Added PHP Extensions talk for TEK.

php-ext-tek17.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<presentation css="10gen-strict.css">
+<topic>MongoDB</topic>
+<title>Introduction into PHP Extensions</title>
+<event>php[tek]</event>
+<location>Atlanta, GA, USA</location>
+<date>June 25th, 2017</date>
+<speaker>Derick Rethans</speaker>
+<email>derick@mongodb.com</email>
+<twitter>derickr</twitter>
+<url>http://derickrethans.nl/talks.html</url>
+<joindin>https://joind.in/21363</joindin>
+<slide>slides/mongodb/title.xml</slide>
+<slide>slides/mongodb/me.xml</slide>
+
+<slide>slides/internals/extension-agenda.xml</slide>
+<slide>slides/internals/extension-agenda2.xml</slide>
+<slide>slides/internals/extension-what1.xml</slide>
+<slide>slides/internals/extension-why1.xml</slide>
+<slide>slides/internals/extension-why-wrap.xml</slide>
+<slide>slides/internals/extension-why-not-possible.xml</slide>
+<slide>slides/internals/extension-why-speed.xml</slide>
+
+<slide>slides/internals/rdp-intro.xml</slide>
+<slide>slides/internals/rdp-intro2.xml</slide>
+<slide>slides/internals/rdp-intro3.xml</slide>
+<slide>slides/internals/rdp-intro4.xml</slide>
+
+<slide>slides/internals/extension-parts.xml</slide>
+<slide>slides/internals/extension-on-a-slide.xml</slide>
+<slide>slides/internals/config.m4.xml</slide>
+<slide>slides/internals/config.w32.xml</slide>
+<slide>slides/internals/phpize.xml</slide>
+
+<slide>slides/internals/extension.h.xml</slide>
+<slide>slides/internals/extension.c-part1.xml</slide>
+<slide>slides/internals/extension.c-part2.xml</slide>
+<slide>slides/internals/extension.c-part3.xml</slide>
+
+<slide>slides/internals/function.xml</slide>
+<slide>slides/internals/rdp_simplify-part1.xml</slide>
+<slide>slides/internals/rdp_simplify-zedval.xml</slide>
+<slide>slides/internals/rdp_simplify-part1b.xml</slide>
+<slide>slides/internals/rdp_simplify-convert-data.xml</slide>
+<slide>slides/internals/rdp_simplify-run-algorithm.xml</slide>
+<slide>slides/internals/rdp_simplify-php.xml</slide>
+<slide>slides/internals/rdp_simplify-c.xml</slide>
+<slide>slides/internals/rdp_simplify-return-result.xml</slide>
+<slide>slides/internals/rdp_simplify-return-scalars.xml</slide>
+<slide>slides/internals/memory-management.xml</slide>
+
+<slide>slides/internals/tests.xml</slide>
+<slide>slides/internals/rdp-test.xml</slide>
+
+<slide>slides/mongodb/questions.xml</slide>
+<slide>slides/mongodb/resources.xml</slide>
+</presentation>

slides/internals/ast.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="abstract-tree.jpg">
 <title>Abstract Syntax Tree</title>
-<image align="center" filename="abstract-tree.jpg" attr=""/>
 </slide>

slides/internals/branches.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="branches.jpg" background_attr="Sergey Kochkarev - https://www.flickr.com/photos/skochkar/24747666840/ - Public Domain">
 <title>Branch Analysis</title>
-<image align="center" filename="branches.jpg" attr="Sergey Kochkarev - https://www.flickr.com/photos/skochkar/24747666840/ - Public Domain"/>
 </slide>

slides/internals/bytecode0.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="bytecode.jpg">
 <title>Byte Code</title>
-<image align="center" filename="bytecode.jpg" attr=""/>
 </slide>

slides/internals/catch.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="catch.jpg" background_attr="Soggydan Benenovitch (https://www.flickr.com/photos/38518750@N00/4858510277)">
 <title>Exceptions (Try/Catch)</title>
-<image align="center" filename="catch.jpg" attr="Soggydan Benenovitch (https://www.flickr.com/photos/38518750@N00/4858510277)"/>
 </slide>

