Browser based WYSIWG Editor and Designer

We want to create a Broswer based WYSIWYG editor to prepare templates which will be used to render images (PNG, BMP etc). - WYSIWYG editor should user friendly, intutive and should have the ability to import data from external sources like ( Database,XML or JSON). - Editor shall include toolbox containing objects like ( text, line, rectangle , circle , image etc.) - GUI shall have a canvas on which objects from toolbox will be drawn ( drag and drop). User can change the properties like font , line width , size of the objects. - Editor shall connect to back end server (Spring application running on tomcat ) to upload or retrieve the templates . - Templates will be saved in XSL format, prior XSLT knowledge is not mandatory but will be an added advantage.