# The PanoramIX Authoring Tool

## Version 0.1.4.92, February 26, 1998

## 4.5 The Hot Spots and Link Actions Dialog

Creation of hot spots requires two types of information:

1. where are the hot spots, and
2. what should happen when a hot spot is selected.

The description of what happens when a hot spot is selected is called the "link action". The hot spot locations and the link actions associated with each hot spot may be specified with the Hot Spots and Link Actions Dialog.

It is possible to define link actions with no hot spots. Such link actions are not selectable, except for the case of the "free link". Link actions without hot spots may be used as place holders with the hot spots to be filled in later. If one or more link actions have been defined, but no hot spots have been created for any of them, then the entire panorama is treated as "hot" for the last defined link action. This "free link" can be used to make the entire panorama responsive to an action such as an AUTOLOAD link without the need to create a "hot everywhere" link map.

The Hot Spots and Link Actions dialog is opened by selecting the Hot Spots entry from the Edit menu.

The first row of the Link Actions dialog has a Previous Button, a link ordinal number, a link ID number, and a Next button. The Previous and Next buttons allow one to advance the selected link action to the preceding or following members of the link action list. The link ordinal number and link ID ("slot") number are assigned automatically by the PanoramIX Authoring Tool when one selects the New Link button near the bottom of the dialog box. Most users will not need to know or use these values, but advanced users may need this information to manipulate link maps with external tools. The link ordinal number indicates the position of the currently selected link action within the list of link actions (#1 = first, #2 = second, etc.). The link ID number indicates the actual value assigned to this link action in the link map.

There is a series of check boxes below the Previous button. These check boxes allow one to select one or more of the following types of link actions:

- Autoload,
- Panorama,
- URL,
- Audio,
- Music,
- Sprite,
- Command,

There are four buttons below the sequence of check boxes. These buttons are labelled:

- QuickLink,
- Copy Link Map,
- Paste Link Map,
- Erase Link Map,

The bottom row of the Link Actions dialog has three buttons labelled New Link, Delete, and Close.

The New Link button creates a new link ID and allows one to specify the link action and hot spot map associated with this link ID.

The Delete button deletes the currently selected link action.

The Close button closes the Hot Spots and Link Action dialog.

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### Autoload Link Actions

The AutoLoad link action specifies a link to another panorama control file (pan file). This is similar to the Panorama link action (below) except that the link is triggered automatically as soon as the cursor passes over the hot spot. If the entire panorama is hot ("hot everywhere"), the Autoload link action is triggered as soon as the current panorama finished loading.

The panorama control file being linked by the AutoLoad link action is specified in the edit box next to the Panorama check box. This edit box is shared by both of these mutually exclusive options.

An AutoLoad link action cannot be used in combination with any other type of link action.

An AutoLoad hot link, in combination with the free link option may be used to implement a progressive resolution display. In this case, the current panorama, based on a low-resolution panoramic image, can be linked to a higher resolution image of the same scene. The hot everywhere "free link" is obtained by doing nothing about the hot spot link map. As long as there is no explicit hot spot link map, the current panorama will be hot everywhere for this link action and loading of the linked panorama will be initiated as soon as the current panorama is loaded. If the new panorama requires image files to be downloaded over a network or modem, then the user may continue to navigate through the current panorama while waiting for these files to arrive.

As an alternative to a progressive resolution display, the AutoLoad link action could be used to present a message such as "Please wait" while files for the a panoramic scene are downloaded. In this case, the message could be presented in an animated sprite providing blinking text, running dots, or other diversions.

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### Panorama Link Actions

A Panorama link action specifies a link to another panorama control file (name.pan). When the cursor passes over a hot spot associated with a Panorama link action, the cursor changes to the right or left hyperlink arrow. When a user double clicks on a hot spot associated with this type of link action, the current panorama is replaced by the specified panorama.

The name of the control file for the linked panorama is specified in the text box next to the Panorama check box. There is also a Browse button next to this edit box. This is supposed to open an Open File dialog in order to enable a user to search the current file system for the desired panorama control file, but this has not yet been implemented.

The linked panorama control file and all of the image files it requires must all be in the same file folder with the current panorama.