slides/internals/config.m4.xml

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+<slide>
+<title>Build Instructions</title>
+<subtitle>config.m4</subtitle>
+
+<blurb>Comments:</blurb>
+<example><![CDATA[
+dnl $Id$
+dnl config.m4 for extension geospatial
+]]></example>
+
+<blurb>Configure option definition:</blurb>
+<example><![CDATA[
+PHP_ARG_ENABLE(geospatial, whether to enable geospatial support,
+[  --enable-geospatial           Enable geospatial support])
+]]></example>
+
+<blurb>Build instructions:</blurb>
+<example><![CDATA[
+if test "$PHP_GEOSPATIAL" != "no"; then
+  PHP_NEW_EXTENSION(geospatial, geospatial.c geo_array.c, $ext_shared)
+fi
+]]></example>
+</slide>

slides/internals/config.w32.xml

@@ -0,0 +1,23 @@
+<slide>
+<title>Build Instructions</title>
+<subtitle>config.w32</subtitle>
+
+<blurb>Comments:</blurb>
+<example><![CDATA[
+// $Id$
+// vim:ft=javascript
+]]></example>
+
+<blurb>Configure option definition:</blurb>
+<example><![CDATA[
+ARG_ENABLE("geospatial", "enable geospatial support", "no");
+
+]]></example>
+
+<blurb>Build instructions:</blurb>
+<example><![CDATA[
+if (PHP_GEOSPATIAL != "no") {
+    EXTENSION("geospatial", "geospatial.c geo_array.c");
+}
+]]></example>
+</slide>

slides/internals/deadcode.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="rosetta.jpg" background_attr="Cristian Bortes - https://www.flickr.com/photos/bortescristian/2931856207 - CC-BY">
 <title>Dead Code</title>
-<image align="center" filename="rosetta.jpg" attr="Cristian Bortes - https://www.flickr.com/photos/bortescristian/2931856207 - CC-BY"/>
 </slide>

slides/internals/extension-agenda.xml

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+<slide style="title" background="agenda.png">
+<title>Agenda</title>
+</slide>

slides/internals/extension-agenda2.xml

@@ -0,0 +1,11 @@
+<slide>
+<title>Questions</title>
+
+<list>
+	<bullet>What are extensions?</bullet>
+	<bullet>Why would you write an extension?</bullet>
+	<bullet>How do you write an extension?</bullet>
+</list>
+<break/>
+<image filename="elephpants.jpg"/>
+</slide>

slides/internals/extension-parts.xml

@@ -0,0 +1,13 @@
+<slide>
+<title>What makes up an Extension?</title>
+
+<list>
+    <bullet>%config.m4%: configure options and build instructions</bullet>
+    <bullet>%php_extension.h%: header files and glue</bullet>
+    <bullet>%extension.c%: extension definition and function implementation</bullet>
+</list>
+<break/>
+<list>
+    <bullet>%algorithms.c%: C implementation of algorithms</bullet>
+</list>
+</slide>

slides/internals/extension-what1.xml

@@ -0,0 +1,12 @@
+<slide>
+<title>What are extensions?</title>
+
+<list>
+	<bullet>Additional functions and classes</bullet>
+	<bullet>Written in C</bullet>
+	<bullet>Either compiled in, or a shared object</bullet>
+	<bullet>Bundled with PHP, distributed through PECL, or distributed separately</bullet>
+</list>
+<break/>
+<image filename="limo.png" attr="https://commons.wikimedia.org/wiki/File:Luxury_Stretched_Limousine_Cadillac.png - Keithmsyverson - CC-BY 4.0"/>
+</slide>

slides/internals/extension-why-not-possible.xml

@@ -0,0 +1,9 @@
+<slide background="escher.jpg">
+<title>Unpossible in userland</title>
+
+<break lines="3"/>
+<list>
+	<bullet>Information or resources shared between requests: *persistent connections*, *PHP objects*</bullet>
+	<bullet>Peeking into internals: *vld*, *Xdebug*, *opcache*</bullet>
+</list>
+</slide>

slides/internals/extension-why-speed.xml

@@ -0,0 +1,9 @@
+<slide background="tracing.jpg">
+<title>Speed</title>
+
+<break lines="3"/>
+<list>
+	<bullet>PHP is fast, but things can be ~faster~</bullet>
+	<bullet>Implementations in C (and C++) usually ~outperform~ code in PHP</bullet>
+</list>
+</slide>

