U.S. patent application number 11/788385 was filed with the patent office on 2007-10-04 for navigating hierarchically organized information.
Invention is credited to Stanley Lyness.
Application Number | 20070234202 11/788385 |
Document ID | / |
Family ID | 23256113 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070234202 |
Kind Code |
A1 |
Lyness; Stanley |
October 4, 2007 |
Navigating hierarchically organized information
Abstract
Hierarchies are navigated easily through a user interface that
is continuous in its presentation of node information and may be
implemented using a small display space.
Inventors: |
Lyness; Stanley;
(Auburndale, MA) |
Correspondence
Address: |
GOODWIN PROCTER LLP;PATENT ADMINISTRATOR
EXCHANGE PLACE
BOSTON
MA
02109-2881
US
|
Family ID: |
23256113 |
Appl. No.: |
11/788385 |
Filed: |
April 19, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10263218 |
Oct 2, 2002 |
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11788385 |
Apr 19, 2007 |
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09322720 |
May 28, 1999 |
6496842 |
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10263218 |
Oct 2, 2002 |
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Current U.S.
Class: |
715/234 ;
709/226 |
Current CPC
Class: |
G06F 16/168 20190101;
G06F 16/904 20190101; G06F 3/0482 20130101; G06F 16/9027
20190101 |
Class at
Publication: |
715/513 ;
709/226 |
International
Class: |
G06F 17/00 20060101
G06F017/00; G06F 15/173 20060101 G06F015/173 |
Claims
1-55. (canceled)
56. A method of displaying hierarchically organized information in
a two-dimensional space, the method comprising displaying
representations of nodes of a hierarchy in a two-dimensional space
on a display, each node representation fully occupying a subspace
within the space, and allocating the space entirely to the
subspaces, the allocation of the display space to the subspaces
being dependent on a two-dimensional value representing a focus of
a view of the hierarchy displayed to a user, such that a position
and dimensions of the portion of the space allocated to each
subspace of the display space vary only by an arbitrarily small
amount for an arbitrarily small change in the two-dimensional focus
value.
57. The method of claim 56 in which the two-dimensional value
comprises a floating-point value.
58. The method of claim 56 in which one dimension of the
two-dimensional value represents a depth of the hierarchy, and the
extent of the display space allocated to a subspace in a dimension
that represents the hierarchy depth is a function of the
corresponding node's focus-relative depth, the focus-relative depth
comprising the difference between the node's depth in the hierarchy
and the component of a user-indicated focus in the dimension
corresponding to hierarchy depth.
59. The method of claim 56 in which the extent of the display space
allocated to a subspace in the dimension that does not represent
the hierarchy depth is, for nodes within a central range of
focus-relative depth, a function of the node's focus-relative depth
and the number of the node's child nodes, and for nodes that are
children to nodes within the central range, a function of the
extent of the space allocated to the node's parent and the number
of the node's siblings and its order with respect to them, and for
nodes that are parent to nodes within the central range, a function
of the extents of its child nodes.
60. A method comprising receiving at a server a request from a
client for information about a hierarchy, in response to the
request, providing to the client information about only a portion
but not all of the hierarchy, the portion including references to
information about other portions of the hierarchy, and determining
the size of the portion to be provided to the client adaptively
based on parameters for optimizing communication between the server
and the client.
61. The method of claim 60 in which each of the portions comprises
a sub-hierarchy of the hierarchy.
62. The method of claim 60 in which the server automatically builds
a hierarchy definition portion that is as near as possible in size
to a given minimum portion size.
63. The method of claim 60 in which the server generates references
to sub-hierarchies and includes them with definitions of nodes of
the portion provided.
Description
BACKGROUND
[0001] This invention relates to a user interface for navigating a
set of information arranged hierarchically, even a very large
set.
[0002] In a typical hierarchy or "tree" of nodes, each "node" is
connected to zero or more "child" nodes and to one "parent" node,
except for one "root" node, which has no parent.
[0003] Hierarchies are common in data processing. Often a hierarchy
provides a clear way to organize a large amount of information so
that a user can find a particular piece of information. Generally,
a user "navigates" a tree by iteratively viewing descriptions of a
selected node's neighboring nodes and selecting one of the
neighbors until the sought information is found.
[0004] A user navigates the Windows file system hierarchy, for
example, by iteratively viewing a directory--the file names and
subdirectory names are these neighbors' "descriptions"--then
selecting a neighboring directory to view, until the sought file is
found. Windows offers multiple user interfaces for the
viewing/selection process: a file-selection dialog in applications;
successive directory views starting with "My Computer"; a "tree
view" in Windows Explorer; and even a command line shell which
permits displaying and changing the "current" directory.
[0005] Other, richer user interfaces for presenting and navigating
hierarchies have been proposed. Some, such as "cone trees", attempt
to represent much of a hierarchy using 3D effects to convey
relationships on a crowded display. Several use "focus+context"
techniques; that is, the portion of the hierarchy upon which the
user is currently focused, such as a current directory, is
presented in full, and portions further from this focus are
presented with progressively less detail. This can be achieved by
wrapping a 2D representation of the tree about a curved surface and
shading parts of the view away from the focus (these two techniques
create a "fish-eye lens" effect), by fractal techniques, or by
nesting boxes so that rectangles representing child nodes fill the
rectangle representing the parent. ("tree-maps"). Some techniques
depict the nodes as objects in a 3D landscape, with more distant
nodes appearing smaller.
[0006] As for navigation, a theme which is common from "tree view"
to "tree-maps" is to detect user input selecting a node (as by a
mouse click "on" the node) and redraw the view of the hierarchy
with the selected node as the new "focus". A few user interfaces
portray the change in views with an animated sequence of
intermediate views to suggest an object-like persistence. Some user
interfaces, e.g. the 3D landscapes, allow a mode of navigation
where the hierarchy view changes continuously, suggesting flight
over the landscape.
[0007] Hierarchically organized information is ubiquitous. Computer
file systems, dictionaries, indexes, tables of contents, and XML
documents are hierarchical. The functions available in some
applications are organized hierarchically in menus. On the web,
many portals and retail sites are organized hierarchically. Web
sites are not constrained to be hierarchical, but, again, hierarchy
is a clear way to organize large amounts of information.
