Property Floorplan Creator

We have developed and operate an online property advertising and CRM system for our realtors. The system is web-based and users access all features through a web-browser. We plan to add a new feature enabling users of our system to create and save property floorplans. The floorplan creator should run on our servers, completely independent from third-party resources and doesn't require any additional browser extensions, such as Java, flash etc. Operates with HTML, Javascript and PHP for the output. Users should be able to access it as an integrated part of our property system. The floorplan creator must provide a simple image format output which can be utilized further in our system. The required functionality starts with creating the floorplan and ends with the image output. Software language: English is enough, Hungarian would be perfect, at least easily translatable.