I strongly disagree with this general philosophy. One should be able to use an absolute, non-relativistic unit of measure that requires no external knowledge at all. Not even to other parts of the same layout.
Relativistic units are inadequate if they are free to cause non-pixel perfect transformations of designers intent from platform to platform. It is no more reasonable to re-layout a carefully designed UI then it is to reposition objects and people in a movie scene played on devices of different resolution, in fact it is much less reasonable.
Perhaps, in some circumstances this will call for platform specific design, and that is correct and appropriate. Perhaps a UI will look like a postage stamp on a high pixel density display. Adjusting for that difference is the domain of the operating system and the user. Even the OS may be unaware of the actual physical size of the display, for example when using a projector.
Automatic layout is a convenance, but it works against not for good design.
It doesn't mean compromised useably, it is a guarantee of usability. Dynamic layout, re-flow and responsive design compromise usability. The utility of responsive design is not improved usability, its improved designer productivity at the cost of usability.
> Perhaps a UI will look like a postage stamp on a high pixel density display. Adjusting for that difference is the domain of the operating system and the user
... how? If you've fixed the layout, there's no way to do this other than zooming the whole thing.
Nobody wants to re-layout movies because they generally aren't trying to read text off the screen.
Text is displayed on the movie screen all the time, so I'm unclear what your argument is here. Yes zoom the whole thing, as apposed to zooming only the text and then changing the layout to accommodate. As a user I do this all the time in browsers, in video games, and even in display settings. It works great, because everything stays locked together, and there are never any unanticipated interactions between elements. The absolute worst case scenario is the aspect ratio doesn't fit the device perfectly.
You know what doesn't work great? When I resize my browser window and the responsive designed threshold decides my 3k monitor is a phone. So much engineering effort to achieve a bad user experience, when zooming the entire UI is superior in every way.
Just use pixels, they are unambiguous units that are consistent across all digital media, scaleable without changing layout, and understood by both designer and user alike.
If you have two fonts at size X, they should both display the same number of lines in Y space... The problem is the relativistic measure isn't even consistent between fonts.
> It is no more reasonable to re-layout a carefully designed UI then it is to reposition objects and people in a movie scene played on devices of different resolution
Is this unreasonable? We don't have the ability to design this kind of responsive control over video streams, but we do have the ability to speed up and slow down videos, embed captions that use native device fonts rather than bake themselves into the video file, adjust contrast and brightness, skip over segments and timestamps, and to adjust audio balance. And many players also have the ability to zoom in and cut off black bars. None of that seems like a problem?
I'm regularly thankful for the ability to auto-skip intros and adjust playback speed. Every single video player should have the ability to play at 1.5x speed.
I think in general it's important to separate practical design from art. I don't think any user has any obligation to worry about whether or not it's "reasonable" for to adjust an interface in whatever way works best for them. The goal of design is to make it easier to accomplish a task; the designers individual vision doesn't take precedent over that.
> Adjusting for that difference is the domain of the operating system and the user.
That's exactly why we have semantic units that are tied to a specific meaning/purpose, not ones that just represent abstract concepts like pixel width. The purpose of an `em` unit for widths is to describe the design of a column based on its intended use -- to show X characters in a line. The more specific we are about not just the width of an element, but also the intent behind that width, the easier it is for an OS and a user to adjust for size differences in specific scenarios.
If I drop a page to 300 pixels, did I do that because I want the font to be bigger? Am I scaling the entire window down including the font? Do I want the same design and font-size in a single column? Semantic units allow me as a user to communicate the context a page is in, which allows the page to respond to that context.
Absolutist design is anti-customization; it imposes the designer's will over the user's will. This matters because even in a single device/platform, it can often be impossible to design a single interface that always works. I use i3wm, so when I open a program it opens in tiled mode. You might get half of the screen, you might get 1/3rd, you might just get the upper left corner. The websites and programs on my computer that are designed responsively handle that, and the ones that aren't, don't. Thankfully, native programs have (slowly) started to get better about things like dropping out of 3-column views when they only have 300 pixels to work with.
But the answer to that problem can not be that from now on I'll just open every program in full screen mode so the designer can perfectly position every element. The answer is responsive design, and if that means that a few pixels are out of place when I jam the design into a 328x451 pixel box, then that's fine. I want the interface to work inside the box first, to fulfill its functional requirements, and then to look pretty second.
Relativistic units are inadequate if they are free to cause non-pixel perfect transformations of designers intent from platform to platform. It is no more reasonable to re-layout a carefully designed UI then it is to reposition objects and people in a movie scene played on devices of different resolution, in fact it is much less reasonable.
Perhaps, in some circumstances this will call for platform specific design, and that is correct and appropriate. Perhaps a UI will look like a postage stamp on a high pixel density display. Adjusting for that difference is the domain of the operating system and the user. Even the OS may be unaware of the actual physical size of the display, for example when using a projector.
Automatic layout is a convenance, but it works against not for good design.