158 lines
3.1 KiB
HTML
158 lines
3.1 KiB
HTML
<HTML
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><HEAD
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><TITLE
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>Client Applications</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.63
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"><LINK
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REL="HOME"
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TITLE="X Window System Architecture Overview HOWTO"
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HREF="index.html"><LINK
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REL="PREVIOUS"
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TITLE="Window Managers"
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HREF="window-managers.html"><LINK
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REL="NEXT"
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TITLE="Widget Libraries or toolkits"
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HREF="toolkits.html"></HEAD
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><BODY
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CLASS="SECT1"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>X Window System Architecture Overview HOWTO</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="window-managers.html"
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>Prev</A
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></TD
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WIDTH="80%"
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></TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="toolkits.html"
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>Next</A
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="SECT1"
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><H1
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CLASS="SECT1"
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><A
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NAME="CLIENT-APPLICATIONS"
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>5. Client Applications</A
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></H1
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><P
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>Let's focus on the client programs for a moment. Imagine you
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wanted to write a client program from scratch, using only the
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facilities provided by X. You'd quickly find that Xlib is pretty
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spartan, and that doing things like putting buttons on screen, text,
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or nice controls (scrollbars, radio boxes) for the users, is terribly
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complicated.</P
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><P
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>Luckily, someone else went to the trouble of programming these
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controls and giving them to us in a usable form; a library. These
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controls are usually known as "widgets" and of course, the library is
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a "widget library". Then I just have to call a function from this
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library with some parameters and have a button on-screen. Examples of
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widgets include menus, buttons, radio buttons, scrollbars, and
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canvases.</P
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><P
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>A "canvas" is an interesting kind of widget, because it's
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basically a sub-area within the client where i can draw
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stuff. Understandably, since I shouldn't use Xlib directly, because
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that would interfere with the widget library, the library itself gives
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a way to draw arbitrary graphics within the canvas widget.</P
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><P
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>Since the widget library is the one actually drawing the
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elements on-screen, as well as interpreting user's actions into input,
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the library used is largely responsible for each client's aspect and
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behavior. From a developer's point of view, a widget library also has
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a certain API (set of functions), and that might define which widget
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library i'll want to use.</P
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></DIV
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="window-managers.html"
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>Prev</A
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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>Home</A
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></TD
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><TD
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="toolkits.html"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Window Managers</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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> </TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Widget Libraries or toolkits</TD
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></TR
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></TABLE
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></DIV
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></BODY
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></HTML
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> |