slides/internals/extension-why-wrap.xml

@@ -0,0 +1,10 @@
+<slide background="bubble-wrap.jpg" background_attr="https://pixabay.com/en/bubble-wrap-blow-packaging-1183728/ — CC0">
+<title>Wrapping Libraries</title>
+
+<break lines="3"/>
+<list>
+	<bullet>Database drivers: *libmongoc*, *libmysql*, …</bullet>
+	<bullet>Image processing: *GD*, *Cairo*, *ImageMagick*, …</bullet>
+	<bullet>Image recognition: *OpenCV*, *Dlib*, …</bullet>
+</list>
+</slide>

slides/internals/extension-why1.xml

@@ -0,0 +1,11 @@
+<slide>
+<title>Why write an extension?</title>
+
+<list>
+	<bullet>Wrap existing library</bullet>
+	<bullet>Not everything can be done in userland</bullet>
+	<bullet>Speed</bullet>
+</list>
+<break/>
+<image filename="limo.png" attr="https://commons.wikimedia.org/wiki/File:Luxury_Stretched_Limousine_Cadillac.png - Keithmsyverson - CC-BY 4.0"/>
+</slide>

slides/internals/extension.c-part1.xml

@@ -0,0 +1,30 @@
+<slide>
+<title>The Meat</title>
+
+<blurb>Header inclusions:</blurb>
+<example><![CDATA[
+#include "php.h"
+#include "php_ini.h"
+#include "ext/standard/info.h"
+#include "php_geospatial.h"
+#include "Zend/zend_exceptions.h"
+#include "ext/spl/spl_exceptions.h"
+]]></example>
+
+<blurb>Argument Information:</blurb>
+<example><![CDATA[
+ZEND_BEGIN_ARG_INFO_EX(rdp_simplify_args, 0, 0, 2)
+    ZEND_ARG_INFO(0, pointsArray)
+    ZEND_ARG_INFO(0, epsilon)
+ZEND_END_ARG_INFO()
+]]></example>
+
+<blurb>List of functions:</blurb>
+<example><![CDATA[
+const zend_function_entry geospatial_functions[] = {
+    PHP_FE(rdp_simplify, rdp_simplify_args)
+    { NULL, NULL, NULL }
+};
+]]></example>
+
+</slide>

slides/internals/extension.c-part2.xml

@@ -0,0 +1,31 @@
+<slide>
+<title>The Meat</title>
+
+<blurb>Module (Extension) definition:</blurb>
+<example><![CDATA[
+zend_module_entry geospatial_module_entry = {
+#if ZEND_MODULE_API_NO >= 20010901
+    STANDARD_MODULE_HEADER,
+#endif
+    "geospatial",
+    geospatial_functions,
+    PHP_MINIT(geospatial),
+    NULL,
+    NULL,
+    NULL,
+    PHP_MINFO(geospatial),
+#if ZEND_MODULE_API_NO >= 20010901
+    PHP_GEOSPATIAL_VERSION,
+#endif
+    STANDARD_MODULE_PROPERTIES
+};
+]]></example>
+
+<blurb>Handle Shared Object Loading:</blurb>
+<example><![CDATA[
+#ifdef COMPILE_DL_GEOSPATIAL
+ZEND_GET_MODULE(geospatial)
+#endif
+]]></example>
+
+</slide>

slides/internals/extension.c-part3.xml

@@ -0,0 +1,24 @@
+<slide>
+<title>The Meat</title>
+
+<blurb>Module INITialisation</blurb>
+<example><![CDATA[
+PHP_MINIT_FUNCTION(geospatial)
+{
+    REGISTER_DOUBLE_CONSTANT("GEO_DEG_TO_RAD", GEO_DEG_TO_RAD, CONST_CS|CONST_PERSISTENT);
+    return SUCCESS;
+}
+]]></example>
+
+<blurb>Module INFO</blurb>
+<example><![CDATA[
+PHP_MINFO_FUNCTION(geospatial)
+{
+    php_info_print_table_start();
+    php_info_print_table_header(2, "Geospatial functions", "enabled");
+    php_info_print_table_row(2, "Version", PHP_GEOSPATIAL_VERSION);
+    php_info_print_table_end();
+}
+]]></example>
+
+</slide>

