To create a theme use the create_css() method. It will scan the path to theme folder and it will generate there the required CSS file using sizes of existing images. You will need write permissions on that folder.
A theme needs images named:
frame_foot_left.gif, frame_foot_right.gif, frame_right.gif, frame_top_mid.gif cell.gif, frame_foot_mid.gif, frame_left.gif, frame_top_left.gif, frame_top_right.gif

Buttons are: but_clos.gif but_mini.gif but_maxi.gif
Used/generated CSS: windows.css

The method will check the size of frame_* images and basing on that will generate working CSS. It may require some tweaking (like background color etc.). See existing themes to catch the "structure" of those files (like frame_foot_left.gif is top left border, frame_foot_mid.gif - is the foot middle graphics)


$a = new prtw('themes/rk', '');
echo $a->js_init();
echo $a->do_window('aaaa', 'bla', 'w1', 'window1');
echo $a->do_window('aaaa', 'bla', 'w2', 'window2');
echo $a->exec_windows(array('w1' => array('x' => 100, 'y' => 100, 'id' => 'window1', 'width' => 400, 'height' => 200),
'w2' => array('x' => 300, 'y' => 300, 'id' => 'window2', 'width' => 300, 'height' => 200)));

Where to get more themes: you can use graphics from my themes for my old CMS - RkCMF1. Download most of them contains those 8 frame_* files. CSS may be generated by the class.