Presentation system providing alternative presentation sequences

A method for defining a presentation tree for displaying a plurality of images includes creating a presentation tree structure having a plurality of branches, each branch being connected to a plurality of other branches by a branch node, each branch node having a plurality of branches descending therefrom, assigning at least one image of the plurality of images to each branch of the presentation tree structure, and defining a sequence control for each of the plurality of branches descending from a branch node, wherein a sequence control is defined for each branch node.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to computerized presentation systems such as 
systems which provide a computerized slide or multi-media presentation. 
More particularly, the present invention concerns a computerized 
presentation system which allows changes to presentation sequences, such 
as by allowing selection from among plural different presentation 
sequences during the presentation itself. 
2. Description of the Related Art 
Visual aids have long been known as effective vehicles for conveying 
information to an audience. For example, exhibit boards, overhead 
projection of transparencies, and slide projections are all commonly used 
to assist in presentations. However, proceeding from one exhibit board, 
transparency, or slide to the next during a presentation disrupts 
presentation flow and, as a result, audience interest suffers. 
To this end, computerized presentation systems, such as Microsoft 
PowerPoint, have been utilized to address the "disruption" problem. These 
systems allow a presenter to define and to store several image 
presentation sequences which can later be presented to an audience. During 
such a presentation, these systems interface to a conventional projection 
device so as to project images onto a display screen. A typical 
arrangement is illustrated in FIGS. 1 and 2, and includes portable-sized 
personal computer ("laptop") 2 and projector 7. Progression through a 
presentation sequence of images is controlled by depressing a key on a 
keyboard, a mouse button, or the like. 
Unfortunately, these devices only provide a presenter with a capability to 
advance one image forward or one image backward through a predetermined 
presentation sequence As a result, a presenter cannot deviate from an 
initiated presentation sequence in response to feedback from his audience. 
Therefore, so as to account for differences in knowledge, experience, or 
attitudes of prospective audiences, a presenter must, in advance, define 
and store several alternative presentation sequences. 
Even if several alternative presentation sequences are stored in advance, 
problems still arise. Consider, for example, a situation in which a 
presenter has anticipated an uninformed audience and has prepared a 
presentation sequence which includes many introductory images. If during 
the presentation the presenter realizes; that the audience is better 
informed than expected, his options are limited. 
First, the presenter could stop the presentation, create a new presentation 
sequence tailored for the more sophisticated audience, and begin the new 
presentation sequence. Second, the presenter could stop the presentation 
and begin a previously-created presentation sequence tailored for the more 
sophisticated audience. Finally, the presenter could continue with the 
already-begun presentation sequence. In each of these cases, the presenter 
will likely lose the attention of the audience. 
FIG. 3, comprising FIGS. 3A and 3B, illustrates two sample prior art slide 
presentation sequences. In this regard, the term "slide" is used herein to 
describe images, including animated and modifiable images, which are 
stored in a computer and projected onto a screen using conventional image 
hardware. However, it should be noted that the present invention may be 
used in conjunction with any type of presentation aid, including audio and 
multimedia aids. 
The sample presentation sequences of FIGS. 3A and 3B are each intended to 
set forth a fictional company's current market position and plans for 
future action. Accordingly, the presentation sequences share common 
slides, such as slides 31, 32, 37 and 40. However, FIG. 3A shows a 
presentation sequence intended for a relatively uninformed audience. For 
example, the FIG. 3A sequence includes introductory slides 34 to 36, which 
describe relevant competitors, industry terms, and general market 
structure, respectively. Slides 39 and 41 of the FIG. 3A sequence also 
include general information. 
In contrast, FIG. 3B illustrates a presentation sequence intended for a 
more informed audience. In this regard, the presentation sequence of FIG. 
3B includes slides 45 and 46, which contain detailed information. 
As described above, it is necessary for a presenter to define, in advance, 
both the FIG. 3A and FIG. 3B presentation sequences in order to prepare a 
presentation to an uninformed audience as well as a presentation to a more 
informed audience. However, in a case that a presenter initiates the FIG. 
3A presentation sequence and subsequently determines that the FIG. 3B 
presentation sequence is more suitable to his audience, the presenter must 
either terminate the FIG. 3A presentation sequence and initiate the FIG. 
