Snap-and-go helping users align objects without the modality of traditional snapping patrick...
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Transcript of Snap-and-go helping users align objects without the modality of traditional snapping patrick...
snap-and-go
helping users align objectswithout the modality of traditional snapping
patrick baudisch
ed cutrellken hinckleyadam eversolemicrosoft research
CHI 2005
kind of a solution
• hold down <shift> key to activate• hold down <alt> key to deactivate
• problems1. <shift>, <alt>, <ctrl> may be in use (Adobe)2. more snapping functions than qualifier keys
(Visio)3. target audience may not know
(who knows that <alt>tab switches windows?)in the real world 18% do
traditional snapping
inaccessible
snap location
inaccessible
snap-and-gosnap location
enlarged inmotor space only
Fuzzing with pointer speed• Sticky icons [Worden…, CHI 97]• Semantic pointing [Blanc, 04]• Object pointing [Guiard 04]
and yes, it also works also for target acquisition
target
target
• vs. bubble cursor [Grossman, CHI 05]• selecting handles
vs. Bubble Cursor [CHI 05]
• bubble cursor can’t help selecting these handles
• snap-and-go can• because we insert
simplest code
snapTo(x, width, snapX) {
if (x >= snapX + width)
return x - width + 1;
if (x > snapX)
return snapX;
else return x;
}
“real” implementation
• written in C#
• rectangular “friction objects”• friction gradient of configurable direction and
strength• combine multiple friction objects
• algorithm• integrate friction along interpolated pointer path
ok, even if pointer jumps over a widget• track in subpixels to avoid accumulated error
3 studies
snap-and-go compared to traditional snapping…
snap-and-go with distractors…
…in 1D study 1 study 2
…in 2D study 3
experimental design
• within subjects design• 2 x 4 x 4 (Snapping Technique x Attractor Width
x Target Distance)• 8 repetitions for each cell• Distances 100, 200, 400, and 800 pixels• Widths 5, 10, 18, and 34 pixels• recorded task completion time and error
• 9 participants
hypotheses
• snap-and-go faster than no snapping
• stronger attractors reduce task time
• snap-and-go slightly slower than traditional snapping
results: task time
No Attractor 5 10 18 340
0.5
1
1.5
2
2.5
Re
spon
se T
ime
(se
con
ds
± S
EM
)
Attractor Width (pixels)
Traditional Snapping
Snap-and-Go
fitts analysis of task time
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 1 2 3 4 5 6 7 8
Mov
emen
t Tim
e (s
econ
ds ±
SE
M)
Fitts Index of Difficulty
Traditional Snapping
Snap-and-Go
experimental design
• single distance• only two attractor widths• only snap-and-go (no traditional snapping) (2 x 2 x 2 x 2 x 2 x 2) (Target Attractor on x
Distractor 1 x Distractor 2 x Distractor 3 x Distractor 4 x Attractor Width)
• 4 repetitions for each cell• recorded task completion time and error
• 9 participants
results: task time
0 1 2 3 40
0.5
1
1.5
2
2.5
Re
spon
se T
ime
(se
con
ds
± S
EM
)
Number of Distractors
Width=10
Width=34
“Oh, I see, you don’t put any targets really close the light bulbs, because I could not reach them there”
study 3: task 1
• within subjects• 2 x 4 x 4 (Snapping Technique x Attractor Width x
Approach Angle)• 8 repetitions for each cell• distance to the target was 200 pixels• approach angles were 0, 15, 30, and 45 degrees, • recorded task completion time and error
• 11 participants
results task 1
No Attractor 5 10 18 340
0.5
1
1.5
2
2.5
3
3.5
Re
spon
se T
ime
(se
con
ds
± S
EM
)
Attractor Width (pixels)
Traditional Snapping
Snap-and-Go
study 3: task 2
• within subjects• 2 x 2 x 2 x 2 x 2 x 2 (Target Attractor Vertical
x Target Attractor Horizontal x Distractor Vertical10 x Distractor Horizontal10 x Distractor Vertical60x Distractor Horizontal60
• 4 repetitions for each cell• recorded task completion time and error
• 11 participants
results task 2
No Target Attractor
1 Target Attractor
2 Target Attractors
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Res
pons
e T
ime
(sec
onds
± S
EM
)
Number of Distractors (Vertical & Horizontal)10 2 3 4 10 2 3 4 10 2 3 4
discussion all 3 studies
• faster with snap-and-go than without• 138% in 1D• 231% in 2D
• as predicted slightly slower then traditional snapping• 3% in 1D• 14% in 2D
• fairly robust against distractors
conclusions: snap-and-go
• unlike traditional snappingdoes not require deactivation omit the deactivation interface
• allows deployment where complexity of deactivation interface would be prohibitive
contributions
1. manipulations of mouse gain can help align objects
2. extended technique to 2D by introducing guides that guide dragged objects to snap locations (plus and the bar widgets)
3. three user studies evaluating
• future work: extend snap-and-go to such as pen and touch input