| /* |
| * Copyright (C) 2013 Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** |
| * @constructor |
| * @param {WebInspector.ViewportControl.Provider} provider |
| */ |
| WebInspector.ViewportControl = function(provider) |
| { |
| this.element = document.createElement("div"); |
| this.element.className = "fill"; |
| this.element.style.overflow = "auto"; |
| this._topGapElement = this.element.createChild("div"); |
| this._contentElement = this.element.createChild("div"); |
| this._bottomGapElement = this.element.createChild("div"); |
| |
| this._provider = provider; |
| this.element.addEventListener("scroll", this._onScroll.bind(this), false); |
| this._firstVisibleIndex = 0; |
| this._lastVisibleIndex = -1; |
| } |
| |
| /** |
| * @interface |
| */ |
| WebInspector.ViewportControl.Provider = function() |
| { |
| } |
| |
| WebInspector.ViewportControl.Provider.prototype = { |
| /** |
| * @return {number} |
| */ |
| itemCount: function() { return 0; }, |
| |
| /** |
| * @param {number} index |
| * @return {Element} |
| */ |
| itemElement: function(index) { return null; } |
| } |
| |
| WebInspector.ViewportControl.prototype = { |
| /** |
| * @return {Element} |
| */ |
| contentElement: function() |
| { |
| return this._contentElement; |
| }, |
| |
| refresh: function() |
| { |
| if (!this.element.clientHeight) |
| return; // Do nothing for invisible controls. |
| |
| // Secure scroller. |
| this._contentElement.style.setProperty("height", "100000px"); |
| this._contentElement.removeChildren(); |
| var itemCount = this._provider.itemCount(); |
| if (!itemCount) { |
| this._firstVisibleIndex = -1; |
| this._lastVisibleIndex = -1; |
| return; |
| } |
| |
| if (!this._rowHeight) { |
| var firstElement = this._provider.itemElement(0); |
| this._rowHeight = firstElement.measurePreferredSize(this._contentElement).height; |
| } |
| |
| var visibleFrom = this.element.scrollTop; |
| var visibleTo = visibleFrom + this.element.clientHeight; |
| |
| this._firstVisibleIndex = Math.floor(visibleFrom / this._rowHeight); |
| this._lastVisibleIndex = Math.min(Math.ceil(visibleTo / this._rowHeight), itemCount) - 1; |
| |
| this._topGapElement.style.height = (this._rowHeight * this._firstVisibleIndex) + "px"; |
| this._bottomGapElement.style.height = (this._rowHeight * (itemCount - this._lastVisibleIndex - 1)) + "px"; |
| |
| for (var i = this._firstVisibleIndex; i <= this._lastVisibleIndex; ++i) |
| this._contentElement.appendChild(this._provider.itemElement(i)); |
| // Release scroller protection. |
| this._contentElement.style.removeProperty("height"); |
| }, |
| |
| /** |
| * @param {Event} event |
| */ |
| _onScroll: function(event) |
| { |
| this.refresh(); |
| }, |
| |
| /** |
| * @return {number} |
| */ |
| rowsPerViewport: function() |
| { |
| return Math.floor(this.element.clientHeight / this._rowHeight); |
| }, |
| |
| /** |
| * @return {number} |
| */ |
| firstVisibleIndex: function() |
| { |
| return this._firstVisibleIndex; |
| }, |
| |
| /** |
| * @return {number} |
| */ |
| lastVisibleIndex: function() |
| { |
| return this._lastVisibleIndex; |
| }, |
| |
| /** |
| * @return {?Element} |
| */ |
| renderedElementAt: function(index) |
| { |
| if (index < this._firstVisibleIndex) |
| return null; |
| if (index > this._lastVisibleIndex) |
| return null; |
| return this._contentElement.childNodes[index - this._firstVisibleIndex]; |
| }, |
| |
| /** |
| * @param {number} index |
| * @param {boolean=} makeLast |
| */ |
| scrollItemIntoView: function(index, makeLast) |
| { |
| if (index > this._firstVisibleIndex && index < this._lastVisibleIndex) |
| return; |
| |
| if (makeLast) |
| this.element.scrollTop = this._rowHeight * (index + 1) - this.element.clientHeight; |
| else |
| this.element.scrollTop = this._rowHeight * index; |
| } |
| } |