SUMMARY
[0008] In general, in one aspect, the invention features
identifying a hierarchy position in a space defined by a hierarchy
of nodes. The space has at least two dimensions. Each node is
uniquely identifiable within the space by values in the respective
dimensions, including a node level identifying the node's hierarchy
level and a node-in-level identifying the node uniquely among nodes
in that level. The hierarchy position is identified by position
values in the same dimensions. Position values need not correspond
to actual node level or node-in-level values.
[0009] Implementations of the invention may include one or more of
the following features.
[0010] The position values may include depth value and
position-within-level values both in the form of non-integral
numbers. The position-within-level value may include a
node-in-value value identifying one node plus a floating-point
number representing an offset of the position from that node. The
hierarchy position may be used to identify a focus of a user's view
of the hierarchy.
[0011] In general, in another aspect, the invention features
displaying representations of nodes of a hierarchy in a space on a
display, each node representation fully occupying a subspace within
the space, and allocating the space entirely to the subspaces.
[0012] Implementations of the invention may include one or more of
the following features. The nodes are organized in levels in the
hierarchy and the space is allocated among the levels so that one
level is fully represented in a dimension of the display that
corresponds to changing levels. The levels of the hierarchy above
and below the one level are at least partially represented. Each of
the levels is represented as a band in the space. Nodes represented
in one band have a parent-child relationship with nodes represented
in an adjacent band. Within a band, space is allocated so that the
subspace of a parent has the same dimension along the band as the
sum of the dimensions of its children along the adjacent band.
[0013] In general, in another aspect, the invention features
rendering a container associated with the node and a representation
of information associated with the node. The container has
dimensions that change with an amount of space dynamically
allocated to the node based on a changing focus in the hierarchy.
The representation has unchanging dimensions. The container and the
representation are drawn on a display. When the focus changes, the
container is re-rendered with updated dimensions and drawn on the
display. Without re-rendering, the rendered representation is
recopied to a new location.
[0014] In implementations of the invention, the drawn container
indicates the node's position in the hierarchy and its relationship
to nearby nodes, and the representation includes graphics or text
or both.
[0015] In general, in another aspect, information is received
indicating a displacement of a user input device within a
two-dimensional frame of reference. Displacement in at least one of
the dimensions is translated to a rate of change of a hierarchy
position used to identify a focus of a user's view of the
hierarchy.
[0016] In general, in another aspect, the invention features
displaying a representation of a portion of a hierarchy of nodes to
a user. Each node may have associated an action to be performed by
an application, the action being other than navigation of the
hierarchy. A user navigates in the displayed representation of the
portion of the hierarchy by using a first type of action. The user
triggers the action associated with a displayed node of the
hierarchy by invoking the node using a second type of action.
[0017] In implementations of the invention, the first type of
action may be dragging and the second type of action may be
clicking.
[0018] In general, in another aspect of the invention an emulation
of a return-to-center input device enables a user to navigate the
hierarchy. The user manipulates a non-return-to-center input device
to indicate an intended manipulation of the emulation for purposes
of navigating the hierarchy. The user's manipulation is treated as
a manipulation of the return-to-center input device.
[0019] Implementations of the invention may include one or more of
the following features. The non-return-to-center input device is a
computer mouse, trackball, or pad. The return-to-center input
device is a joystick. The emulation includes rendering the device
on a display. The response to the user manipulation is to change a
focus position in the hierarchy. The focus position is changed by
periodically adding a focus increment vector to a focus position,
the focus increment vector being a function of the vector by which
the emulated controller is displaced from its center or rest
position. The user manipulates the non-return-to-center controller
in a single dragging action to view an arbitrarily large hierarchy
of nodes. The function is nonlinear to permit the user to vary
navigation velocity over a wide two-dimensional range.
[0020] In another aspect, the invention features displaying
information at a client about a portion of a hierarchy of nodes
including a node at the top of a sub-hierarchy of the hierarchy. As
a user's navigation causes sub-hierarchies to approach view in the
displayed information, information about the sub-hierarchy that is
approaching view is fetched from a server.
[0021] In another aspect, a request is received at a server from a
client for a hierarchy definition. In response, the client is
provided a portion but not all of the hierarchy definition, the
portion referencing other portions of the hierarchy.
[0022] In implementations of the invention, the size of the portion
to be provided to the client may be determined adaptively based on
parameters for optimizing communication between the server and the
client. The server may automatically build a hierarchy definition
portion that is as near as possible in size to a given minimum
portion size. The server may generate references to sub-hierarchies
and include them with definitions of nodes of the portion
provided.
[0023] In another aspect, a web page includes an area that provides
a navigational interface to permit continuous navigation of a
hierarchy of nodes of, e.g., links to other web pages.
[0024] In another aspect, a user interface includes a device that
permits continuous navigation for selecting from a hierarchy.
[0025] In implementations, the hierarchy may include a function
menu, a file system, an XML document, an index constructed from a
document, list, or table, an encoded hierarchy, the Dewey Decimal
System, categorized products, postal addresses or other location by
geographic region, a character set to be selected for text entry,
or a corpus which is not hierarchical in its native form and upon
which hierarchy has been imposed using a similarity-seeking
technology.
[0026] Among the advantages of the invention may be one or more of
the following.
[0027] An indefinitely large hierarchy may be navigated. The
interface permits fast navigation of the hierarchy.
[0028] The interface reduces the cognitive load to the user in at
least the following ways.
[0029] The user is offered a simple metaphor of the hierarchy as a
continuous plane, the view of which can only change smoothly as the
user navigates. The user is spared abrupt, jarring (to novices,
frightening) changes in view by allowing direct control over rate
of change of focus, so that the view of the hierarchy changes
smoothly over time. Any effects of such discontinuities in the view
as are necessary are minimized by being split into smaller
discontinuities distributed over time. The nodes in a level do not
appear full blown all at once, but appear first as small outlines,
with detail arriving at different times for different nodes.
[0030] The user is not burdened with separate controls for
scrolling, for rotation, or for zooming--all navigation is done
with one intuitive control with a simple physical metaphor. The
single control functionally replaces, for instance, the four scroll
buttons, two sliders, and numerous buttons labeled "+" or "-" in
Windows "TreeView". The interface in this way reduces repetitive
hand and eye movements as well as cognitive demands.
