All About Curves - Part 1: Using Antialias

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This tutorial covers using the antialias option to make curves on shapes like circles and ellipses, and for smooth fonts. The tutorial has two parts - making curves with antialias, and selecting curves after antialias is applied.

What is antialias?

When a graphics program creates an image, the image is made up of thousands of small squares called pixels. Each pixel contains a color, and all the colors together, and the variations in shades, when zoomed out, create the picture. The same happens with fonts and shapes like lines, squares, circles and ovals.

The pixels are very small, and most graphics programs let you choose how many to put in a square inch. That is called resolution. The normal resolution for PSP images is 72, that means in each inch there are 72 pixels.

Even with that many small squares making an image, smooth curves using a single color are not possible without applying an antialias option. Take a look at these two images. The first is a curve with no antialias applied. The second one has antialias applied. Can you see how the first has jagged edges on the curves?

Now look at the pictures again, when magnification is on, and we zoom in. The second picture, which has antialias applied, takes the main color of the shape, and blends it outwards to create a smoother edge.



So, antialias is simply telling PSP to blend the edges of curves using graduated shades of the main color of the curve. It produces smoother edges on anything curved, and should be used for most fonts and any time you want a smooth edge. It does, however, present special challenges for reselecting areas after they have been created, so be sure to read part two of this tutorial.

How to apply Antialias

Antialias is applied through the control box when applying fonts, shapes or selections. To use antialias, simply click beside the antialias option in the control box, so a checkmark appears. If the checkmark is there, antialias will be applied. The following images show the control boxes, for fonts and shapes where antialias may be applied.


Antialias when applying a font.


Antialias when using the shapes tool.

You can also apply antialias to lines and boxes, but use this with caution. Since lines and boxes already have nice crisp edges, you would rarely want to apply antialias to them. It makes it very difficult to reselect the area afterwards.

Finally, antialias can be used when making selections, however, again use caution here. It is useful when trying to select part of an image to make a tube. To make perfect selections of curved areas, you may want to use alpha channels instead. Alpha channels are explored in the second part of this tutorial.

A special note on selections with antialias.

Have you ever cropped an image and found it had a white or red or blue or some other colored faint box around it? That's likely because you had antialias applied when you made the selection. Generally, when making selections for cropping, antialias should not be applied.

All About Curves - Part 2: Using Alpha Channels for Selections and Reselections