Animating
Direct Manipulation
Bruce H. Thomas Advanced Computing Research Centre School of Computer and Information Science University of South Australia The Levels, SA, Australia 5095 mabht@graceland. Levels. UniSA.Edu.Au
ABSTRACT tion
applied,
can enhance
many
human
particular, in
the
the
real
use to animate scribes
tools
porate
the
that
object.
into
by To
and
used
simple
drawing
on
editor
demonstrates
simple
the
is practical
even
idea,
new
the
sugcan
and it de-
use to easily
of
on standard
ani-
vince
users
animation,
cal interfaces, its,
warp
direct
the
a
The
to this
the
user interface
plore
how
techniques
puter
animation
ing
with
here
with
algorithm
animation
Rather,
we
Permission personal are not right given
wish
as to
enhance to make
to republish,
data,
[15])
toolk-
copies
is granted for profit
of the publication is by permission
of all
~IST 95 Pittsburgh PA USA @ 1995 ACM O-89791-709-x/95/l
be the
(such
as an
using
anima-
of otherwise
static
system
to
the
or part
of this
and its date of the ACM,
appear, Inc. To
reversible can conwith
it’s
Brenda
all
Laurel that
appli-
an illusion. calls
the
manipulation.
but
the
drag
all
times.
on drawing to
object
give to
More
the
too
solid;
used
by
that
mimic
start
move
cartoon
they
stretch
the
moving
the
the fullsolidity
must One
[10]
is to
such
do more approach use
tech-
as inertia
and
of substance.
and than
Cartoon
come
to a gradual
along
straight
to suggest
real
somehow
solid.
effects
slowly
is
the
object.
objects
illusion
rather
and squash
operation than
the object
animators
physical
in curves
to implement
the
as drawing
gives
also feel
where
techniques
a sense of substance;
must
to reinforce
they
such
drag
object
knows
rather
solid-seeming they
niques objects
that
easy to manipulate
widely
friction
the
user
are cheap
schemes
an
continuous
feedback
object
to convey
be convincing, look
the
outlines
during
moving provide
Simple
impression
ambitious fail
of must
so that
a surrogate
object
can still
than
operation
application
is at
tend
featured
stop,
lines,
interaction
with
and their
environment.
of hu-
material
for
the copies tht COpy -
and notice is copy otherwise,
to lists. r~wir~s
sPecific
Although
we have
informal
experience
enhance
the
with had
by
inertia;
wiggle
not
objects. it
if it collides sense
formal
these
The that
For with
distort
other
overall “things
are
our can
interacting
if an object slightly
objects, effect
trials,
techniques
when
example,
might
user
same
of substance
a corner,
as if bumped.
a stronger
conducted
is that
impression
application
dragged
has
as
they
is that
UIST ’95
is if
it
might
the
happening”
user and
1..$3.50
November 14-17, 1995
sus-
applica-
[17]).
interface
without fee provided that or commercial advantage.
fee.
com-
concerned
effectiveness
to post on sewers or to r~distril~ute and/or
and
ex-
of interact-
tools
help
the
to
as would
animation
augment
out
not
or when
animated
apply
or
are
editing
presentation an
digital/hard
or classroom use made or distributed
notice, the title that copyright
permission
the
(such
set
cartoons
we
animated
to supplement
itself—to
from
animation editor
have
the experience
However,
portraying operating
we
borrowed
a computer.
information
[2],
can enhance
case when tion
during
happening
graphi-
common The
object
but
hardware.
the
feedback
To workers
know
which the
and
interacting
they
the
immediate
changes,
[9], is the feedback
to track
dragging.
based
INTRODUCTION recent
identified
characteristics
are directly
illusion,
generates
it seems
other
a graph-
manipulation:
these
though
of disbelief
technique
InterViews
Like
even
Central
animation
manipulation,
transformation,
they
pension
thing.
