Subsections

• Integer, Real Value, and Character String Input
• Boolean Value Input
• Graphical Menu Choices
• Graphical Coordinate Input

Parameter Value Input

FIT2D has been developed in a very modular fashion and the user interface exhibits this modularity. This means efficient development and easy use. The same ``components'' are re-used many times and the user will soon become familiar with the input style.

At the most basic level of user input is parameter input. This may be a number e.g. a value for the number of pixels for the internal arrays in one direction, a character string e.g. a title for a data-set, or a choice between a limited number of values.

The following different types of input exist:

Integer Value

Real Value

Boolean Value

Character String

Graphical Menu Choice

Graphical Coordinate

Integer, Real Value, and Character String Input

Figure 4 shows the typical display box for the input of an integer value. A very similar style is used for the input of real and character string values.

Figure 4: Example of the User Input of an Integer Value

The following ``components'' of the dialogue box are apparent:

Descriptive Text: At the top (with the white background) is a short text describing the required input. This includes the text (Range: 1 to 10000) which tells that the value must by between 1 and 10000. For parameters where any value may be input this text is not present.

CANCEL The cancel button cancels the parameter input without changing its value. This may also cancel the operation for which the parameter value was being requested.

HELP The help button may be clicked to obtain more detailed information concerning the parameter value being input and its context in relation to the operation being undertaken.

O.K. The O.K. button may be clicked to accept the current value which is in the text input box. Initially this is a default value from FIT2D. This is equivalent to typing the <ENTER> key.

Text Input Box: The yellow lower rectangle is the area for the display of input text. The box already contains the text 512, which is the default value for the parameter, and the cursor to the right of the number. Text entered from the keyboard will appear in this box at the cursor position.

The text may be ``edited'' using the left and right arrow keys to move the cursor, the ``backspace'' or ``delete'' key to remove text and other numerical or alphabetic keys to enter characters. Additionally the up arrow and down arrow keys allow previous inputs to be scrolled. The up-arrow key allows previous input to be ``re-called''. Each time the up-arrow key is pressed the previous input replaces any entered text. The down-arrow key can be used after the up-arrow key to scan through the previous inputs. If used by itself, or when the current input is being displayed, it removes all characters. This can be useful for quickly removing all the characters of a presented default response.

When the text is as required, the <ENTER> (or $<$ RETURN$>$) key is used to enter the value. If the value is correct the parameter input is completed, otherwise an error message will presented, followed by the full information ``help'' message, and the user will be required to re-enter the parameter value.

Boolean Value Input

Many times a simple ``yes/no'' choice is offered to the user. This sort of ``boolean'' parameter value input is controlled with a simple menu of four buttons. An example is shown in Figure 5.

Figure 5: Example of the User Input of a Boolean Value

The buttons are:

? Help information on the parameter value being requested

CANCEL Cancel input without changing the value of the parameter. This will also in many cases cancel the operation for which the parameter was requested.

YES Set the value to ``Yes''.

NO Set the value to ``No''.

The ``CANCEL'' button will cancel the operation and the parameter will keep its previous value.

The ``?'' button will display help text describing the purpose of the parameter and the type of value required.

Graphical Menu Choices

Graphical Menus are the normal manner in which data analysis operations may be chosen by the user. The choice of ``scientific interfaces'' is a graphical menu, and each of the interfaces is a menu. Various menu commands may themselves produce sub-menus e.g. the Z-SCALING command produces a sub-menu.

When a button is pressed, it will be re-drawn pressed-in, to show that it has indeed been pressed. (Note: afterwards it may be re-drawn normally, and if this happens quickly enough the pressed-in button may not be noticed.)

Different interfaces have different commands, but the following commands are common to several or all menus:

EXIT Every menu has an exit button which is used to exit the menu and return to the previous menu, or in the case of the ``scientific interfaces'' menu to exit FIT2D, provided confirmation is given.

? The question mark button provides a message with the available button commands and a short explanation of the commands.

HELP The help button provides a ``context'' related help message on the menu and the overall functionality which it provides.

INPUT Input data from a file (see Section 4.4 for more details).

OUTPUT The output button is used to save the current ROI of the data to an output file.

EXCHANGE Exchange the current data with the memory data. If the memory was previously undefined, then the current data array becomes un-defined (see Section 3.2).

ZOOM IN Define a smaller ROI using graphical cursor input (see Section 3.3).

FULL Set the ROI to be the whole of the currently defined data (see Section 3.3).

UN-ZOOM Increase the size of the ROI. This is done symmetrically if possible (see Section 3.3).

PRINT Save the currently displayed graphical image to a PostScript file. The name for the PostScript file is requested.

DISPLAY Sub-menu with variety of alternative data display possibilities to the false colour image e.g. contour or 3-D surface views (see Section 5.4).

OPTIONS Sub-menu offering control of graphical display style options (see Section 5.5).

Graphical Coordinate Input

FIT2D has a true graphics user interface in that the user interface includes the graphics display, as opposed to only buttons and dialogue boxes, of most programs with ``GUI's''. For many operations the most convenient form of user interaction is for the user to indicate some feature in the data. This is performed by clicking on a false colour image of the data (or an X/Y graph for 1-D data).

An example of the dialogue box associated with graphical coordinate input is shown in Figure 6.

Figure 6: Example of Graphical Coordinate Input

The various components of this dialogue region are:

``Spy-Glass'': On the left is the ``spy-glass'' or zoom window which shows the region around the cursor at full pixel resolution. As the cursor is moved within the data image, so the image within the spy-glass changes. The cross-hairs in the centre of the spy-glass show the position of the cursor. Unlike the main image display, the spy-glass is always full range automatic intensity scaling.

User Prompt: The white background rectangle contains ``prompt'' information describing the purpose of the required coordinate input. Note: For some coordinate input, this region can be replaced by a yellow button, to be pressed to end input e.g. when the user can enter a variable number of coordinates.

Cross-Hair: Drawn on top of all the graphics is the cursor cross-hair. These vertical and horizontal lines follow the cursor, and may be useful when the input coordinate needs to be aligned with features in the data.

HELP The help button will provide a message describing in greater detail than the ``prompt'' the required input and its purpose.

CANCEL The cancel button allows the input to be cancelled. This will usually also cancel the operation for which the coordinate was required.

KEYBOARD The keyboard button may be used to enter the X and Y coordinate position, by entering two numbers from the keyboard instead of the graphical click. This can be useful when some precise value is required.

TWO CLICK Enter ``two click mode''. In this mode for graphical coordinate input the first click within the image stops the spy-glass, and then a second within the spy-glass defines the input coordinate. This allows more accurate input, particularly for very large images which will be displayed at much lower than single pixel resolution. When in ``two click mode'' this button will change to ONE CLICK, and may be used to return to normal ``one click mode''.

When a coordinate is selected, a double cross is drawn on the image at the appropriate position. The double cross is made from a black horizontal/vertical cross, and a white diagonal cross. Thus, regardless of the colour of the data the cross will be visible.

Often when two or more coordinates are input, the later coordinates are related in some way to the first, or previous coordinate. In such a case, a ``rubber-band'' line or rectangle is drawn and re-drawn as the cursor moves. e.g. The ZOOM IN command requires two coordinates to define the new ROI; and a rectangular box will be drawn defined by the first coordinate and the cursor position, whilst the second coordinate is being input.