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Retidy, removing align=left from headings and empty paragraphs

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James Gregory 2013-12-30 15:37:13 +11:00
commit a96a114403
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@ -1,5 +1,4 @@
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
@ -19,17 +18,21 @@
<center>
<table border="1">
<tr>
<td><a href="32-04.html">Previous</a></td>
<td>
<a href="32-04.html">Previous</a>
</td>
<td><a href="index.html">Table of Contents</a></td>
<td>
<a href="index.html">Table of Contents</a>
</td>
<td><a href="33-01.html">Next</a></td>
<td>
<a href="33-01.html">Next</a>
</td>
</tr>
</table>
</center>
<p><br /></p>
<p>The key to solving this problem lies in recalling that the VGA is designed to drive a monitor that sweeps the electron beam across the screen at exactly the same speed, no matter what mode the VGA is in. If the monitor always sweeps at the same speed, how does the VGA manage to display both 640 pixels across the screen (in high-resolution graphics modes) and 720 pixels across the screen (in 80-column text modes)? Good question indeed&mdash;and the answer is that the VGA has not one but <i>two</i> clocks on board, and one of those clocks is just sufficiently faster than the other clock so that an extra 80 (or 40) pixels can be displayed on each scan line.</p>
<p>In other words, there&rsquo;s a slow clock (about 25 MHz) that&rsquo;s usually used in graphics modes to get 640 (or 320) pixels on the screen during each scan line, and a second, fast clock (about 28 MHz) that&rsquo;s usually used in text modes to crank out 720 (or 360) pixels per scan line. In particular, 320x400 256-color mode uses the 25 MHz clock.</p>
@ -40,7 +43,7 @@
<p>Once all that&rsquo;s done, the VGA is in 360x480 mode, awaiting our every high-resolution 256-color graphics whim.</p>
<h4 align="left" id="Heading8">Accessing Display Memory in 360x480 256-Color Mode</h4>
<h4 id="Heading8">Accessing Display Memory in 360x480 256-Color Mode</h4>
<p>Setting up for 360x480 256-color mode proved to be quite a task. Is drawing in this mode going to be as difficult?</p>
@ -65,16 +68,20 @@
<p>There&rsquo;s more and better to come, though; in later chapters, we&rsquo;ll return to high-resolution 256-color programming in a big way, by exploring the tremendous potential of these modes for real time 2-D and 3-D animation.</p>
<p><br /></p>
<center>
<table border="1">
<tr>
<td><a href="32-04.html">Previous</a></td>
<td>
<a href="32-04.html">Previous</a>
</td>
<td><a href="index.html">Table of Contents</a></td>
<td>
<a href="index.html">Table of Contents</a>
</td>
<td><a href="33-01.html">Next</a></td>
<td>
<a href="33-01.html">Next</a>
</td>
</tr>
</table>
</center>