The PostScript option on the main menu, allows the user to produce a hardcopy PostScript file of the current screen image. The PostScript option is selected from the main menu (figure 9.1).
Figure 9.1 The Main Menu
Colours used for creating a postscript file are found in files with a matching prefix to the colour file used (Section 7: Colour) but with the suffix .psrgb. A set of .psrgb files are provided with the software and should be installed in the same directory as the colour files. When creating a postscript file, a search is conducted to find a .psrgb , usually in the same directory as the colour_file. If a match has been found, the new colours will be loaded in the array for the postscript colours and the PostScript control panel [figure 9.4] will be displayed.
If no matching .psrgb file is found with the same directory path and prefix name, a search will be made in the colour directory. If a file is still not found, the control panel for setting up the psrgb colours will be opened on the screen ( figure 9.2).
Figure 9.2: Control panel for setting PostScript Colours
The psrgb colours can be initialised in one of two ways:
1. Using colours from the current RGB File.
Using the colours in the existing colour file, where each red, green and blue value is divided by 255.0 and then used to set the postscript colour array which is used in turn to set the colours in the postscript file. This is the default setting.
If the "Use RGB File" tick box displays a tick, then simply click once on the Accept button. This will calculate the psrgb colours and load the psrgb colour array. These colours will be used for all future postscript files, unless the colourmap is changed. If the tick box is not selected, then click once using the left hand mouse button in the tick box window, and then select the Accept button.
2. Naming a .psrgb file.
If you wish to use an existing .psrgb file, click once on the "Name .psrgb file" tick box and ensure that a tick is seen in the window. This will now activate the "Filename" text input object. To enter the name of a file, place the cursor on the text input line and click once using the left hand mouse button. The prompt will now appear on the line. Enter the name of the file using the keyboard. When the name of the file has been entered, click once on the Accept button. If an error occurs whilst trying to open the file, the following error dialog message will appear on the screen.
Figure 9.3:Error Message if unable to open named psrgb file
The user will be unable to continue in creating a postscript file of the current image. If the file exists, the colours will be loaded from the file in the postscript colours array , the control panel closed, and the PostScript control panel displayed on the screen. The user may now continue to create the file.
The PostScript control panel.
The PostScript control panel contains several windows for setting the parameters for a hardcopy file. If a matching psrgb file is located when the PostScript option is selected from the main menu, this panel will be displayed immediately.
Figure 9.4 The PostScript control panel.
Draft/Presentation: The draft / Presentation tick boxes set the colour used for land , the default setting is Draft. In Draft mode, the land will not be filled and will appear white on the hardcopy output. To select the Presentation option, which will draw the land in black, place the cursor over the tick box , and click once using the left hand mouse button.
Filename: The Filename text input window, takes the name of the output file. By default, the file will be called mplot.ps. To change the name of the current file, place the cursor on the text input line and click once using the left hand mouse button. This will activate the window to recieve input from the keyboard. Using the backspace/delete key, remove the exisiting filename and then re-type the name you wish to give to the file.
Grid Lines On: The grid lines option specifies whether to draw grid lines. If the grid lines are already drawn on the image, this option will be set. If no lines are drawn on the current image but the user wishes to draw them on the image in the Output file, then using the mouse button, place the cursor in the tick box window, and click once using the left hand mouse button. If the Grid Lines On option is set to true, this will activate the GridSpace X and GridSpace Y text input lines, and also the Grid Text on tick box, otherwise these options are inactive and will recieve no event actions from the mouse or the keyboard.
GridSpace X, GridSpace Y: These values specify the spacing for the horizontal and vertical grid lines respectively. By default, these values are set to 10 degrees. If grid lines are already drawn on the image, then these values will be set to the current specified values ( refer section 5:The Co-ordinate Menu: Grid Overlay).The minimum specified grid spacing allowed is 1.0 degree.
Grid Text On: The Grid Text On option specifies whether to overlay grid text for the grid lines set for the image. To activate this option. click once using the left hand mouse button, in the tick box.
To process the PostScript file, click on the SUBMIT button at the bottom of the control panel. The program will now create the PostScript file. If no pathname is specified in the filename, the file will be written to the current working directory. To stop the processing of the PostScript file at any time, select the CANCEL button.