A Panorama link action may be combined with an Audio link action, a Music link action, a Sprite link action, and/or a Command link action.

A Panorama link action cannot be used in combination with an AutoLoad or URL link action.

Back to the Hot Spots and Link Actions Dialog

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### URL Link Actions

A URL link action specifies a link to another web page (e.g., http://server/pagename.htm). When the cursor passes over a hot spot associated with a Panorama link action, the cursor changes to the right or left hyperlink arrow. When a user double clicks on a hot spot associated with a URL link action, the current web page or frame containing the panorama is replaced by the specified web page.

The identity of the linked web page (URL) is specified in the text box next to the URL check box.

A URL link action may be combined with an Audio link action, a Music link action, and/or a Sprite link action.

A URL link action cannot be used in combination with an AutoLoad link action, a Panorama link action, or a Command link action.

URL link actions are supported only by the Netscape plug-in and ActiveX control for PanoramIX. This type of link action is not recognized by the stand-alone PanoramIX browser.

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### Audio Link Actions

An Audio link action indicates that the sounds recorded in a "wave" file (name.wav) are to be reproduced when this hot spot is selected. When the cursor passes over a hot spot with an Audio link action, the cursor changes to a right or left speaker shape. When a user double clicks on a hot spot with an Audio link action, the sounds recorded in the specified wave file are played, assuming the user's platform is equipped with hardware capable of producing sounds from wave files. If another wave file is already being played when this hot spot is selected, the wave file in progress is terminated.

The name of the wave file to be played is specified in the text box next to the Audio check box. There is also a Browse button next to this edit box. This is supposed to open an Open File dialog in order to enable a user to search the current file system for the desired audio file, but this has not yet been implemented.

The wave file must be in the same file folder with the current panorama.

An Audio link action may be combined with a Panorama link action, a Music link action, a Sprite link action, and/or a Command link action.

An Audio link action cannot be used in combination with an AutoLoad or URL link action.

Back to the Hot Spots and Link Actions Dialog

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

### Music Link Actions

A Music link action indicates that the sounds specified in a MIDI file (name.mid) are to be played when this hot spot is selected. When the cursor passes over a music hot spot, the cursor changes to a right or left speaker shape. When a user double clicks on a hot spot associated with a music hot spot, the sounds recorded in the indicated midi file are played, assuming the user's platform is equipped with audio hardware capable of MIDI synthesis.

The name of the MIDI file to be played is specified in the text box next to the Music check box. There is also a Browse button next to this edit box. This is supposed to open an Open File dialog in order to enable a user to search the current file system for the desired MIDI file, but this has not yet been implemented.

The specified MIDI file must be in the same file folder with the current panorama.

A Music link action may be combined with a Panorama link action, an Audio link action, a Sprite link action, and/or a Command link action.

An Music link action cannot be used in combination with an AutoLoad or URL link action.

Back to the Hot Spots and Link Actions Dialog

Back to the Edit Menu.

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### Sprite Link Actions

A Sprite link action allows the user to modify the properties of an animated overlay (sprite) associated with this hot spot. When the cursor moves over this type of hot spot, the cursor changes to the left or right wand. When the user double clicks on this type of hot spot, the properties of the associated sprite are changed as specified by the parameters described below. If the "Control" option is selected, then the user can control the sprite pose by pressing the (left) mouse button when the cursor is over this hot spot, then moving the mouse while

A Sprite link action is associated with a particular sprite identified by the sprite ID tag specified in the text box to the right of the Sprite check box. The sprite ID tag must match or form a unique substring of the name of the image file name for one of the sprites defined for the panorama. A list of currently defined sprite names can be obtained from the pull-down list associated with the sprite ID text box. (This may be slightly different on the Macintosh version.) A valid sprite ID tag can be selected from this list.

It is recommended that all sprites be imported first before creating hot spots linked to a sprite. This makes it possible to select the sprite ID from the pull-down list of sprite names. If the intended sprite has not yet been imported, it is possible to ender any string for the sprite ID in the text box. It is also possible to disable the link to a sprite by altering the sprite ID so it does not match any sprite in the panorama.

