Problem displaying image with alpha channel in a transparent window
Hi, I'm trying to write a program to display a picture with full transparency in its own window (without border), using Composite extension (ARGB colormap and visual). I've written a couple of programs doing this using Xlib alone or with libXrender. Using GTK+ to do the same seems easy since programs like cairo-clock [1] are able to draw window with non rectangular shape and full transparency. But after many hours, and many version of my GTK+ demonstration program, I'm still wandering how to display a GdkPixBuf with alpha layer in a GtkWindow without any background or artefact. So here are my little demonstration programs - test-gdkpixbuf.c : This program does the following: - looks up the RGBA colormap with gdk_screen_get_rgba_colormap() - installs the colormap with gtk_widget_set_default_colormap() - creates a GdkPixbuf with gdk_pixbuf_new_from_file() - creates a GtkWindow - sets the widget as GTK_APP_PAINTABLE with gtk_widget_set_app_paintable() - disables double buffering with gtk_widget_set_double_buffered() - in the realize signal handler, it removes any background pixmap using gdk_window_set_back_pixmap() - in the expose event handler, it draws the GdkPixBuf using gdk_draw_pixbuf() At first, it seems to work, but in fact, as soon as you move the picture using CTRL+Button 1, you will realize the problem: the window's background is a snapshot of the root window (see post from Matt Hoosier [2]), and is fixed for the window's lifetime. At least, the content of the picture is well composited with the background, but it's not the full transparency I'm looking for. See: - test-gdkpixbuf.png - test-gdkpixbuf-bg.patch: Apply the patch on top of test-gdkpixbuf.c to create test-gdkpixbuf-background.c This patch set a pixmap as a background, and draw nothing on the window. Only the realize signal and expose event handlers are modified: - realize signal handler creates a new pixmap with gdk_pixmap_new(), writes the content of the GdkPixBuf with gdk_draw_pixbuf() and then install the background with gdk_window_set_back_pixmap(). - expose event handler only call to gdk_window_clear() With this version, the background is really transparent, but many artefacts are visibles: the background is corrupted. On some configuration, I'm even able to see some other pixmap content as background, strange ! See: - test-gdkpixbuf-background.png Note: those were tested with Gtk+ 2.10 and Gtk+ 2.12. So I'm stuck. Either I'm always getting a unwanted background (filled with solid color or a root window snapshot) or I'm getting a corrupted image. I've tried to: - use a GtkImage widget made from the GdkPixBuf - use a GtkDrawingArea in the main window and draw into it - use gdk_draw_rgb_32_image() instead of gdk_draw_pixbuf() - paint with gdk_cairo_set_source_pixbuf() I'm always getting an image composited with the window background. Could someone provide me a link, a tips, or something to help me. Thanks. [1] http://macslow.thepimp.net/?page_id=23 [2] http://mail.gnome.org/archives/gtk-list/2006-October/msg00246.html -- Yann Droneaud [EMAIL PROTECTED] ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
save image and display image from postgresql
i am very new to gtk programming. I am sorry for this beginner questions, but after asking google i fail the get the right answer. I hope this mailing list will help me. anyone can please point me a way on how to save image to postgresql database and display the image again. thank you ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: Screenshot of a GtkWindow
On Wed, 2008-07-23 at 13:32 +0200, Gabriele Greco wrote: I need to make a screenshot of a GtkWindow from the program itself We used code from gnome-utils's gnome-screenshot/gnome-screenshot.c and gnome-screenshot/screenshot-utils.c to add a capture capability to java-gnome (we wanted window decorations and all, not just the GdkWindow behind something; the drop shadows are nice too). We use this when generating our API documentation, for example: http://java-gnome.sourceforge.net/4.0/doc/api/org/gnome/gtk/AboutDialog.html I certainly appreciate now that gathering a screenshot (window borders and all) is very tricky and involves some voodoo mucking about with X. I am quite thankful that such code existed to be reused. Unfortunately it's not a library as yet, so we had to copy it manually. Our import of it was a bit hack-and-slash, but our versions of the above two files, as gnome_screenshot_capture.c and gnome_screenshot_utils.c, can be found in a checkout of a java-gnome in the src/jni/ directory, ie http://research.operationaldynamics.com/bzr/java-gnome/mainline/src/jni/ AfC Sydney -- Andrew Frederick Cowie Operational Dynamics is an operations and engineering consultancy focusing on IT strategy, organizational architecture, systems review, and effective procedures for change management. We actively carry out research and development in these areas on behalf of our clients, and enable successful use of open source in their mission critical enterprises, worldwide. http://www.operationaldynamics.com/ Sydney New York Toronto London ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: Screenshot of a GtkWindow
2008/7/23 Gabriele Greco [EMAIL PROTECTED]: I need to make a screenshot of a GtkWindow from the program itself, there is a crossplatform way to do it (with 2.12 stable)? I thought about copying the window-window drawable to a gdkpixbuf, but maybe there is a cleaner way No, that's what you need, as far as I know: http://library.gnome.org/devel/gdk/stable/gdk-Pixbufs.html#gdk-pixbuf-get-from-drawable John ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
Re: save image and display image from postgresql
2008/7/23 paragasu [EMAIL PROTECTED]: i am very new to gtk programming. I am sorry for this beginner questions, but after asking google i fail the get the right answer. I hope this mailing list will help me. anyone can please point me a way on how to save image to postgresql database and display the image again. To save an image in Postgres, you can sither use a blob type, a binary string, or convert your picture to an ASCII string (in base64 for example) and use a normal string field. Loading it back is a matter of doing the reverse. As to display the image in GTK+, you can use gtk_image_new_from_pixbuf() along with a GdkPixbufLoader. This is what's done in Libgnomedb (for example in http://svn.gnome.org/viewvc/libgnomedb/trunk/libgnomedb/plugins/common-pict.c?revision=1686view=markup). Regards, Vivien ___ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
