The Daily WTF: Curious Perversions in Information Technology

2009-04-30 Reply Admin

Sick! Sick! Sick!

2009-04-30 Reply Admin

noscript is not just useful for paranoids who seriously think the browser is going to take over their computer and empty their bank accounts (as opposed to redirecting their clicks to fraudulently pump up a third party's ad revenue). I know a lot of people who use it just because they're sick of looking at stupid rollover ads.

2009-04-30 Reply Admin

Calli Arcale:
noscript is not just useful for paranoids who seriously think the browser is going to take over their computer and empty their bank accounts (as opposed to redirecting their clicks to fraudulently pump up a third party's ad revenue). I know a lot of people who use it just because they're sick of looking at stupid rollover ads.

Noscript is also good at preventing drive-by downloads/malware installation/etc. All it takes is one wrong click to get the crap onto your machine. Even legitimate adservers sometimes serve malware javascript.

Noscript also highlights the general illiteracy that web developers have - there are websites you browse that are literally completely functional without javascript (I didn't realize Apple's website was not "allowed" - it just kept working), and websites where clicking a link requires javascript to move one page.

2009-04-30 Reply Admin

Lars:
It doesn't even zoom!
I had the same thought -- it needs to zoom!
All you'd have to do is, in the "bisqwit-mandelbrot-slot" template, make each element an that passes the boundaries of the cell back to the server as URL parameters.

But without allowing any server-side programming, I don't think there's any way for the XSLT stylesheet to access those URL parameters. :-S

Sure you could do it with javascript, but that would be cheating...

OK, I did it with server-side PHP to put the URL parameters into the XML data. Here's mandelbrot.php (incidentally my first php script, I think):

<?php
header("Content-type: text/xml");
echo '<?xml version="1.0" encoding="UTF-8"?>

<!-- XSLT Mandelbrot
    Written by Joel Yliluoma, http://iki.fi/bisqwit/
    Copyright 1992,2007
    Modifiied by Lars Huttar, http://www.huttar.net/
      to enable zooming in
-->

<?xml-stylesheet type="text/xsl" href="mandelbrot.xsl"?>
<fractal>
    <scale>100</scale>
    <y>';
if ($_GET['ymin'] === NULL) { echo '
      <min>-120</min>
      <max>120</max>
      <step>3.9</step>
';} else {
$ymin =  $_GET['ymin'];
$ymax = $_GET['ymax'];
$step = ($ymax - $ymin) / 61.5;
    echo '
        <min>' . $ymin . '</min>
        <max>' . $ymax . '</max>
        <step>' . $step . '</step>
';}
echo '
    </y>
    <x>';
        if ($_GET['xmin'] === NULL) { echo '
      <min>-203</min>
      <max>100</max>
      <step>1.4</step>
        ';} else {
        $xmin =  $_GET['xmin'];
        $xmax = $_GET['xmax'];
        $step = ($xmax - $xmin) / 216.4;
        echo '
        <min>' . $xmin . '</min>
        <max>' . $xmax . '</max>
        <step>' . $step . '</step>
        ';}
        echo '
    </x>
    <maxiter>28</maxiter>
    