KEYWORDS:
present
Shneiderman
incremental
applied,
that
data,
tion
[14], of direct
to actions, Properly
Consider
to build
workstation
response
by
inter-
feedback.
that
paper
ingredients
effects.
a warping
of the
it shows
seminal
user
transformation
effectiveness
that
manipu-
we added Interviews
uses animated
and
of
the
his
cation
incor-
a range
view
to the
that
operations,
paper
interfaces,
suggesting
the
the
editor
In
code.
distorting explore
This
programmers
can
their
capability
face toolkit
done.
applications
The Problem essential
strengthening
application
manipulation
is based
transformation
for
is being
that
In
of substance
manipulates,
with
interface.
that
to present.
a feeling
interaction
ical
anima-
manipulation
strive
programmers
effects
effects
lated
work
direct
approach
mation
a user
techniques
of cartoon
of direct
interfaces can convey
that
that
techniques
the illusion
computer
objects
gests some
Our
the
animation
sense
Paul Calder Department of Computer Science The Flinders University of South Australia GPO Box 2100, Adelaide, Australia 5001
[email protected] .edu. au
man
If judiciously
Interfaces
3
that
real
work
is being
done.
niques
is straightforward
some Adding
animation
plication
to
action.
In
being
to
display
and
to
the
object
the
user
tion
also
extra
understanding
the
inter-
suggest
that
the
an
gives of an ac-
the
effects
can
interface,
mer’s
but
task. animation
and
to provide
incorporate
can
toolkit
[11]. and
the
context additions
First
the
can
purpose
hardware.
modified
Finally,
that
in user
of the
project
that
that
In
Prosodic
Interfaces
gestures.
Audible
ment
the
the
addition
sense of presence.
repertoire
the
Gestures
way of issuing of tools their
the
contextual
while
that
interface
and
sounds
the
also
of requirements though basic
for
making
developed principles
in both
in the also
disciplines,
ing
sequences
For
interface
context
apply
to
animations
of images
in rapid
of film computer are
2. The
predefine
4
paths,
the
that
move
application
three
in
fixed
in
stays
an
application
to feel
principles
that
that,
can for
they
apply
of solidity,
these,
when
we
its
are in
to car-
exaggeration,
add
animating
should
principle
in general,
two
more
a direct,
states
at all times
of reluctance reluctant
Adherence
to the
impression
that
and
a
and extend
tion.
that
manipula-
that,
the
remain
object
attached
states
that
objects
are,
maintains
the
to change.
the
illusion
objects
of attachment
user
to the
is always
principle
of substance
requires
effort
of the
of reluctance
by
on the
in control
suggesting
that
part
user.
of the
ac-
reinforces changing
can
a basic
the
applied
animation.
Al-
simple
figures
animation,
the
simple
editing
animation
[8];
rotating.
display-
being
the Effect these
interaction
drawing
by
principle the
Adherence
The such
editor
as lines
such
task
objects
supports and
1 shows
to move
to the
graphical
operations
Figure used
principles
with
editor.
the
polygons,
a slrnple
creation aud
as moving,
a screen
of animatin
scaling,
image
of
it allows
of the
and editor
an object.
succession. Figure
objects
a fixed
leaning
sense of substance
users
an direc-
pointer.
set
created
object,
base
these,
of attacl~ment
cues
programmers
a successful
its
principles
manipulated
sense of di-
will
outlines
to move
the
while like
To
apply
principle
to the
ing [10],
list the
Demonstrating
Book
in the
interface:
being
and
creations.
Anzmutzon
an object,
engage-
INTERACTION
Lay bourne’s
show
allowing
Ungar
reinforcement.
We have
ANIMATING
pull
animator to suggest
distorted
an attempt,
of a greater
still
and tion
and specifying
techniques
an ob-
application
example,
dragging
object
could
techniques
animation:
and
a smoother
commands
three
to move the
com-
20],
improve
can provide
these
[19,
strengthen
how
of an object
a cartoon
For
someone the
the
illusion
toon
an
of human with
can
providing
Together,
use to enrich
is concerned
and
by
project,
animation
reinforcement
interface
expressive
to
to
to drag
example,
should
how
To suggest
of
With
create
by
animator
direction
should
other
a set of tools
the prosody
objects
tries
inertia
a
interfaces.
