gistfile1.js

Panel.prototype = {
    _init : function() {
        let me = this;
        let global = Shell.Global.get();

        // Put the background under the panel within a group.
        let group = new Clutter.Group();

        // Create a box with the background and the shadow.  The background
        // is drawn using two gradient boxes.  We let the backBox divide the
        // panel's height between these instead of calculating their heights
        // here, to prevent rounding errors.  The shadow gets a fixed height.
        let backBox = new Big.Box({ orientation: Big.BoxOrientation.VERTICAL,
                                    x: 0,
                                    y: 0,
                                    width: global.screen_width,
                                    height: PANEL_HEIGHT + SHADOW_HEIGHT });
        let backUpper = global.create_vertical_gradient(PANEL_TOP_COLOR,
                                                        PANEL_MIDDLE_COLOR);
        let backLower = global.create_vertical_gradient(PANEL_MIDDLE_COLOR,
                                                        PANEL_BOTTOM_COLOR);
        let shadow    = global.create_vertical_gradient(SHADOW_COLOR,
                                                        TRANSPARENT_COLOR);
        shadow.set_height(SHADOW_HEIGHT);
        backBox.append(backUpper, Big.BoxPackFlags.EXPAND);
        backBox.append(backLower, Big.BoxPackFlags.EXPAND);
        backBox.append(shadow,    Big.BoxPackFlags.NONE);
        group.add_actor(backBox);