by Miguel Sousa
When you see text displayed on a modern computer screen or on a handheld device’s display, you are likely to be looking at a font that has been rasterized, i.e. converted, from vector outlines to pixels. There are currently three main ways of accomplishing this rasterization. The most basic one is aliased rendering, where the letters are drawn in black and white pixels only. The next one is anti-aliased rendering, where the pixels can assume shades of gray, in addition to black and white. And the third one is sub-pixel rendering, where the intermediate degrees of pixel opacity between black and white are displayed in color rather than grayscale. Microsoft’s sub-pixel rendering technology is called ClearType.
If you are reading this blog on a computer with Microsoft Windows XP, you are likely to be looking at aliased text, since that’s the system’s default rasterization mode. It is also possible, but less likely, for ClearType to be turned off manually in later versions of Windows. How can you tell for sure? Well, if the text on this page looks similar to the image below, then you’re definitely looking at aliased text rendering.
You can improve the way the text looks on this blog by turning on ClearType. To accomplish it, follow the steps below.
- Right-click on the Desktop and select Properties. This will open the “Display Properties” window.
- Select the pane named Appearance.
- Click on the button labeled “Effects…”, which will open a window with the same name.
- Check the box labeled “Use the following method to smooth edges of screen fonts”,
- and select ClearType from the drop-down list below it.
- Click on the two OK buttons.
That’s it! You’ve just enabled sub-pixel rendering on your Windows XP system, and now that same paragraph of text looks like this:
Be advised that this is a system-wide setting and you’re likely to see the changes take effect in other parts of the system and in applications other than the browser.
Also, keep in mind that ClearType rendering is not unique to XP. If you are on Windows Vista or Windows 7 and the text looks aliased, you can and should turn on ClearType. The instructions for doing so are somewhat different but the results will be the same.