<html>
<body>
<div style="font-family: Verdana, Arial, Helvetica, Sans-Serif;">
<table bgcolor="#f9f3c9" width="100%" cellpadding="8" style="border: 1px #c9c399 solid;">
<tr>
<td>
This is an automatically generated e-mail. To reply, visit:
<a href="http://svn.reviewboard.kde.org/r/6109/">http://svn.reviewboard.kde.org/r/6109/</a>
</td>
</tr>
</table>
<br />
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<p style="margin-top: 0;">On December 13th, 2010, 8:21 p.m., <b>Torsten Rahn</b> wrote:</p>
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<table width="100%" border="0" bgcolor="white" style="border: 1px solid #C0C0C0; border-collapse: collapse; margin: 2px padding: 2px;">
<thead>
<tr>
<th colspan="4" bgcolor="#F0F0F0" style="border-bottom: 1px solid #C0C0C0; font-size: 9pt; padding: 4px 8px; text-align: left;">
<a href="http://svn.reviewboard.kde.org/r/6109/diff/1/?file=42509#file42509line85" style="color: black; font-weight: bold; text-decoration: underline;">/trunk/KDE/kdeedu/marble/src/lib/FastMercatorTextureMapper.cpp</a>
<span style="font-weight: normal;">
(Diff revision 1)
</span>
</th>
</tr>
</thead>
<tbody style="background-color: #e4d9cb; padding: 4px 8px; text-align: center;">
<tr>
<td colspan="2"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "></pre></td>
<td colspan="2"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">void FastMercatorTextureMapper::mapTexture( ViewParams *viewParams )</pre></td>
</tr>
</tbody>
<tbody>
<tr>
<th bgcolor="#b1ebb0" style="border-right: 1px solid #C0C0C0;" align="right"><font size="2"></font></th>
<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "></pre></td>
<th bgcolor="#b1ebb0" style="border-left: 1px solid #C0C0C0; border-right: 1px solid #C0C0C0;" align="right"><font size="2">85</font></th>
<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">painter</span><span class="p">.</span><span class="n">drawImage</span><span class="p">(</span> <span class="n">rect</span><span class="p">,</span> <span class="o">*</span><span class="n">tile</span><span class="o">-></span><span class="n">resultTile</span><span class="p">()</span> <span class="p">);</span></pre></td>
</tr>
</tbody>
</table>
<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">This is very expensive.
- On one hand it would improve performance dramatically if you'd cache the scaled images.
- On one hand you're using QImage for scaling which is slower than QPixmap.
So ideally you'd create pixmaps from the original QImage tiles and then store the pixmaps in a hash which maps a key that consists of the tile_id + targetsize and you'd map that to the pixmap. This should improve performance dramatically.
</pre>
</blockquote>
</blockquote>
<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">I haven't tried using a QPixmap but your suggestion sounds promising.
As for the cache, I figure that each tile would need to be cached up to four times. The reason is that the target tile size probably oscillates by one pixel in each dimenstion when moving the map. Perhaps this could be prevented using QRectF.</pre>
<br />
<p>- Bernhard</p>
<br />
<p>On December 12th, 2010, 11:11 p.m., Bernhard Beschow wrote:</p>
<table bgcolor="#fefadf" width="100%" cellspacing="0" cellpadding="8" style="background-image: url('http://svn.reviewboard.kde.orgrb/images/review_request_box_top_bg.png'); background-position: left top; background-repeat: repeat-x; border: 1px black solid;">
<tr>
<td>
<div>Review request for marble.</div>
<div>By Bernhard Beschow.</div>
<p style="color: grey;"><i>Updated 2010-12-12 23:11:04</i></p>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: 1px solid #b8b5a0">
<tr>
<td>
<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">This patch introduces an optimized code path for the case that both the tile projection and the map projection are of type Mercator. In this very common case, the tiles can be scaled rather than reprojected, promising a significant speedup. Moreover, it seems to avoid crashes in high zoom levels on the N900.</pre>
</td>
</tr>
</table>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: 1px solid #b8b5a0">
<tr>
<td>
<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">I have measured speedups of up to 2.7 on my system. This seems to depend on the QImage::Format, so format conversion should be avoided in a future version if possible.
The image quality is roughly of outline quality when a discrete zoom level isn't hit.</pre>
</td>
</tr>
</table>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
<ul style="margin-left: 3em; padding-left: 0;">
<li>/trunk/KDE/kdeedu/marble/src/lib/AbstractScanlineTextureMapper.h <span style="color: grey">(1205882)</span></li>
<li>/trunk/KDE/kdeedu/marble/src/lib/AbstractScanlineTextureMapper.cpp <span style="color: grey">(1205882)</span></li>
<li>/trunk/KDE/kdeedu/marble/src/lib/CMakeLists.txt <span style="color: grey">(1205882)</span></li>
<li>/trunk/KDE/kdeedu/marble/src/lib/FastMercatorTextureMapper.h <span style="color: grey">(PRE-CREATION)</span></li>
<li>/trunk/KDE/kdeedu/marble/src/lib/FastMercatorTextureMapper.cpp <span style="color: grey">(PRE-CREATION)</span></li>
<li>/trunk/KDE/kdeedu/marble/src/lib/TextureLayer.cpp <span style="color: grey">(1205882)</span></li>
</ul>
<p><a href="http://svn.reviewboard.kde.org/r/6109/diff/" style="margin-left: 3em;">View Diff</a></p>
</td>
</tr>
</table>
</div>
</body>
</html>