    <background>#500</background>
    
    <magnitude value="0"><symbol>░</symbol><color>#115</color></magnitude>
    <magnitude value="1"><symbol>░</symbol><color>#228</color></magnitude>
    <magnitude value="2"><symbol>░</symbol><color>#22B</color></magnitude>
    <magnitude value="3"><symbol>░</symbol><color>#33D</color></magnitude>
    <magnitude value="4"><symbol>░</symbol><color>#44F</color></magnitude>
    <magnitude value="5"><symbol>▒</symbol><color>#55C</color></magnitude>
    <magnitude value="6"><symbol>▒</symbol><color>#55D</color></magnitude>
    <magnitude value="7"><symbol>▒</symbol><color>#55E</color></magnitude>
    <magnitude value="8"><symbol>▓</symbol><color>#55F</color></magnitude>
    <magnitude value="9"><symbol>▓</symbol><color>#66F</color></magnitude>
    <magnitude value="10"><symbol>▓</symbol><color>#77F</color></magnitude>
    <magnitude value="11"><symbol>▓</symbol><color>#88F</color></magnitude>
    <magnitude value="12"><symbol>█</symbol><color>#88F</color></magnitude>
    <magnitude value="13"><symbol>▓</symbol><color>#99F</color></magnitude>
    <magnitude value="14"><symbol>█</symbol><color>#99F</color></magnitude>
    <magnitude value="15"><symbol>▓</symbol><color>#AAF</color></magnitude>
    <magnitude value="16"><symbol>█</symbol><color>#AAF</color></magnitude>
    <magnitude value="17"><symbol>▓</symbol><color>#BBF</color></magnitude>
    <magnitude value="18"><symbol>█</symbol><color>#BBF</color></magnitude>
    <magnitude value="19"><symbol>▓</symbol><color>#CCF</color></magnitude>
    <magnitude value="20"><symbol>█</symbol><color>#CCF</color></magnitude>
    <magnitude value="21"><symbol>▓</symbol><color>#DDF</color></magnitude>
    <magnitude value="22"><symbol>█</symbol><color>#DDF</color></magnitude>
    <magnitude value="23"><symbol>▓</symbol><color>#EEF</color></magnitude>
    <magnitude value="24"><symbol>█</symbol><color>#EEF</color></magnitude>
    <magnitude value="25"><symbol>▓</symbol><color>#FFF</color></magnitude>
    <magnitude value="26"><symbol>█</symbol><color>#FFF</color></magnitude>
    <magnitude value="27"><symbol>░</symbol><color>#000</color></magnitude>
</fractal>'; ?>

and here's the modified mandelbrot.xsl:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<!-- XSLT Mandelbrot
    Written by Joel Yliluoma, http://iki.fi/bisqwit/
    Copyright 1992,2007
    Modifiied by Lars Huttar, http://www.huttar.net/
        to enable zooming in
-->

<xsl:output method="html" indent="no"
    doctype-public="-//W3C//DTD HTML 4.01//EN"
    doctype-system="http://www.w3.org/TR/REC-html40/strict.dtd"
/>
<xsl:template match="/fractal">
    <html>
        <head>
            <title>XSLT fractal</title>
            <style type="text/css">
                body { color:#55F; background:#000 }
                pre { font-family:monospace; font-size:7px }
                pre span { background:<xsl:value-of select="background" /> }
                pre a { background:<xsl:value-of select="background" /> }
                a:link { text-decoration: none; }
            </style>
        </head>
        <body>
            <div style="position:absolute;top:20px;left:20em">
                Copyright &#169; 1992,2007 Joel Yliluoma
                (<a href="http://iki.fi/bisqwit/">http://iki.fi/bisqwit/</a>)
            </div>
            <h1 style="margin:0px">XSLT fractal</h1>
            <pre><xsl:call-template name="bisqwit-mandelbrot" /></pre>
        </body>
    </html>
</xsl:template>

<xsl:template name="bisqwit-mandelbrot"
    ><xsl:call-template name="bisqwit-mandelbrot-line">
        <xsl:with-param name="y" select="y/min"/>
    </xsl:call-template
    ></xsl:template>

<xsl:template name="bisqwit-mandelbrot-line"
    ><xsl:param name="y"
    /><xsl:call-template name="bisqwit-mandelbrot-column">
        <xsl:with-param name="x" select="x/min"/>
        <xsl:with-param name="y" select="$y"/>
    </xsl:call-template
    ><xsl:if test="$y &lt; y/max"
        ><br
        /><xsl:call-template name="bisqwit-mandelbrot-line">
            <xsl:with-param name="y" select="$y + y/step"/>
        </xsl:call-template
        ></xsl:if
    ></xsl:template>

<xsl:template name="bisqwit-mandelbrot-column"
    ><xsl:param name="x"
    /><xsl:param name="y"
    /><xsl:call-template name="bisqwit-mandelbrot-slot">
        <xsl:with-param name="x" select="$x" />
        <xsl:with-param name="y" select="$y" />
        <xsl:with-param name="zr" select="$x" />
        <xsl:with-param name="zi" select="$y" />
    </xsl:call-template
    ><xsl:if test="$x &lt; x/max"
        ><xsl:call-template name="bisqwit-mandelbrot-column">
            <xsl:with-param name="x" select="$x + x/step"/>
            <xsl:with-param name="y" select="$y" />
        </xsl:call-template
        ></xsl:if
    ></xsl:template>