slides/internals/extension.h.xml

@@ -0,0 +1,33 @@
+<slide>
+<title>Header File</title>
+
+<blurb>Guard:</blurb>
+<example><![CDATA[
+#ifndef PHP_GEOSPATIAL_H
+#define PHP_GEOSPATIAL_H
+]]></example>
+
+<example><![CDATA[
+#define PHP_GEOSPATIAL_VERSION "0.1.1-dev"
+]]></example>
+
+<blurb>Module definition:</blurb>
+<example><![CDATA[
+extern zend_module_entry geospatial_module_entry;
+#define phpext_geospatial_ptr &geospatial_module_entry
+]]></example>
+
+<blurb>Module initialiser declarations:</blurb>
+<example><![CDATA[
+PHP_MINIT_FUNCTION(geospatial);
+PHP_MINFO_FUNCTION(geospatial);
+]]></example>
+
+<blurb>Forward declarations:</blurb>
+<example><![CDATA[
+PHP_FUNCTION(rdp_simplify);
+
+#endif /* PHP_GEOSPATIAL_H */
+]]></example>
+
+</slide>

slides/internals/function.xml

@@ -0,0 +1,13 @@
+<slide>
+<title>Implementing the function</title>
+
+<list>
+    <bullet>Parse Input Parameters</bullet>
+    <bullet>Convert Data into Right Format</bullet>
+    <bullet>Run Algorithm</bullet>
+    <bullet>Return Result</bullet>
+</list>
+
+<break lines="3"/>
+<image filename="einstein.jpg"/>
+</slide>

slides/internals/jumps.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="jumps.jpg" background_attr="Thor-Wiggo Skille (http://www.nfk.no/Artikkel.aspx?AId=25071&amp;back=1&amp;MId1=4557&amp;MId2=&amp;MId3=&amp;)">
 <title>Jumps</title>
-<image align="center" filename="jumps.jpg" attr="Thor-Wiggo Skille (http://www.nfk.no/Artikkel.aspx?AId=25071&amp;back=1&amp;MId1=4557&amp;MId2=&amp;MId3=&amp;)"/>
 </slide>

slides/internals/loops.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="loops.png" background_attr="http://xkcd.com/657">
 <title>Complex Loops</title>
-<image align="center" filename="loops.png" attr="http://xkcd.com/657"/>
 </slide>

slides/internals/memory-management.xml

@@ -0,0 +1,18 @@
+<slide>
+<title>Memory Management</title>
+
+<list>
+    <bullet>If you allocate something, you need to free it</bullet>
+    <bullet>PHP Memory Management helpers: %emalloc%, %efree%</bullet>
+    <bullet>To prevent PHP from cleaning up input arguments:<break/>
+        <example>Z_ADDREF(zval);</example>
+    </bullet>
+</list>
+<div effect="fade-in">
+<list>
+    <bullet>But make sure to remove the reference later:<break/>
+        <example><![CDATA[zval_ptr_dtor(&zval);]]></example>
+    </bullet>
+</list>
+</div>
+</slide>

slides/internals/phpize.xml

@@ -0,0 +1,9 @@
+<slide>
+<title>Building the Extension</title>
+
+<list>
+    <bullet>%phpize%<break/>Brings in headers and creates %configure% script</bullet>
+    <bullet>%./configure%<break/>Runs system checks, and creates %Makefile%</bullet>
+    <bullet>%make%<break/>Builds the extension</bullet>
+</list>
+</slide>

slides/internals/rdp-intro.xml

@@ -0,0 +1,3 @@
+<slide style="title" background="limit.gif" background_attr="© Copyright OpenStreetMap and contributors — ODbL">
+<title>Oh, Belgium!</title>
+</slide>

slides/internals/rdp-intro3.xml

@@ -0,0 +1,14 @@
+<slide>
+<title>Ramer–Douglas–Peucker algorithm</title>
+
+<list>
+    <bullet>Recursive algorithm for line/polygon simplification</bullet>
+    <bullet>Computationally intensive</bullet>
+    <bullet>100 runs with episilon of 0.01:<list>
+        <bullet>PHP function: *45.3s*</bullet>
+        <bullet>C implementation in extension: *0.37s*</bullet>
+    </list></bullet>
+</list>
+<break/>
+<image filename="Douglas-Peucker_animated.gif" attr="https://commons.wikimedia.org/wiki/File:Douglas-Peucker_animated.gif — CC-By_SA"/>
+</slide>

