3  Supplement

3.1  Dialog windows

3.1.1  Default properties

The dialog window Default properties contains the program settings, with their values stored in the Windows registry database. On starting up Gravity, these data will get in the program from the registry and on exiting they can be saved back there.

In Figure 18, the dialog window Default properties are shown with the number of descriptions:

Figure 18. The dialog window Default properties

3.1.1.1  Default units

Table 17 shows the units with their conversion ratio and default unit each:

Table 17. Units

The units of the dialog window Create new system/System properties as displayed in the menu item Main menu/File/New... will be filled in with the values set here.

3.1.1.2  Gravitational constant

The value of the universal gravitational constant can be determined experimentally, which is very difficult, due to the extremely low power of gravity (as compared to other physical powers). The measuring results are only approximative and generally set the limiting error as well.

See further the value and unit of the gravitational constant in the section The classical physics of gravity.

3.1.1.3  Default changes to view and zoom

The change view and zoom velocity has effect on the velocity of continuous operations (see Continuous change to parameter).

The change to view velocity has effect to:

• continuous change to view (see Continuous change to view, View+),
• continuous change to body position (see Continuous move of body, Move+),
• continuous change to position of body selected (see Continuous move of body selected, Move select+),
• continuous change to body velocity vector (see Continuous change of velocity vector, Velocity+) and
• continuous change to velocity vector of body selected (see Continuous change to velocity vectors selected, Velo select+).

The change to zoom velocity has effect on:

• continuous change to zoom (see Continuous zoom, Zoom+), and
• continuous zoom of body selected(see: Continuous zoom of body selected, Zoom select+).

Velocity can be of values from 1 to 100, with a lower number involving a higher velocity. The scale is non-linear, e.g. the difference in velocity between 5 and 10 is greater than between 80 and 100.

3.1.1.4  Default visibility of toolbar and statusbar

They are default settings for the ToolBar and the StatusBar. In accordance to the values set here, these objects are displayed on the screen on pressing the OK button in the dialog window.

3.1.1.5  Dialog box transparency

The transparency of the Control Panel and System description dialog boxes in percent.

3.1.1.6  Dialog box fading

The dialog boxes appear and disappear with or without fading effect.

3.1.1.7  Text defaults

These texts will be body names and for each name to be different, they contain a star character (*), the program substitutes with a number increasing automatically.

The first name will appear by pressing the Add button, the second one by pressing the Ins button on the page Bodies in the dialog window Create new system/System properties. The base values are: Add_* and Ins_*.

The third one contains the body names you can create by the mouse. The base value is Add-*. See further the section Create new body by using the mouse.

The fourth one is displayed in the dialog window Properties of body selected. The base value is Sel-*.

3.1.1.8  Background and mouse pointer default character set

The character sets of the dialog window Create new system/System properties displayed in the menu item Main menu/File/New... will appear with the values set here.

See further the section Character sets for the background and mouse pointer.

3.1.1.9  Appearance of default character sets

These controls show the appearance of the default character set of the background and mouse pointer,

See further the section Character sets for the background and mouse pointer.

3.1.1.10  On-Screen Information font

The On-Screen Information text displays with the font of the background or the mouse pointer.

See further the section Character sets for the background and mouse pointer.

3.1.1.11  Paint mode

The repaint of the screen can be fast or steady. In the fast mode, the painting speed primarily depends of the repainting area size. In the steady mode, the painting speed primarily depends of the window size.

3.1.1.12  Log file name

You can enter the place and name of the log file (see Description of the log file) in this text field, and you can select this from the file system with the browse button.

See further the section Log.

3.1.1.13  Startup picture name

You can enter the place and name of the startup picture in this text field, and you can select this from the file system with the browse button.

3.1.1.14  Brief of controls

Using this switch, you can switch on and off the small windows (tooltips) that display brief text information belonging to the dialog windows. Fixing the mouse pointer above the control, a one-line information appears on that control.