forked from AuroraMiddleware/gtk
104 lines
3.5 KiB
XML
104 lines
3.5 KiB
XML
<?xml version="1.0"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
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"http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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]>
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<refentry id="chap-input-handling">
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<refmeta>
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<refentrytitle>The GTK+ Input Handling Model</refentrytitle>
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<manvolnum>3</manvolnum>
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<refmiscinfo>GTK Library</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>The GTK+ Input Handling Model</refname>
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<refpurpose>
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GTK+ input handling in detail
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</refpurpose>
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</refnamediv>
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<refsect1 id="input-overview">
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<title>Overview of GTK+ input handling</title>
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<para>
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This chapter describes in detail how GTK+ handles input. If you are interested
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in what happens to translate a key press or mouse motion of the users into a
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change of a GTK+ widget, you should read this chapter. This knowledge will also
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be useful if you decide to implement your own widgets.
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</para>
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<refsect2>
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<title>Devices and events</title>
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<!-- input devices: master/slave, keyboard/pointer/touch -->
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<para>
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The most basic input devices that every computer user has interacted with are
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keyboards and mice; beyond these, GTK+ supports touchpads, touchscreens and
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more exotic input devices such as graphics tablets. Inside GTK+, every such
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input device is represented by a #GdkDevice object.
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</para>
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<para>
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To simplify dealing with the variability between these input devices, GTK+
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has a concept of master and slave devices. The concrete physical devices that
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have many different characteristics (mice may have 2 or 3 or 8 buttons,
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keyboards have different layouts and may or may not have a separate number
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block, etc) are represented as slave devices. Each slave device is
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associated with a virtual master device. Master devices always come in
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pointer/keyboard pairs - you can think of such a pair as a 'seat'.
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</para>
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<para>
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GTK+ widgets generally deal with the master devices, and thus can be used
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with any pointing device or keyboard.
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</para>
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<!-- input events: button, touch, key, motion, etc -->
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<para>
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When a user interacts with an input device (e.g. moves a mouse or presses
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a key on the keyboard), GTK+ receives events from the windowing system.
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These are typically directed at a specific window - for pointer events,
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the window under the pointer (grabs complicate this), for keyboard events,
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the window with the keyboard focus.
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</para>
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<para>
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GDK translates these raw windowing system events into #GdkEvents.
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Typical input events are:
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<simplelist>
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<member>GdkEventButton</member>
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<member>GdkEventMotion</member>
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<member>GdkEventCrossing</member>
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<member>GdkEventKey</member>
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<member>GdkEventFocus</member>
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<member>GdkEventTouch</member>
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</simplelist>
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</para>
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<para>
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When GTK+ is initialized, it sets up an event handler function with
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gdk_event_handler_set(), which receives all of these input events
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(as well as others, for instance window management related events).
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</para>
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</refsect2>
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<refsect2>
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<title>Event propagation</title>
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<!-- capture/bubble, event handler chain, event controllers -->
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<!-- grabs -->
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</refsect2>
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<refsect2>
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<title>Keyboard input</title>
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<!-- focus, tab, directional navigation -->
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<!-- mnemonics, accelerators, bindings -->
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</refsect2>
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<refsect2>
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<title>Gestures</title>
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<!-- touch sequences, states, anything else -->
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</refsect2>
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</refsect1>
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</refentry>
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