Interfaces
to provide
project
manipulation
operations.
aims
can improve
interfaces.
with
Prosodic
how
consider
show
pull.
the
Chang
special
we describe
animation
for
for
the
with response
control.
interactions, without
of the
object,
1. The
is part
techniques
more
and
screen,
behaviour.
caused
objects
InterViews
to show
applied
in
Context
work
ongoing
new
such
could
place.
we discuss
the
need
If a user
Or if a user tries
is to
depict
the
techniques
animated
implementation
has considered
Research
the
to create
be successfully
graphics
that
how
to
ani-
InterViews
Then
made
faced
accurate
restraint?
movement
to the prob-
of our
editor.
we
suggest
our
approach
effect
drawing
the
for
the
in position,
approach
would animator
support
into
our
overall
changes
outline
is fixed the
the
represent
its movement?
Our
experience,
can use to easily
built
across
resisting that
with
of di-
of object
Our Approach
interfaces.
we have
rapidly
are
and
behaviour.
ject
tion
can be used
briefly
rect
their
we describe
and
techniques
puter
program-
is at odds
[5] provide
are in control
programmers
the application
suggest
with
to suggest
interactive
of interactions
components,
This
application
programmers
of a simple
components
work
satisfaction
is twofold:
the
into
how
kinds
illustrate
the
the
that
effects
describes
certain
and
to the then,
enhance
tools
mating
toolkit
add
user’s
of the Paper
paper
lem
the
problem,
the
Structure
they
The
how
This
improve
object
Ungar
in the context,
for immediate
realistic-seeming
should
users
application
actions
and
However
where
the need
to user have
on an object.
These
manipulation,
dilemma:
prevent
results
rect
(Chang
examples).
movements,
actions,
information
of the
ap-
objects
by a user’s
of constraints The
the
of the
can
caused
changing.
a better
state
animation
presence
allows
about
current
of change
the
from
also
information
the
the
rate
or it can imply
feedback
more
addition
manipulated,
direction
the
excellent
spontaneously
or along
of Lay bourne’s
tech-
tion not
UIST ’95
2 shows
how
on a rectangle. fully
convey
the
the
editor
Of
course,
dynamic
animates these feel
a move
static
of the
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strategy
all
other
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same
mouse,
that
for
figure
4 shows
the part
suggests
works
example,
to
In each animate
that the
is
case,
the
in-
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bulk
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of the
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while
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the
of the the the object
successive
the
operation
shows
corner
several
effect.
without moves
rectangle bulk that
the
with stays
of the
effect
The
to follow
operation
object
is that distorts
frames top
of
the
attached
to the
as it is pushed
figThe
note
slightly
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the
animation
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November 14-17, 1995
from
how
mouse
the
extra
for
is fixed simply
effects
information
example, in place.
that about
an attempt One
be to prevent
mouse.
of the
to
response
to
the object
from
correctly.
of response.
allow
the object
back
to its original
avoids
this
of visible
feed-
to follow
the problem when
place with
lack
as the result
at the operation lack
surprises
However,
be misinterpreted
the object
attempts superimposed to
that
might
might
“grasp”
interaction
constraining
_-”w
Figure 2: Animating
have
Consider,
an object attempt
simple
can convey
A user before
realising
Another
when lack
but
of feedback, object
to
several
the true
released.
placed
make
strategy
the mouse,
a carefully
might
of a failure
cause
might,
be to
then
to snap
This
approach
but
it
can lead to
suddenly
jumps
back.
behind. a heavy
and pulled.
Figure ing
UIST ’95
5 shows
animation.
how
our
editor
As the user
avoids
attempts
both
problems
to drag
the
us-
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surface object, the
the
bulk
user
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is pulling
in place.
The
object
will
The
move
succeed.
same
effect
For example,
figure
under
the
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to snap
the
object
away
yond and
the
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teraction
and
to the
it clear
is, what
result, any
snaps
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fixed.
gravity next
what
happen
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the
animation
them
chose
powerful
the
effects
into
all underlying
the effect
our
determines
editor
mation,
applies
to draw
the object
angle
from
its
to
suggest
be to represent
the responses the a much
effect
the
of the
and
of the in-
points.
images
[22].)
applied
to
a rectangle,
an appropriate drawing
for example,
warping
system,
transfor-
then
rectangle.
proceeds
When
it will
the rect-
appear
distorted.
model: warp;
complex
the code the
approach an approach
that
(indeed,
graphics
this with
draws
effect
will
two
of)
apply
key
based
the warped
is unaware
as to a simple
has
on a
objects
the
presence
as well
to more
rectangle.
the desired
is released
to generate,
toolkit
[11]
because
at
extend
we intoolkit. it
Computing
has
a
the Warp Vectors
warping
transformation
bound
vectors
to key
points
for
points
lated
to include
interaction
with
physical
the
with
a physical
simpler
objects
as forces
of the objects physical
we want.
