User Interface

1. Main view

Each Tracker tab, like "Untitled" above, displays the following components:

2. Toolbar

The order of the buttons on the main toolbar closely match the steps used to analyze a video. Buttons include (from left to right):

Buttons near the right end of the toolbar control documentation tools and refreshes data:

The lower tier of the toolbar is used mainly for selected track data and input fields, but also contains a memory manager button that manages and monitors Tracker's memory status. See memory management for more information.

3. Additional views

Here a particle model track has been added and the split panes have been opened to display all view types and positions.

Except for the main video view, any view pane can display any type of view. To select a desired view type, click the view chooser button at the left end of a view toolbar and choose from the drop-down list.

4. Supplemental HTML and PDF files

Tracker experiments that are packaged into a Tracker ZIP file may contain supporting documents such as instructions, report forms, etc. that are not displayed in Tracker itself but instead in a separate desktop application. These supporting documents are called supplemental files.

All supplemental files are opened on the desktop when the Tracker ZIP is first opened. HTML files are displayed in the user's default web browser and PDF files in the user's default PDF viewer.

The Documents button on the toolbar is enabled whenever supplemental files or page view HTML files are available for viewing on the desktop. To open (or re-open) a file, click the Documents button and choose the name of the document from the popup list.

5. Hints

By default, Tracker displays hints in a yellow box at the bottom right corner of the main view. Hints are very useful for new and occasional users of Tracker. Experienced users can turn off hints by unchecking the Show Hints checkbox in the Help menu or in the Display tab of the preferences dialog.

6. Pencil

Pencil drawings are colored lines drawn by hand on the video. They can be very useful for documentation since they are saved in Tracker files (TRK).

To draw a line, click the Pencil button Pencil popup  menu on the toolbar or press "D" on the keyboard, then click and drag the pencil cursor. Clicking the arrow on the button or right-clicking the pencil cursor displays a popup menu to change the pencil color, control the visibility or erase the drawing.

Pencil drawing Pencil popup  menu

7. Font level

The Font Level determines the size of the fonts displayed by Tracker. In most cases, the default font level is best, but larger fonts are often useful when making a presentation or using a high screen resolution. To change the font level choose the desired level from the Edit|Font Level menu. You can also set a preferred font level in the Display tab of the preferences dialog.

8. Number formats

Real numbers displayed on the toolbar or in datatables may be formatted using either decimal or scientific notation. For scientific notation, the letter E is used to mean "times 10 to the power of" so the number 1.3 x 10^3 is written 1.3E3. By default, the choice of decimal or scientific notation and number of decimal places varies based on the magnitude of the number.

It is often desirable to set a fixed format for some variables in order to make reading and comparing values easier. You can do this using the Number Formats dialog.

To display the Number Format dialog right-click a text field or datatable and select Number Formats... from the popup menu. In the dialog, select the track and names of the variables you wish to format. Use the shift and control keys to add or remove names from the selection. Enter the desired format into the format field to apply it to the selected variables. The sample field shows the result of the format applied to the number PI. Changes are also seen immediately wherever the variables are displayed.

To apply format pattern changes to all tracks of the same type, select All tracks of type X.

To apply changes to all variables with the same dimensions, select All variables with dimensions "X". This is a very fast way to apply the same pattern to all length and position variables in all tracks (dimension "L"), for example.

Click the Help button to display sample formats and dimension definitions.

Format help

9. Background mat

The background mat is a white area normally hidden behind the video. It is never smaller than the video, but may be made larger if desired by choosing from the Edit|Mat Size menu. A larger mat size increases the area that is drawn in the video and world views. This is useful when some of a track's steps, or the axes, would otherwise be drawn offscreen--a common situation when using particle model tracks, calibration point pairs or offset origins.

10. Languages

Select a language other than that of the default locale by choosing from the Edit|Language menu or in the Display tab of the preferences dialog.

If your preferred language is not available, and you wish to provide a translation, please contact Douglas Brown at dobrown at cabrillo dot edu.

11. Undo and redo

Most operations in Tracker can be undone and redone using the Undo and Redo items in the Edit menu. There is no limit to the number of undo actions.

12. Memory management

By default Tracker has at least 64MB of memory available (machine-dependent), enough to handle most moderate-sized videos. But when analyzing large or multiple videos, or long image sequences, additional memory will likely be needed. The memory manager button on the lower tier of the toolbar displays information about the current memory status. The button text turns red when the current memory limit is approached.

Larger memory sizes are set in the Runtime tab of the preferences dialog. Clicking the memory manager button pops up a menu item that provides easy access to this tab.

13. Tracker Preferences

The preferences dialog enables a user to set the configuration and other properties of Tracker. These preferences are saved in a ".tracker.prefs" file that is automatically read every time Tracker starts. To display the preferences dialog, choose the Edit|Preferences menu item. To relaunch Tracker immediately with changed preferences, click the Relaunch Now button.

Set preferences in the following tabs:

  1. Configuration tab. The "configuration" refers to the menus, buttons and other user interface features included in Tracker. By unchecking items in the configuration tab, you can hide unwanted features. This is particularly useful when introducing students to Tracker for the first time. As they gain familiarity with the program, additional features can be displayed as needed.
  2. Display tab.
  3. Runtime tab.
  4. Video tab.
  5. General tab.