Introduction to Vector Graphics - 1

Vector graphics differ from the normal raster (or bitmap) graphics that we are all used to. Instead of storing your graphic as pixel by pixel information, it is stored as instructions on where to draw the lines. The PSP Help File describes Vector Graphics so:

A vector layer does not use pixels for storing image information. Instead, it stores a vector object as a set of properties that describe its attributes, dimensions, and position in the image. Each time an image is opened, these properties are used as instructions for drawing the objects. Because the objects are independent elements, you can move them without affecting the rest of the image.

It is this ability to move the different parts of a vector graphic that make them so useful. Any object created as a vector layer can be moved, pulled, stretched, bent....

You have all used vector graphics, maybe without realising it. All those wonderful clip-art drawings in Microsoft Word or Works Word Processor that you can resize without any loss of edge quality are vector graphics.

Let's get started. First, open a new graphic, then the Tool Options - keyboard letter O. Now for the big moment - click on the Preset Shapes Tool Bar button. In the Tool Options window, check the Antialias and Create as Vector boxes and make sure the Retain style box is unchecked, and pick the Ellipse shape. Choose Style settings - in the Color panel at the right side of the main PSP window - of a color for the foreground and no style for the background. You can play with a background setting later.

Somewhere in your new graphic draw an ellipse.

Whoa - what has happened as soon as you let go the mouse button !! The little square blocks surrounding your ellipse are called "nodes", and these are the points where you can grab hold and change shape by moving them around. You will also see that you have a new layer - a vector layer. If you click on the + next to the layer it will open and show you all the vectors on that layer. In this case we have only the ellipse.

When you put your cursor over the different nodes you will see it change - on the corner nodes it changes to a 4 way arrow, on the sides it changes to a 2 way arrow, and on the center it changes to a move cursor. The node out the side from the center is a rotation node. Grab it and move it up or down to rotate the ellipse.

The Control (Ctrl) key changes the behaviour of the side and corner movement. Try it and see. If you draw a square instead of an ellipse you will see the effects better.

Corner node	Side node
Center move node	Rotate node
Rotated ellipse using the rotate node

So far, nothing really startling...

Open a new graphic, only this time select the Draw tool button, we are going to draw a straight line.

Draw your line diagonally across your new graphic, leaving space at each end. You should use these settings, and end up with something similar to my line.

From here we will look at adding more nodes, and changing the type of node - Oh yes, there is more than one type !

The content and design of this site are the property of WebTech University
and may not be used without written consent of the owner.
Copyright © 1998-2010 WebTech University. All rights reserved.
Privacy Statement