3B presentation sequence, continue with the FIG. 3A sequence, or search, 
during the presentation, for appropriate slides to display. All of these 
options reduce the effectiveness of the presentation. 
One proposed method to address the above problems is described in U.S. Pat. 
No. 5,469,192 to Allen et al. The system described therein allows a 
presenter to activate, during a presentation, a "pop-up" window upon 
laptop 2. The pop-up window provides a control panel for selecting several 
options, one of which is a "jump" option. Upon selection of the jump 
option, a second window is displayed which lists information corresponding 
to images available for display. The presenter then selects an appropriate 
image based on the listed information. Next, the selected image is 
displayed. 
Although the above system allows a presenter to diverge from a 
predetermined presentation sequence, the presenter must execute several 
time-consuming steps in order to do so. This approach is extremely 
disruptive to the continuity of a presentation. Accordingly, because a 
slide presentation relies on continuity as a means for holding audience 
attention, the disruptions resulting from the system described in Allen 
reduce the effectiveness of the presentation. 
Therefore, what is needed is an improved presentation system which allows a 
presenter to define a presentation sequence containing several alternative 
sequences, to select from the several alternative sequences while 
progressing through the presentation sequence, and which allows such 
selectability without causing significant disruption of the presentation. 
SUMMARY OF THE INVENTION 
The present invention addresses the foregoing by providing a system for 
creating a presentation tree representing alternative presentation 
sequences. The present invention also provides a system for proceeding 
through one of the alternative sequences during a presentation without 
causing significant disruption of the presentation. As a result, the 
present invention allows a presenter to switch smoothly from one 
presentation sequence to another during a presentation. 
Accordingly, in one aspect, the present invention is a system to define a 
presentation tree for displaying a plurality of images, the system 
including creation of a presentation tree having a plurality of branches, 
each branch being connected to a plurality of other branches by a branch 
node, and each branch node having a plurality of branches descending 
therefrom, assignment of at least one image of the plurality of images to 
each branch of the presentation tree, and definition of a sequence control 
corresponding to each of the plurality of branches descending from a 
branch node, wherein the definition of a sequence control is performed for 
each branch node in the presentation tree structure. 
By virtue of the foregoing, a presenter is able to select from two or more 
predefined alternative sequences within a single presentation tree during 
execution of the presentation tree. In contrast, conventional presentation 
systems do not allow a presenter to define a single presentation tree 
having several alternative presentation sequences, and therefore do not 
allow navigation among the alternative sequences using predefined sequence 
control. 
In a related aspect, the present invention provides a system to create a 
presentation tree for displaying a plurality of images in which a 
graphical user interface is displayed, user manipulations of the graphical 
user interface are received, and, in response to the user manipulations, a 
presentation tree is created, the presentation tree having a plurality of 
branches, each branch being connected to a plurality of other branches by 
a branch node, each branch node having a plurality of branches descending 
therefrom. Moreover, each of the plurality of branches is associated with 
at least one of the plurality of images. 
The above-described presentation tree allows a presenter to select from two 
or more predefined alternative sequences during execution of the 
presentation tree. Conventional presentation systems, however, do not 
allow a presenter to create a presentation tree and do not provide 
on-the-fly selection of alternative presentation sequences. 
The present invention also concerns a user interface for creating a 
presentation tree. The interface includes a workspace for defining 
alternative presentation sequences of a presentation tree, the 
presentation tree having a plurality of branches, each branch being 
connected to a plurality of other branches by a branch node, each branch 
node having a plurality of branches descending therefrom. The interface 
also includes controls for defining a sequence control for each of the 
plurality of branches. 
A graphical user interface according to the invention allows a presenter to 
define a presentation tree having alternative presentation sequences. As a 
result, the presenter can utilize the tree to execute several alternative 
presentation sequences. Conventional presentation systems, on the other 
hand, do not provide user interfaces having such capabilities. 
In another aspect, the present invention is a system to control 
presentation flow through a presentation tree defined by a plurality of 
branches, each branch being connected to a plurality of other branches by 
a branch node, each branch node having a plurality of branches descending 
therefrom, and each branch having assigned thereto at least one 
presentation image. The system includes display of each presentation image 
assigned to one branch of the tree, the one branch connected to a branch 
node, execution of a sequence control to select one of a plurality of 
branches descending from the branch node, and display of each presentation 
image assigned to the selected one branch. 
