Computer Graphics

LAYERS

What are Layers?

• “Layers are used in digital image editing to separate different elements of an image.”

http://en.wikipedia.org/wiki/Layers_(digital_image_editing)

Consider a Cake

CAKE WITH LAYERS DIGITAL IMAGE WITH LAYERS

• Looking at a cake from the side, reveals that it has layers.

• How many layers does this cake have?

• An image viewed from the side, shows that it too can have layers.

• How many layers does this digital image have?

2 Views of the Same Image

SIDEWAYS VIEW STRAIGHT ON VIEW

• This view helps you understand how layers work.

• This is the normal view you would see in a graphics program that supports layers.

Stack of Paper vs. Image with Layers

WHAT CAN YOU DO WITH A STACK OF PAPER?

WHAT CAN YOU DO WITH A DIGITAL IMAGE?

• Each paper in the stack can be shifted to the left, right, up, down.

• Each paper in the stack can be reordered within the stack.

• Move the dog left, right, up, down.• Reorder the house by moving it

behind the grass.

The “Dog layer” is being shifted to the left in Picture 2

PICTURE 1 PICTURE 2

The “grass layer” is being raised to the top of the stack in Picture 2.

PICTURE 1 PICTURE 2

The Layers Palette

Imagine that the Layers Palette is your side view of a cake or a stack of papers.

Active Layer

•Currently, the “Sky” layer is active or highlighted in blue. •That means it is the ONLY element of the picture that can currently be edited (moved up, down, erased, etc.)

Hide an Active Layer

•Programs that support layers give the ability to hide/show a layer. •Currently, the Active Layer is “Hills”, and it’s visibility is set to hidden…as indicated by the unchecked box.

The End

• Layers are your friend!• Use layers often to separate elements of your

image.• This gives you amazing control over your

digital images!