material-design-lite/src/ripple/ripple.js

/**
 * @license
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

(function() {
  'use strict';

  /**
   * Class constructor for Ripple MDL component.
   * Implements MDL component design pattern defined at:
   * https://github.com/jasonmayes/mdl-component-design-pattern
   *
   * @constructor
   * @param {HTMLElement} element The element that will be upgraded.
   */
  var MaterialRipple = function MaterialRipple(element) {
    this.element_ = element;

    // Initialize instance.
    this.init();
  };
  window['MaterialRipple'] = MaterialRipple;

  /**
   * Store constants in one place so they can be updated easily.
   *
   * @enum {string | number}
   * @private
   */
  MaterialRipple.prototype.Constant_ = {
    INITIAL_SCALE: 'scale(0.0001, 0.0001)',
    INITIAL_SIZE: '1px',
    INITIAL_OPACITY: '0.4',
    FINAL_OPACITY: '0',
    FINAL_SCALE: ''
  };

  /**
   * Store strings for class names defined by this component that are used in
   * JavaScript. This allows us to simply change it in one place should we
   * decide to modify at a later date.
   *
   * @enum {string}
   * @private
   */
  MaterialRipple.prototype.CssClasses_ = {
    RIPPLE_CENTER: 'mdl-ripple--center',
    RIPPLE_EFFECT_IGNORE_EVENTS: 'mdl-js-ripple-effect--ignore-events',
    RIPPLE: 'mdl-ripple',
    IS_ANIMATING: 'is-animating',
    IS_VISIBLE: 'is-visible'
  };

  /**
   * Handle mouse / finger down on element.
   *
   * @param {Event} event The event that fired.
   * @private
   */
  MaterialRipple.prototype.downHandler_ = function(event) {
    if (!this.rippleElement_.style.width && !this.rippleElement_.style.height) {
      var rect = this.element_.getBoundingClientRect();
      this.boundHeight = rect.height;
      this.boundWidth = rect.width;
      this.rippleSize_ = Math.sqrt(rect.width * rect.width +
          rect.height * rect.height) * 2 + 2;
      this.rippleElement_.style.width = this.rippleSize_ + 'px';
      this.rippleElement_.style.height = this.rippleSize_ + 'px';
    }

    this.rippleElement_.classList.add(this.CssClasses_.IS_VISIBLE);

    if (event.type === 'mousedown' && this.ignoringMouseDown_) {
      this.ignoringMouseDown_ = false;
    } else {
      if (event.type === 'touchstart') {
        this.ignoringMouseDown_ = true;
      }
      var frameCount = this.getFrameCount();
      if (frameCount > 0) {
        return;
      }
      this.setFrameCount(1);
      var bound = event.currentTarget.getBoundingClientRect();
      var x;
      var y;
      // Check if we are handling a keyboard click.
      if (event.clientX === 0 && event.clientY === 0) {
        x = Math.round(bound.width / 2);
        y = Math.round(bound.height / 2);
      } else {
        var clientX = event.clientX ? event.clientX : event.touches[0].clientX;
        var clientY = event.clientY ? event.clientY : event.touches[0].clientY;
        x = Math.round(clientX - bound.left);
        y = Math.round(clientY - bound.top);
      }
      this.setRippleXY(x, y);
      this.setRippleStyles(true);
      window.requestAnimationFrame(this.animFrameHandler.bind(this));
    }
  };

  /**
   * Handle mouse / finger up on element.
   *
   * @param {Event} event The event that fired.
   * @private
   */
  MaterialRipple.prototype.upHandler_ = function(event) {
    // Don't fire for the artificial "mouseup" generated by a double-click.
    if (event && event.detail !== 2) {
      // Allow a repaint to occur before removing this class, so the animation
      // shows for tap events, which seem to trigger a mouseup too soon after
      // mousedown.
      window.setTimeout(function() {
        this.rippleElement_.classList.remove(this.CssClasses_.IS_VISIBLE);
      }.bind(this), 0);
    }
  };

