I am attempting to write an applet to be used online that will allow a user to:
1- Upload a photo
2- Perform basic edits (Stuff like resize, crop, rotate, etc.)
3- Download the edited photo
Does anyone know of any existing open source libraries or projects that are available with these kind of tools? Either that, or is anyone aware of some basic tutorials? Technical documents are okay. I'm well-versed in Java, but have not done much WYSIWYG-type photo manipulation, or much work with image files at all. (Most of my work to date has been with databases and other computation application.)
There are some image manipulation libs in Java but I found them incompletey developed and difficult to grasp.
Try Web4j and ( especailly ) Java Tips on the Navbar at the left on this site. There seems to be almost always some cannoical code from Java Tips to do pretty much just about anything.
First, why write it as an applet?
Second, why not just use The Gimp? its free, open source, etc.
As far as image editing goes, it takes a bit of getting used to, but the Graphics2D API does everything you are discussing. If your image is a BufferedImage (which it is if you used ImagIO to get it), then you can create a new BufferedImage, get it's graphics context, cast it to a Graphics2D (all graphics contexts are Graphics2D types since 1.2), and apply any kind of AffineTransform you want, then just call one of the drawImage methods of your graphics context to render back to the BufferedImage....and finally, use ImageIO again to write it out. (don't forget to dispose teh graphics context).
It's really pretty simple once you know what elements of the API to use.