In a document management program that I’m writing I’m displaying images in a QGraphicsView. The QGraphicsView supports a drag mode that allows a user to simply click and drag within the view to pan around, which works great when a large image is displayed and the user has zoomed in quite far.

Panning the image this way does mean that the user has to click back on the image and move the mouse again when the mouse reaches the end of the screen. I needed a way to implement mouse wrapping so that when the mouse reaches the end of the QGraphicsView during panning and the user is still holding down the left mouse button the mouse will jump to the opposite edge, giving a smooth continuous pan.

Here’s what I came up with…

Most databases store dates in the format YYYY-MM-DD. When using a QTableView to display a database table in PyQt it’s useful to be able to display this in a different format. Being from the UK I’d rather have the date displayed in the UK style – DD/MM/YYYY. This is where QStyledItemDelegate comes in.

I’d put off looking into this for a while because whenever I tried to look in to using QStyledItemDelegate I saw people mentioning paint methods. I know nothing about painting in PyQt and get quite scared when I see it mentioned. I really need to get over that.

Not to worry though, because it’s not needed…

Poppler is a PDF rendering library based on the xpdf-3.0 code base. It has bindings for Qt4 which we can use through Python/PyQt. Using these libraries under most popular Linux distributions is as simple as installing the Poppler package, but under Windows I’ve found that things are a little more tricky to get working.

I’ve been looking for a new personal project to work on for a while and I’ve been having trouble finding something. I wanted something that I’d use myself, otherwise my interest would quickly drop. Something that ideally I would use every day. I also wanted to write something that other people would find a use for as well. And it had to be written in Python and be something completely different to anything I’ve played with before. So I’ve decided to write a desktop client for Subsonic.