6
of moving
compared
Again,
state
in the
the
is characterised
describe
do not idea;
by a set of
the transformations
coordinate
space. with
vectors
between
the
vectors.
a later
section
points
that
applied
Transformations
coincide
interpolating
illustrates lation
that
that
by
tors
and the interaction
that
certain
distort
is
and the
are
calcu-
Figure
describes
the
7
calcu-
in detail.
effect.
way
ulating
at
effect
primitives.
simplicity,
when
In the example, One
The sheet,
to
on the screen,
by
The Model would
distorted. a rubber
pulling
as a simple
is displayed
is unaffected
we could
onto
as
of the drawing
as a transformation
it to the
physical
interface
that
warp
To suggest
be-
user
model
drawn
drawing
go”
object
easy
the
“lets
an existing
InterViews
graphics
new
used
Our
corporated
the
by
is widely
then
advantages
time.
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stretched
technique
Apart
corner
MAKING IT EASY TO USE To
was
(The
pulled
do to achieve
appears
sheet
When point.
view
objects
system
causes
user
grasped
current
if the
an ob-
that
the
manipulated
were
suddenly
grid
the
the user must will
As
point,
stays the
the
on objects.
field
grid.
the
the
coordinate
attempt
of moving
of a ‘(gravity”
object
is
shape.
effect
to a regular
distance,
the
so that
draw
the
as if the objects
We implement
user
is released,
constraints
the
a grid
the
that
point
but
is as if
is anchored
that
but
grab
other
6 shows
the
clear
mouse
effect
that
to its original
from
while
The
it
object, the
influence
a certain
feedback
the
can suggest
ject
stretches
makes
back
to the
fixed.
of an object
When
spring
attached
stays
feedback
to
not
stays
object
on a corner
attempting will
point
of the
is to
to warp
acting could
objects
be determined
system.
However,
model
is sufficient
our
points
model
on the objects.
are
are
depend
Then
grid
transformed
by
transformed
on their
relative
the by
coincide
specified
with
intermediate
distances
warp
amounts.
from
vecOther
amounts
that
the specified
vec-
tors.
by sim-
experience
to produce
is the
To need
add
animation
only
calculate
appropriate
warp.
UIST ’95
to
the
interaction,
a set of vectors We
have
found
November
then, that that,
the
editor
characterise for
the
an kinds
14-17, 1995
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new . .. ..
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and
algorithm in the
operations
gives
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interaction,
we have
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we calculate
the
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a simple
For each
warping
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frame
vectors
as
follows:
1. Compute
the new positions
of the vertexes
of the shape
as usual. , 2. Place
a zero
grasped 3. Place
by the
at each
other
of that
vertex
8 shows dashed
new
positions.
the
point
by
the
rectangle
idea dots
(in
its
top
that
vertex
that
cases, of the
show
is
other
zero the
...
old
and
vectors
..
Figure 8: Calculating warp vectors for move and rotate
at
has been
arrows
warp
shape
under
its
rectangle
and
back
frame.
operations.
at
the
the
the
be drawn
points
and rotate
corner),
sizes
will
previous
a rectangle
both
strokes
that
in the
represent
right
and
solid
the
vertex
for move
show
The
positions
nally,
the
outlines
mouse
grasped
at
mouse.
position
The the
vector
a vector
to the
Figure
magnitude
show
vectors.
of the
Fi-
distorted
the warped
transfor-
mation. Although
the
physical
model,
sion
that
weights
effect
the
this shape
attached
behind
the
elastic
vertexes
that
the
to
material,
cause
a
impreswith
them
to lag
class
the
warping
user interface InterViews
this
capabilities original
tion.
Figure
with
the
such 9 shows
transformation.
part
a new Since
to coordinate
object
to add
all
of the we
only and
class interface,
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to
support
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scale
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as rotation,
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to
objects.