By providing a system to control presentation flow through a presentation 
tree using a sequence control, the present invention also provides for 
presentations which are both continuous and adaptable to various audiences 
and occasions. 
In contrast, conventional systems do not utilize a presentation tree having 
alternative sequences. Therefore, continuous and adaptable presentations 
are difficult to achieve using these systems. 
In a related aspect, the present invention is a system for displaying a 
presentation sequence of a plurality of images in which a command to 
initiate a presentation sequence is received and a plurality of images are 
displayed sequentially in accordance with a presentation tree having a 
plurality of branches, each branch being connected to a plurality of other 
branches by a branch node, each branch node having a plurality of branches 
descending therefrom. Preferably, each of the plurality of images is 
assigned to at least one of the plurality of branches. 
According to this aspect, the present invention displays one of several 
alternative presentation sequences defined by a presentation tree. This 
feature allows a presenter to define a single presentation tree for use in 
displaying several presentation sequences. In contrast, conventional 
systems require a presenter to define several linear presentation 
sequences. 
This brief summary has been provided so that the nature of the invention 
may be understood quickly. A more complete understanding of the invention 
can be obtained by reference to the following detailed description of the 
preferred embodiments thereof in connection with the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a view showing an outward appearance of computing equipment used 
in connection with the present invention. Computing equipment 1 includes 
laptop 2, preferably an IBM PC-compatible computer having a windowing 
environment, such as Microsoft.TM. Windows95. Provided with laptop 2 are 
display screen 3 comprising an active-matrix color display or the like, 
keyboard 4 for entering text data and user-commands, and pointing device 
8. Pointing device 8 preferably comprises a trackball with plural buttons 
corresponding to right and left mouse buttons, and is used for pointing to 
and for manipulating objects displayed on display screen 3. 
Laptop 2 also includes a computer-readable memory medium, such as a floppy 
disk stored within floppy disk drive 5, and fixed computer disk 6. Floppy 
disk drive 5 provides means whereby laptop 2 can access information, such 
as data, application programs, etc., stored on floppy disks. A similar 
CD-ROM interface (not shown) may be provided within computing equipment 1, 
through which laptop 2 can access information stored on CD-ROMs. 
Disk 6 stores, among other things, application programs by which laptop 2 
generates files, manipulates and stores those files on disk 6, and 
presents data in those files to an operator via display screen 3. Disk 6 
also stores an operating system which, as noted above, is preferably a 
windowing operating system such as Windows95. Device drivers are also 
stored in disk 6 for communicating with display screen 3, and with other 
peripherals. 
Projector 7 is connected to laptop 2 and is used to project stored 
presentation images upon a projection screen, wall, or the like. Projector 
7 is be a projection device which interfaces as a second display screen to 
laptop 2. Alternatively, projector 7 may comprise a conventional overhead 
projector having an electronic overlay device placed thereon, with the 
overlay device interfaced to laptop 2. Preferably, images projected by 
projector 7 are simultaneously displayed on display screen 3 to allow a 
presenter to confirm that a correct image is being projected and to 
facilitate execution of sequence control, which is described in detail 
below. 
During a presentation, and under control of the windowing operating system, 
the presentation application program is executed to display a sequence of 
presentation images to an audience via projector 7 and, in order to 
provide control over the presentation, to display simultaneously the 
sequence of images to a presenter via screen 3. 
FIG. 2 is a detailed block diagram showing the internal architecture of 
computing equipment 1. As shown in FIG. 2, computing equipment 1 includes 
a central processing unit (CPU) 10, such as a programmable microprocessor 
for executing computer-executable process steps, interfaced to computer 
bus 15. Also interfaced to computer bus 15 are display interface 17 and 
projector interface 18. 
Read only memory (ROM) 20 is interfaced to computer bus 15 and stores 
invariant instruction sequences such as start-up instruction sequences or 
basic input/output operating system. (BIOS) sequences for operation of 
keyboard 4. 
Main memory 25, such as a random access memory (RAM), is also interfaced to 
computer bus 15 so as to provide CPU 10 with access to memory storage. In 
particular, when executing stored application program instruction 
sequences or other computer-executable process steps, CPU 10 loads those 
instruction sequences from disk 6 (or other storage media, such as a 
floppy disk or CD-ROM, or from a network or the World Wide Web) into main 
memory 25 and executes these sequences or steps out of main memory 25. 