[0031] The relationship between parent and child nodes is made
apparent to first-time users by depicting parent nodes as
containing the children instead of by drawing ambiguous connecting
lines.
[0032] The interface is frugal with respect to available computer
display "real estate". Space is allocated extremely efficiently,
freeing most of a typical computer display for other tasks.
[0033] The interface requires only a small implementation size. The
algorithms for hierarchy rendering can be realized in compact code
for low memory use and fast delivery over a network.
[0034] The interface is frugal with respect to hierarchy-loading
bandwidth. Hierarchy information --which can be of indefinite
size--is transferred in small portions on demand as the user
"approaches" them. A user can navigate all levels of a huge
hierarchy, acquiring a sense of its size, having caused only a
small fraction of the hierarchy information to be loaded.
[0035] The interface is especially useful in "World-Wide Web"
applications. Novice users distracted by advertisements have a
lower capacity for new metaphors and surprising changes of view.
The interface accommodates the user's expectation that web
navigation is to be effected with a small "navigation frame" on the
left. The code implementing the user-interface for the web is
compact enough to be downloaded with a page (as an applet) which
accommodates the user's resistance to installing "plug-ins". The
web surfer need not wait for the information describing a huge
hierarchy to be loaded over a slow network.
[0036] Each node can have a distinct text and/or graphical
representation. Associated with each node can be an apparent way to
execute a distinct action apart from navigation when the node is
selected.
[0037] The hierarchical structure, text and/or graphical
representation of each node, and action associated with each node,
are defined in human readable formats. This hierarchy definition
may be requested and delivered incrementally and on demand. The
delivery is a special case of "streaming" data in which the data
are dispersed in two dimensions and the order in which the data are
required cannot be predicted with confidence.
[0038] Other advantages and features will become apparent from the
following description and from the claims.
DESCRIPTION
[0039] FIG. 1 illustrates relationships in a simple hierarchy.
[0040] FIG. 2 illustrates an allocation of display area to a
portion of the sample hierarchy, arranged in the horizontal
direction.
[0041] FIG. 3 illustrates an allocation of display area to a
portion of the sample hierarchy, arranged in the vertical
direction.
[0042] FIG. 4 shows a hierarchy view-and-control loop including the
user and the invention in a computer network context.
[0043] FIG. 5 is an overall flow diagram.
[0044] FIG. 6 illustrates concepts involved in allocating one
dimension of the display area to hierarchy levels.
[0045] FIG. 7 shows logic involved in reallocating that
dimension.
[0046] FIG. 8 illustrates concepts involved in allocating a level's
display allocation to nodes within that level.
[0047] FIG. 9 shows logic involved in that allocation.
[0048] FIG. 10 and FIG. 11 illustrate a process of rendering a
portion of the hierarchy.
[0049] FIG. 12 illustrates a subroutine used to draw a node at one
level and its children.
[0050] FIG. 13 illustrates a subroutine used to draw a node at
another level.
[0051] FIG. 14 illustrates logic used to load hierarchy information
from a server.
[0052] FIG. 15 illustrates how a "control stick" can be emulated
and shows alternate appearances of emulated controllers.
[0053] FIG. 16 shows a sample sequence of views presented to a user
navigating a hierarchy by nudging the control stick at the bottom
of the view, where the implementation is configured horizontally
with the top of the hierarchy at the top of the view.
[0054] FIG. 17 shows a sample sequence of two views presented to a
user navigating a dictionary, where the implementation is
configured vertically with the top of the hierarchy at the left
side of the view.
[0055] FIG. 18 shows a hypothetical deployment at a single web site
to allow rapid seamless navigation of that site.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0056] FIG. 1 illustrates relationships that can exist among nodes
comprising a hierarchy 18 and introduces some naming conventions.
Each node has zero or more "child" nodes, and each node has exactly
one "parent" node except for the "root" node 20 which has no parent
node. For instance, node 26 is the child of node 24, which is the
parent of two nodes 26, 27. It will be useful later to number
children from left to right; node 26 thus has a "child index" of 0
and node 27 has a child index of 1. A node with no child nodes,
like node 22, is called a "leaf" node.
[0057] Nodes can grouped by their hierarchy "level", which we
define as the number of steps of descent by which they can be
reached starting from the root node. There are four levels 30 in
the hierarchy of FIG. 1.
[0058] Implementations of the invention present in a limited
display area a view of the hierarchy that can be changed under user
control. At any one time the view is "focused" or centered either
at one node or between nodes, and contains all nodes surrounding
this center of view or "Focus". A user may see one of these
surrounding nodes and manipulate the Focus toward that node so that
all nodes surrounding that node are now in view. By continued
navigation of this sort, and exploiting the fact that any node in
the hierarchy can be reached from any other node by a series of
steps through intermediate nodes, the user may view any point in
the entire hierarchy. Methods discussed below make this navigation
experience "smooth"--the Focus changes gradually, and the resulting
changes in the view are "animated" or rendered in many small
steps.
[0059] FIGS. 2 and 3 show two examples of limited display areas.
FIG. 2 shows a horizontally aligned display area 31, which is
efficiently apportioned to nodes about a Focus near Node 24. The
Focus is an imaginary point in the hierarchy that corresponds to
the point at the exact center of the display area. In this
"horizontal" layout, the nodes of each of the levels 30 are arrayed
horizontally. Because of the small size of this sample hierarchy,
some of the display area (33, shaded) is unallocated for this
particular Focus.
[0060] FIG. 3 shows a vertically aligned limited display area as
might be particularly useful in web applications. Here nodes in
each of the levels are arranged vertically, with the top of the
hierarchy to the left of the display area.
[0061] For convenience, the rest of this description refers only to
the horizontal layout depicted in FIG. 2.
[0062] Referring to FIG. 4, in some implementations based on
software resident on a computer 59, a software routine 50 updates
both an on-screen representation 52 of an emulated return-to-center
controller such as a "joystick" and data representing the emulated
controller's displacement from its center or rest position. This
update is in response to a physical computer pointing device 66
such as a mouse. A focus update routine 54 causes continual updates
of internal data representing the user's focus in the hierarchy.
