Mac rendering on Windows

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Hrant H Papazian's picture
Joined: 3 May 2000 - 11:00am

> go with Vista today

On my XP, CT is off. :->


Karsten Luecke's picture
Joined: 6 Aug 2005 - 8:41am

Jason C -- but I’d like to point out that Randy’s problem with the PC screenshots he’s provided are due to the TrueType Instructions in the Verdana font, not with ClearType as a rendering system. [...] This all boils down to the advice that Simon and hrant gave; for a better comparison, use the Cleartype fonts.

The comparison screenshots are valuable since they exhibit the rasterizers' different philosophies. Maybe the comparisons could be more systematic as regards the choice of both fonts and rasterizers: test Apple system fonts, older heavily hinted MS system fonts, ClearType fonts, each of them in all environments, OSX, WinXP, Vista.

As to the advice to better test the ClearType rasterizer with ClearType fonts ... that would make a strange 'comparison', wouldn't it?   ;-)

Jason Campbell's picture
Joined: 8 Oct 2005 - 11:52am

k.l., "As to the advice to better test the ClearType rasterizer with ClearType fonts … that would make a strange ‘comparison’, wouldn’t it? ;-)"
I know it sounds like a strange idea, but that's because the CT fonts have less restrictive TT instructions in them. The point is that to evaluate optimal results, use fonts designed to give optimal results for each rasterizer. But because of the way tha Mac OS works, it doesn't much matter which font you use, there's no such thing as optimal tuning for the Mac.
It's true that if you instead wanted to test pure results, not optimized results, you should use fonts with no TT instructions.

From a technical perspective, the Mac solution is really the problem. We've got different TrueType font engines here, but the Win rasterizer scales and renders type as one would expect from reading the TT (OT) specs, while the Mac rasterizer follows most of the TT (OT) specs, but virtually ignores a fairly critical section of the spec (Hint Instructions.)
I don't want to dredge up the old fight about whether the TT hint instruction set was a good idea (for the 12 or so of us who care ;), but technically, the Win engine follows the specs more closely, and is truer to a font developer's intentions, than the Mac engine.

However that whole idea doesn't affect the real quality of display type. Shifts in hardware technology, and sociological changes in the way we read and process text over the last 10 years have really changed what the "optimal" way to render text is.

I've gotten off topic here, but my real comment on the Verdana problems is that the TT instructions in the font were designed to specifically work in a 2-bit, black and white rendering mode. They suffer more than many other faces in some greyscale rendering situations.

Jason C