Vincent Gable

Here’s Jakob Nielsen’s economic justification for giving employees large screens,

Big monitors are the easiest way to increase white-collar productivity, and anyone who makes at least $50,000 per year ought to have at least 1600×1200 screen resolution. A flat-panel display with this resolution currently costs less than $500. So, as long as the bigger display increases productivity by at least 0.5%, you’ll recover the investment in less than a year. (The typical corporate overhead doubles the company’s per-employee cost; always remember to use loaded cost, not take-home salary, in any productivity calculation.)

Jeff Atwood has written a “one-stop-shop for research data supporting the idea that, yes, having more display space would in fact make you more productive”. But he warns us that “Having all that space can make you less productive due to all the window manipulation excise you have to deal with to make effective use of it.”He calls this the Large Display Paradox. But, there are solutions to this problem. Using software to divide the large single-display into a “grid” of virtual “monitors” is the one he proposes.

A recent and widely publicized University of Utah study concluded that people were less productive on a 26″ screen then an 18″ screen. (Unfortunately I haven’t found a better link to their actual data then this crappy PDF brochure.) However, they also found that people were more productive with two 20″ screens. Their 26″ monitor was 1920×1200 pixels = 2.3 MP, their 20″ was 1600×1200 pixels = 1.92MP, so two 20″ screens = 3.84 MP, quite a bit bigger then the 26″ screen, and with greater productivity. This supports the theory with the right windowing system, productivity increases as the number of usable pixels increases.

I’ve only found one exception to the “bigger is better” rule of workspaces. Portability (Availability) can be worth more then pure productivity. There’s an old gunslinger saying that “The best gun in the world is the the one I’ve got in my hand right now”. Similarly, having a “big iron” on your office isn’t much use if you are flying somewhere over the atlantic. There’s no substitute for having a computer in-hand. Even if you would be more productive using a 17″ laptop, it’s better to get a 13″ ultra-portable, if it means you are more likely to actually have it around when you need it.

Business travelers, and creative professionals who work better in eclectic settings, are examples of people who are better served by the smallest sufficiently-powerful laptop they can find. But for most people bigger is better. Fortunately, small laptops can be connected to large displays.

I love foreach. What I really mean is that I really like dead-simple ways to iterate over the items in a container, one at a time. It goes beyond syntactic sugar; making errors harder to write, and easier to spot.

I’m using the term “foreach”, because the first time I realized the utility of simple iteration was seeing Michael Tsai’s foreach macro. I instantly fell in love with the ‘keyword’, because it greatly simplifies iterating over items in a Cocoa container. My reaction was so strong, because the (then current) Cocoa iteration idiom I was using was so bad. As Jonathan ‘Wolf’ Rentzsch says:

I have a number of issues with enumeration in Cocoa/ObjC. Indeed, I have a problem with every one of the three lines necessary in the standard idiom. It even goes beyond that — I have an problem with the very fact it’s three lines of code versus one.

Objective-C 2.0 (Leopard and later) introduced Fast Enumeration. It’s a better way of handling enumeration then Michael Tsai’s macro, but if you are stuck using Objective-C 1.0, then I highly recommend using his foreach macro.

I do not like the C++ stl for_each idiom. It’s not simple enough.

To explain what’s wrong with for_each I should explain what a “foreach” should look like. It should be a two-argument construct: “foreach (item, container)“, and no more. container should be evaluated only once. Syntax details aren’t terribly important, as long as they make sense.
foreach(child, naughtyList)
iterate(child, naughtyList)
ForEach(String child, naughtyList)
for child in naughyList:
for(NSString *child in naughtyList)
Are all fine constructs.

The most obvious benefits of a foreach is that it’s less code, easier to write, and less work to read. Implemented correctly, it also makes bugs harder to write — mostly because it minimizes side effects in the loop construct. For example, do you see the bug in the following code?

for( list<shared_ptr<const Media> >::iterator it = selectedMedias->selectedMediaList().begin(); it != selectedMedias->selectedMediaList().end(); ++it )

I didn’t; and it’s kind of a trick question. ->selectedMediaList() isn’t an accessor function — it constructs a new list every time it is called. So selectedMediaList() != selectedMediaList() because it returns a different list each time. The loop never terminates because it will never equal end(), since it is the end of a different list. But you have no way of knowing this without knowing details of what selectedMediaList() does.

Using BOOST_FOREACH avoids the problem:
BOOST_FOREACH(shared_ptr<const CSMediaLib::Media> media, selectedMedias->selectedMediaList())
works regardless of how selectedMediaList() is implemented, because it is only evaluated once. It’s also easier to write, and to read. I haven’t used BOOST_FOREACH much, but it’s been totally positive so far. (Yes, the name is ugly, but that’s not important).

Loops are a staple of programming. Simplifying and error-proofing the most common kind of loop is a huge productivity win. foreach regardless of it’s flavor, is worth a try.

