Tag Archive | "how-to"

Creating a Character Sequence In PHP


Note: Before you read this, read the edit at the bottom.

Recently I needed to created a character sequence in PHP like this: aa, ab, ac and so forth. The range() function can’t handle multiple characters, so I wrote a function to generate the next string in the sequence based on the string sent in. The function “carries the one”, so to speak, meaning the next string after az is ba. After zz comes aa again. You can use any amount of characters, so aaaa will yield aaab.

function get_next_in_sequence($str) {
	$letters = range('a', 'z');
	$arr = str_split($str);
	// Replace each character with numeric equivalent
	foreach ($arr as $key => $char) {
		$arr[$key] = array_search($char, $letters); 
	}
	$digits = count($arr)-1; // Count digits
	for ($i=$digits; $i > -1; $i--) { // Starting at the right-most spot, move left
		if ($i == $digits) // If this is the right most spot
			$arr[$i]++; // Increment it
		if ($arr[$i] == 26) { // If this spot has moved past "z"
			$arr[$i] = 0;	// Set it to "a"
			if ($i != 0) // Unless it is the left most spot
				$arr[$i-1]++;  // Carry the one to the next spot
		} 
	}
	// Rebuild characters from numeric equivalent
	foreach ($arr as $key => $char) { 
		$arr[$key] = $letters[$char];
	}
	$str = implode($arr);
	return $str;
}

CRUTIAL EDIT:

Thanks to a helpful comment from Daniel, it has been brought to my attention that this is now unnecessary. Use this instead:

http://php.net/language.operators.increment.php

Thanks Daniel!

Posted in CodeComments (2)

Circular Motion in Flash AS3


Sometimes you want to move an object in a circular path in Flash. Sometimes you don’t. Sometimes you’d rather knit a sweater, or take a nap. But sometimes you do. For those times, I’ve created a walk-through for how to accomplish this in AS3.

A few notes before we begin:

  1. You might not need this at all. Consider the fact that most circular motion can be simulated by creating an object with an off center axis, and then simply rotating it.
  2. If you decide that you do indeed need to plot your own circular path, just know that it can get a bit mathy. But fret not, as fretting is not good for your health.

Ok, here we go.

  1. Get your object ready. Put it on the stage. Give it an instance name. I called mine “red_dot”.
  2. You’ll need the following data:
  • A center point. Your object will rotate around it.
  • A radius. Your object will maintain that distance from the center point.
  • A step value. How much to move to object in radians per frame around the circle. I call mine angleStep.
var centerX = 150;
var centerY = 150;
var radius = 80;
var angleStep = .01;

Then I set the current angle and cache 2 pi.

var twoPI = 2 * Math.PI;
var currentAngle = 0;

Next I need button to start the whole mess. I add an click event listener to the start button.

start_btn.addEventListener(MouseEvent.CLICK, startCircle);
function startCircle (e:Event) {
	stage.addEventListener(Event.ENTER_FRAME, advanceCircle);
}
 

So once the button is clicked, advanceCircle will be called once per frame. Every frame a new angle is calculated in radians by reducing the current angle by angleStep, and a new X and Y are calculated using our old friend the unit circle from trig. Once the current angle goes once around, reset the whole thing, buttons and all.

function advanceCircle(e:Event) {
	start_btn.removeEventListener(MouseEvent.CLICK, startCircle);
	currentAngle -= angleStep;
	red_dot.x = centerX + Math.cos(currentAngle * twoPI) * radius;
	red_dot.y = centerY + Math.sin(currentAngle * twoPI) * radius;
	if (currentAngle < -1 ) {
		currentAngle = 0;
		stage.removeEventListener(Event.ENTER_FRAME, advanceCircle);
		start_btn.addEventListener(MouseEvent.CLICK, startCircle);
	}
}

Here is the culmination of this knowledge:

Posted in CodeComments (4)