When the focus is updated, a hierarchy draw routine 56 is invoked
to render on-screen a representation 58 of a portion of the
hierarchy surrounding the focus. (More detailed views of the
emulated control and the rendered hierarchy are shown and discussed
below.) Through the user's eye 60 the user's brain 62 continuously
monitors the evolving hierarchy representation 58 as well as the
current "joystick" position 52 over which the user has the feeling
of direct control, the brain directing the hand 64 to move the
physical pointing device 66 with its button depressed to effect
further change in the focus and therefore in the portion of the
hierarchy visible to the user. In this manner: [0063] The user
quickly learns through continuous feedback how to manipulate the
rendered hierarchy to view beyond any node currently shown, and by
iteration and the fact that all nodes are connected, to view the
entire hierarchy. [0064] No abrupt changes in rendering can occur
and no abrupt changes in user hand or eye position are
necessary.
[0065] In a network environment, a software component 70 of the
invention is able to load hierarchy information from a remote
hierarchy server 72 by way of a network of computers 74 onto the
computer 59, which may represent a client of the hierarchy server.
Typically a server will serve many clients concurrently. Hierarchy
information loading 70 is described in more detail below with
respect to FIG. 14.
[0066] Referring to FIG. 5, starting at step 100, a software
implementation initially performs some gathering 102 of
configurable parameters which may include the display area
dimensions and a network source for the hierarchy information. This
is followed by initialization 104 of other variables. In step 104,
a dummy root node is created and the hierarchy information source
is associated with it. Step 104 also initializes the user
"Focus"--the center of that portion of the hierarchy drawn on the
screen--to a point near this dummy root node, which is all that
exists of the local hierarchy data at this time. Next, the
hierarchy loader 70 is launched to asynchronously load hierarchy is
information using standard network protocols from the configured
source. The flow of hierarchy loading is described in more detail
below with respect to FIG. 14. For now we note that: the source may
exist on a remote server 72; the information may arrive following
user--perceptible delay; and as information about a node arrives,
it is added to the local hierarchy data.
[0067] The software next initializes 108 the emulated joystick and
its on-screen representation. Next routines 120-126 are launched to
asynchronously monitor the physical pointing device, while on a a
parallel path the main loop is launched. This loop begins with
drawing 140 the hierarchy on the screen.
[0068] Step 120 monitors the user input device to detect a change
in the physical user-input device's "state"--position and button
state. A change may require an update 122 of the emulated joystick
position 130. If a change in the emulated joystick position is
detected at 124, the emulated joystick is redrawn at 126. This is
illustrated below with respect to FIG. 15.
[0069] Returning to the main loop (the right side of the drawing),
the emulated joystick is monitored at 142 for any displacement from
its center position. When the displacement is non-zero in any
dimension, the displacement is mapped by 144 to an incremental
change in hierarchy "Focus". "Focus" means where in the hierarchy
the user's current view of the hierarchy is centered. Focus is
defined as a two-element vector, {Depth,Position-in-Level}.
Hierarchy "Depth" is like hierarchy level, but is permitted to take
floating-point values between the integers to which "level" is
confined. "Position-in-Level" is a position among the nodes in a
level, the leftmost having Position-in-Level 0.0, like an index,
but permitted to take floating-point values between integral
indices. For instance, a Focus of {1.1,1.5} in the sample hierarchy
of FIG. 1 means that the user view is centered between levels 1 and
2 but closer to level 1, and horizontally midway between nodes 24
and 28.
[0070] As will be seen in FIG. 8, an alternate method of specifying
position within a level has two parts: [0071] "FocalNode", a
reference to that node in level <integral component of Depth>
with an index of <integral part of Position-In-Level>; and
[0072] "horiFract", the fraction of that node appearing to the left
of the center of user view. "FocalNode" therefore corresponds to
the integral component of Position-in-Level and "horiFract" is the
fractional component. It is this method of specifying position
within a level which we will use in descriptions which follow.
[0073] The exact mapping 144 of emulated joystick displacement to a
change in Focus {dDepth,dFract} depends upon the configuration of
the embodiment, but for a configuration in which hierarchy levels
are arranged horizontally and hierarchy descent/ascent are shown
vertically, the mapping may be as simple as [0074]
depth=k1*vertical displacement of emulated joystick [0075] dFract
(change in horiFract)=k2*horizontal displacement of emulated
joystick. where k1 and k2 are numbers fixed during navigation. For
a configuration in which hierarchy levels are arranged vertically,
dDepth would follow the horizontal joystick displacement and dFract
would follow the vertical displacement. Additional mapping tweaks
found to be useful include: [0076] greater-than-linear mapping to
allow both fine control and high-speed navigation from an emulated
return-to-center controller with limited travel.
[0077] One implementation uses a dDepth proportional to the square
of emulated controller displacement in one direction, for instance.
This allows for a navigation speed "dynamic range"--ratio of
fastest to slowest non-0 speed--of 12.times.12 in the case where
emulated controller displacement in one dimension varies from -12
to 12 pixels. [0078] attenuating diagonal navigation, particularly
in the direction of hierarchy ascent. During hierarchy ascent the
user typically does not intend any lateral navigation at the same
time. During hierarchy descent diagonal navigation is often desired
but can be attenuated to minimize risk that a user might sense
losing control. [0079] limiting emulated controller movement to one
dimension at a time. This suggests an alternative rendering of the
controller. FIG. 15 shows the "joystick" look and some
alternatives. One implementation allows the user to select among
alternative controller "look and feel" designs to find one most
suitable to the user. [0080] a mapping of displacement to dFract
which is a function not only of displacement but which is sensitive
to the fractional component of Depth in a way which eliminates
2.sup.nd-order discontinuities in the rendered location of nodes,
given constant emulated controller displacement. (Implementations
we are describing prohibit by design 1.sup.st-order discontinuities
in node location or size regardless of controller state; this
enhancement further eliminates a 2.sup.nd-order discontinuity.)
[0081] After adding the incremental change dDepth to Depth in 146,
step 148 updates the "vertical" parameters using the logic shown in
FIG. 7, discussed below. "Vertical" here means "in the direction of
hierarchy descent or ascent", which may be visually either
horizontal or vertical depending upon the configuration.
[0082] After adding the incremental change dFract to horiFract in
150, "horizontal" ("in the direction from a node to its sibling")
parameters are updated in step 152 using the logic shown in FIG. 9,
discussed below.