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method
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by adding
was sufficient
to all InterViews
transformations
Specifically,
model
is subject
addition
as an extension
toolkit.
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mation,
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model
drawing
of transformation: in InterViews
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public: . . .
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of
exactly
gives
interviews
the InterViews
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algorithm
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We implemented
kind
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movement.
Extending
tended
does simple
affine transla-
““”
Figure 9: Extension to Transformer class
together the
new
transformation.
November 14-17, 1995
UIST ’95
7
most class
Warp
{
common
mations
case),
when
but
it allows
for
arbitrary
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necessary.
public: void
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vy
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vy.
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figure
11 shows
of figure
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steps
of affine
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of this
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property, modified
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warp
be represented
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mapping
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isnot
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operations.
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as
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transform
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Algorithm the
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a displacement
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defined
we compute
a by
the
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n
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of
a scaling
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One can
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as-is
the new warp
minor
i.=1 where Cqi
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Wqi
=
~
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E
coordinate ofaffine
Cqj
j=l
map-
operation.
Transformer
stored
transformations to reflect
mations
are
while warp
and
on
the
transformation of the represents
into
new
Cqi
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new the
in turn. original only
This
matrix
Transformer: list
of items
implementation transformations
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it
im-
keeps
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item
are represented
implementation affine
affine
combicannot the
so that
successive a single
through
andso warping
We modified class
transformations
items.
iterates
matrix.
items;
combined
warp
affine, involve
Transformer
of transformation
efficiency
each
the
For
matrix
matrix
that
as a single
plementation
method
sequence
successive
of transformations
vidual
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the original
3 x 2 matrix;
how
a
other.
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l/lq
=
pil[
–
operation.
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the
by a rotation.
mappings products
with
a succession
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be represented
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followed
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adding
required
drawing
of
reachieved.
applied
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8
example,
a Transformer
as matrix
system;
former
adds compo-
a Transformer
acteristic
be used
a location
initially
and
by a translation
puted
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point
exthat
operations.
for
point
vectors;
object
:add.vector
For
mapping
of warp
Warp
(z,g)
the
effect
Conceptually,
a set A
calling at
transformation
discrete
represents interface.
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drawings, objects
class,
code.
existing use the
implementation
that
vector
Warp
the
do not
Figure 11: Applying a warp for a move operation
Warp
although
stage.
transformation
displays
The Warp Transformation
10 shows
model,
this
perspective
to InterViews
Our
new
at
point”
that
to the new
glyphs,
t.warp(&w);
figure
a “vanishing
transformation
O);
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graphics any
suggests be incor-
MAKING IT WORK
t;
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class could
scaling.
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fore,
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implemented
ample,
uniform
the
of transformations
);
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of kinds
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tation,
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transform we
distance
vector
compute
the
distance
tion
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is zero that that
and
pil
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vector
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reciprocal
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of the point
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as the
is treated
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the Pil;
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remain
weights
of the
case
when
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in the range
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: transform applying
each
retains if the
the
Trans-
Apart gorithm
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its simplicity
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complexity
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has
implementation
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UIST ’95
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colleague
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warp
Bottema
relative for leads
(the
vectors),
to several
suggested
November
efficiency
n warp
alour
properties
the algorithm.
14-17, 1995
that
simplify
a desired
the
warp
selection
of a suitable
set of vectors
for
solutions have
effect:
to this
been
used
Performance 1. Points
coincident
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by the
one
amount
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the
of that
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vector.
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from
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vectors.
drawing about
3. In
the
limit,
the
approaches
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vector
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average.
To
understand
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of the
proaches
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without
bound;
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vector
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drawing
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performance.
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generation
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second
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ethernet
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complex
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The
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use
magnitudes,
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systems.
speedup
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we have
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war-p
vectors.
warp
is applied.
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be avoided.
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ation
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loaded
vectors such
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Since
computation
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q’
q +
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warp
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vectors
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at
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Since
manipulations
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ment
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transformation
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pz = p~ = p.I = P,
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drawing
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to transform between
recursively
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to those
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images).
