Posted on Mon 06 September 2010

TrueType vs. OpenType

Some background first. According to Wikipedia OpenType is “built on its predecessor TrueType, retaining TrueType’s basic structure and adding many intricate data structures for prescribing typographic behavior.” And according to Adobe...

The two main benefits of the OpenType format are its cross-platform compatibility (the same font file works on Macintosh and Windows computers), and its ability to support widely expanded character sets and layout features, which provide richer linguistic support and advanced typographic control.

I’ve been looking for my ideal programmer’s font for years now. It needs to be a fixed width font, look good both on the screen and printed, work with Windows and Mac OS X and support a good range of Unicode glyphs. With those requirements an OpenType font would appear to be the ideal choice. As we’ll see, it’s not as simple as that.

My latest candidate is the Droid Sans Mono Pro family from Ascender which is an enhanced version of the Droid family developed with Google and the Open Handset Alliance for Android, an open source mobile platform.

The screenshot below shows how the OpenType version of this font looks running under Mac OS X.

Opentype 1

Under Windows XP the same font looks really poor¹.

Opentype 2

When I asked Ascender about this they advised that I should switch to the TrueType version of the font because “the PostScript rendering in Windows is not great”. I did this and the results now look as shown below. Much better.

Opentype 3

Why is this?

The Droid Pro fonts all have hinting instructions (a process that improves the on-screen legibility of a font) and should display smoothly in both greyscale and ClearType display environments. According to Ascender a well-hinted TrueType font is always better than an OpenType (OTF) font, because TrueType is the native rendering system in Windows. The PostScript rendering software is not so good, so TTF is typically better.

I’ve learned two things from this.

  • If you are planning to use a font cross-platform it’s better to stick with TrueType.
  • Ascender’s customer support is fantastic!

I’m also here:
→ @BestofTimes on Twitter
→ Flickr

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