As also shown in FIG. 2, and as previously-noted, fixed disk 6 stores 
program instruction sequences for a windowing operating system and for 
various application programs such as a presentation application program 
and the like. In addition, stored on fixed disk 6 are image files such as 
those displayed by a presentation application program according to the 
present invention. These files may be created by the above-mentioned 
presentation application or received from an outside source. Fixed disk 5 
also stores device drivers for communication with the various peripherals. 
FIG. 4 represents a presentation tree according to the present invention. 
The tree shown in FIG. 4 incorporates both presentations shown in FIG. 3. 
In order to more fully describe the benefits of the invention, the FIG. 4 
tree also includes slide 47, which is not present in either the FIG. 3A or 
FIG. 3B sequences. As described in more detail below, upon display of 
common slides 32 or 37, a presenter may choose one of two alternative 
sequences through which the presentation will proceed. Similarly, upon 
display of common slide 40, a presenter may choose one of three 
alternative sequences. Accordingly, use of a tree such as the FIG. 4 tree 
enables a presenter to easily select from alternative presentation 
sequences during a presentation. 
FIG. 5 shows a conceptual representation of the FIG. 4 tree for purposes of 
more clearly defining the terms used hereinbelow. As shown in FIG. 5, 
presentation tree 50 includes a plurality of branches, with each branch, 
such as branch 51, being connected to a plurality of other branches, such 
as branches 54 and 55, by a branch node such as branch node 52. Each other 
branch node in tree 50, specifically branch node 56 and branch node 60, 
has a plurality of branches descending therefrom. In the case of branch 
node 56, branches 57 and 59 descend therefrom, while branches 61, 62, and 
64 descend from branch node 60. 
Tree 50 reflects the FIG. 4 presentation tree as follows. Slide 31 is 
assigned to branch 51 of tree 50 and slide 32 is assigned to branch node 
52. Similarly, slide 42 is assigned to branch 54, slides 34 to 36 are 
assigned to brarch 55, and slide 37 is assigned to branch node 56. Slides 
44 and 45 are assigned to branch 59, slide 39 is assigned to branch 57, 
and slide 40 is assigned to node 60. Finally, slides 41, 46, and 47 are 
assigned, respectively, to branches 61, 62, and 64. Construction of a 
presentation tree according to the preferred embodiment of the invention 
will be described below with respect to FIGS. 6 to 8. 
FIG. 6 shows a graphical user interface for creating a presentation tree in 
accordance with the present invention. In particular, FIG. 6 shows main 
window 70 of a presentation application program according to the present 
invention. Main window 70 includes tool bar 71, from which several 
pull-down menus providing access tc various functions may be accessed. 
Also within window 70 is icon bar 72, in which are displayed icons 
representative of regularly-used functions. Each function represented in 
icon bar 72 may also be executed via a pull-down menu accessed through 
tool bar 71. Advantageously, icon bar 72 includes icon 74 and icon 75. 
Icon 74 corresponds to an "add hot-key" function and icon 75 corresponds 
to an "add hot-corner" function. Details of these functions will be 
described in more detail below. 
Position indicator 76 indicates a position in a presentation tree at which 
a particular slide is displayed. The particular slides are entered into 
workspace 77 according to their title. For example, presentation slide 31, 
entitled "Welcome" is entered into a position in workspace 77 
corresponding to numeral "1" within position indicator 76. Accordingly, 
"Welcome" slide 31 is a first slide in a presentation tree defined within 
workspace 77. Similarly, since slide 36 is located at position "5" and 
slide 35 is located at position "4", slide 36 is displayed after slide 35. 
Other slides are also entered into workspace 77 so as to construct 
presentation tree 50. 
It should be noted that the positions of slides entered into workspace 77 
correspond directly to the locations of those slides in presentation tree 
50. For example, slides 34 to 36 correspond to branch 55, and slides 44 
and 45 correspond to branch 59. Moreover, the positions of slides in 
workspace 77 indicate which slides to the various branch nodes of tree 50. 
In this regard, slide 37 immediately precedes both slides 39 and 44, and 
therefore corresponds to branch node 56. 
As shown, more than one slide may be entered on a line corresponding to a 
numeral in position indicator 76. In this case, a sequence control 
indicator, such as indicators 81 and 84, is displayed above each slide in 
the line in order to indicate that a sequence control should be defined 
for each slide in the line. 