  /**
   * Initialize element.
   */
  MaterialRipple.prototype.init = function() {
    if (this.element_) {
      var recentering =
          this.element_.classList.contains(this.CssClasses_.RIPPLE_CENTER);
      if (!this.element_.classList.contains(
          this.CssClasses_.RIPPLE_EFFECT_IGNORE_EVENTS)) {
        this.rippleElement_ = this.element_.querySelector('.' +
            this.CssClasses_.RIPPLE);
        this.frameCount_ = 0;
        this.rippleSize_ = 0;
        this.x_ = 0;
        this.y_ = 0;

        // Touch start produces a compat mouse down event, which would cause a
        // second ripples. To avoid that, we use this property to ignore the first
        // mouse down after a touch start.
        this.ignoringMouseDown_ = false;

        this.boundDownHandler = this.downHandler_.bind(this);
        this.element_.addEventListener('mousedown',
          this.boundDownHandler);
        this.element_.addEventListener('touchstart',
            this.boundDownHandler);

        this.boundUpHandler = this.upHandler_.bind(this);
        this.element_.addEventListener('mouseup', this.boundUpHandler);
        this.element_.addEventListener('mouseleave', this.boundUpHandler);
        this.element_.addEventListener('touchend', this.boundUpHandler);
        this.element_.addEventListener('blur', this.boundUpHandler);

        /**
         * Getter for frameCount_.
         * @return {number} the frame count.
         */
        this.getFrameCount = function() {
          return this.frameCount_;
        };

        /**
         * Setter for frameCount_.
         * @param {number} fC the frame count.
         */
        this.setFrameCount = function(fC) {
          this.frameCount_ = fC;
        };

        /**
         * Getter for rippleElement_.
         * @return {Element} the ripple element.
         */
        this.getRippleElement = function() {
          return this.rippleElement_;
        };

        /**
         * Sets the ripple X and Y coordinates.
         * @param  {number} newX the new X coordinate
         * @param  {number} newY the new Y coordinate
         */
        this.setRippleXY = function(newX, newY) {
          this.x_ = newX;
          this.y_ = newY;
        };

        /**
         * Sets the ripple styles.
         * @param  {boolean} start whether or not this is the start frame.
         */
        this.setRippleStyles = function(start) {
          if (this.rippleElement_ !== null) {
            var transformString;
            var scale;
            var size;
            var offset = 'translate(' + this.x_ + 'px, ' + this.y_ + 'px)';

            if (start) {
              scale = this.Constant_.INITIAL_SCALE;
              size = this.Constant_.INITIAL_SIZE;
            } else {
              scale = this.Constant_.FINAL_SCALE;
              size = this.rippleSize_ + 'px';
              if (recentering) {
                offset = 'translate(' + this.boundWidth / 2 + 'px, ' +
                  this.boundHeight / 2 + 'px)';
              }
            }

            transformString = 'translate(-50%, -50%) ' + offset + scale;

            this.rippleElement_.style.webkitTransform = transformString;
            this.rippleElement_.style.msTransform = transformString;
            this.rippleElement_.style.transform = transformString;

            if (start) {
              this.rippleElement_.classList.remove(this.CssClasses_.IS_ANIMATING);
            } else {
              this.rippleElement_.classList.add(this.CssClasses_.IS_ANIMATING);
            }
          }
        };

        /**
         * Handles an animation frame.
         */
        this.animFrameHandler = function() {
          if (this.frameCount_-- > 0) {
            window.requestAnimationFrame(this.animFrameHandler.bind(this));
          } else {
            this.setRippleStyles(false);
          }
        };
      }
    }
  };

  // The component registers itself. It can assume componentHandler is available
  // in the global scope.
  componentHandler.register({
    constructor: MaterialRipple,
    classAsString: 'MaterialRipple',
    cssClass: 'mdl-js-ripple-effect',
    widget: false
  });
})();