GNOME Bugzilla – Bug 128167
Problems with background implementation for applets
Last modified: 2004-12-22 21:47:04 UTC
Filing a new bug for last issues related to bug #107617. There are a few problems I came across trying to implement transparency and color backgrounds for applets. 1) For pixmap backgrounds sometimes the panel is sending NULL pixmaps. This happens when the user switches from a color background to a pixmap for instance and also at startup. If I then move the applet along the panel, the pixmap is good. 2) Changing the background type (for instance from color to pixmap) seems to generate more than one background events. 3) Setting colors seems to work fine by doing a "gtk_widget_modify_bg (applet, GTK_STATE_NORMAL,color)" on the PanelApplet widget. It does not seem to work if I do it on the GtkLabel in test-bonobo-applet for instance. Something weird with Gtk that I don't understand here. 4) A side effect of 2) is that if I set the bg color of the PanelApplet widget, then the About and prefs dialogs will have the panel background color. 5) Using gdk_window_set_back_pixmap does not seem to work for pixmap backgrounds. To get this to work I had to do this (test-bonobo-applet): style = gtk_widget_get_style (GTK_WIDGET (&applet->base)); style->bg_pixmap[0] = pixmap; 6) Doing 5) for geyes placed the pixmap okay, but for test-bonobo-applet the pixmap was ofset a small amount, probably due to the handle. 7) Again setting the background pixmap of the PanelApplet widget as in 5) will also change the about and prefs dialogs. So for the most part, the panel seems to be working okay, we just need to figure out the proper way to do things on the applets side.
One other problem that might be useful: we should provide an easy way for the applet to know if the background is dark or light, so it can set a good color for the text. Like what nautilus does for icon labels on the desktop. Useful code for reference: eel-background.c (eel_background_is_dark), nautilus-icon-container.c (setup_label_gcs).
For (1), the panel isn't sending a NULL pixmap -- the problem is that the pixmap hasn't been fully created yet so when the applet looks up the pixmap ID, it can't find it. My patch on bug 157303 seems to fix this one. As for (3), I don't know if the label actually draws its own background, which might explain it. Setting the background on the parent of the label might work. (4) sounds like an error caused by modifying a shared style. gtk_widget_modify_bg() shouldn't cause a problem though. For (5), you should be copying the existing style, setting bg_pixmap[GTK_STATE_NORMAL] (remember to unref the old pixmap and ref the new one), and then call gtk_widget_set_style() to apply the new style. (7) also sounds like problems with shared styles.
Everything seems to work fine now. Closing.