slides/internals/rdp-intro4.xml

@@ -0,0 +1,3 @@
+<slide style="title" background="warp.png" background_attr="NASA/JPL-Caltech/STScI/IRAM + Modifications">
+<title>From 45.3s down to 0.37s</title>
+</slide>

slides/internals/rdp-test.xml

@@ -0,0 +1,29 @@
+<slide>
+<title>Example Test File</title>
+
+<blurb>%tests/rdp-belgium.phpt%</blurb>
+
+<example inline="2"><![CDATA[
+*--TEST--*
+Test for rdp_simplify
+*--FILE--*
+&lt;?php
+$json = json_decode( file_get_contents( dirname( &#95;&#95;FILE&#95;&#95; ) . '/rdp-belgium.json' ) );
+$points = $json[0]->geometry->coordinates[0];
+
+$result = RDP_Simplify( $points, 0.001 );
+var_dump( count( $result ) );
+
+$result = RDP_Simplify( $points, 0.01 );
+var_dump( count( $result ) );
+?>
+*--EXPECT--*
+int(1029)
+int(261)
+]]></example>
+
+<list>
+    <bullet>Sections: TEST, INI, FILE, EXPECT, EXPECTF</bullet>
+    <bullet>Simple PHP script</bullet>
+</list>
+</slide>

slides/internals/rdp_simplify-c.xml

@@ -0,0 +1,42 @@
+<slide>
+<title>RDP (C)</title>
+
+<example><![CDATA[
+void rdp_simplify(geo_array *points, double epsilon, int start, int end)
+{
+    double firstX = points->x[start], firstY = points->y[start];
+    double lastX = points->x[end], lastY = points->y[end];
+    int    index = -1, i;
+    double dist  = 0.0, current_dist;
+
+    if (end - start < 2) {
+        return;
+    }
+
+    for (i = start + 1; i < end; i++) {
+        if (!points->status[i]) {
+            continue;
+        }
+
+        current_dist = rdp_find_perpendicular_distable(points->x[i], points->y[i], firstX, firstY, lastX, lastY);
+
+        if (current_dist > dist) {
+            dist = current_dist;
+            index = i;
+        }
+    }
+
+    if (dist > epsilon) {
+        rdp_simplify(points, epsilon, start, index);
+        rdp_simplify(points, epsilon, index, end);
+
+        return;
+    } else {
+        for (i = start + 1; i < end; i++) {
+            points->status[i] = 0;
+        }
+        return;
+    }
+}
+]]></example>
+</slide>

slides/internals/rdp_simplify-convert-data.xml

@@ -0,0 +1,46 @@
+<slide>
+<title>Converting from PHP variables</title>
+
+<div effect="fade-out">
+<example><![CDATA[
+    points = geo_hashtable_to_array(points_array TSRMLS_CC);
+    if (!points) {
+        return;
+    }
+]]></example>
+</div>
+
+<div effect="fade-in">
+<example inline="2"><![CDATA[
+geo_array \*geo_hashtable_to_array(zval \*array TSRMLS_DC)
+{
+    geo_array *tmp;
+    int element_count, i = 0;
+    zval *entry;
+    double lon, lat;
+
+    element_count = *zend_hash_num_elements*(Z_ARRVAL_P(array));
+    *tmp = geo_array_ctor(element_count);*
+
+    *ZEND_HASH_FOREACH_VAL*(Z_ARRVAL_P(array), entry) {
+        if (!parse_point_pair(entry, &lon, &lat TSRMLS_CC)) {
+            goto failure;
+        }
+
+        tmp->x[i] = lon;
+        tmp->y[i] = lat;
+        tmp->status[i] = 1;
+
+        i++;
+    } ZEND_HASH_FOREACH_END();
+
+    return tmp;
+
+failure:
+    *geo_array_dtor(tmp);*
+    return NULL;
+}
+]]></example>
+</div>
+
+</slide>

