KiCad V5.1.0 New Undocumented (curious uncertain) Features?


#1

I think this is a little bit different in context than:
Post-v5 new features and development news:

At the moment, I have more questions about the changes to PcbNew. What does:

Under “Preferences/Preferences/Common/File History Size:” what does it actually do?

Under “Preferences/Preferences/Common/Graphics (Accelerated):” what does it actually do?
The choices are:

  1. No Antialiasing
  2. Subpixel Antialiasing (High Quality)
  3. Subpixel Antialiasing (Ultra Quality)
  4. SuperSampling (2X)
  5. SuperSampling (4X)

It is not clear, by the order of the descriptions which selection should result in the cleanest representation of the lines drawn by KiCad. In fact, with testing, I found no noticeable effect on on the presentation of any layer information. However, it did seem to affect the Grid presentation to a moderate degree on my Windoze installation; my good friend that runs KiCad under Ubuntu stated that anything other than option five(5) made the grid display unusable as it was totally overwhelming in brightness.

Anyways, this is a start to me learning how this version is quite a bit different than the other UpRevs; I can not believe that I am the only one.


#2

Anti aliasing is done to remove frequencies that are too high to be correctly handled from any signal. (Example: anti aliasing filters in front of an adc.)

In computer graphics anti aliasing is used to get smoother edges for computer generated images. (Displays have a limited number of pixels.) The problems that you get without anti aliasing are best noticed on text or when drawing straight lines at an angle. (And on a display with low resolution.)

There is no clear best algorithm. It depends a bit on what you like and what your hardware looks like.

I further fear that the terms used might not have been created with clear communication in mind. (They are not coined by the kicad devs) The terms might be that way to sound good to customers to differentiate your new graphics card or graphics engine from the competition.

A more technical explanation:

If i remember correctly then subpixel anti aliasing is done to reduce colored shadows. (different colors of the same pixel are not on the same physical place.) This is also sometimes called font anti aliasing as it fixes a problem most likely seen when rendering black text on white background.

Right now most google results for subpixel anti aliasing are about mac osx mojave removing this option. In combination with complains that this OS now only supports displays of high resolution (ie retina displays as they call it.)


#3

There now seems to be much more “fiddly bits” than there was before. The feature “Warp and Zoom” might not even make it past the current development team if introduced today.

EVERY PC based video game I have played, has always placed the menu selections such that the highest quality image came along with more processing time. It would be a real surprise if no one else agreed with my statement.

Does this mean that every user now needs to read, and understand, these definitions to choose the KiCad settings such that they can have their best user experience with KiCad?

I’ve spent 30 minutes testing, and asked here, with no clear answer… Is this the information that is going to be put into the next text of the KiCad User Manual?


#4

Are you sure about that? Did you test it to the same amount of scrutiny you now do for kicad?

Oh and if we are at it: Define best quality. I fear there are trade-offs to be made here as anti aliasing does remove some information from the original signal. Different levels of it (and different algorithms) have different pros and cons that highly depend on your hardware setup.

Only users who are unhappy with the default rendering. (optimizing your setup always requires deeper understanding of it than using the default that will fit most people.) And when you bring pc games into play: Why is kicad not allowed to expect users to learn stuff on their own in the same way as pc games do?


#5

Without antialiasing the picture looks crisp and clear and it has perfect contrast between an item and its surroundings or between two adjacent colors. But the larger the pixels the rougher it looks because you can clearly see every pixel. In retina or ultra high density or whatever it’s called monitor or display you don’t see pixels so you don’t need antialiasing for CAD programs or text editors etc. which use clear lines and other graphic items against clear background.

Seeing pixels may not bother you in CAD programs. Actually it may even be beneficial when you e.g. want to see if a line is exactly horizontal/vertical/45deg. You can see some sharp pixels in the middle of the line if it’s not. That would be distracting in a game and that’s one reason why antialiasing is used in them.

For a CAD program it’s important to see the same size as same everywhere. That was a problem when eeschema moved to the “modern” graphics canvas some months ago. When you have a two wires they should look the same no matter where they are and in which position. But it’s difficult to make them so for example if the view is zoomed out and there are several lines close to each other. It needs an algorithm to decide how they should be rendered. Antialiasing may help here but it always makes the view blurry because it mixes a pixel with its surrounding pixels.

But the story is different for games. You just can’t compare 3D games and CAD programs. Games have moving graphics and they try to mimic real world looks (more or less). It’s annoying to see sharp edges and pixels especially when the picture changes. It’s not important to have clear lines but have smooth overall experience without distracting pixel-sized details.

When you try antialiasing for a CAD program the result may look blurry. Different antialiasing settings work differently and the differences may look clearer than in games.

Furthermore, different settings work differently with different monitors/displays. For example I have in KDE font settings the option Sub-pixel rendering type. The options are: Horizontal RGB and BGR and vertical RGB and BGR. That’s because displays can have their physical pixel’s subpixels (red, green, blue) in different order.

The quality vs. speed doesn’t matter for KiCad. It matters for games where the 3D graphics acceleration reaches its speed limits under heavy load.

In short, it’s different for games and for CAD, drawing, fonts etc. You can’t compare them. And there’s no one best option for all users and all situations. I prefer no antialiasing.


#6

File->Open Recent (or in Windows the system Start menu recently used programs).