+
+
+This demonstrates how to animate the position of an element along a curve.
Click the button or drag the dots to see the animation. You can use this + example as a tool to find the right XY values for start, end, and control points + that will give you the right shape path for your own animation on a curve.
+The curved line shown here between points 0 and 3 is just for preview + purposes, and is not part of animation on a curve. The draggable points 0 - 3 + are displayed only for UI interactivity.
+
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+ To see anim along a path, click the button above, or drag point 0, 1, 2, or 3.
+The X and Y of point 0 is [92,103]
The X and Y of 1, 2, and 3, are the sub-arrays in array value of "curve:" in the anim.set()
+anim.set('to', {curve: [
+ [147,317],
+ [532,179],
+ [538,288] ]});
+
+
+
+ 0
+
+
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+
+ 1
+
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+ 2
+
+
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+ 3
+ A
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+
+Setting up the HTML
+First we add some HTML to animate.
+<div class="example"> + <button id="btn-animate" class='yui3-button'>Animate On Path</button> + <div id="demo">A</div> +</div>+ + +
Creating the Anim Instance
+Now we create an instance of Y.Anim, passing it a configuration object that includes the node we wish to animate.
var demoA = Y.one('#demo');
+
+var anim = new Y.Anim({
+ node: demoA,
+ duration: 1.5,
+ easing: Y.Easing.easeOut
+});
+
+
+Changing Attributes
+A click handler will set the to value before run is called.
var startAnim = function(e) {
+ anim.set('to', {
+ curve: [ [x1, y1], [x2, y2], [x3, y3] ] // Where 1 and 2 are curve control points, and 3 is the end point.
+ });
+ anim.run();
+};
+
+
+Running the Animation
+If the animation will be run multiple times, you'll need to reset the position of the animated element.
+Finally we add an event handler to run the animation.
+ +var resetToAnimStart = function(){
+ demoA.setStyles({'left': x0, 'top': y0}); // Where x0, y0 is the animation starting point
+}
+
+Y.one('#btn-animate').on('click', function(){
+ resetToAnimStart();
+ startAnim();
+});
+
+
+Complete Example Source
+The code shown above does the basics. +This example however, allows dragging the points, displays xy values for each point +while you drag, and displays a path preview of the animation using YUI Graphics +Utility. This adds some complexity.
+<style>
+.example {
+ position: relative;
+ padding: 0;
+ margin: 0;
+ width: 100%;
+}
+
+.example div, .example p, .example span{
+ padding: 0;
+ margin: 0;
+}
+
+#mygraphiccontainer {
+ width: 650px;
+ height: 400px;
+}
+
+.example #demo {
+ position: absolute;
+ left: 92px;
+ top: 103px;
+ background-color: #f00;
+ text-align: center;
+ line-height: 1.5em;
+ border: solid 1px #cc0000;
+ border-radius: 0;
+ -moz-box-shadow: 3px 3px 7px rgba(0,0,0,0.4);
+ -webkit-box-shadow: 3px 3px 7px rgba(0,0,0,0.4);
+ width: 20px;
+ height: 20px;
+}
+
+.dot {
+ position: absolute;
+ color: #396491;
+ font-size: 20px;
+ height: 0;
+ line-height: 12px;
+ opacity: 0.8;
+ width: 0;
+ cursor: move;
+}
+
+.dot .point {
+ background-color: #000;
