Difference between revisions of "Image By Building byte array in Expression (BIRT)"

Revision as of 14:07, 16 May 2007

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Introduction

This example demonstrates how to include an image by creating a byte array in an expression.

BIRT Version Compatibility

This example was built and tested with BIRT 2.1.2.

Example Files

This example has no example attachment.

Description

BIRT Image elements support URLs, Embedded images within the report, Images from resource folders, and Dynamic images (BLOB) types usually from databases. Another way of using the Dynamic image is construct your own byte array within the birt expression. This can also be done within a Java Event Handler on the image element.
When selecting the Dynamic image radial in the Image editor, the expression return value needs to be a byte array which contains the data for the image. As an example the following expression will return a working image.

importPackage(Packages.java.io);
importPackage(Packages.java.lang);

var file = new File("c:/temp/test.png");
var ist = new FileInputStream(file);
var lengthi = file.length();

bytesa = new ByteArrayOutputStream( lengthi);
var c;
while((c=ist.read()) != -1){
		bytesa.write(c);
}	  
ist.close();
bytesa.toByteArray();

If you are using an SWT ImageLoader you can build an expression similar to:

importPackage(Packages.java.io);
importPackage(Packages.java.lang);
importPackage(Packages.org.eclipse.swt.widgets);
importPackage(Packages.org.eclipse.swt.graphics);
importPackage(Packages.org.eclipse.swt);

imgl = new ImageLoader();
imgl.load("c:/temp/test.png");
baos = new ByteArrayOutputStream();

imgl.save(baos, SWT.IMAGE_PNG);
myout = baos.toByteArray();

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