Just a curiosity, but it happens that in a yes-no binary response test, the reaction time to select “no” is longer than for “yes.”

Source

I haven’t taken the time to verify this, or see if anyone has quantified the difference in response times.

http://apple.com/hypercard/ is redirected to http://en.wikipedia.org/wiki/HyperCard (”HyperCard was an application program from Apple Inc. (at the time Apple Computer, Inc.) that was among the first successful hypermedia systems before the World Wide Web.”).

This definitely shows that Wikipedia is gaining credibility, and utility.

And kudos to Apple for linking to a 3rd party account, which can give a more unbiased history (particularly, it can say bad things directly). This decision might have just been a way to pass the job of creating and maintaining a history to someone else. But regardless, I think we are all better served by as complete a history as possible.

Displays are getting sharper all the time. Sharpness is very important, because things don’t just look better on high-resolution displays; they are measurably faster to use.

according to Jakob Nielsen:

Low-resolution monitors (including all computer screens until now) have poor readability: people read about 25% slower from computer screens than from printed paper. Experimental 300 (PPI) displays (costing $30,000 (in 1998)) have been measured to have the same reading speed as print, so we will get better screens in the future.

The resolution of a display is measured in PPI, Pixels Per Inch, the number of pixels used to draw a one inch long, one pixel thick, line. A higher PPI means smaller pixels, and clearer images. You can calculate the PPI of your screen by

PPI ≅ sqrt(pixels_across^2 + pixels_down^2) / diagonal_inches

I am writing this article on an iMac with a 24″ screen, showing 1920 x 1200 pixels, so my PPI ≅ sqrt(1920*1920+1200*1200)/24 ≅ 93 PPI.

The resolution of a printer is measured in DPI, or Dots Per Inch. Unfortunately, DPI is often used as another term for PPI. That is technically inaccurate, but even Microsoft does it. SPI, Scans Per Inch, is another term that is used instead of PPI, but fortunately is correct when describing digital displays.

Bitmapped images are smaller on high-resolution displays, because the pixels the picture is made of are smaller. This can be a big problem for interface elements.

For example, today Apple’s interface guidelines say “The standard Help button is 20 pixels in diameter and should be placed at least 12 pixels from other interface elements.” On my iMac, a 20-pixel wide circle is about 0.21″ in diameter — roughly 1/3rd the diameter of a Dime. But on a 300 PPI display, it would be 0.07″ in diameter — roughly as thick as three pieces of mechanical pencil lead . As you can see, it’s way too small to comfortably click!

Just scaling bitmapped images, so a 20-pixel wide picture is always drawn 0.21″ wide, isn’t a good work around. It’s just emulating a low-definition, low-readability, display on a more expensive high-definition display. Another problem is that it looks terrible when everything else on the system is crystal clear.

It gets more ugly when the scaling-factor is higher, say for a display that matched the print fidelity of the tawdry magazines you see in the grocery check-out isle.

A resolution independent interface can be usably, and pleasantly, displayed on high-definition or standard-definition screens. There are two ways to build a resolution-independent display.

You can use vector images, which can be resized without problems. SVG and PDF are two popular formats. This sounds like an elegant “design once, show anywhere” solution. But in practice today building a vector image of the same quality as a bitmapped image can be very difficult, especially with complex images. This will change in time. Today designers create bitmap images by embellishing a vector image with bitmap-effects. As vector-imiging tools improve, they will be able to perform equivalent effects, but in a resolution-independent way.

Alternately, your app can carry-around a set of bitmapped images and draw the one that most-closly matches the current resolution. If you only have to support a handful of well-definied resolutions, this might be the best choice with today’s tools. The only caveat is that all signs point to vector-images being the future. Loading one vector image is also easier the selecting one of many bitmapped images to load. (And theoretically a vector image won’t have to be tweaked if we suddenly get one million PPI displays).

Already Solved

I think it’s important to note that Fonts have been facing an even more severe resolution-independence problem for decades, and have mostly solved it. The same font can be rendered well on a 1200 DPI printer, and a 72 PPI display. That’s a much bigger resolution disparity then a computer interface will ever have to deal with, because by the time a screen close to the resolution of a 1200 DPI printer is common, nobody will be using 72 PPI displays anymore (they aren’t even sold today).

Early fonts were bitmap fonts — a collection of bitmaps of what the font should look like at a particular scaling. But today vector fonts have replaced bitmapped fonts on the desktop, and even the iPhone. Vector fonts let us do amazing things with scaling (font specific stuff starts at 1:18). Vector fonts have been such an unqualified success, that it’s hard to imagine vector images not replacing bitmapped images for interface elements.

When Will It Happen

Jeff Atwood “did some research to document how far we’ve come in display resolution over the last twenty years.”