[0083] Step 154 tests if either Depth or horiFract has changed by
more than a predefined threshhold since its last use in drawing the
hierarchy. If so, the hierarchy is redrawn in step 140 using the
logic shown in FIGS. 10 and 11. The purpose of the threshholds is
to reduce demands on computer power by not launching expensive
redrawing operations for visual differences small enough to
approach imperceptibility.
[0084] In either case, the main operation loop continues with the
monitoring 142 of the emulated controller's position. This loop is
performed at nearly constant time intervals. As the logic of 144
maps a given two-dimensional emulated controller displacement to a
two-dimensional Focus change per loop iteration, periodic iteration
further maps it to a two-dimensional Focus velocity.
[0085] FIG. 6 shows how the display area 402 is to be allocated
among some number of hierarchy levels by the logic in FIG. 7. 406
shows one possible allocation to three adjacent levels we call
"hiLevel", "loLevel", and "be loLevel", where the parent of a
loLevel node is in hiLevel and its children if any are in
beloLevel. The allocated bands may lie partially outside (as with
hiLevel) or completely outside (as with hiLevel-1) the actual
display area 402. The thickness of allocated bands decreases
geometrically with increasing level. For instance, if the ratio of
thicknesses R.sub.th of adjoining bands is 2.0, as in the example
shown, each level is allocated half the space allocated to its
parent level. Note that as the user descends the hierarchy, a level
of nodes is very small at its first appearance and gains visual
weight as it approaches the focus; this seemingly gradual
appearance of each node permits a visually smooth navigation
experience.
[0086] The geometric relationship among band thicknesses is
accomplished by arranging the lines delimiting the bands
"exponentially". More rigorously, define a "Virtual Display Area"
404 of which the actual display area 402 is but a fraction
H.sub.ADA/H.sub.VDA between 0.5 and 1.0. Then the distance to the
line at the top of level N from the bottom of the Virtual Display
Area is: Virtual Display Area height*R.sub.th.sup.(Depth-N)
(remembering "Depth" is one component of Focus), or for our
example, Virtual Display Area height*2.0.sup.(Depth-N) These
level-delimiting lines will fall outside (above) the display area
for N much less than Depth, and for increasing N, the lines
approach the bottom of the Virtual Display Area, falling below the
actual display area. The implementation illustrated chooses
H.sub.ADA/H.sub.VDA32 3/4 so that exactly two complete levels are
shown. If Depth were a multiple of 1.0, hiLevel and loLevel would
then be assigned the top 1/2 and next 1/4 of the Virtual Display
Area, totalling all of the actual display area. In the case
illustrated, all of loLevel and parts of hiLevel and beloLevel fall
in the actual display area. For any choice of
H.sub.ADA/H.sub.VDA<=3/4, only the two lines 408 and 410
delimiting loLevel need be calculated for the purpose of drawing,
as all others fall outside the actual display area. Drawing is sped
up by the fact that at most 3 levels of nodes are involved. For
implementations having access to greater resources,
H.sub.ADA/H.sub.VDA may be chosen closer to 1.0, so that more of
the delimiting lines 412 fall within the actual display area, and
more levels and many more nodes need to be represented.
[0087] Turning to FIG. 7, we see the logic 148 which accomplishes
the vertical allocation illustrated in FIG. 6 in the case
R.sub.th=2.0, H.sub.ADA/H.sub.VDA<=3/4. This logic is invoked
from the main operation flow of FIG. 5 when Depth has changed by a
small fraction of 1 or -1, and serves to precalculate some drawing
parameters. At step 418, Focus Depth is first forced to be greater
than some minimum which is configurable but is typically near 1.0
and to be less than a maximum which is tied to the greatest level
of any node loaded. Step 420 then determines which levels will be
represented in the display area, or in other words what integers
correspond to "hiLevel", "loLevel", and "beloLevel". The remainder
from this rounding operation "vertFract" will be saved to determine
the placement of the delimiting lines in step 428 and for later
drawing calculations. A check 422 is made to see whether hiLevel
has changed; that is if Depth has crossed an integer boundary. In
most cases it has not. If hiLevel has decreased, horizontal
parameters are changed in step 424: FocalNode's parent node becomes
FocalNode, and horiFract is loaded with what fraction the former
FocalNode's child index, augmented by the former horiFract, is of
the parent's children. If hiLevel has increased, horizontal
parameters, are changed in step 426: the FocalNode child with a
child index of horiFract times the number of children, rounded,
becomes FocalNode, and the remainder from the rounding becomes
horiFract.
[0088] Step 428 now calculates the placement of the delimiting
lines. This was stated above to be Virtual Display Area
height*2.0.sup.(Depth-N) from the bottom of the Virtual Display
Area. The formulae in 428 calculate the more useful distances from
the top of the display area, hence the "1-". These distances
"hiLevelBot" and "loLevelBot" are shown as 408 and 410 on FIG. 6.
For H.sub.ADA/H.sub.VDA=3/4 this need only be calculated for the
two integral levels N for which Depth-N is between 0 and B2.
[0089] FIG. 8 illustrates what "horizontal" allocation must do. The
display area 520 having been "vertically" allocated into bands for
the hierarchy levels hiLevel 522, loLevel 524, and beloLevel 526,
each band must be further allocated to specific nodes. "Focus" can
be thought of as an imaginary point in the hierarchy that
corresponds to the center of the display area 532. "FocalNode" is
that node which will be drawn to include this center; the shaded
box 534 is its allocation. "horiFract" is the ratio of FocalNode
appearing to the left of the center, 0.0<=horiFract<=1.0.
That is, horiFract is the ratio of the solid black line 536 to the
width of FocalNode's rectangular allocation 534. "Horizontal"
allocation occurs mostly during drawing using the logic illustrated
in FIGS. 10 through 13. FIG. 9 shows some precalculation which is
performed after an incremental change to horiFract: If at 552
horiFract has spilled over and is no longer>=0, step 556
replaces FocalNode with the node to its "left" in the hierarchy and
1.0 is added to horiFract, unless there is no left node in which
case step 558 clips horiFract to 0.0. If at 562 horiFract has
spilled over and is no longer<=1, step 566 replaces FocalNode
with the node to its "right" in the hierarchy and 1.0 is subtracted
from horiFract, unless there is no right node in which case step
568 clips horiFract to 1.0.
