forked from AuroraMiddleware/gtk
67 lines
2.9 KiB
Markdown
67 lines
2.9 KiB
Markdown
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# GTK for the X Window System {#gtk-x11}
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On UNIX, the X backend is enabled by default, so you don't need to do anything
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special when compiling it, and everything should "just work."
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To mix low-level Xlib routines into a GTK program, see
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[GDK X Window System interaction](#gdk-X-Window-System-Interaction)
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in the GDK manual.
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## X11-specific environment variables {#x11-envar}
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:
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The X11 GDK backend can be influenced with some additional environment variables.
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### GDK_SYNCHRONIZE
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If set, GDK makes all X requests synchronously. This is a useful
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option for debugging, but it will slow down the performance considerably.
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### GDK_SCALE
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Must be set to an integer, typically 2. If set, GDK will scale all
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windows by the specified factor. Scaled output is meant to be used on
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high-dpi displays. Normally, GDK will pick up a suitable scale factor
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for each monitor from the display system. This environment variable
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allows to override that.
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## Understanding the X11 architecture {#gtk-X11-arch}
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People coming from a Windows or MacOS background often find certain
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aspects of the X Window System surprising. This section introduces
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some basic X concepts at a high level. For more details, the book most
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people use is called the "Xlib Programming Manual" by Adrian Nye; this
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book is volume one in the O'Reilly X Window System series.
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Standards are another important resource if you're poking in low-level
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X11 details, in particular the ICCCM and the Extended Window Manager
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Hints specifications. [freedesktop.org](http://www.freedesktop.org/standards/)
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has links to many relevant specifications.
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The GDK manual covers [using Xlib in a GTK program](#gdk-X-Window-System-Interaction).
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### Server, client, window manager
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Other window systems typically put all their functionality in the
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application itself. With X, each application involves three different
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programs: the _X server_, the application (called a _client_ because
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it's a client of the X server), and a special client called the
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_window manager_.
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The X server is in charge of managing resources, processing drawing
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requests, and dispatching events such as keyboard and mouse events to
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interested applications. So client applications can ask the X server
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to create a window, draw a circle, or move windows around.
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The window manager is in charge of rendering the frame or borders
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around windows; it also has final say on the size of each window,
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and window states such as minimized, maximized, and so forth.
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On Windows and MacOS the application handles most of this.
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On X11, if you wish to modify the window's state, or change its frame,
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you must ask the window manager to do so on your behalf, using an
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established [convention](http://www.freedesktop.org/standards/).
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GTK has functions for asking the window manager to do various things;
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see for example gtk_window_minimize() or gtk_window_maximize().
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Keep in mind that most window managers *will* ignore certain requests
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from time to time, in the interests of good user interface.
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