The following properties of a sprite may be modified when a hot spot with a sprite link action is selected:

- Azimuth (the horizontal view angle in degrees)
- Elevation (the vertical view angle in degrees)
- Scale (the size of the sprite)
- 1/Distance (the (inverse) distance from the viewer)
- Rate (the update rate for a sprite in frames per second)

Each of these properties is accompanied by a numerical value and an "absolute" check box. If the "absolute" box is not checked, then the numerical value associated with this property specifies an amount by which the current value of this property is to be changed. In this case, the numerical value specifies an incremental change to the specified property.

If the "absolute" box is checked, then the current value of the specified property will be replaced by the numerical value indicated for this property.

Appropriate range limitations are enforced for each property, depending on the state of the "absolute" check box. For example, the absolute scale factor cannot be zero or negative, but an incremental change to the scale factor can be zero or negative. Additional run-time range checking is also performed to protect against invalid properties. For example, an incremental change in the scale factor resulting in a negative result is ignored.

The inverse distance property only affects "flat" sprites. If a sprite has a depth map, the depth map takes priority over the flat depth value and changes to the flat depth value have no effect on the panorama, unless the resulting depth value is negative. A sprite with a negative depth value is always treated as hidden.

Non-negative values of the depth (inverse distance) have no effect unless a depth map is provided for the panoramic background. If a depth map is provided for the background, a depth value of zero represents infinite distance from the viewer, and a depth value of 255 represents the closest possible distance to the viewer. If the depth value for a sprite is less than the depth value for a corresponding point on the panorama, then the sprite will be hidden by this point of the panorama.

Like all other hot spots, a hot spot with a sprite link action is a property of the panoramic background. A sprite link action defines an association between an area of the panoramic background and a particular sprite, whereever that sprite may be located. The area of the hot spot and the location of the sprite are typically chosen to coincide, but this is the responsibility of the panorama creator.

A sprite link action is not a property of the sprite. If a sprite is positioned over a hot spot associated with it by a sprite link action, the panorama creator can give the end-user the impression that the responses are cause by "clicking on the sprite". However, moving the sprite does not move the hot spot. If the sprite link action is used to change the azimuth or elevation of a sprite, then the sprite will no longer be located on top of the same hot spot.

The panorama creator is free to create multiple hot spots that a sprite can hop between. The hot spot(s) associated with a sprite can be unmarked areas identified only by cursor changes, or they can be clearly identified by graphical elements to let the end-user know what will happen. For example, there could be a box with the text "Click here to see the object".

A Sprite link action may be combined with a Panorama link action, an Audio link action, a Music link action, and/or a Command link action.

An Sprite link action cannot be used in combination with an AutoLoad or URL link action.

Back to the Hot Spots and Link Actions Dialog

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

### Command Link Actions

A Command link action specifies an operating system command line to be executed when the hot spot is selected. When the cursor passes over a hot spot associated with a Command link action, the cursor changes to the left or right wand. When a user double clicks on a hot spot associated with a Command link action, a new process is started based on the text string associated with this hot spot.

For security reasons, this type of link action is not permitted on network-based panoramas, including the Netscape plug-in and ActiveX control for PanoramIX. This type of link action is permitted only with the stand-alone PanoramIX browsers (for Windows 95, Windows NT/x86, PowerPC Macintosh, AIX, and IRIX). The command text associated with this type of link action can be expected to be specific to one particular environment such as Windows or UNIX. Consequently, any control file which uses this type of link action should be considered to be platform-specific. This type of link action is most useful for "kiosk" or CD-ROM based delivery formats.

An example of a Command link action might be a command to play a video file using a platform-specific video player.

The command to be executed is specified in the text box next to the Command check box.

A Command link action may be combined with an Audio link action, a Music link action, a Sprite link action, and/or a Panorama link action.

A Command link action cannot be used in combination with an AutoLoad or URL link action.

Back to the Hot Spots and Link Actions Dialog

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### The QuickLink Button

The QuickLink button provides a simple way to create simple rectangular hot spots. When the QuickLink button is selected, the edit image window for the current edit image is opened, if it is not already open. One may use the tab key or double click on the main window to change the selected edit image.