[0090] Horizontal allocation is driven by determining the widths of
nodes in level loLevel as they are drawn, first for FocalNode, then
iterating through nodes to its left until the display area is used,
then iterating through nodes to its right. The display area width
required for a node depends on the width required to render it and
the sum of rendering widths of its children. The geometric weight
given to each of these two factors varies with the fractional
component of Depth. As illustrated, a loLevel node is narrower than
another having more children (in beloLevel) but its children are
wider than those of the other node. From loLevel width allocations:
[0091] child node width allocations are simply prorated.
[0092] For implementations which can show more than three levels of
nodes at a time (H.sub.ADA/H.sub.VDA>3/4), proration continues
beyond beloLevel. For instance, if a loLevel node has width W and 3
children each with 3 children, each child has width W/3 and each
grandchild has width W/9 allocated. [0093] parent node (in hiLevel)
width allocations are summed from their children's widths. In FIG.
8, four loLevel nodes have one parent 540 and the last has another
542.
[0094] Before turning to the drawing logic in FIGS. 10 and 11 which
accomplishes this, note the horizontal-parameter terminology that
will be used: "left" and "rite" are the left and right boundaries
of a node's display allocation, marked by 544 and 546 for FocalNode
on FIG. 8.
[0095] The drawing logic of FIGS. 10 and 11 can be roughly divided
into areas drawing FocalNode, drawing nodes to its left, then
drawing nodes to its right. The software routine "loDraw(node,
horizontal position, fraction to left)" which will be described in
reference to FIG. 12 is invoked for each loLevel node (steps 612,
618, 652) not only to draw it but to calculate and return its
"left" and "rite" boundary locations, and to draw its children.
After each loLevel node is drawn, its width is added to that of an
accumulating parent node "hiNode", either a new one (steps 614,
630, 660) or an existing one (steps 622, 656). A new "hiNode" is
needed when the loLevel node just drawn has a parent which is not
hiNode, as checked at 620 and 654. At this time, and at the end of
the routine, the existing hiNode is drawn using the software
routine "hiDraw(node)" (steps 626, 642, 658, 662).
[0096] FIG. 12 illustrates the logic of software routine
"loDraw(node, horizontal position, fraction to left)". Step 714
outlines the node and step 718 draws the node-specific
representation concentric with the outline. For each child, step
720 outlines the node and step 724 renders it in the case where the
outlined area is large enough to hold the rendering. How many
outlined nodes are fully rendered for any given Focus depends upon
the space demands of rendering each, upon the display area
dimensions, and upon how quickly the hierarchy fans out. However,
for typical applications, nodes on three levels are always outlined
and are fully rendered about half the time, and nodes on only two
levels are fully rendered the other time.
[0097] Prior to the outlining and drawing, loDraw( ) must first
(step 710) calculate the node's allocated display width "Wide"
given the fractional component of Depth "vertFract", the number of
child nodes, and a target rendering width using the formula target
render width*childcount.sup.vertFract It must then (step 712)
convert "Wide" and the incoming parameters "horizLoc" and
"fractionLeft" to "left" and "rite", its left and right edges.
"horizLoc" is a horizontal location; it specifies the left edge if
"fractionLeft" is 0, right edge if "fractionLeft" is 1, and some
point in between for 0<fractionLeft<1.
[0098] To "draw node-specific rendering" may mean invoking
primitive code to render text and/or graphics. However for
performance reasons in some implementations this means copying a
prerendered image to the outline center, so that the time spent in
rendering each node need only be incurred once.
[0099] FIG. 13 illustrates the much simpler logic of drawing a
hiLevel node: outline the node, then draw its node-specific
rendering.
[0100] If calculations of level-delimiting lines and node widths
would place some of a node outside the actual display area, node
outlines are made to respect the boundaries of the actual display
area. Centering node-specific rendering in this reduced area
minimizes the number of cases in which node-specific rendering
overflows the actual display area. Such cases can be completely
eliminated or can be permitted by choices in defining "target
render width" and "min render width" used in steps 710 and 716.
[0101] It is not a part of drawing, but associated with outlining
any node in step 802 on FIG. 13 and steps 714 and 720 on FIG. 12,
the node is checked for an unread input source. If it has one,
software routine "hierarchyLoad" is launched to asynchronously
populate the hierarchy beneath this node from hierarchy information
read from the source. The hierarchy information loaded by the first
invocation of hierarchyLoad, which populated the hierarchy under
the dummy root node, may not be the complete hierarchy for this
application. The hierarchy server may deliver only a portion of the
hierarchy information, with references to additional portions. This
can allow a user to widely navigate an immense hierarchy while
triggering the transfer of only a small fraction of the hierarchy
information from the hierarchy server to the client. The portions
are loaded on demand but before they are actually needed for
rendering by calling for them when their parent nodes are first
outlined.
[0102] Division of the total hierarchy into smaller portions can be
accomplished by human or automated extraction of the information
into separate files resident on the hierarchy server.
Alternatively, the hierarchy server can automatically divide the
hierarchy into portions, each with a magnitude appropriate to the
network bandwidth, and automatically generate references to
information "files" describing sub-hierarchies of the total
hierarchy. That is, the "files" sent over the network may never
exist in the file format.
[0103] We call the delivery of a hierarchy in portions and on
demand "hierarchy streaming", whether division into portions is
prior to or a part of server operation. "Hierarchy streaming" is
comparable to "streaming" as the term is generally applied to the
transmission of data incrementally over a network concurrent with
use of the (already-received) data by the client, as for instance
when sound information is played by a client computer as additional
sound information is still being transmitted. However, hierarchy
streaming differs in that the information delivered is of more than
one "dimension" and there is a strong likelihood that not all of
the information will be needed at the client. Therefore two-way
communications are useful in hierarchy streaming. Not only must the
server deliver information, but the client must request different
portions of the hierarchy as they are needed. A hierarchy-streaming
performance enhancement is to maintain exactly two connections (one
for each direction) between the client and the server, rather than
opening and closing a connection for each portion.
