_____    ___     
    /    /   /  /     ofxPlaylist
   /  __/ * /  /__    (c) ponies & light, 2009-2015. 
  /__/     /_____/    poniesandlight.co.uk

  ofxPlaylist
  Created by Tim Gfrerer 2009-2015.
  
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ofxPlaylist

A playlist-based animation library. Developed over a couple of years and used in a growing number of permanent installations, deployed on OS X, Windows and Linux.

Playlists hold a sequence of Keyframes, which either:

• point to values to be tweened over time.
• pause for a given duration
• trigger an Event

Keyframes are cleared from their Playlist upon completion. Additional Keyframes can be pushed onto the end of any Playlist at any time. Playlists can also be cleared at any time, even from within a Keyframe Event triggered by a playlist itself.

Compatible with openFrameworks 0.9.0

Key Features:

• Tweens using any of Robert Penner' functions via ofxTween
• Pause
• Event Keyframes (special thanks to James George for suggesting these!)
• Internal memory management using ofPtr()
• Keyframes can be set to execute in sequence or in parallel
• Calculate total remaining duration of Playlist
• Tweens following Bézier curves, mirroring the functionality of Adobe After Effects temporal timeline curves.

Use:

Each Keyframe holds a pointer to the variable it has been assigned to modify, so the variable is updated directly, everytime their Playlist is updated.

Assuming you'd want to tween a float xPos to a randomly assigned target value, here's a mockup:

// .h

class testApp(){
	// …
	ofxPlaylist playlist1;
	float xPos;
	// …
}

// .cpp

void testApp::setup(){

	xPos = ofRandomuf(ofGetWidth());

}

void testApp::update(){

	playlist1.update();

	ofLog(OF_LOG_VERBOSE) << "xPos: " << ofToString(xPos);
}

void testApp::draw(){
	// let's do something with xPos so that we can see the tween happening
	// ...
	ofCircle(xPos, ofGetHeight()/2.f, 10); 
}

void testApp::keyPressed(){
	using namespace Playlist;

	if (key == ' '){
		float targetXPos = ofRandomuf(ofGetWidth());
		
		playlist1.addKeyFrame(Action::tween(1000.f, &xPos, targetXPos));
		// adds a new keyframe to playlist1
		// the playlist will now start tweening xPos towards targetXPos at the next update() cycle.
	} 
}

See also:

A more hands-on example of how to use ofxPlaylist and a run-down of its key features is shown in the included example Project:

example/ofxPlaylistExample

Reference Render

This is a screenshot of the included example project. At every click, a random rectangle gets animated.

Dependencies:

	none. (ofxPlaylistAEHelper makes heavy use of ofxXMLSettings, which is part of the openFrameworks Core Addons)