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draw
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warping
is implemented
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figures
on bitmapped
model
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for
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expensive of the
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distorted
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frame
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algorithms
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lines)
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techniques
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step
experience
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tions
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in the original
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November 14-17, 1995
and produces but
q + P(wqz
=
Although
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area in the transformed
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for
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scheme
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implementation
ear
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the
in the
complexity
number
the number
and scaling,
symmetries
of the
of vectors,
algorithm
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of arithmetic
some
and
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lin-
computation
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simplification
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For rotatalthough
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We are investigating
to
Another stitution
UIST ’95
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calculating
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at many
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and
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Robertson,
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RELATED WORK section
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The
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imation
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approach
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agent’s
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of computing
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what
[8].
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physical
computer
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and
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Figure 12: Symmetry of Translation Vectors
figures
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Small,
offered programs
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November
14-17, 1995
help to
Finally,
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Toolkits
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grammer
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plex
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ject,
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on
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time
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draw
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resources.
grained
work Flinders
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members
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goal
real-time
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is a high-end
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user
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2. Ronald the
in graphical
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ciples
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effects
based
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4.
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interfaces,
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graphics
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feedback suits
need
Systems,
Krishna
can
be
Bharat
effects
that,
helped
improve
Computers
Small.
Inc.,
Animation editor,
MA,
at
The
Design.
Reading,
Small,
and
In
Art
Addison1990.
1–6,
Richard
Mander.
Proceedings
on Humun
and
of
Factors
ACM
In Coli!pnt -
1991.
Piyawadee
interfaces
Interface
using
ACM
Sukaviriya.
animation and
Ani-
servers.
SIG GRAPH
Sofiwur-e
users
In
Symposautn
Technology,
pages
of animation the effects
and to
of the ACM
David
the
user
Unger.
SIG GRAPH
Soflwure
unrt
Animation:
interface.
In
Proceerl-
Sympostum
Technology,
on
pages
User
45-55,
1991.
the
into user
cost
of
even
on
how the
and standard
7. Adobe
animated
that
good
reusable
re-
und Systems
1985.
Lasseter.
on the of other
November 14-17, 1995
user’s
.perception .
aesthetic
elements
of the
9. Brenda
such
Wesley
UIST ’95
3D
on
pages
User
57-67,
PostScript
Addison-Wesley,
Principles
robust, of the Int erfuce
1991. Lunyuuge
Reading,
of traditional
Anaheim,
Animation
Flexible, Proceedings
Symposium
computer
35-44,
Stasko.
In
Incorporated.
sachusetts,
to
T. toolkit:
Technology,
Manuel.
applied
John
abstractions.
Reference
8. John
workstation
and
SIG GRAPH
software
new
toolkit.
drawing
Hudson
in a user interface
ACM
effects
underlying
interface
and
prothe
E.
support
operation
application
describes
be prohibitive,
achieved
Chang cartoons
‘87’, pages
(like
the
and
1991.
ACM The
for
work,
Laurel,
life.
of the
Interface
hardware.
interface
Ian to
pages
user
User
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that
animation
incorporated
that not
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incorporate
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3. It
at, Flinders
Interface
Conference
69-79,
prin-
of direct
transformation
transformation model
thank
objects.
geometric
grammers their
Ian
Co.,
icons
6. Scott
based
from
We
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Apple
Brenda
Baecker,
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comments
and In
Publishing
CHI’91
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to the
on cartoon
to enhance
are manipulating 2. It
a grant
interfaces:
can be used
nipulation
research
Human-Computer
From It shows
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paper.
Baecker
.5. Bay-Wei 1
in part
HyperCard.
interface.
Wesley
toolkit.
contributions
an
to use.
of Research.
context for
Atkinson.
on
makes
and
make
1987.
CONCLUSIONS work
TGI
of this
Proceedings This
childish
it, can
applications
workstations;
interface
seem
enjoyable
Board
reviewers
presentation
1. W.
full-
However,
interactive
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or draw
toolkit
animation. 3D
uses
uses of animation.
applied,
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3. Ronald
[16]
disasters
bad
REFERENCES
ob-
instead
Inventor
and
in-
possible;
great and
will
sensibly
a stimulating
Bringing The
equally
bad
this
are
good
animation
But
University
anonymous
For
a solid
detail
and
graceful
has
providing
quality
to draw
more
This
com-
in a timely
presentation
available
fine
mainthere
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the
the
when
to user input adapt
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