Chapter 8. Command-Line mode for Image Generation

You can use KStars to generate an image of the sky without actually launching the GUI portion of the program. To use this feature, start KStars from a command prompt using arguments to specify the filename for the image, as well as the desired image dimensions:

If no filename is specified, it generates a file named kstars.png. It will attempt to generate an image that matches the extension of your filename. The following extensions are recognized: “png”, “jpg”, “jpeg”, “gif”, “pnm”, and “bmp”. If the filename extension is not recognized, it defaults to the PNG image type.

Likewise, if the image width and height are not specified, they default to 640 and 480, respectively.

By default, KStars will read in the options values stored in your $KDEHOME/share/config/kstarsrc file to determine where the image will be centered, and how it is rendered. This means you need to run KStars in normal GUI mode, and exit the program when it is set up with the desired options for the generated images. This is not very flexible, so we also provide the ability to execute a KStars D-Bus script to set the scene before generating the image. The filename you specify as the script argument should be a valid KStars D-Bus script, such as one created with the Script Builder Tool. The script can be used to set where the image is pointing, set the geographic location, set the time and date, change the Zoom level, and adjust other view options. Some of the D-Bus functions make no sense in non-GUI mode (such as waitForKey()); if these functions are encountered while parsing the script, they are simply ignored.

By default, KStars will use the system CPU time and date for generating the image. Alternatively, you may specify a time and date with the “--date” argument. You can also use this argument for specifying the startup date in normal GUI mode.