I am currently investigating the best development tools to use to create a web browser based application that will cater for the following functionality

1) Import of a PDF document (that represents a diagram and is the bottom layer)
2) Manipulate other standard graphic images (from a set of available images shown on the side of the web page)
3) Superimpose these other graphic images on another layer on top of the PDF diagram by dragging and dropping
4) Create superimposed grouping of sections of the PDF diagram (by clicking various points that eventually form a bounded/coloured rectangular shape)
5) Mirroring, Rotating, Scaling the bounded areas (including the implied contents beneath the bounded area i.e. from the PDF layer)
6) I also need to perform scaled measurements on the diagram using mouse clicks.
7) Save some representation of the work performed back to a server database (probably using AJAX and json)

Assuming this is all possible to do in a browser (DOM), then this will obviously be a reasonably detailed bit of development work and what I am after are suggestions as to which tools (javascript librarys? or ? ) I should consider investigating as candidates to simplify and make the best job of the task.

I would also be interested in any comments on what are the merits of using different graphical formats (SVG etc...).

Feel free to throw any comments into the mix. I am at the learning/investigating stage and any comments or insights that save me headaches downline () would be very much appreciated.

[Sorry for this long winded question ()]

Thanks in advance