A defined sequence control, which consists either of a hot-key sequence or 
a hot-corner selection, is used by a presenter to select one of 
alternative presentation sequences during a presentation. For example, 
upon reaching slide 37 (node 56 of FIG. 5), a presenter must select 
between a sequence indicated by arrow 86 or a sequence indicated by arrow 
87. In order to select sequence 87, for example, the presenter executes 
the sequence control defined for sequence 87 (branch 59 of FIG. 5) and 
indicated by sequence control indicator 81. 
Dialog box 82 is displayed during definition of sequence control, which is 
described in more detail below. As shown, dialog box 82 contains check box 
84, which indicates whether a sequence corresponding to dialog box: 82 
should be utilized as a default sequence. A default sequence is a sequence 
which, during execution of a presentation tree, is automatically selected 
upon reaching a node in a presentation tree. Execution of a presentation 
tree is also described in more detail below. 
FIG. 7 is a flow diagram for describing creation of a presentation tree 
according to the invention. The presentation tree i:s defined in advance 
of presentations, so as to allow the presenter to select different 
branches of the tree during a presentation. Briefly, a method for defining 
a presentation tree for displaying a plurality of images includes the 
steps of creating a presentation tree having a plurality of branches, each 
branch being connected to a plurality of other branches by a branch node, 
each branch node having a plurality of branches descending therefrom, and 
at least one image of the plurality of images being assigned to each 
branch of the presentation tree. The method also includes defining, for 
each branch node in the presentation tree, a sequence control 
corresponding to each of the plurality of branches descending from the 
branch node. 
More specifically, in step S701, a presenter inputs a slide into workspace 
77 shown in FIG. 6. In step S702, the presenter determines whether a 
sequence control need be defined corresponding to the slide input in step 
S701. If not, flow proceeds to step S704 wherein the presenter determines 
whether to input additional slides into workspace 77. If so, flow returns 
to step S701. If not, flow terminates. If the determination in step S702 
is affirmative, flow continues to step S705, wherein the required sequence 
controls are defined. 
For example, in a case that the slide input in step S701 is the second 
slide input onto line "3" in workspace 77, it is determined in step S702 
that two sequence controls must be defined. One of the two sequence 
controls is defined for the second-input slide and the other control is 
defined for the slide first input onto line "3". 
One preferred method for defining a sequence control proceeds as follows. 
First, a sequence control indicator such as indicator 81 is selected. 
Next, either icon 74 or icon 75 is selected, depending on whether a 
presenter wishes to assign a hot-key sequence control or a hot-corner 
sequence control. After selecting one of the icons, dialog box 82 is 
displayed. Dialog box 82 instructs a presenter to execute a desired 
hot-key or a desired hot-corner depending on which of icons 74 or 75 is 
selected. In the case shown in FIG. 6, icon 74 is selected, resulting in 
display of a "press desired hot-key" instruction within dialog box 82. 
Alternatively, icon 74 and icon 75 may be used as toggles between a "define 
hot-key" mode and a "define hot-corner" mode. In this case, an appropriate 
corresponding dialog box is immediately displayed upon selection of 
sequence control indicator 81. It should be understood that, due to the 
foregoing, hot-corners may be utilized instead of hot-keys, or both 
hot-corners and hot-keys may be utilized in a single presentation tree. 
It should also be noted that, although FIG. 6 shows a graphical user 
interface according to the present invention, a presentation tree 
structure according to the present invention may be created using other 
interactive methods. One possibility is a system in which separate linear 
presentation sequences are input and a tree structure is automatically 
constructed based on common elements of the separate sequences, such as 
common slides 31, 32, 37, and 40. Another possibility is a system in which 
a diagram such as that shown in FIG. 5 is first constructed, and slides 
and sequence controls are then assigned to the various branches and branch 
nodes. Moreover, three-dimensional displays may be utilized in order to 
allow more complex relationships between several alternative sequences 
within a single presentation tree. 