<xsl:template name="bisqwit-mandelbrot-slot"
    ><xsl:param name="x"
    /><xsl:param name="y"
    /><xsl:param name="zr"
    /><xsl:param name="zi"
    /><xsl:param name="iter" select="0"
    /><xsl:variable name="zrsqr" select="($zr * $zr)"
    /><xsl:variable name="zisqr" select="($zi * $zi)"
    /><xsl:choose>
        <xsl:when test="(4*scale*scale >= $zrsqr + $zisqr) and (maxiter > $iter+1)"
            ><xsl:call-template name="bisqwit-mandelbrot-slot">
                <xsl:with-param name="x" select="$x" />
                <xsl:with-param name="y" select="$y" />
                <xsl:with-param name="zi" select="(2 * $zr * $zi) div scale + $y" />
                <xsl:with-param name="zr" select="($zrsqr - $zisqr) div scale + $x" />
                <xsl:with-param name="iter" select="$iter + 1" />
            </xsl:call-template
            ></xsl:when>
        <xsl:otherwise
            ><xsl:variable name="magnitude" select="magnitude[@value=$iter]"
            /><a style="color:{$magnitude/color}" href="mandelbrot.php?xmin={$x - 2*(x/step)}&amp;xmax={$x + 3*(x/step)}&amp;ymin={$y - 2*(y/step)}&amp;ymax={$y + 3*(y/step)})"
                ><xsl:value-of select="$magnitude/symbol"
                /></a></xsl:otherwise>
    </xsl:choose
    ></xsl:template>

</xsl:stylesheet>

Unfortunately, the rendering is much slower, probably because the output is much larger (all those long URL params... four per pixel!). Moreover it chokes after a couple of zoom levels when the step size gets down to using E-notation, which is apparently not parsed correctly by the next step. Also, it doesn't look like the zoomed-in rendering shows exactly the right location... maybe I need to change the scale? Anyway, fixing those issues is left as an exercise to some other reader.

Kudos to Joel/bisqwit for a fun toy and an interesting way to render raster results in a browser.

2009-04-30 Reply Admin

Ilyak:
... Each template can output any number of XML subtrees and also call other templates, making the language turing compatible. There are variables, for-loops, condition statements. Any questions?

Yes.

Why do we allow something that is supposed to be for formatting (stylesheets, xslt) have both the full power of a turing machine and full access to browser state and data, and the ability to upload that information back to whereever?

2009-05-01 Reply Admin

... an example of Greenspun's Tenth Rule. (Assuming XSL was coded in C or derivatives, of course.)

2009-05-01 Reply Admin

PS: The result is slightly elongated horizontally on Firefox 3.5 Beta 4 / linux, also.

Arancaytar · 2009-05-02 Reply Admin

OH NO!

I took care to disable images in my browser to avoid being lethally brain-crashed by Langford's Parrot-basilisk, and now you tell me you can draw it on my screen just using XML? I'm so screwed.

2009-05-05 Reply Admin

Andy Gottit:
XML or not, with scripting turned off, that's how it looks. What, you think I made that up?

The Real WTF #1 is that you consider XSLT "scripting". The Real WTF #2 is that my Firefox with NoScript enabled (including on TDWTF) renders the XML just fine. The Real WTF #3 is that because of something you did in 1998, you think you had a clue.

2009-08-18 Reply Admin

WayneCollins:
There is plenty of use for an "identity" transform. As in "I have to supply a transform, but I don't want to actually change my XML. So I need an identity transform."
It would be convenient if the "identity transform" were trivial to write.

Maybe not trivial to write, but trivial to have in your toolbox:

 <xsl:template match="node()|@*">
   <xsl:copy>
     <xsl:apply-templates select="@*"/>
     <xsl:apply-templates/>
   </xsl:copy>
 </xsl:template>

(Thanks to dpawsons XSLT FAQ which every XSLTer should have a bookmark to.

2018-11-27 Reply Admin

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2020-02-10 Reply Admin

That's by Bisqwit, he has a YouTube channel and he's really good

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Stupid Coding Tricks: XSLT Mandelbrot

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