All computer displays show images in bitmap mode. What this means is that every image is really a bunch of tiny little squares that make up the image. What this essentially means is that computers can't display really smooth curves.
These two letters are printed with the same font face, size, and style. The only difference between them is that the top letter is aliased and the bottom is not.
As you can see, the top letter has a jagged, "stair-step" effect that is the hallmark of aliasing. It is the way that computers display curves on the screen. The bottom letter, on the other hand, has a smoother, fuzzier look to it. It is anti-aliased to simulate the look of a smooth curve on the screen.
How does anti-aliasing work?
Anti-aliasing works with the way that our eyes see things. Human eyes do not see in as precise detail as we would like to think. In reality, the mind converts the images into what it "thinks" they are supposed to look like.
With anti-aliasing, the curve is created with squares of color that are shaded darker or lighter depending on how much of the curve would take up that square. For instance, if a portion of a curve takes up 10% of a pixel, that pixel would be shaded with 10% of the color saturation of the curve.
What this amounts to is that anti-aliasing adds shading along the curve to "fool the eye" into thinking it's seeing a smooth curve rather than a jagged bitmap.
Anti-aliasing Pros and Cons
- Makes fonts look smoother
- Rounded edges look round
- Type is easier to read (for some) because it looks more like what printed type looks like
- It's just plain prettier (some would argue)
- Small fonts become too fuzzy to read
- Sharp edges may be fuzzy and not precise
- You can't print anti-aliased text as it comes out blurred
- Images are generally larger
- Type is easier to read (for some) because the blurring is reduced and the fonts are clear
Understanding Antialiasing and Transparency
Images, though, have two fundamental limitations for supporting graphic elements. First, rather than being vector-based (as are text and graphics created in programs such as Illustrator), images are a collection of pixels. Second, images are always rectangular.
In order to make your graphics look as smooth and accurate as possible, and in order to seamlessly integrate them into your design, you will need to understand antialiasing, and how it relates to transparency. This tutorial will explain the basics of antialiasing, and how to use succesfully use it in tandem with transparency.
In our case, the smooth and continuous feature we are interested in is vector data, such as text or an illustration. The sampling that occurs is due to rasterization: the process of converting vector data into pixel data. The limitation of this representation is that while vector data can represent limitless shapes and has infinite resolution, pixels are square and are relatively large.
This limitation isn't visible when dealing with rectangular objects, as in the images below:
|Rectangular features, even when magnified (right) suffer from no visual artifacts.|
|Diagonal lines are rendered less accurately. A magnified view demonstrates jaggies.|
The example below demonstrates the most effective technique of antialiasing graphics: taking advantage of the many levels of color that our monitors can represent.
Here is a simple image that is still complex enough to show jaggies when rendered. This is even more noticeable in the detail image.
|A large atmark rendered without antialiasing.|
|Antialiasing smoothes out the jaggies.|
In this case the border pixels are shades of gray because the foreground is black and the background is white. If the foreground were red, however, the border pixels would be shades of pink.
|With a red foreground and a white background, intermediate pixels are pink.|
To enable smoothed fonts in Wine you will need to run regedit and change these settings.
You may also want to install the free windows core fonts and even the Tahoma font. Most Linux/Unix operating systems come with nice fonts also such as the Liberation font set.
OK, this sounds like chinease to you...Don't worry their is a handy little script that will do everything for you as Wine has supported font smoothing, including subpixel since wine 1.1.12.
Here is a screenshot of the script running.
Wine font smoothing English version can downloaded from here.
And a Russian version can be downloaded from here.
To run the script: