What is the difference between GtkImage, GdkImage, GdkPixmap and GdkBitmap?
Hi all, I don't know the difference between these types(GtkImage, GdkImage, GdkPixmap and GdkBitmap) although I have read the GTK and GDK API Reference Manual. Suppose I want to create a new RGB bitmap with 3 x 3 in size and I want to set all pixel values to be 0. After clicking a button, all pixel values will change to 255. Which one of the above types should I use? Should GdkImage be used as I can see there are functions to change the pixel values (gdk_image_put_pixel) in this type, but not in other types. But when I use this type to create a bitmap, this function (gdk_image_new) is used. There is a parameter with the type (GdkVisual*) which I don't know how to set/initialize. When I use gdk_visual_get_system (void) to initialize the type of GdkVisual*, I can compile it. But when I run it, there are some errors as below and the bitmap cannot be generated. example_font_selector[8794]: GLIB CRITICAL ** GLib-GObject - gtype.c:2217: initialization assertion failed, use IA__g_type_init() prior to this function example_font_selector[8794]: GLIB CRITICAL ** Gdk - gdk_screen_get_system_visual: assertion `GDK_IS_SCREEN (screen)' failed example_font_selector[8794]: GLIB CRITICAL ** GLib-GObject - gtype.c:2217: initialization assertion failed, use IA__g_type_init() prior to this function example_font_selector[8794]: GLIB CRITICAL ** Gdk - gdk_visual_get_screen: assertion `GDK_IS_VISUAL (visual)' failed example_font_selector[8794]: GLIB CRITICAL ** Gdk - _gdk_image_new_for_depth: assertion `visual || depth != -1' failed Thank you for your kind attention. Regards, Hung ___ maemo-developers mailing list maemo-developers@maemo.org https://lists.maemo.org/mailman/listinfo/maemo-developers
Re: What is the difference between GtkImage, GdkImage, GdkPixmap and GdkBitmap?
On Fri, 25 Jan 2008, LIU Chun Hung wrote: example_font_selector[8794]: GLIB CRITICAL ** GLib-GObject - gtype.c:2217: initialization assertion failed, use IA__g_type_init() prior to this function You need to initialize the glib type system before using the gtk/glib functions. Put g_type_init(); somewhere in your code before using any other functions. -- Kaj-Michael Lang ___ maemo-developers mailing list maemo-developers@maemo.org https://lists.maemo.org/mailman/listinfo/maemo-developers
Re: What is the difference between GtkImage, GdkImage, GdkPixmap and GdkBitmap?
Suppose I want to create a new RGB bitmap with 3 x 3 in size and I want to set all pixel values to be 0. After clicking a button, all pixel values will change to 255. Which one of the above types should I use? Should GdkImage be used as I can see there are functions to change the pixel values (gdk_image_put_pixel) in this type, but not in other types. You would use a GdkImage to manipulate the pixels, and a GtkImage to display it. Yes, it is exactly what I want to do, but I don't know how to do it. Can anyone guide me to do it? The first thing to do is to create a new GdkImage. I use this function, gdk_image_new(GdkImageType type, GdkVisual *visual, gint width, gint height) to create. type = GDK_IMAGE_SHARED; width = 3; height = 3; visual = ? For the GdkVisual*, I don't know how to initialize it. I have tried with different methods as below, but errors will occur when I run the program. visual = gdk_visual_get_system(); example_font_selector[11303]: GLIB CRITICAL ** Gdk - gdk_screen_get_system_visual: assertion `GDK_IS_SCREEN (screen)' failed visual = gdk_visual_get_best(); qemu: uncaught target signal 11 (Segmentation fault) - exiting visual = gdk_visual_get_best_with_depth(8); qemu: uncaught target signal 11 (Segmentation fault) - exiting visual = gdk_visual_get_best_with_type(GDK_VISUAL_TRUE_COLOR); qemu: uncaught target signal 11 (Segmentation fault) - exiting visual = gdk_visual_get_best_with_both(8, GDK_VISUAL_TRUE_COLOR); qemu: uncaught target signal 11 (Segmentation fault) - exiting In fact, which one should I use? ___ maemo-developers mailing list maemo-developers@maemo.org https://lists.maemo.org/mailman/listinfo/maemo-developers
Re: What is the difference between GtkImage, GdkImage, GdkPixmap and GdkBitmap?
On Fri, Jan 25, 2008 at 05:36:43PM +0800, LIU Chun Hung wrote: I don't know the difference between these types(GtkImage, GdkImage, GdkPixmap and GdkBitmap) although I have read the GTK and GDK API Reference Manual. Disclaimer: IANAEGD (I Am Not An Experienced Gtk+ Developer). GtkImage is a widget that you can stick into a window to display image data (stored in a GdkImage). GtkPixmap is a widget that you can stick into a window to display image data (stored in a GdkPixmap). The difference between an image and a pixmap is that the image is stored on the client and transfers pixel data to the X server on every redraw request, while a pixmap is stored on the X server. Usually this is more efficient, but if you plan to modify the image, you cannot use pixmaps. A GdkBitmap is a *bit* map: it's a 1-bit per pixel image, usually used for things like transparency maps. Suppose I want to create a new RGB bitmap with 3 x 3 in size and I want to set all pixel values to be 0. After clicking a button, all pixel values will change to 255. Which one of the above types should I use? Should GdkImage be used as I can see there are functions to change the pixel values (gdk_image_put_pixel) in this type, but not in other types. You would use a GdkImage to manipulate the pixels, and a GtkImage to display it. Marius Gedminas -- All programs evolve until they can send email. -- Richard Letts Except Microsoft Exchange. -- Art (found on the Snort web site) signature.asc Description: Digital signature ___ maemo-developers mailing list maemo-developers@maemo.org https://lists.maemo.org/mailman/listinfo/maemo-developers
