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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>The Be Book - System Overview - The Interface Kit</title><link rel="stylesheet" href="be_book.css" type="text/css" media="all" /><link rel="shortcut icon" type="image/vnd.microsoft.icon" href="./images/favicon.ico" /><!--[if IE]>
<link rel="stylesheet" type="text/css" href="be_book_ie.css" />
<![endif]--><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /><meta name="keywords" content="Access, BeOS, BeBook, API" /><link rel="start" href="index.html" title="The Be Book" /><link rel="up" href="TheInterfaceKit_Overview.html" title="The Interface Kit" /><link rel="prev" href="BDragger_Overview.html" title="BDragger" /><link rel="next" href="BListItem_Overview.html" title="BListItem" /></head><body><div id="header"><div id="headerT"><div id="headerTL"><a accesskey="p" href="BDragger_Overview.html" title="BDragger"><img src="./images/navigation/prev.png" alt="Prev" /></a> <a accesskey="u" href="TheInterfaceKit_Overview.html" title="The Interface Kit"><img src="./images/navigation/up.png" alt="Up" /></a> <a accesskey="n" href="BListItem_Overview.html" title="BListItem"><img src="./images/navigation/next.png" alt="Next" /></a></div><div id="headerTR"><div id="navigpeople"><a href="http://www.haiku-os.org"><img src="./images/People_24.png" alt="haiku-os.org" title="Visit The Haiku Website" /></a></div><div class="navighome" title="Home"><a accesskey="h" href="index.html"><img src="./images/navigation/home.png" alt="Home" /></a></div><div class="navigboxed" id="navigindex"><a accesskey="i" href="ClassIndex.html" title="Index">I</a></div><div class="navigboxed" id="naviglang" title="English">en</div></div><div id="headerTC">The Be Book - System Overview - The Interface Kit</div></div><div id="headerB">Prev: <a href="BDragger_Overview.html">BDragger</a>  Up: <a href="TheInterfaceKit_Overview.html">The Interface Kit</a>  Next: <a href="BListItem_Overview.html">BListItem</a></div><hr /></div><div class="section"><div xmlns="" xmlns:d="http://docbook.org/ns/docbook" class="titlepage"><div><div xmlns:d="http://docbook.org/ns/docbook"><h2 xmlns="http://www.w3.org/1999/xhtml" class="title"><a id="BFont_Overview"></a>BFont</h2></div></div></div><a id="id548211" class="indexterm"></a><p>
A <a class="link" href="BFont.html" title="BFont"><code class="classname">BFont</code></a>
object records a set of font attributes, such as the font's
family, style, size, and so on. You can set most of these attributes to
modify the font and then use the object to set the font of a
<a class="link" href="BView.html" title="BView"><code class="classname">BView</code></a>. A
<a class="link" href="BView.html" title="BView"><code class="classname">BView</code></a>'s
font determines how the characters that it draws (with the
<a class="link" href="BView.html#BView_DrawString" title="DrawString()"><code class="methodname">DrawString()</code></a> and
<a class="link" href="BView.html#BView_DrawChar" title="DrawChar()"><code class="methodname">DrawChar()</code></a>
functions) will be rendered.
</p><p>
A <a class="link" href="BFont.html" title="BFont"><code class="classname">BFont</code></a>
object can perform calculations based on the metrics of the
particular font it represents. For example, it can tell you how much
screen real estate it needs to display a given line of text.
</p><p>
To find which fonts are currently installed on the system, call
<a class="link" href="TheInterfaceKit_Functions.html#get_font_family" title="get_font_family(), count_font_families(), get_font_style(), count_font_styles()"><code class="function">get_font_family()</code></a> and
<a class="link" href="TheInterfaceKit_Functions.html#get_font_style"><code class="function">get_font_style()</code></a>.
</p><div class="section"><div xmlns="" xmlns:d="http://docbook.org/ns/docbook" class="titlepage"><div><hr /><div xmlns:d="http://docbook.org/ns/docbook"><h3 xmlns="http://www.w3.org/1999/xhtml" class="title"><a id="id548304"></a>Using a BFont Object</h3></div></div></div><p>
A <a class="link" href="BFont.html" title="BFont"><code class="classname">BFont</code></a>
object by itself doesn't do anything. To be able to draw
characters in the font, the object must be passed to
<a class="link" href="BView.html" title="BView"><code class="classname">BView</code></a>'s
<a class="link" href="BView.html#BView_SetFont" title="SetFont(), GetFont()"><code class="methodname">SetFont()</code></a>
function (or
<a class="link" href="BTextView.html" title="BTextView"><code class="classname">BTextView</code></a>'s
<a class="link" href="BTextView.html#BTextView_SetFontAndColor" title="SetFontAndColor(), GetFontAndColor()"><code class="methodname">SetFontAndColor()</code></a>).
</p><p>
A <a class="link" href="BFont.html" title="BFont"><code class="classname">BFont</code></a>
object is always a full representation of a font; all attributes
are always set. However, you can choose which of these attributes will
modify a
<a class="link" href="BView.html" title="BView"><code class="classname">BView</code></a>'s
current font by passing a mask to
<a class="link" href="BView.html#BView_SetFont" title="SetFont(), GetFont()"><code class="methodname">SetFont()</code></a> (or
<a class="link" href="BTextView.html" title="BTextView"><code class="classname">BTextView</code></a>'s
<a class="link" href="BTextView.html#BTextView_SetFontAndColor" title="SetFontAndColor(), GetFontAndColor()"><code class="methodname">SetFontAndColor()</code></a>).
