# The PanoramIX Authoring Tool

## Version 0.1.4.92, February 26, 1998

## 4.10 The Edit Sprites Dialog

The properties of sprites can be controlled using the Edit Sprites dialog. This dialog is opened by selecting Sprites in the Edit menu.

The Edit Sprites dialog contains three sections:

1. Sprite Identification and Selection
2. Sprite Properties
3. Apply, Delete, and Close Buttons

### 4.10.1 Sprite Identification and Selection

The upper part of the Edit Sprites dialog provides two fields for selecting and identifying a sprite image. These fields indicate the names of the image files providing the sources of the color values and depth values for the selected sprite. Each of these fields is accompanied by a Browse button which is intended to provide the ability to replace the indicated file with other suitable files. These functions have not yet been implemented, so these Browse buttons do nothing.

Back to the Edit Sprites Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

### 4.10.2 Sprite Properties

The Edit Sprites dialog enables one to inspect and alter the following characteristics of sprites:

- Azimuth angle
- Elevation angle
- Scale
- Rate
- Number of Horizontal Steps
- Number of Vertical Steps
- Number of Time Steps
- Behavior
- Depth

Each of these properties can be modified by typing new values in the associated edit fields. Most of these can also be adjusted incrementally by clicking on the little "spin controls" at the right side of the corresponding edit boxes. In addition, the Azimuth angle, the Elevation angle, and Scale factor can be adjusted interactively using the mouse or cursor control (pointing) device.

#### Interactive Positioning and Scaling

When the Edit Sprites dialog is open, move the cursor into the main window and move the view direction until the currently selected sprite is located near the center of the window. When the sprite is located in a suitable position, place the cursor near the center of the sprite. The shape of the cursor should change to a hand. When the cursor is shaped like a hand, press and hold the left mouse button, then drag the cursor. At this point, the panoramic background should move while leaving the sprite in a fixed location. You can move the background until the sprite is located over the destination location.

While the background is moving behind the sprite, the azimuth angle and elevation angle for the sprite are continuously updated in the edit boxes.

To adjust the size of the sprite, press and hold the right mouse button, then drag the mouse vertically. Moving tge cursor up will enlarge the sprite, and moving the cursor down will shrink the sprite. The resulting scale factor will be updated continuously in the corresponding edit box.

#### 4.10.2.1 Sprite Azimuth

(horizontal angle about the vertical axis), of the sprite's location in the panoramic scene,

#### 4.10.2.2 Sprite Elevation

(vertical angle between 90 (straight up and -90 (straight down) for the sprite's position in the panoramic scene,

#### 4.10.2.3 Sprite Scale

(relative size of the sprite with respect to the background),

#### 4.10.2.4 Sprite Rate

(number of frames per second for time-based animation),

#### 4.10.2.5 1-d Sprites

(number of images in a one-dimensional sprite)

PanoramIX supports 1-d, 2-d, and 3-d sprites. An animated GIF (GIF89) is an example of a 1-d sprite. In this case, the sprite is defined by a sequence of nPoses images, where nPoses is determined by the "number of horizontal steps" specified in the EditSprites dialog. The number of vertical steps and the number of time steps must be set to zero for this type of sprite. This type of sprite is animated by advancing through these images at the rate determined by the Rate property. This type of sprite can also be controlled by using the horizontal position of the pointing device to select one of the images comprising the sprite. The sequence of images comprising a 1-d sprite may be specified in a standard animated GIF file, or they may be concatenated into a single TIFF, GIF, or JPEG image with individual poses arranged in a row ordered from left to right.

Back to Sprite Properties.

Back to the Edit Sprites Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

#### 4.10.2.6 2-d Sprites

(number of rows in a two-dimensional sprite)

A 2-d sprite is defined by having non-zero values for both the number of horizontal steps and the number of vertical steps. The number of time steps remains zero. This type of sprite is determined by a set of nPoses images where nPoses is the product of the number of horizontal steps and the number of vertical steps. These images are treated as a set of rows where the number of rows is specified by the number of vertical steps, and the number of images within each row is specified by the number of horizontal steps. Animation of such a sprite is restricted to a selected row of images. The active row of images can be selected based on the vertical position of the pointing device. In this case, the horizontal position of the pointing device determines the particular image within the selected row. The images comprising a 2-d sprite may be stored in an animated GIF file, or they may be combined into a single TIFF, GIF, or JPEG image in which all of the images are concatenated from left to right in a long row.

Back to Sprite Properties.

Back to the Edit Sprites Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

#### 4.10.2.7 3-d Sprites

(number of frames in a three-dimensional sprite)

A 3-d sprite is similar to a 2-d sprite, except that where a 2-d sprite is effectively an array of images, a 3-d sprite is an array of cells, where each cell is a sequence of images. The number of images within each cell is specified by the number of time steps. This type of sprite is animated by stepping through the images within a single cell. The current cell may be determined by the horizontal and vertical position of the pointing device. This allows an animated object to be manipulated in two-dimensions. For example, an object with blinking lights may be rotated about each of two axes while the lights continue to blink. The total number of images in a 3-d sprite is the product of the number of horizontal steps, the number of vertical steps, and the number of time steps. These images may be stored in an animated GIF file, or they may be combined into a single TIFF, GIF, or JPEG image in which all of the images are concatenated from left to right in a long row.

Back to Sprite Properties.

Back to the Edit Sprites Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

#### 4.10.2.8 Sprite Behavior

(how to repeat sequences after passing the last image of a sequence),

The following behavior types are supported:

1:
  Run through a sequence once, then stop,
2:
  Run through a sequence in alternating order (first image to last image, then last image back to first image, then repeat)
3:
  Run through a sequence from first image to last image, then jump back to the beginning and repeat.
100+X:
  Same as type X, except that Azimuth and Elevation refer to a position on the screen instead of on the panoramic background. Users can still zoom in and out.
200+X:
  Same as type X, except that Azimuth and Elevation refer to a position on the screen instead of on the panoramic background, and the scale is fixed.

Back to Sprite Properties.

Back to the Edit Sprites Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

#### 4.10.2.9 Sprite Depth

The Depth value is an alternative to providing a depth map for a sprite in order to determine what is occluded when comparing a sprite to a background panorama with a depth map. The value specified here represents the inverse (1/d) of the distance from the viewer to the object on a scale of 0 (for infinite distance) to 255 (for the closest possible distance to an object). Negative depth values are used to represent hidden objects which are not visible no matter what is found in the dapth map. Negative depth values can be used to hide sprites even when no depth map is provided for the background. Positive depth values have no effect unless a depth map is provided for the panoramic background. If no depth map is provided for a sprite, the sprite is treated as flat, with all points equidistant (at 1/depth) from the viewer. Sprites which are not flat can be specified by providing a depth map for a sprite.

Back to Sprite Properties.

Back to the Edit Sprites Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

### 4.10.3 Apply, Delete, and Close buttons

The bottom of the Edit Sprites dialog has three buttons labeled Apply, Delete, and Close. The Apply button updates the panorama based on the currently specified properties. The Close button closes the Edit Sprite dialog, discarding any property changes entered since the most recent use of the Apply button. The Delete button removes the selected sprite from the list of images comprising the current panorama and advances the sprite selection to the next available sprite, if any.

Back to the Edit Sprites Dialog.

Back to the Edit Menu.

Back to the PanoramIX Authoring Tool.

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