<ul><li><strong>woo_1col_height</strong> - 200</li><li><strong>woo_2col_height</strong> - 200</li><li><strong>woo_3col_height</strong> - 150</li><li><strong>woo_4col_height</strong> - 100</li><li><strong>woo_about_button</strong> - </li><li><strong>woo_about_enable</strong> - false</li><li><strong>woo_about_header</strong> - </li><li><strong>woo_about_photo</strong> - </li><li><strong>woo_about_text</strong> - </li><li><strong>woo_ads_rotate</strong> - false</li><li><strong>woo_ad_content_adsense</strong> - </li><li><strong>woo_ad_content_disable</strong> - false</li><li><strong>woo_ad_content_image</strong> - http://www.woothemes.com/ads/woothemes-468x60-2.gif</li><li><strong>woo_ad_content_url</strong> - http://www.woothemes.com</li><li><strong>woo_ad_image_1</strong> - http://www.woothemes.com/ads/125x125a.jpg</li><li><strong>woo_ad_image_2</strong> - http://www.woothemes.com/ads/125x125b.jpg</li><li><strong>woo_ad_image_3</strong> - http://www.woothemes.com/ads/125x125c.jpg</li><li><strong>woo_ad_image_4</strong> - http://www.woothemes.com/ads/125x125d.jpg</li><li><strong>woo_ad_mpu_adsense</strong> - </li><li><strong>woo_ad_mpu_disable</strong> - true</li><li><strong>woo_ad_mpu_image</strong> - </li><li><strong>woo_ad_mpu_url</strong> - </li><li><strong>woo_ad_top</strong> - false</li><li><strong>woo_ad_top_adsense</strong> - <script type=\"text/javascript\"><!--
google_ad_client = \"pub-7104284053033310\";
/* whit.info 468x60, created 3/16/10 */
google_ad_slot = \"1507544677\";
google_ad_width = 468;
google_ad_height = 60;
//-->
</script>
<script type=\"text/javascript\"
src=\"http://pagead2.googlesyndication.com/pagead/show_ads.js\">
</script></li><li><strong>woo_ad_top_disable</strong> - true</li><li><strong>woo_ad_top_image</strong> - http://www.woothemes.com/ads/468x60a.jpg</li><li><strong>woo_ad_top_url</strong> - http://www.woothemes.com</li><li><strong>woo_ad_url_1</strong> - http://www.woothemes.com</li><li><strong>woo_ad_url_2</strong> - http://www.woothemes.com</li><li><strong>woo_ad_url_3</strong> - http://www.woothemes.com</li><li><strong>woo_ad_url_4</strong> - http://www.woothemes.com</li><li><strong>woo_all_category_title</strong> - Categories</li><li><strong>woo_alt_stylesheet</strong> - darkblue.css</li><li><strong>woo_archives</strong> - Select a page:</li><li><strong>woo_archive_layout</strong> - 3_columns.php</li><li><strong>woo_author</strong> - false</li><li><strong>woo_auto_img</strong> - false</li><li><strong>woo_block_image</strong> - http://whit.info/blog/wp-content/themes/livewire/images/300x250.gif</li><li><strong>woo_block_url</strong> - http://www.woothemes.com</li><li><strong>woo_blog_category</strong> - Select a category:</li><li><strong>woo_blog_cat_id</strong> - </li><li><strong>woo_blog_navigation</strong> - false</li><li><strong>woo_blog_navigation_footer</strong> - false</li><li><strong>woo_blog_permalink</strong> - </li><li><strong>woo_blog_sidebar</strong> - Select a sidebar:</li><li><strong>woo_blog_subnavigation</strong> - false</li><li><strong>woo_breadcrumbs</strong> - false</li><li><strong>woo_button_link</strong> - </li><li><strong>woo_cat_menu</strong> - false</li><li><strong>woo_custom_css</strong> - </li><li><strong>woo_custom_favicon</strong> - </li><li><strong>woo_disclaimer</strong> - </li><li><strong>woo_enable_all_category</strong> - false</li><li><strong>woo_enable_blog_category</strong> - false</li><li><strong>woo_exclude_pages_footer</strong> - </li><li><strong>woo_exclude_pages_main</strong> - </li><li><strong>woo_exclude_pages_subnav</strong> - </li><li><strong>woo_featured_category</strong> - Featured</li><li><strong>woo_feat_entries</strong> - 1</li><li><strong>woo_feat_height</strong> - 210</li><li><strong>woo_feat_width</strong> - 280</li><li><strong>woo_feedburner_id</strong> - Feedburner ID</li><li><strong>woo_feedburner_url</strong> - </li><li><strong>woo_flickr_entries</strong> - Select a Number:</li><li><strong>woo_flickr_id</strong> - </li><li><strong>woo_flickr_url</strong> - Flickr URL</li><li><strong>woo_google_analytics</strong> - </li><li><strong>woo_home</strong> - false</li><li><strong>woo_homepage</strong> - layout-default.php</li><li><strong>woo_home_layout</strong> - 3_columns.php</li><li><strong>woo_home_sidebar</strong> - Select a sidebar:</li><li><strong>woo_home_thumb_height</strong> - 57</li><li><strong>woo_home_thumb_width</strong> - 100</li><li><strong>woo_image_single</strong> - false</li><li><strong>woo_inc_intro_page</strong> - false</li><li><strong>woo_inc_intro_page_left</strong> - false</li><li><strong>woo_inc_intro_page_right</strong> - false</li><li><strong>woo_inc_tabber_pages</strong> - false</li><li><strong>woo_intro_page</strong> - </li><li><strong>woo_intro_page_left</strong> - </li><li><strong>woo_intro_page_right</strong> - </li><li><strong>woo_layout</strong> - blog.php</li><li><strong>woo_logo</strong> - </li><li><strong>woo_mag_featured</strong> - Select a number:</li><li><strong>woo_mag_secondary</strong> - Select a number:</li><li><strong>woo_manual</strong> - http://www.woothemes.com/support/theme-documentation/gazette-edition/</li><li><strong>woo_mid_exclude</strong> - </li><li><strong>woo_nav_exclude</strong> - </li><li><strong>woo_other_entries</strong> - Select a Number:</li><li><strong>woo_page_sidebar</strong> - Select a sidebar:</li><li><strong>woo_port_images</strong> - false</li><li><strong>woo_resize</strong> - true</li><li><strong>woo_shortname</strong> - woo</li><li><strong>woo_show_carousel</strong> - false</li><li><strong>woo_show_video</strong> - false</li><li><strong>woo_single_height</strong> - 180</li><li><strong>woo_single_width</strong> - 250</li><li><strong>woo_slider</strong> - false</li><li><strong>woo_smallthumb_height</strong> - 42</li><li><strong>woo_smallthumb_width</strong> - 56</li><li><strong>woo_subnav</strong> - false</li><li><strong>woo_tabber_pages</strong> - </li><li><strong>woo_tabs</strong> - false</li><li><strong>woo_themename</strong> - Gazette</li><li><strong>woo_the_content</strong> - true</li><li><strong>woo_thumb_height</strong> - 76</li><li><strong>woo_thumb_width</strong> - 100</li><li><strong>woo_twitter</strong> - </li><li><strong>woo_twitter_enable</strong> - true</li><li><strong>woo_twitter_username</strong> - woothemes</li><li><strong>woo_video_category</strong> - Select a category:</li></ul>