For example, this code sets only the font shear and
spacing:
</p><pre class="programlisting example cpp"><code class="classname">BFont</code> <code class="varname">font</code>;
<code class="varname">font</code>.<code class="methodname">SetShear</code>(60.0);
<code class="varname">font</code>.<code class="methodname">SetSpacing</code>(<code class="constant">B_CHAR_SPACING</code>);
<code class="varname">myView</code>-&gt;<code class="methodname">SetFont</code>(&amp;<code class="varname">font</code>, <code class="constant">B_FONT_SHEAR</code> | <code class="constant">B_FONT_SPACING</code>);</pre><p>
Alternatively, the <code class="classname">BView</code>'s font could have been modified and reset as
follows:
</p><pre class="programlisting example cpp"><code class="classname">BFont</code> <code class="varname">font</code>;
<code class="varname">myView</code>-&gt;<code class="methodname">GetFont</code>(&amp;<code class="varname">font</code>);
<code class="varname">font</code>.<code class="methodname">SetShear</code>(60.0);
<code class="varname">font</code>.<code class="methodname">SetSpacing</code>(<code class="constant">B_CHAR_SPACING</code>);
<code class="varname">myView</code>-&gt;<code class="methodname">SetFont</code>(&amp;<code class="varname">font</code>);</pre><p>
Notice that we had to explicitly reset the view's font (through
<a class="link" href="BView.html#BView_SetFont" title="SetFont(), GetFont()"><code class="methodname">SetFont()</code></a>)
after changing the font's attributes.
</p></div><div class="section"><div xmlns="" xmlns:d="http://docbook.org/ns/docbook" class="titlepage"><div><hr /><div xmlns:d="http://docbook.org/ns/docbook"><h3 xmlns="http://www.w3.org/1999/xhtml" class="title"><a id="id548523"></a>System Fonts</h3></div></div></div><p>
The Interface Kit constructs three
<a class="link" href="BFont.html" title="BFont"><code class="classname">BFont</code></a> objects (plain, bold, and
fixed)for each application when the application starts up. The values of
these fonts are set by the user through the FontPanel preferences
application. You can get to these objects through global pointers :
</p><table class="variablelist constants"><thead><tr><th>Constant</th><th>Description</th></tr></thead><tbody><tr><td><p><span class="term">const <span class="type">BFont*</span> <code class="varname">be_plain_font</code></span></p></td><td><p>
The font that's used to display most gadgets in the user interface,
such as check box labels and menu items. All
<a class="link" href="BControl.html" title="BControl"><code class="classname">BControl</code></a>
objects use this font.
</p></td></tr><tr><td><p><span class="term">const <span class="type">BFont*</span> <code class="varname">be_bold_font</code></span></p></td><td><p>
The font that's used to display window titles and
<a class="link" href="BBox.html" title="BBox"><code class="classname">BBox</code></a> labels.
</p></td></tr><tr><td><p><span class="term">const <span class="type">BFont*</span> <code class="varname">be_fixed_font</code></span></p></td><td><p>
The font that's used to display fixed-width characters.
</p></td></tr></tbody></table><p>
The global fonts are const objects that can't be modified by your
application, and aren't updated by the system, even if the user changes
their definitions while your app is running. The new values take effect
the next time your application is launched.
</p><p>
To use a system font in a view, simply call
<a class="link" href="BView.html#BView_SetFont" title="SetFont(), GetFont()"><code class="methodname">SetFont()</code></a>:
</p><pre class="programlisting example cpp"><code class="varname">myView</code>-&gt;<code class="methodname">SetFont</code>(<code class="varname">be_bold_font</code>);</pre><p>
If you want to modify some attributes of a system font, you have to make
a copy of it first (and modify the copy):
</p><pre class="programlisting example cpp"><code class="classname">BFont</code> <code class="varname">font</code>(<code class="varname">be_bold_font</code>);
<code class="varname">font</code>.<code class="methodname">SetSize</code>(13.0);
<code class="varname">myView</code>-&gt;<code class="methodname">SetFont</code>(&amp;<code class="varname">font</code>);</pre><p>
Applications should respect the user's choices and base all font choices
on these three system fonts, rather than hard-code font names into the
application. You should not try to predict the fonts that will be
installed on the user's machine.
</p></div></div><div id="footer"><hr /><div id="footerT">Prev: <a href="BDragger_Overview.html">BDragger</a>  Up: <a href="TheInterfaceKit_Overview.html">The Interface Kit</a>  Next: <a href="BListItem_Overview.html">BListItem</a> </div><div id="footerB"><div id="footerBL"><a href="BDragger_Overview.html" title="BDragger"><img src="./images/navigation/prev.png" alt="Prev" /></a> <a href="TheInterfaceKit_Overview.html" title="The Interface Kit"><img src="./images/navigation/up.png" alt="Up" /></a> <a href="BListItem_Overview.html" title="BListItem"><img src="./images/navigation/next.png" alt="Next" /></a></div><div id="footerBR"><div><a href="http://www.haiku-os.org"><img src="./images/People_24.png" alt="haiku-os.org" title="Visit The Haiku Website" /></a></div><div class="navighome" title="Home"><a accesskey="h" href="index.html"><img src="./images/navigation/home.png" alt="Home" /></a></div></div><div id="footerBC"><a href="http://www.access-company.com/home.html" title="ACCESS Co."><img alt="Access Company" src="./images/access_logo.png" /></a></div></div></div><div id="licenseFooter"><div id="licenseFooterBL"><a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/" title="Creative Commons License"><img alt="Creative Commons License" style="border-width:0" src="https://licensebuttons.net/l/by-nc-nd/3.0/88x31.png" /></a></div><div id="licenseFooterBR"><a href="./LegalNotice.html">Legal Notice</a></div><div id="licenseFooterBC"><span id="licenseText">This work is licensed under a
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