Anti-aliasing torture test

Xara first brought real-time anti-aliasing to vector drawing, back around 1991-92, I think (Acorn Artworks), bringing this to Windows around 1994-95. (Feel free to give me exact dates, anyone.) Since then, all vector drawing tools have implemented this lovely technique. But how good are these various A-A implementations? I don't have Freehand (nor do I want it), but here's a telling comparison between Illustrator CS and XX1.

These ellipses are all the same size, all aligned on integer screen pixels, all viewed at 100%, all of the same colors, stroke widths are given on the right. The PNG file displayed here is a 24-bit color, non-dithered version - i.e., it is _totally_ identical with my screengrabs.

This torture test brings out the worst in A-A algorithms, and it's quite clear that XX1 is best. Granted, for most uses this subtle quality difference will not matter much - but it's fun to see that the old man is still holding up well against the new kid (if a behemoth like AICS can be called that)!

Well done, Charles & Co.!

Xara first brought real-time anti-aliasing to vector drawing, back around 1991-92, I think (Acorn Artworks), bringing this to Windows around 1994-95. (Feel free to give me exact dates, anyone.) Since then, all vector drawing tools have implemented this lovely technique. But how good are these various A-A implementations? I don't have Freehand (nor do I want it), but here's a telling comparison between Illustrator CS and XX1.

These ellipses are all the same size, all aligned on integer screen pixels, all viewed at 100%, all of the same colors, stroke widths are given on the right. The PNG file displayed here is a 24-bit color, non-dithered version - i.e., it is _totally_ identical with my screengrabs.

This torture test brings out the worst in A-A algorithms, and it's quite clear that XX1 is best. Granted, for most uses this subtle quality difference will not matter much - but it's fun to see that the old man is still holding up well against the new kid (if a behemoth like AICS can be called that)!

Well done, Charles & Co.!

Fantastic comparison. Thanx.

Klaus

Have you tried this test using the enhanced rendering quality? It's disabled by default and only changable in Registry or by using Dmitry's X1 Tune utility. It would be interesting to see how your torture test looks in that mode.

I have requested from Charles a description of the differences and benefits and drawbacks to the enhanced rendering and asked why it is not the default setting.

When I hear back I'll share it here or maybe Charles can answer that question here.

As far as FreeHand. I know that Flash has a pretty decent anti-aliasing engine and I suspect that FreeHand shares the same technology.

Gary

No sooner did I post than I received a response.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Well we really refer to it as ultra-high quality rendering because our rendering is already better than the competition.

What is does is double the quality of the anti-aliasing of near horizontal edges and makes it the same as for vertical edges.

The reason we've not included support for it is that it slows all rendering down and the difference is not noticeable by the vast majority of users - indeed it's really only noticeable on lower resolution screens where the pixels are very large <HR></BLOCKQUOTE>

So, perhaps my suggestion of testing this rendering mode is not relevant.

Gary

I had, in fact, used the utility to set my XX1 to HQ rendering.

But here is a new version, showing both Normal and HQ. Needless to say, the HQ rendering _does_ matter quite a bit, especially regarding thin near-horizontal lines, like Charles described.

So HQ - that's my default for sure!

I dug out my copy of FreeHand 10. At 100% zoom I was not able to distinguish any difference in the three outline widths. I exported the three ellipses as Flash 6 SWF files and viewed them in the Flash viewer. No discernable difference.

I have had a review copy of DRAW 12 on my desk for some time and I thought I would see if Corel has finally solved their anti-aliasing problem (they have had 4 previous attempts in which case the anti-aliasing got worse each time). The other thing that has always made me crazy in DRAW is there is no 1:1 option so even with my resolution set to 96dpi and the zoom factor set to 100% the image was smaller than in Xara. So after some scaling, I arrived at 162% (go figure).

At this size, as with FreeHand/Flash, there was no discernable difference in the outline widths. Though the anti-aliasing seems to be better.

Gary

Hmmm. Weird. My hypothesis would be that Freehand/Flash/Corel's A-A engine is much cruder, in that they disregard lines bordering on 1 pixel screen display, treating them all as the same. So they produce pretty good A-A - by sacrificing the greater subtlety and precision found in the XX1 and AICS approach, which _tries_ to take account of "border-line cases" line widths.