Year	Model	Resolution	Size	DPI
1984	Original Macintosh	512 x 342	9″ (8.5″)	72
1984	IBM PC AT	640 x 350	13″ (12.3″)	60
1994	Apple Multiple Scan 17 Display	1024 x 768	17″ (16.1″)	80
2004	Apple Cinema HD display	2560 x 1600	30″	100

I used the Tag studios Monitor DPI calculator to arrive at the DPI numbers in the above table. I couldn’t quite figure out what the actual displayable area of those early CRT monitors were, so I estimated about 5% non-displayable area based on the diagonal measurement.

Regardless, it’s sobering to consider that the resolution of computer displays has increased by less than a factor of two over the last twenty years. Sure, displays have gotten larger– much larger– but actual display resolution in terms of pixels per inch has only gone up by a factor of about 1.6.

I can’t think of any other piece of computer hardware that has improved so little since 1984.

It certainly doesn’t not look like we will get 300 PPI displays anytime soon! At the present rate, it will be decades before a $2000 display matches the clarity of a $20 printer.

However today’s smarphones and small-devices have much sharper screens then computers. The first generation iPhone is 160 PPI, the Kindle is 167 PPI. Now these are much smaller screens then full-sized computers use, and I don’t know how cost-effective it is to scale the screens up from 3.5″ to 30″. But I do know that significantly higher resolution displays are being produced in increasing volume today for smartphone. So we may be fortunate enough to have, say 180 PPI, displays many years sooner then Atwood’s data suggests.

time = a + b*log2(distance/target_size + 1)

This is far and away the best article on Fitts’ Law I’ve seen.

Here’s how you can apply it.

The Accot-Zhai “Steering Law”, which predicts how quickly a person can “steer” something down a 2-dimensional road without “crashing” can be derived from Fitt’s Law. As you would expect, the wider the road, the faster it can be traveled. This might be my favorite implication of Fitt’s Law, since it implies that my small car may have a higher “usable speed” then a bulkier muscle car. :-p

Within minutes of riding on the first trains in Japan, I notice a significant change in advertising, from train to television. The trend? No more printed URL’s. The replacement? Search boxes! With recommended search terms!

A very interesting observation from Cabel Sasser (with lots of pictures).

…a study done at Apple almost ten years ago found that the user’s mouse gravitates toward red objects almost as though they were possessed with magnetism. The study forced us to abandon the idea of making close boxes and the Shut Down option red.

–Ask Tog, February, 2000

I am interested to know if this is still true when you are using your own finger to directly touch a red screen element. I expect it still is true, but you never know for sure until you test. Real fingers don’t tend to be drawn towards real flame, even if cursors are drawn to animations of flame.

All languages should include well-written error messages as part of their specification. These messages should include a link to a good explanation of the problem, and anything someone learning the language might want to know, like the design behind the error.

Every standards-compliant compiler would be required to emit the readable error messages.

This could eliminate inscrutable error messages, in one fell swoop.

(The old MPW Compiler had some
quirky and humorous error messages. “This struct already has a perfectly good definition”, for example. Unfortunately, I don’t know of any compiler that had different but more useful error messages. It’s time somebody wrote one.)

I hadn’t realized until today that “zooming” was a nontrivial task. I’m habituated to choose “zoom in” to see more detail, but less of the big picture, and “zoom out” to see how less-defined blocks fit together. But selecting which flavor of zoom is appropriate is not as easy as it first appears.

I didn’t realize this until I saw two participants in usability tests frequently choose the opposite kind of zoom from what they wanted. One lady would even explain how zooming would be helpful to what she was going to do, then say that she should perform the opposite kind of zooming that she described.

Understanding zooming involves forming and manipulating a three-dimensional model of abstract data represented on a two-dimensional screen. Sometimes there’s even the question of what is being zoomed. If you zoom in on a window containing a map, should the window itself change size (take up the fullscreen perhaps), or should the contents of the window be changed?

Small wonder then that some people choose the wrong kind of zoom, especially if they are not spatially-oriented.

The good news is that a zoom error is easy to recover from. You just hit the other button. Recovery is even easier if a knob, or other reversible input device, controls zoom. You just twist in the opposite direction, without having to acquire another button first. The scroll-wheel on a mouse is such a control, but …

But be careful when using the scroll-wheel to zoom, because users may trigger a zoom when they meant to scroll. I have this problem all the time with Google Maps. After a few hours of using the scroll-wheel to scroll webpages, I look something up in the Google Maps webpage — but if I attempt to use the scroll wheel to scroll the map it shoots my viewpoint up hundreds of miles into the atmosphere. Even though recovery is easy, it’s very disorienting, and quite annoying. It’s also slow, because the data has to be loaded over an internet connection — even the fast connection at the office is still orders of magnitude slower then loading the data from local memory.

It’s interesting that Mac OS X’s Exposé feature, while arguably a zooming-interface, is not described as one. To quote the help, “Your computer includes Exposé, a tool that temporarily rearranges windows to help find things.” No spatial reasoning is needed to use it.