi,

I have in macro class this code:

ChartUtilities.saveChartAsPNG(new File("myChart.png"), chart, 1000, 500, null, true, 0);
String chartImageName = chart.createChart();
context.put("chartImageName", chartImageName);
        
return VelocityUtils.getRenderedTemplate("template/chart_report_show.vm", context);

I dont know how I can access in Velocity Template to generated image show on web page.

Thanks for answers.

[diego diego]

Only second mentioned solution is available in my project, but how I get image file from memory in created servlet? I dont find any possible way how i can get it from request...

[Micha Kops]

Depending on your user's target browser I could imagine the following two solutions:

1) Embed the image Base64 encoded in your HTML

e.g. <img alt="Your Chart" src="data:image/png;base64,sdafdsff23f..." />

Supported browsers - Wikipedia says:

Data URIs are currently supported by the following web browsers:

• Gecko-based, such as Firefox, SeaMonkey, XeroBank, Camino, Fennec and K-Meleon
• Konqueror, via KDE's KIO slaves input/output system
• Opera (including devices such as the Nintendo DSi or Wii)
• WebKit-based, such as Safari (including on iOS), Android's browser, Epiphany and Midori (WebKit is a derivative of Konqueror's KHTML engine, but Mac OS X does not share the KIO architecture so the implementations are different), and Webkit/Chromium-based, such as Chrome
• Trident
• Internet Explorer 8: Microsoft has limited its support to certain "non-navigable" content for security reasons, including concerns that JavaScript embedded in a data URI may not be interpretable by script filters such as those used by web-based email clients. Data URIs must be smaller than 32 KiB in Version 8.[3] Data URIs are supported only for the following elements and/or attributes
• [..]

2) Create a parameterized servlet plugin to deliver your image

How to achieve this is documented in Atlassian's documentation: http://confluence.atlassian.com/display/CONFDEV/Servlet+Module