The Fitts law of the important rules of human-computer Interaction Design

Fitzpatrick Law is a very important rule in the field of human-computer interaction, which has been widely used in the past 10 years. The basic point of the Fitts rule is that any time a person uses the mouse to move the mouse pointer, certain features of the target on the screen make it easy or difficult to click. The farther away the goal is, the harder it is to arrive. The smaller the goal, the more difficult it is. Pretty simple, right? This means that if the target is easier to locate, it should be closer to the current position of the mouse and the target space should be larger. Fitts spent several pages describing the findings, using a mathematically rigorous formula to show how to measure the impact of different speed distances to target dimensions on the target in the user's point. The farther the target and mouse pointer, the smaller the size, the more difficult the goal.

The time to reach the target from the mouse can be computed using the formula times = a + b log2 (d/s + 1). which

• D: Mouse to reach the target distance
• S: The width of the target (size)

The Fitzpatrick Law provides a metric for human-computer interaction, which provides us with a scientific basis for designing human-computer interaction, which is to tell us how to design an interface that makes it easier for users to use and improve the user's operating experience. From the formula above, we can draw a conclusion: if we want to mouse faster hit target can take two measures, either reduce the distance between the mouse and the target, or make the target large enough (ha, of course, have a good mouse, I used a mouse suddenly out of the question, The mouse pointer away from the button is very close but it took me a few seconds to move to the top of the button, a smile. Another great thing about this is to keep the buttons together as much as possible, and to put the buttons you use most often in the most eye-catching positions.

And let's take a look at some of the application of the law of Watts:

1. Adding an option from the operating system Start menu after Windows XP is to hide a menu that is not used for a long time, simply by using frequency, and actually I think it is also to reduce the length of the pop-up menu after the user clicks the start, and to reduce the distance between the mouse and the target menu.
2. The OfficeXP menu also provides the ability to hide menus and toolbars.
3. Mac operating system Shortcut bar on the button is very large, like Stardock company to provide us with the Mac operating system toolbar implementation, click a button hit probability is much larger, and Windows taskbar buttons are 16x16, inadvertently also easy to point wrong.

And let's look at a couple of bad interaction designs.

1. The ability to use pagination is often used in web pages, but often the number of pages displayed is particularly small, and dense, if you have used the DataGrid control provided by ASP.net to know how difficult the page number of pages displayed, it is really difficult to select a page number, but also careful.

2. GotDotNet Query page also has a paging function, but it provides a "next>>" way, click Pagination is not particularly difficult, but the page scroll down to the next if you want to turn the page will also roll to the top pages, use is very inconvenient.

3. In a tool like uninstall, the interface has only one main window, but the buttons that are not used frequently are large, and the buttons that are often used are small, as shown in the following illustration:

The Fitzpatrick formula provides a basis for our design interaction, so does it answer all the questions? The main disadvantages are:

1. Its application range is only 2D. I think the lack of a factor is the direction of the problem, for right-handed users to the left and the lower left in the direction of the general hit to be difficult, because of the reasons for the inconvenience, do not believe that you can try, so if you want to do a special meticulous, it is necessary to consider the layout of the button on the interface, the General button on the right side may be better.
2. Lack of measurement of virtual distances. From the mouse to the target is a measurable distance, that is, the distance is continuous, however, in the actual use of the distance and must be continuous, in fact, it may be discrete. For example, when you're working on a document, you need to format the paragraph, with a special paragraph menu in Word, in the document window, on the toolbar, so that the user can quickly format the paragraph and provide as many portals as possible, then the goal here is not one-to-one, but a one-to-many one. The other proposition here is that in order for users to hit the target quickly, you have to set the equivalent goal of multiple goals in the program, that is, to make the goal as ubiquitous as possible within a limited range. The SendTo in Windows shell provides another, more efficient solution. Another feasible solution is to let users according to their own habits and preferences to DIY goal placement, like the Windows Start menu, we can according to their preferences for grouping.