slides/internals/rdp_simplify-part1.xml

@@ -0,0 +1,28 @@
+<slide>
+<title>Parsing Input Parameters</title>
+
+<example inline="2"><![CDATA[
+PHP_FUNCTION(rdp_simplify)
+{   
+    *zval*      *points_array;
+    *double*     epsilon;  
+    
+    if (*zend_parse_parameters*(ZEND_NUM_ARGS() TSRMLS_CC, *"zd"*, &points_array, &epsilon)
+            == FAILURE) {
+        return; 
+    }
+                    
+    if (Z_TYPE_P(points_array) != IS_ARRAY) {
+        return;
+    }
+]]></example>
+
+<break/>
+<blurb>%zend_parse_parameters%</blurb>
+<list>
+    <bullet>A format letter for every type</bullet>
+    <bullet>Matched with a C data type</bullet>
+    <bullet>Cleaned up for you</bullet>
+</list>
+
+</slide>

slides/internals/rdp_simplify-part1b.xml

@@ -0,0 +1,19 @@
+<slide>
+<title>Parsing Input Parameters</title>
+
+<table>
+<tr><th>letter</th><th>variable</th><th>C data-type</th></tr>
+<tr><td>a</td><td>array</td><td>%zval*%</td></tr>
+<tr><td>b</td><td>boolean</td><td>%zend_bool%</td></tr>
+<tr><td>d</td><td>double</td><td>%double%</td></tr>
+<tr><td>l</td><td>long</td><td>%zend_long%</td></tr>
+<tr><td>O</td><td>object of specific type</td><td>%zval*%, %zend_class_entry%</td></tr>
+<tr><td>P</td><td>path</td><td>%zend_string*%</td></tr>
+<tr><td>s</td><td>string</td><td>%char*%, %size_t%</td></tr>
+<tr><td>S</td><td>string</td><td>%zend_string*%</td></tr>
+<tr><td>z</td><td>the actual zval</td><td>%zval*%</td></tr>
+</table>
+
+<image filename="inputs.jpg" attr="Clive Darra - https://www.flickr.com/photos/fsse-info/3414368958/ - CC-BY-SA"/>
+
+</slide>

slides/internals/rdp_simplify-php.xml

@@ -0,0 +1,42 @@
+<slide>
+<title>RDP (PHP)</title>
+
+<example><![CDATA[
+static private function simplifyInternal( &$points, $epsilon, $start, $end )
+{
+    $firstPoint = $points[$start];
+    $lastPoint = $points[$end];
+    $index = -1;
+    $dist  = 0;
+
+    if ( $end - $start < 2 ) {
+        return;
+    }
+
+    for ( $i = $start + 1; $i < $end; $i++ ) {
+        if ( !isset( $points[$i] ) ) {
+            continue;
+        }
+
+        $cDist = self::findPerpendicularDistance( $points[ $i ], $firstPoint, $lastPoint );
+
+        if ( $cDist > $dist ) {
+            $dist = $cDist;
+            $index = $i;
+        }
+    }
+
+    if ( $dist > $epsilon ) {
+        self::simplifyInternal( $points, $epsilon, $start, $index );
+        self::simplifyInternal( $points, $epsilon, $index, $end );
+
+        return;
+    } else {
+        for ( $i = $start + 1; $i < $end; $i++ ) {
+            unset( $points[$i] );
+        }
+        return;
+    }
+}
+]]></example>
+</slide>

slides/internals/rdp_simplify-return-result.xml

@@ -0,0 +1,24 @@
+<slide>
+<title>Return Result</title>
+
+<example inline="2"><![CDATA[
+PHP_FUNCTION(rdp_simplify)
+{
+…
+    zval       pair;
+…
+    array_init(*return_value*);
+
+    for (i = 0; i < points->count; i++) {
+        if (points->status[i]) {
+            *array_init(&pair);*
+            *add_next_index_double*(&pair, points->x[i]);
+            add_next_index_double(&pair, points->y[i]);
+            *add_next_index_zval*(*return_value*, &pair);
+        }
+    }
+
+    *geo_array_dtor(points);*
+}
+]]></example>
+</slide>

slides/internals/rdp_simplify-return-scalars.xml

@@ -0,0 +1,19 @@
+<slide>
+<title>Returning Scalar Values</title>
+
+<blurb>Return Immediately:</blurb>
+<example>RETURN_BOOL(!mongoc_cursor_is_alive(intern->cursor));</example>
+<example>RETURN_LONG(zend_memory_usage(0));</example>
+<example>RETURN_STRING(i->function.function);</example>
+
+<break/>
+
+<blurb>Just Set Return Value:</blurb>
+<example>RETVAL_FALSE;</example>
+<example>#if PHP_VERSION_ID >= 70000
+    RETVAL_STRING(trace_fname);
+#else
+    RETVAL_STRING(trace_fname, 1);
+#endif
+</example>
+</slide>

