Can I grab and manipulate shapes I've already drawn and text I've already written on the canvas?
Once shapes and text are committed to the canvas, you cannot grab them like the way you can with a layout application such as Pages or a presentation application such as Keynote or PowerPoint. Patina is a painting, drawing, and sketching application and in this regard you can think of the canvas as a paper painting canvas that absorbs paint. However, depending on what you want to do and whether there are other elements behind or overlapping the shape or text you want to edit, you might find you can indirectly edit it. For example, you can use the Select tool to frame part or all of a shape or text area and then move it, rotate it, delete it, etc. You might also be able to change the color of a shape with the Fill (paint bucket) tool.