+ position: absolute;
+ left: -3px;
+ top: -3px;
+ width: 6px;
+ height: 6px;
+ border-radius: 3px;
+ font-size: 0px;
+}
+
+.number-label {
+ position: absolute;
+ top: -1em;
+ left: -0.9em;
+ width: 1em;
+ height: 1em;
+ line-height: 1em;
+}
+
+/* Gives the points a larger target area to drag */
+.dot .fat-finger {
+ position: absolute;
+ top: -30px; /* minus half the fat-finger height */
+ left: -30px;
+ width: 60px;
+ height: 60px;
+ -moz-border-radius: 30px;
+ -webkit-border-radius: 30px;
+ border-radius: 30px;
+ background-color: #abc;
+ opacity: 0.3;
+ filter: alpha (opacity = 30);
+}
+
+#dot-3 .fat-finger {
+ background-color: #f80;
+ opacity: 0.4;
+}
+
+#dot-0 .fat-finger {
+ background-color: #8DAA16;
+ opacity: 0.4;
+}
+
+#dot-0, #demo {
+ top: 103px;
+ left: 92px;
+}
+
+#dot-1 {
+ top: 317px;
+ left: 147px;
+}
+
+#dot-2 {
+ top: 179px;
+ left: 532px;
+}
+
+#dot-3 {
+ left: 538px;
+ top: 288px;
+}
+
+#info {
+ position: absolute;
+ width: 450px;
+ height: 15em;
+ right: 1em;
+ top: 1em;
+}
+
+code span {
+ color: #CC3300;
+}
+
+.point {
+ font-size: 24px;
+ left: 5px;
+ position: absolute;
+ top: -5px;
+}
+
+</style>
+<!-- In order for the script to run, this HTML markup must be nested in a <div class="example"> -->
+ <div id="mygraphiccontainer"></div> <!-- Container for the preview of the curve line -->
+ <div id="info">
+ <button id="btn-animate" class='yui3-button'>Animate On Path</button>
+ <p>To see anim along a path, click the button above, or drag point 0, 1, 2, or 3.</p>
+ <p>The X and Y of point 0 is <code>[<span class="arr0">92,103</span>]</code></p>
+ <p>The X and Y of 1, 2, and 3, are the sub-arrays in array value of "curve:" in the anim.set()</p>
+ <p><code>anim.set('to', {curve: [
+ [<span class="arr1">147,317</span>],
+ [<span class="arr2">532,179</span>],
+ [<span class="arr3">538,288</span>] ]});</code></p>
+ </div>
+ <div id="dot-0" class="dot zero">
+ <div class="point"></div>
+ <div class="fat-finger" title="Drag to change start point"></div> <!-- Gives the points a larger target area to drag -->
+ <div class="number-label">0</div>
+ </div>
+ <div id="dot-1" class="dot one">
+ <div class="point"></div>
+ <div class="fat-finger" title="Drag to change path"></div>
+ <div class="number-label">1</div>
+ </div>
+ <div id="dot-2" class="dot two">
+ <div class="point"></div>
+ <div class="fat-finger" title="Drag to change path"></div>
+ <div class="number-label">2</div>
+ </div>
+ <div id="dot-3" class="dot three">
+ <div class="point"></div>
+ <div class="fat-finger" title="Drag to change end point"></div>
+ <div class="number-label">3</div>
+ </div>
+ <div id="demo">A</div>
+
+<script>
+YUI().use('anim', 'dd-drag', 'graphics', 'cssbutton', function(Y){
+
+ var mygraphic = new Y.Graphic({render:"#mygraphiccontainer"}),
+ origin = Y.one('.example'), // The XY values for the animation are based on the upper-left corner of this element
+ demoA = Y.one('#demo'), // The animated element
+ dotList = Y.all('.dot');
+ // Draggable points
+ dot0 = Y.one('#dot-0'), dot1 = Y.one('#dot-1'), dot2 = Y.one('#dot-2'), dot3 = Y.one('#dot-3'),
+
+ // Array of XY arrays of draggable points
+ arrDot = [
+ [parseInt(dotList.item(0).getStyle('left'), 10), parseInt(dotList.item(0).getStyle('top'), 10)],