[0104] The minimize size of streamed portions may be a fixed server
parameter. For a performance enhancement, the hierarchy server may
adjust the minimum portion size in response to network
characteristics as they vary between clients and over time. For
instance, a server receiving rapid-fire requests for portions from
one client might infer a high-bandwidth connection and deliver
larger portions to that client, and it might infer a high error
rate from repeated requests for the same portion from another
client and deliver smaller portions to that client.
[0105] Here is how a hierarchy server might serve a request for
hierarchy information while respecting a minimum portion size:
[0106] From the request, identify the parent node of the hierarchy
or subhierarchy for which information is requested. [0107] Copy
that node's information from the overall hierarchy data--which may
be in a database, one or more files, or an in-memory data
structure--to a new hierarchy data structure, as the root node
information. [0108] Among information copied for each node can be a
reference to the portion of the hierarchy for which that node is
the root. A "reference" to a portion is information from which a
request for the portion to the server can be constructed. For this
first copy, the reference simply reflects the original hierarchy
information request. [0109] Among references that have been added
to the new hierarchy data structure and still remain, take that
added earliest, remove it from the data structure, and copy
information for all child nodes (of the node containing the
reference) from the overall hierarchy data to the new hierarchy
data structure.
[0110] Again, the copied information may contain references. [0111]
Repeat the previous step while references remain and while the new
hierarchy data structure is smaller than the minimum portion
size.
[0112] FIG. 14 shows the hierarchy-loading process from the client
point of view. Software routine "hierarchyLoad" is passed a node
that has an associated "unread input source". This is a string that
names a path, such as a "URL" for internet access or a filename, to
a hierarchy definition file. The hierarchy source could also be a
database, a data structure, or another program, but here we will
describe transfer of a file over the internet. Step 832 "opens" the
source or makes it available for reading. In a client-server
context, this "open" constitutes a request to the server to provide
the hierarchy information. In a loop, step 836 is used to read each
line, until failure to read detected at 838 terminates the routine
at 840. Each line describes one node, specifically: [0113] The node
level relative to the top node level of the file. This is a
relative specification so that hierarchy definition files can be
combined by simply referring to a hierarchy definition file from a
node specification in a "parent" hierarchy file. The top level of
the "child" hierarchy definition file is then one more than the
referring node's level. In this way hierarchy modules can be
readily split and recombined by humans using editors. In some
implementations, hierarchy definition files are human-readable and
editable; the format facilitates this by using line indentation to
specify relative level. Indentation increased from the previous
line indicates a level one greater; indentation decreased to a
previously used indentation indicates the level previously
indicated by the indentation. For instance a file like this [0114]
Node 1 [0115] Node 2 [0116] Node 3 [0117] Node 4 [0118] would cause
node 1 and 4 to be placed at level N, node 2 at level N+1, and node
3 at N+2, where N is one greater than the level of the node
referring to the file. [0119] (optional) text used as a node
"label" for rendering the node [0120] (optional) a path to a
graphic "image" for rendering the node. If both a label and a
graphic are specified, the label is rendered on top of the graphic.
A current implementation uses the format "<image=URL>" for
this information. [0121] (optional) a specification of an "action"
to take if the user selects the node, as by "clicking" it with a
pointing device. Each "action" is interpreted by software
communicating in an application-dependent way. The format
"<action=URL>" can be used for this information. Some
implementations render those nodes which have associated actions
with a push-button-like appearance to suggest to the user that
clicking the screen appearance will have an effect. [0122]
(optional) a "hier" reference specifying the source for a hierarchy
to be loaded beneath this node. A current implementation uses the
format "<hier=URL>" for this information. [0123] (optional)
any number of "<key=value>" specifications assigning a short
string to represent a long string so that "action", "image", and
other specifications can use a sort of shorthand. Such assignments
are valid for such specifications for all of the node's
descendants. Step 842 represents the parsing of node level. Parsing
of the other specifications is shown in steps 844 and 846.
[0124] At step 848, the new node is placed in the hierarchy data
structure as a child of the node added most recently (by this
execution instance of hierarchyLoad) at the previous level, and
this node is recorded to be the most recently added at this level.
This can trigger a redrawing of the hierarchy in cases where the
affected parent node is currently being displayed.
[0125] FIG. 15 shows a preferred screen layout of an emulated
return-to-center controller (a pointing device like a joystick
which returns to a resting position when it is released) and a few
alternatives.
[0126] Referring to the "control stick" view 920 we describe how a
return-to-center controller is emulated when the user has available
a non-return-to-center pointing device with a button such as a
mouse. Navigation begins when the user guides the mouse to "drag"
display object 922, here an oval representing the top of a control
stick, in any direction from its rest position 924 in the center of
the region 926 (shown shaded) in which the object may travel.
"Drag" means that the user clicks on the object and moves the mouse
with its button depressed. While the button is depressed, the
emulation moves display object 922 to follow the pointer as limited
by the travel region. Specifically, if the "cursor" 928--an
on-screen representation of the position of a user mouse or other
pointing device provided by an operating system--is at the position
shown in view 920 when the button is depressed, and the user
subsequently causes it to move to its position shown in view 930
with the button still depressed: [0127] Step 120 "Monitor User
Input Device" of FIG. 5 detects these events. [0128] Step 122
"Update Emulated Joystick Position" then moves display object 922
by the same amount in each dimension that the cursor has moved, and
will record this current displacement, the vector 932. [0129] This
displacement of the emulated controller is then used by other parts
of the invention as if it were the displacement of a physical
return-to-center controller. Step 120 also detects the release of
the mouse button, at which time step 122 moves the display object
922 back to its rest position centered at 924 and updates the
emulated controller displacement to {0, 0}.
[0130] The further the object is dragged from the rest position,
the greater the emulated controller displacement, and the more
rapidly the Focus changes, by the mapping 144 of FIG. 5.
[0131] By always rendering the "stick" part of the control stick
with one end at the bottom of the travel region and the other end
near the center of display object 922, the image approximates the
look of a control stick viewed from above but not directly above,
so that in view 930 the stick appears foreshortened.
[0132] Each of the following alternative layouts also show a round
draggable object at its rest position in a shaded region of allowed
travel. Alternate layout 940 is for a vertically displayed
hierarchy with the hierarchy root being to the left. It shows a
round object which can be dragged left in the direction of
hierarchy ascent or in any combination of the opposite and
perpendicular directions. Lateral navigation in combination with
hierarchy ascent is prohibited. Layout 950 shows a layout that
completely restricts travel to one dimension at a time. Layout 960
splits this into two separate scrollers, each of which is
"return-to-center".