FIG. 8 is a flow diagram for describing computer-executable process steps 
performed by CPU 14 during creation of a presentation tree according to 
the present invention. In brief, the computer-executable process steps 
include code 1) to display a graphical interface, 2) to receive user 
manipulations of the graphical user interface, 3) to create, in response 
to the user manipulations, a presentation tree having a plurality of 
branches, each branch being connected to a plurality of other branches by 
a branch node, with each branch node having a plurality of branches 
descending therefrom, and 4) to assign at least one of the plurality of 
images to each of the plurality of branches. Preferably, the presentation 
steps also include code to determine whether or not a manipulation is an 
instruction to assign a sequence control to a branch, and to assign a 
sequence control to a branch in a case that it is determined that a 
manipulation is an instruction to assign a sequence control to a branch. 
The flow of FIG. 8 begins at step S801, in which a graphical user interface 
such as user interface 70 is displayed to a user. User manipulations of 
user interface 70 are received in step S802. Next, in step S804, it is 
determined whether the received user manipulations correspond to an 
instruction to input a new slide onto a line in workspace 77. If so, flow 
proceeds to step S806 in which process steps are executed by CPU 14 to 
determine whether a sequence control is required based on the instruction 
to input a new slide. As described above, this determination is based on 
whether a slide already exists on the line of workspace 77. If so, flow 
proceeds to step S807 in which sequence control indicators are displayed 
where required. For example, entry of slide 44 after entry of slide 39 
into workspace 77 causes sequence control indicators 81 and 84 to be 
displayed in step S807. After step S807, flow returns to step S802. 
If, in step S804, it is determined that the manipulations received in step 
S802 do not correspond to an instruction to input a new slide, flow 
continues to step S808 in which it is determined whether the received 
manipulation corresponds to an instruction to define a sequence control. 
As described above, either selection of sequence control indicator 81 or 
icons 74 or 75 may be interpreted as an instruction to define a sequence 
control. If the determination in step S808 is affirmative, flow proceeds 
to step S809, in which process steps are executed in order to define a 
sequence control to a particular branch of a presentation tree in 
accordance with the manipulations. 
For example, in a case that sequence control indicator 81 is selected in 
step S802, flow proceeds to step S804, step S808, and step S809. In step 
S809, dialog box 82 is displayed, containing text corresponding to icon 74 
if icon 74 is depressed, or corresponding to icon 75 in a case that icon 
75 is depressed. As described above, either a hot-key sequence or a 
hot-corner sequence is executed, which is received by PC 2 in order to 
define a sequence control corresponding to sequence 87 (branch 59 of tree 
50). 
To execute a hot-key sequence, a presenter presses keys on keyboard 6 
corresponding to a defined hot-key sequence. To execute a hot-corner, a 
presenter moves a pointer to an assigned corner of a displayed slide. Of 
course, the assigned location need not be a corner of the displayed slide, 
but may be any position on the displayed slide. Moreover, a presenter may 
also be required to "click" on the assigned location in order to execute 
the hot-corner. 
Returning to the FIG. 8 flow, if the determination in step S808 is 
negative, flow continues to step S810 wherein other process steps are 
executed in accordance with the manipulation received in step S802. 
Examples of such process steps are steps to open a file, to close a file, 
to save a file, to turn selected slides, or to execute a presentation 
sequence. 
FIG. 9 is a flow diagram describing a method for controlling presentation 
flow through a presentation tree defined by a plurality of branches, each 
branch being connected to a plurality of other branches by a branch node, 
each branch node having a plurality of branches descending therefrom, and 
each branch having assigned thereto at least one presentation image. The 
method includes displaying each presentation image assigned to one branch 
of the tree, the one branch connected to a branch node, executing a 
sequence control to select one of a plurality of branches descending from 
the branch node, and displaying each presentation image assigned to the 
selected one branch. 
More specifically, in step S901, a presenter issues a command to initiate a 
presentation sequence. Next, in step S903, each slide corresponding to an 
initial branch of the tree is displayed. The slides are displayed in step 
S903 in the order in which they are assigned to their corresponding 
branch. For example, with respect to slide 34 to 36 of branch 55, slide 34 
is initially displayed, followed by slides 35 and 36. A presentation 
application according to the present invention preferably allows a user to 
select a time duration during which a slide is displayed prior to display 
of a subsequent slide. 
Flow then proceeds to step S905, in which flow terminates if it is 
determined that the end of the presentation tree has been reached. 
Otherwise, it is assumed that a branch node has been reached. Accordingly, 
in step S908, a slide corresponding to the reached branch node is 
displayed. 
