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3. Adding a GUI interface to a bash script
GUI interfaces can be used with bash scripts. The script below uses Zenity to provide a GUI interface for selecting an image to convert to .pdf and a second GUI interface for naming and saving the newly created .pdf file.
#!/bin/bash ############################################################ # con2pdf-gui # Intended to convert scanned document to pdf document # and provides gui interface for file selection. # requires awk # requires convert (from ImageMagick) # requires dirname # requires zenity to create gui file selection dialogs # zenity requires GTK+ ############################################################ input_file=$(zenity --file-selection --title "Select an image file to convert to pdf" --directory ~) if [ $? -eq 1 ]; then exit elif [ $? -eq 1 ]; then zenity --error --text "You did not select a file to convert" exit fi working_dir=$(dirname $input_file) cd $working_dir output_file=$(zenity --file-selection --save --title "Where do you want to save the pdf file?"\ --directory $working_dir --confirm-overwrite) convert $input_file $output_file # end of script
This script could be run by clicking an icon on a desktop and since the interface is GUI there would be no need to open a terminal.
input_file=`zenity --file-selection --title "Select an image file to convert to pdf"`
The first line of this script uses a zenity command within two backticks to assign a file to the variable input_file. The option file-selection specifies that a file selection dialog box is required. The option –title will create a title for the dialog using the text enclosed in double quotes. The option –directory nominates the default directory to be opened. In this instance, ~, will open up the home directory of the current user.
The CLI utility con2pdf either converted an image to a pdf if an image file was entered after the command or it printed out the usage message and retruned to a comman prompt. However, if the user hits the Cancel button or does not select a file, this script will continue to run.
Zenity returns the following exit codes:
- 0 The user has pressed either OK or Close.
- 1 The user has pressed Cancel.
- -1 An unexpected error has occurred, e.g. no file has been selected.
- 5 The dialog has been closed because the timeout has been reached.
An if/else if (elif) statement can be used to exit the script with a 0 exit code or will open a zenity error dialog and then exit the script if the user presses Cancel or does not select a file to convert.