[0133] FIG. 16 shows a sample sequence of views presented to a user
navigating a hierarchy by nudging control stick 992 away from its
rest position in the center of the round area surrounding it. The
illustrated implementation is configured horizontally with the top
of the hierarchy at the top of the view. The views shown here are
only samples from the animated sequence of views the user sees.
While viewing view 994, the user nudges control stick 992 downward
to descend the hierarchy, then at about the time of view 995, the
user moves control stick 992 to the left to swing left as well as
downward through the subnodes of the node labeled "Computers and
Internet". At about the time of view 996, the user is cruising due
left to center "Build Your Visual Studio 6.0 Library". Then as
shown below view 997, control stick 992 is again pushed slightly
downward to bring the child nodes into view 997. At this point the
user releases control stick 992 and it returns to its home position
as shown.
[0134] FIG. 17 shows a sequence of six views 972 through 977
presented to a user navigating indexed data (in this case, a
dictionary), where the implementation is configured vertically with
the hierarchy root at the left side of the view. Again, the views
shown here are only a sampling of the animated sequence of views
the user sees. In this sequence, the user is drilling directly
"down" in the hierarchy by pushing the control stick to the right.
As the non-leaf nodes are of no interest to the user other than as
an aid to navigation, they are not "active". Only the leaf nodes
appearing in view 977 are active and appear as buttons.
[0135] FIG. 18 illustrates a hypothetical deployment at a single
web site to allow rapid seamless navigation of that site as it
would appear in a browser, window. Visually, a page at the site is
composed of a main frame 986 and a navigation frame 984. A
vertically-oriented view of a hierarchy 980 and an emulated control
stick 992 appear in the navigation frame. The hierarchy in this
case is the hierarchical organization of a web site. Each node
corresponds to a page in the site hierarchy which can be loaded
into the main frame, and a node's associated action is interpreted
to cause a load of the corresponding page into that frame. We see
the site just after the button labeled "Museum Review 1998" was
clicked, causing the corresponding content to be loaded into the
main frame.
[0136] Other embodiments are within the scope of the following
claims.
[0137] The invention is easily applicable to a wide range of uses
because: [0138] Hierarchies are ubiquitous. [0139] Hierarchy
geometry is input as part of the hierarchy information rather than
hard-coded in an implementation. [0140] Node-specific appearances
are input as part of the hierarchy information rather than
hard-coded in an implementation. [0141] Node-specific actions are
input as part of the hierarchy information and are interpreted by a
surrounding application in an application-specfic way rather than
by the invention.
[0142] The invention can be applied to navigating a file system.
For such purposes a node-specific action might be, for files, to
open a file in a file-type-specific way, and for directories, no
node-specific action is necessary as navigation itself "opens" the
directory. The invention can be applied to file systems in a
network logically combined as if they comprised one large file
system.
[0143] The invention can be applied to allow easy user navigation
of a hierarchically organized set of pages at a large web site, as
illustrated in FIG. 18. The small display area demanded by the
invention to navigate a hierarchy of any size can be placed in a
"navigation frame" of a browser window, allowing the user to browse
the site and from there control the content of a larger "main
frame" of the window. More generally, the invention can be likewise
be applied to allow easy user navigation of any hierarchically
organized set of web pages which may reside in a large number of
different sites. For such purposes, a node-specific action places
the web page advertised by the selected node in the main frame. The
invention can be deployed for such an application by several means,
including as a "java applet", as a "plug-in", or as a part of the
browser itself.
[0144] The invention can be applied to navigating a document with
an outline. A node-specific action in this case places the user in
the associated part of the document. "Document with an outline"
includes well-outlined books such as most textbooks, Bible versions
which have been divided into book, chapter and verse, and many
reference and how-to books.
[0145] The invention can be applied to navigating a flat list by
"indexing" the list or file. That is, a hierarchy can be created in
which the last level is comprised of leaf nodes associated with the
goal of navigation, the elements of the list. (For a dictionary
example, leaf nodes are associated with words.) All other nodes are
synthesized and labeled to provide reliable signposts for getting
to the right leaf nodes. (In the dictionary example, these would
identify alphabetic ranges like "Aar-Byz".) The non-leaf nodes then
would have no node-specific action. A leaf node's action for a
dictionary might be for the computer to print or to speak a
definition or a translation. The action for a contact list leaf
node might be to print an address, start an email message, or dial
the phone. FIG. 17 illustrates such alphabetic navigation of a word
list.
[0146] The invention can be applied to navigation of an XML file,
either to edit the file or to create a flexible application driven
by the XML file.
[0147] The invention can be applied to user navigation of an
encoded hierarchy such as the Dewey Decimal System. In this case a
node-specific action might bring up information about the book.
[0148] The invention can be applied to allow easy user entry of
postal addresses or other locations by browsing hierarchically
arranged geographic regions. For instance, child nodes of a node
labeled "New England" might be labeled with state names.
[0149] The invention can be applied to allow rapid user entry of
numeric data such as a postal code, where the child nodes of a node
labeled "347" would be "3470", "3471", "3472", "3473", "3474",
"3475", "3476", "3477", "3478", and "3479", and a postal-code
hierarchy could thus be synthesized.
[0150] The invention can be applied to allow easy user selection of
categorized products. A recorded song for instance might be
categorized at the top level as "music", then "rock/pop", then
"hip-hop", then by recording artist, then by recording, then by
track title.
[0151] The invention can be applied to entry of text from any set
of characters. For a large character set such as "hanzi" used for
the Chinese language, characters can be categorized into a
hierarchy using conventional indexing methods (Chinese dictionaries
are typically categorized by number of strokes), or in some other
way, such as categorization by visual similarity. The invention is
particularly applicable when a keyboard is unavailable or
impractical for text entry.
[0152] The invention can be applied to allow easy user navigation
of content which is not hierarchical in its native mode (such as a
large unorganized site, a corpus of literature, or the entire web)
but upon which a hierarchy can be imposed using "self-organizing
maps" or other similarity-seeking technology.
* * * * *