Tools in Opacity:
The Select Tool lets you select a set of vectors and pixels that you can then perform actions on.
The Zoom Tool lets you make your image appear larger on screen.
The Pixels Tool lets you make various pixel level changes to your image.
The Rectangle Tool lets you draw squares, optionally with a corner radius.
The Ellipse Tool lets you draw ellipses.
The Polygon Tool lets you draw polygons, including star shapes.
The Pen Tool lets you draw any arbitrary bezier path.
The Spiral Tool lets you draw spiral shapes.
The Line Tool lets you draw lines. Pretty simple.
The Text Tool lets you add rich text to your image.
The Generator Tool lets you add vectors that use Core Image generator filters to draw their content.
The Crop Tool lets you crop your image to reduce its size.