+ [parseInt(dotList.item(1).getStyle('left'), 10), parseInt(dotList.item(1).getStyle('top'), 10)],
+ [parseInt(dotList.item(2).getStyle('left'), 10), parseInt(dotList.item(2).getStyle('top'), 10)],
+ [parseInt(dotList.item(3).getStyle('left'), 10), parseInt(dotList.item(3).getStyle('top'), 10)]
+ ],
+
+ // Make points draggable
+ dd0 = new Y.DD.Drag({
+ node: '#dot-0'
+ }),
+ dd1 = new Y.DD.Drag({
+ node: '#dot-1'
+ }),
+ dd2 = new Y.DD.Drag({
+ node: '#dot-2'
+ }),
+ dd3 = new Y.DD.Drag({
+ node: '#dot-3'
+ });
+
+ // Puts current XY values of points into displayed code snippet
+ var updateCodeSnippetValues = function(){
+ Y.one('.arr0').setHTML(arrDot[0][0] + ',' + arrDot[0][1]); // Start
+ Y.one('.arr1').setHTML(arrDot[1][0] + ',' + arrDot[1][1]); // Control point 1
+ Y.one('.arr2').setHTML(arrDot[2][0] + ',' + arrDot[2][1]); // Control point 2
+ Y.one('.arr3').setHTML(arrDot[3][0] + ',' + arrDot[3][1]); // End
+ }
+
+ /**
+ * Stops the animation
+ * Updates the array of point XY values
+ * Updates the curve preview
+ * Updates displayed XY point values in code snippet
+ */
+ var dotDragHandler = function(dot){
+ Y.Anim.stop();
+ arrDot[dotList.indexOf(dot)] = [parseInt(dot.getStyle('left'), 10), parseInt(dot.getStyle('top'), 10)];
+ drawCurve();
+ updateCodeSnippetValues();
+ }
+
+ dd0.on('drag:drag', function(e){
+ dotDragHandler(this.get('dragNode'));
+ });
+ dd1.on('drag:drag', function(e){
+ dotDragHandler(this.get('dragNode'));
+ });
+ dd2.on('drag:drag', function(e){
+ dotDragHandler(this.get('dragNode'));
+ });
+ dd3.on('drag:drag', function(e){
+ dotDragHandler(this.get('dragNode'));
+ });
+
+ // button handler
+ Y.one('#btn-animate').on('click', function(){
+ Y.Anim.stop();
+ setTimeout(startAnim, 500);
+ });
+
+ Y.all('.dot').on('mouseup', function(e){
+ setTimeout(startAnim, 500);
+ });
+
+ // Create the animation instance
+ var anim = new Y.Anim({
+ node: demoA,
+ duration: 1.5,
+ easing: Y.Easing.easeOut
+ });
+
+ /**
+ * Sets the anim curve values with the XY values from the arrDot array
+ * Adds the origin offset values because anim works off page coordinates
+ */
+ var startAnim = function(e){
+ var oX = origin.getX(),
+ oY = origin.getY();
+
+ // Reset the animated element to the start position.
+ // This is needed for running the animation multiple times
+ demoA.setStyles({'left':arrDot[0][0], 'top':arrDot[0][1]});
+
+ anim.set('to', {
+ curve: [ [(arrDot[1][0] + oX), (arrDot[1][1] + oY)], [ (arrDot[2][0] + oX), (arrDot[2][1] + oY) ], [ (arrDot[3][0] + oX), (arrDot[3][1] + oY) ] ]
+ });
+ anim.run();
+ };
+
+ // Adds a YUI Graphics path shape to the Graphics instance mygraphic
+ var animPath = mygraphic.addShape({
+ type: "path",
+ stroke: {
+ weight: 4,
+ color: "#aabbcc"
+ }
+ });
+
+ // Draw a preview curve with the Graphics animPath shape to match the Anim curve
+ var drawCurve = function(){
+ animPath.clear();
+ animPath.moveTo(arrDot[0][0],arrDot[0][1]);
+ animPath.curveTo(arrDot[1][0],arrDot[1][1], arrDot[2][0],arrDot[2][1], arrDot[3][0],arrDot[3][1]);
+ animPath.end();
+ }
+
+ drawCurve(); // Initial drawing of the preview curve
+ updateCodeSnippetValues(); // Initial setting of code snippet XY values
+
+});
+
+</script>
+
+