slides/internals/rdp_simplify-run-algorithm.xml

@@ -0,0 +1,7 @@
+<slide>
+<title>Run Algorithm</title>
+
+<example><![CDATA[    rdp_simplify(points, epsilon, 0, points->count - 1);]]></example>
+<break lines="6"/>
+<image filename="Douglas-Peucker_animated.gif" attr="https://commons.wikimedia.org/wiki/File:Douglas-Peucker_animated.gif — CC-By_SA"/>
+</slide>

slides/internals/rdp_simplify-zedval.xml

@@ -0,0 +1,21 @@
+<slide>
+<title>zval?</title>
+
+<blurb>PHP's representation of a value</blurb>
+
+<list>
+    <bullet>Contains the type: %Z_TYPE_P(points_array)%</bullet>
+    <bullet>Contains the value: %Z_ARRVAL_P(points_array)%</bullet>
+</list>
+
+<break/>
+<blurb>%IS_DOUBLE%, %IS_STRING%, %IS_ARRAY%, …</blurb>
+<blurb>%Z_DVAL_P(lat)%, %Z_STRVAL_P(type)%, …</blurb>
+
+<break/>
+<example><![CDATA[
+    if (Z_TYPE_P(points_array) != IS_ARRAY) {
+        return;
+    }
+]]></example>
+</slide>

slides/internals/recap.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="recap.jpg" background_attr="Jens Johnsson - https://www.pexels.com/photo/mountains-nature-arrow-guide-66100/ - CC0">
 <title>Recap</title>
-<image align="center" filename="recap.jpg" attr="Jens Johnsson - https://www.pexels.com/photo/mountains-nature-arrow-guide-66100/ - CC0"/>
 </slide>

slides/internals/rings.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="ring.png" background_attr="© OpenStreetMap contributors">
 <title>Rings</title>
-<image align="center" filename="ring.png" attr="© OpenStreetMap contributors"/>
 </slide>

slides/internals/tests.xml

@@ -0,0 +1,9 @@
+<slide>
+<title>Tests</title>
+
+<list>
+    <bullet>Go into the %tests/% directory</bullet>
+    <bullet>%phpt% format</bullet>
+    <bullet>Run with %make test% in top source directory</bullet>
+</list>
+</slide>

slides/internals/title-parsing.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="tokens.jpg" background_attr="$1LENCE D00600D at English Wikipedia">
 <title>Parsing</title>
-<image align="center" filename="tokens.jpg" attr="$1LENCE D00600D at English Wikipedia"/>
 </slide>

slides/internals/title-stages.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="stages.jpg">
 <title>Stages</title>
-<image align="center" filename="stages.jpg" attr=""/>
 </slide>

slides/mongodb/questions.xml

@@ -1,4 +1,3 @@
-<slide style="title">
+<slide style="title" background="queries.jpg" background_attr="Véronique Debord-Lazaro — https://www.flickr.com/photos/debord/4932655275">
 <title>Any Queries?</title>
-<image align="center" filename="queries.jpg" attr="Véronique Debord-Lazaro — https://www.flickr.com/photos/debord/4932655275"/>
 </slide>

templates/default/slide.ezt

@@ -122,8 +122,10 @@ $('*').keypress(function(event) {
 
 </head>
 {var $img = get_attribute( $node, 'background' )}
+{var $imgAttr = get_attribute( $node, 'background_attr' )}
 {var $maincolor = get_attribute( $node, 'template' )}
-<body{if $img} style='background-image: url({$pres->base}{$img});'{/if}>
+<body{if $img} style='background-image: url({$pres->base}{$img}); background-size: cover;'{/if}>
+<div class='twitter'>@derickr</div>
 <div class='whole-slide{if $maincolor} template-{$maincolor}{/if}'>
 {switch ( get_attribute( $node, 'type' ) )}
 	{case 'agenda'}
@@ -143,5 +145,6 @@ $('*').keypress(function(event) {
 	{/default}
 {/switch}
 </div>
+{if $imgAttr}<p class="bgattribution">{$imgAttr}</p>{/if}
 </body>
 </html>