4 ms·

What is the purpose of a scrollbar? I don’t see the need.

Arnt 3y ago
I worked with this a while ago. It's a navigation/organisation tool for GUIs. GUIs have many such tools, and each of them is unnecessary in the sense that you can use others. But each of them is also better than the others in some cases. Suppose you're working on an interface to show something that's 2D, is generally 3× as wide as the viewport and 5× as as high, and the viewport is big (a computer screen, not a smartwatch). In that case two scrollbars may be the best way to let the user navigate. The user can see at a glance what part of the thing is visible within the viewport, can move the viewport by manipulating the same thing that shows the location, and the movement has a low error rate (the effect is generally close to the user's intent). If the typical sizes are, say, 100× as wide as the viewport, then the scrollbar doesn't work as well. If the viewport is so small that the scrollbar takes up much of the space, ditto. If the viewport is a touch screen, that changes the tradeoff compared to a draggable viewport.
- Quinzel 3y ago
  Oh thank you, I didn’t know that :)
- masswerk 3y ago
  There's also a notable ideological split, a schism, in this amazing instrument combining both the aspects of a positional indicator and a navigational device in a single widget that we call a scrollbar. Namely, it's about the question, whether the scroll thumb should be flexible in size, thus representing the size of the viewport in relation to the total dimension of the document, or not. If it is, the user can obtain information about the approximate size of the entire document nearly immediately. On the other hand, if it does not, it rather emphasizes the position of the viewport in a document and allows for more precise navigation to a certain location in the given document. Moreover, this second type of scrollbar doesn't suffer from issues with very long or very short documents. (As the second option provides a bit more usability, it was quite naturally removed in the process, we know as the history of user interfaces.)
  - Arnt 3y ago
    FWIW, I've seen issues with that type too. Specifically, I once watched a user trying to scroll across a very large model. When the scrollbar moved by just one pixel, the model moved by more than half a screenful. It was painful.
adamzochowski 3y ago
When keyboard is not supported and I can't scroll by pagedown/space buttons. When keyboard is not supported and I can't scroll to the bottom. When I want to scroll to find something in a binary like fashion, scroll to the middle, decide if what I want is at upper half or bottom half, etc. Not all people have scrollwheel to begin with Scrollwheel is broken, as many overwrite OS behaviour, and generally slow even if you specify in settings to perform larger motion per scroll action
2h 3y ago
a scrollbar when done right is the most natural form of moving down a page. most scrollwheels have "notches", so if you move the wheel one "notch", its rarely the exact amount you wanted to move. the middle click is also not ideal, because it starts moving the page based on the current mouse position relative to the original position. so if you accidentally move too far away from the origin, the page shoots up or down. with a scrollbar done right, you have fine grained, manual control of the movement of the page.
- mayoff 3y ago
  I'm not sure why you'd call it the most ‘natural’ form. Scroll bars don't appear in nature. Of all the ways to scroll content, direct manipulation (dragging your finger directly on the document on the screen) is most like the way we move real things around in nature.
  - 2h 3y ago
    yes, because the word "natural" only has one meaning.

Arnt 3y ago

I worked with this a while ago. It's a navigation/organisation tool for GUIs. GUIs have many such tools, and each of them is unnecessary in the sense that you can use others. But each of them is also better than the others in some cases. Suppose you're working on an interface to show something that's 2D, is generally 3× as wide as the viewport and 5× as as high, and the viewport is big (a computer screen, not a smartwatch). In that case two scrollbars may be the best way to let the user navigate. The user can see at a glance what part of the thing is visible within the viewport, can move the viewport by manipulating the same thing that shows the location, and the movement has a low error rate (the effect is generally close to the user's intent). If the typical sizes are, say, 100× as wide as the viewport, then the scrollbar doesn't work as well. If the viewport is so small that the scrollbar takes up much of the space, ditto. If the viewport is a touch screen, that changes the tradeoff compared to a draggable viewport.

Quinzel 3y ago
Oh thank you, I didn’t know that :)
masswerk 3y ago
There's also a notable ideological split, a schism, in this amazing instrument combining both the aspects of a positional indicator and a navigational device in a single widget that we call a scrollbar. Namely, it's about the question, whether the scroll thumb should be flexible in size, thus representing the size of the viewport in relation to the total dimension of the document, or not. If it is, the user can obtain information about the approximate size of the entire document nearly immediately. On the other hand, if it does not, it rather emphasizes the position of the viewport in a document and allows for more precise navigation to a certain location in the given document. Moreover, this second type of scrollbar doesn't suffer from issues with very long or very short documents. (As the second option provides a bit more usability, it was quite naturally removed in the process, we know as the history of user interfaces.)
- Arnt 3y ago
  FWIW, I've seen issues with that type too. Specifically, I once watched a user trying to scroll across a very large model. When the scrollbar moved by just one pixel, the model moved by more than half a screenful. It was painful.

adamzochowski 3y ago

When keyboard is not supported and I can't scroll by pagedown/space buttons. When keyboard is not supported and I can't scroll to the bottom. When I want to scroll to find something in a binary like fashion, scroll to the middle, decide if what I want is at upper half or bottom half, etc. Not all people have scrollwheel to begin with Scrollwheel is broken, as many overwrite OS behaviour, and generally slow even if you specify in settings to perform larger motion per scroll action

2h 3y ago

a scrollbar when done right is the most natural form of moving down a page. most scrollwheels have "notches", so if you move the wheel one "notch", its rarely the exact amount you wanted to move. the middle click is also not ideal, because it starts moving the page based on the current mouse position relative to the original position. so if you accidentally move too far away from the origin, the page shoots up or down. with a scrollbar done right, you have fine grained, manual control of the movement of the page.

mayoff 3y ago
I'm not sure why you'd call it the most ‘natural’ form. Scroll bars don't appear in nature. Of all the ways to scroll content, direct manipulation (dragging your finger directly on the document on the screen) is most like the way we move real things around in nature.
- 2h 3y ago
  yes, because the word "natural" only has one meaning.