[off topic] mouse wheel

[Martijn Mulder]

When the mouse is over a picture, the user can grow or shrink it by rolling
the central mouse wheel. What behavior is typical when the user rolls the
wheel away. Will the picture grow or shrink then?

 

[Jacob]

You can check the delta value of the mousewheel. +1 should indicate
growth (IMHO= zoom in).

 

[Tom Dacon]

Here's my take on it:

A user interface designer has to consider what the typical user thinks
should happen when rolling the mouse wheel forward or backwards.

For example, if the user thinks the mouse wheel moves her EYE closer to and
farther away from the image, then rolling the wheel forward zooms in.

If the user thinks that pushing forward on the mouse wheel moves the IMAGE
farther away from her eye (moving her finger, and thus the image, away from
her), then rolling the mouse wheel forward zooms out.

So it's all down to the user's mental model of the situation. Is she
manipulating the image, or moving her eye? A good user interface is one that
behaves in such a way that the behavior of the application does not conflict
with the user's mental model. So since it's difficult or impossible to find
out what your users' mental models are, and even if you could they wouldn't
all agree, there's just one good way to handle this.

And here it is:

Make the behavior a user-settable preference. For its default value, see if
you can find a consensus among the industry leaders in the same kind of
application you're developing. Look at Photoshop, Paint Shop Pro, etc. If
you can find a consensus, use that as the default setting. If you can't find
a consensus, ask as many as possible of real users of your application (not
just your programmer-testers) what they want to happen.

I'll go farther than that: some people might want the wheel to pan (and the
newest mice allow you to move the wheel left and right, as well as forward
and back). So you might consider letting the user specify in an options
dialog whether they want the wheel to zoom or pan. But if they want to pan,
there's the same mental model issue: are they moving the image left and
right, or the eye left and right? So they'd need to specify their preferred
directional behavior for both modes of operation.

All this is a lot of work, but at least in one small way your users will be
happier people when they're using your app.

Best regards,
Tom Dacon
Dacon Software Consulting

 

[John B]

When the mouse is over a picture, the user can grow or shrink it by rolling
the central mouse wheel. What behavior is typical when the user rolls the
wheel away. Will the picture grow or shrink then?

Excellent question.
IMO when the user rolls the wheel "forward", the picture should grow.



JB

 

[Ole Nielsby]

From what I've seen normaly the mental model is that you are
the one moving not the picture [...]

Would be interesting too look at why this is, is it conditioned
because this is how most software acts, because of scrollbars
or just because the user moves the mouse in the way they
would like to move if the image were real.

I think Pacman is part of the reason...

In an everyday situation, you would typically move the
object. Say someone puts a photo on your desk and asks
you to take a closer look at some detail. Would you bend
over to get a closer look, or would you take up the photo
and hold it closer to your eye?

My feeling is, by far the most of us would lift the photo.
Perhaps we would later put it back on the desk and
bend over it using a magnifier, but that's because of
practical difficulties with light and keeping both the
photo and magnifier steady, not because bending feels
natural.

Say you spot a strange insect walking your desk. If
you're the curious kind, you'll bend over and watch,
but that's merely because you've been taught not to
touch such things. A toddler would not hesitate to
take it up and pull it apart in front of his/her eyes.

Now, in 3D games, it's an established convention that
you move your alter ego around by rolling/pushing/
pressing in whatever direction you want to go, though
this is the opposite of what you would do with your
hands if you were really crawling in a dusty tomb.

It's not because this is the "natural" way. It's a convention
inherited from Pacman where your avatar is more like an
object you move around.

As things are, with Counterstrike, Hitman and their likes
being the typical youngster's first exposure to computers,
this little twart is probably here to stay.

 

[Martijn Mulder]

"Ole Nielsby" schreef in bericht

From what I've seen normaly the mental model is that you are
the one moving not the picture [...]

Would be interesting too look at why this is, is it conditioned
because this is how most software acts, because of scrollbars
or just because the user moves the mouse in the way they
would like to move if the image were real.

I think Pacman is part of the reason...

In an everyday situation, you would typically move the
object. Say someone puts a photo on your desk and asks
you to take a closer look at some detail. Would you bend
over to get a closer look, or would you take up the photo
and hold it closer to your eye?

My feeling is, by far the most of us would lift the photo.
Perhaps we would later put it back on the desk and
bend over it using a magnifier, but that's because of
practical difficulties with light and keeping both the
photo and magnifier steady, not because bending feels
natural.

Say you spot a strange insect walking your desk. If
you're the curious kind, you'll bend over and watch,
but that's merely because you've been taught not to
touch such things. A toddler would not hesitate to
take it up and pull it apart in front of his/her eyes.

Now, in 3D games, it's an established convention that
you move your alter ego around by rolling/pushing/
pressing in whatever direction you want to go, though
this is the opposite of what you would do with your
hands if you were really crawling in a dusty tomb.

It's not because this is the "natural" way. It's a convention
inherited from Pacman where your avatar is more like an
object you move around.

As things are, with Counterstrike, Hitman and their likes
being the typical youngster's first exposure to computers,
this little twart is probably here to stay.

Thank you all. Your discussion helped me a lot. The question is what you
control with the mouse. If you control the picture and 'roll it away', it
will shrink. But if you control the user, the viewer. 'rolling away' means
bending forward and the picture will grow. When you read a document on-line
and you roll forward, you control the eyes of the reader, not the text. If
it was the text you rolled forward, or pushed up, you would go nearer to the
end. But it isn't, rolling forward takes you to the start of the document.
You control the eyes of the reader, not the position of the document. So I
implement the mouse wheel in a similair fashion when growing or shrinking a
picture. Rolling forward is bending over, the picture grows. Rolling
backwards is moving away, the picture shrinks.

 

[=?ISO-8859-1?Q?G=F6ran_Andersson?=]

From what I've seen normaly the mental model is that you are
the one moving not the picture [...]

Would be interesting too look at why this is, is it conditioned
because this is how most software acts, because of scrollbars
or just because the user moves the mouse in the way they
would like to move if the image were real.

I think Pacman is part of the reason...

In an everyday situation, you would typically move the
object. Say someone puts a photo on your desk and asks
you to take a closer look at some detail. Would you bend
over to get a closer look, or would you take up the photo
and hold it closer to your eye?

My feeling is, by far the most of us would lift the photo.
Perhaps we would later put it back on the desk and
bend over it using a magnifier, but that's because of
practical difficulties with light and keeping both the
photo and magnifier steady, not because bending feels
natural.

Say you spot a strange insect walking your desk. If
you're the curious kind, you'll bend over and watch,
but that's merely because you've been taught not to
touch such things. A toddler would not hesitate to
take it up and pull it apart in front of his/her eyes.

Now, in 3D games, it's an established convention that
you move your alter ego around by rolling/pushing/
pressing in whatever direction you want to go, though
this is the opposite of what you would do with your
hands if you were really crawling in a dusty tomb.

So the mouse wheel shouldn't grow or shrink the picture at all, but
replace it with a knife or a machine gun?

 

[Chris Chilvers]

From what I've seen normaly the mental model is that you are the one
moving not the picture unless you give the user the impression they are
grabbing the image (i.e. the hand tool to move things in paint shop
pro).

Would be interesting too look at why this is, is it conditioned because
this is how most software acts, because of scrollbars or just because
the user moves the mouse in the way they would like to move if the image
were real.