After selecting the appropriate edit image, press and hold the (left) mouse button to mark one corner of a rectangle. Then drag the mouse to a second point to specify the diagonally opposite corner of a rectangle. The boundaries of the rectangle are represented as the mouse is dragged. When the mouse button is released, the indicated rectangle is converted to a hot spot associated with the currently selected link action.

Multiple rectangular areas can be associated with the current link action by repeated use of the QuickLink button. In order to move or change a hot spot, use the Erase Link Map button to clear the link map, then start over.

If it is necessary to create a hot spot with any other shape, use the Copy Link Map and Paste Link Map buttons described below.

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### The Copy Link Map Button

The Copy Link Map button copies the current link map for the selected link action for the current edit image to the clipboard. If a link map for this link action has not yet been created, a blank link map is created. The Edit Image window should be open to show the currently selected Edit Image.

The link map copied to the clipboard contains the green and blue elements of the currently selected edit image. The green/blue "ghost" image is provided for reference in aligning hot spots with the corresponding color image. Any regions which are "hot" with respect to the current link action are shown in red. These can be modified by drawing any areas in red or any rgb color with non-zero red values.

Only the areas in the current edit image which are hot with respect to the currently selected link action can be seen in the image pasted into the image processing utility.

After a link map has been pasted into the clipboard, it may be pasted into any image processing tool which supports the clipboard. After using the chosen image processing tool to draw in new hot areas, shoose the "Select All" function provided by the image processing tool and then select the "Copy" function of this tool to copy the modified image back to the clipboard.

The "Copy" function can generally be found in the Edit menu of any standard application. The name and location of the "Select All" function depends on which tool is being used.

If the area of a hot spot spans two or more side images, then each side image must be processed individually.

If you want to define hot spots on the panoramic background instead of the side images, wait until after saving the panoramic image with the Save Panorama function in the File menu. Then use the File/Open operation to reload the current panorama using the panoramic background instead of the original side images as input.

Back to the Hot Spots and Link Actions Dialog

Back to the Edit Menu.

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### The Paste Link Map Button

The Paste Link Map button enables one to paste a link map from the clipboard into the currently selected edit image. This button will paste any image currently occupying the clipboard. It is the author's responsibility to ensure that the current clipboard image is actually a valid link map image. The clipboard will contain a valid link map image following a copy operation in any image processing utility, where the copy operation is based on an image derived from the Copy Link Map operation in this dialog.

In order to perform a valid Paste Link Map operation, one must follow the following steps:

1. Select the edit image (in the EditImage window) to be modified,
2. Select the Copy Link Map button,
3. Select the Edit/Paste operation in any image processing utility,
4. Modify the resulting image in the image processing utility using any shade of red to identify hot areas,
5. Select the "Select All" function of the image processing utility,
6. Select the Edit/Copy operation of the image processing utility,
7. Verify that the image displayed in the EditImage window is the same image selected in step 1,
8. Select the Paste Link Map button.

It is recommended that the image in the EditImage window not be changed during this procedure, but it is permissible to chage the selected image as long as you return to the original selection before selecting the Paste Link Map button.

It is also recommended that steps 6, 7, and 8 be performed immediately after step 5. If an Edit/Copy operation is performed in any other application after step 6 and before step 8, then the clipboard will not contain the image information required in step 8. Performing steps 5, 6, 7, and 8 in sequence without stopping to perform any other tasks is considered "common sense". Any other sequence of operations is risky and unreliable.

After selecting the Paste Link Map button, the green and blue color data in the image found in the clipboard is discarded. Each pixel with a non-zero red value is used to set the corresponding pixel in the link map for the current Edit Image to the value of the current link ID (slot) number. This may overwrite previously set link map index values. Each pixel in a link map may be associated with at most one hot spot. The color image is not affected by this operation.

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### The Erase Link Map Button

The Erase Link Map clears the link map for the current link action. If a more limited or partial erasure is needed, use the Copy Link Map and Paste Link Map operations to transfer the link map to an image processing utility and back.

Back to the Hot Spots and Link Actions Dialog.

Back to the Edit Menu.

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Last modified February 27, 1998.
wluken@watson.ibm.com