In step S909, it is determined whether a sequence control has been executed 
by the presenter. If not, flow proceeds to step S910, in which the next 
slide in the default sequence corresponding to the reached node is 
executed. As discussed above with respect to FIG. 6, the default sequence 
is dictated by selection of "set as default" check boxes, such as check 
box 84, which correspond to a each sequence descending from a branch node 
in a presentation tree. For example, upon reaching slide 37 (node 56 of 
FIG. 5), it is determined whether a control sequence has been executed. If 
not, and if box 84 is checked, flow proceeds to step S910, wherein slide 
44 is displayed. Flow then returns to step S905. 
If, in step S909, a sequence control is executed, flow proceeds to step 
S911, wherein the next slide in a branch corresponding to the executed 
sequence control is displayed. 
It should be noted that only a presentation slide is projected to an 
audience during the above-mentioned loop between steps S905 and S910. An 
example of such a projected slide is shown in FIG. 10. simultaneously, 
screen 3 shows both the projected slide and other information, such as a 
"sequence control needed" indicator or the like, to the presenter. 
Accordingly, upon execution of a hot-key sequence control and resulting 
progression to step S911, a subsequent slide is immediately displayed. 
Advantageously, this procedure does not significantly disrupt the flow of 
a presentation. 
In this regard, FIG. 11 shows an alternative method for projecting a slide 
at steps S907 to S909 before and during execution of a hot-corner sequence 
control. As shown in FIG. 11, pointer 90 is projected along with the 
presentation slide. As described above with respect to FIG. 10, the FIG. 
11 image is also displayed on screen 3 along with other presentation 
information. 
Since pointer 90 is most Likely used during the presentation in order to 
point out various features of displayed presentation slide, selection of a 
hot-corner sequence control using such a pointer should not cause 
significant visual disruption of the presentation. Of course, pointer 90 
may also be projected during a presentation sequence utilizing hot-key 
sequence control. 
It should also be noted that, according to the invention, a slide need not 
be assigned to each, or any, branch node in a presentation tree. In this 
case, upon reaching step S908, the currently-displayed slide is displayed. 
By virtue of this feature, alternative presentation sequences in such a 
presentation tree need not share common slides. 
Due to anticipated difficulty in recalling each defined sequence control in 
a presentation tree, the present invention also provides for a 
presentation flow tool for describing each sequence control in a 
presentation tree. In this regard, FIG. 12, comprising FIGS. 12A and 12B, 
shows presentation flow tools produced by a presentation application 
according to the present invention. In particular, after defining a 
presentation tree, a presenter may instruct a presentation application to 
display such a tool on display screen 3 in order to provide a quick 
reference for controlling a presentation sequence according to the 
invention. As shown in FIG. 12A, hot-key designations are displayed 
adjacent to slides following branch nodes 52, 56, and 60. FIG. 12B shows a 
similar presentation flow tool to be used in conjunction with hot-corner 
sequence control. According to another aspect of the invention, a 
presenter may instruct a presentation application to print a hardcopy 
version of a presentation flow tool also for use as a quick reference. Of 
course, other forms of presentation tools may be used in practicing the 
present invention. 
The present invention also provides a convenient method for printing images 
corresponding to a particular sequence of a presentation tree. For 
example, FIG. 13 shows graphical user interface 100 for indicating which 
slides in a presentation tree are to be printed. As shown in the Figure, 
check boxes 101 and 102 Correspond to common slides 31 and 32 and are 
therefore denoted by numerals "1" and "2", respectively. In contrast, 
check boxes 104 to 106 and 107 reflect slides of alternative presentation 
sequences and are therefore denoted by letters "a" and "b", respectively. 
Along these lines, slides 44, 46, and 47, which represent three 
alternative sequences, are distinguished from one another using letters 
"a", "b", and "c". 
In use, a presenter selects check boxes from interface 100 which correspond 
to desired slides and then selects "PRINT" icon 114 to print the slides 
using printer 10. Advantageously, a presenter may print the slides on 
transparency sheets in order to prepare a manual presentation. "CANCEL" 
icon 112 allows a user to exit interface 100 without printing any slides. 
While the present invention is described above with respect to what is 
currently consider its preferred embodiment, it is to be understood that 
the invention is not limited to that described above. To the contrary, the 
invention is intended to cover various modifications and equivalent 
arrangements includes within the spirit and scope of the appended claims.