Viewing Layers

Now that you've seen what are the basics of manipulating layers, you will more easely understand why layers are such a powerful tool when you are building a diagram with Dia.

Understanding what layers are for can dramaticaly improve the quality and the visual effect your diagrams will produce.

For instance, imagine you are building a diagram with lots of objects in it, like an Electrical or UML diagram, if you drop all of your objects in the same layer, meaning the background, after a while you will get a huge unmanageable draft you won't be able to do anything with it. It will be a pain to change anything in it, you will waste time trying to remenber what object is connected to that object which seems to take all the place in the middle of the mixed up objects you already put there.

Since Dia is a Structured Diagram Builder, all the diagrams you will build with it will be naturaly structured and broken down in many little pieces you will manage with more ease and efficiency than you could do it with a single monolythic block of objects.

By definition, a diagram should be structured, so breaking it down in several logical parts won't be as hard as it seems to be. That's where layers becomes of first use. They allow you to isolate each of these parts in separated slides, so it becomes a real pleasure to manipulate them in any way you like.

First, layers can be renamed to express the part of the diagram they represent, giving them the ability to be rapidely located among others. And most importantly, layers can be shown or hidden depending on what part of the diagram you would like to show.

To rename a layer, at any moment during the construction of the diagram, double-click on the name of the layer in the Layers Dialog. This will bring up the Layer Attributs pop up dialog where you'll be able to change the name of the layer.

Try to find some name which matches the purpose of the layer is a useful way to remember what it is for. Don't hesitate to create many different layers in your diagram, Dia doesn't constrain you on the number of layers you've created, so feel free to adjust your own hierarchy to your needs.

The Eye Icon on the left of the layer's name is what make layers so useful, it aims at hiding or showing the corresponding layer. Meaning if for any reason you decided to not show a particular layer, simply click on the Eye Icon and the layer and everything it contains will disappear from the Canvas.

Viewing only certain layers is really useful when you want manipulate a small part of your diagram without affecting the rest. You can also work that way if you want to print your diagram on different pages or testing different settings which can affect the layout of that part. Again, feel free to experiment with layers, if set up properly they can make your diagram looks pretty much better.

In Dia, Layers creation and manipulation are as common as drawing or selecting objects in the diagram. You must get your hands on them, because you will probably have to use them anytime you will want to creat a new diagram.