【openlayers】CSS3样式的Popups

 一直觉得ol自带的Popup的样式太难看，后来也换了一套自己的皮肤，感觉展示效果还是不怎么地。

看到leafet上的样式挺不错的：

就自己搞个了个，popup主体加个圆角和阴影：

  border-radius: 1.2em 1.2em 1.2em 1.2em;
  box-shadow: 0 3px 14px rgba(0, 0, 0, 0.35);

popup的那个小箭头：矩形旋转45度，使用transform: rotate(45deg)来实现。另外针对不同的浏览器还需要添加不同的hack，例如Opera的-o-transform、Firefox的-moz-transform。

具体效果如下：

 实现的过程如下：

1. 我在OpenLayers.Popup.Framed基础上另写了一个类如下：

   OpenLayers.Popup.CSSFramedCloud = OpenLayers.Class(OpenLayers.Popup.Framed, {
       autoSize: true,
       panMapIfOutOfView: true,
       fixedRelativePosition: false,
   
     positionBlocks: {
           "tl": {
               'offset': new OpenLayers.Pixel(44, -6),
               'padding': new OpenLayers.Bounds(5, 14, 5, 5),
               'blocks': [
                   { 
                       className: 'olwidgetPopupStemTL',
                       size: new OpenLayers.Size(20, 20),
                       anchor: new OpenLayers.Bounds(null, 4, 32, null),
                       position: new OpenLayers.Pixel(0, -28)
                   }
               ]
           },
           "tr": {
               'offset': new OpenLayers.Pixel(-44, -6),
               'padding': new OpenLayers.Bounds(5, 14, 5, 5),
               'blocks': [
                   { 
                       className: "olwidgetPopupStemTR",
                       size: new OpenLayers.Size(20, 20),
                       anchor: new OpenLayers.Bounds(32, 4, null, null),
                       position: new OpenLayers.Pixel(0, -28)
                   }
               ]
           },
           "bl": {
               'offset': new OpenLayers.Pixel(44, 6),
               'padding': new OpenLayers.Bounds(5, 5, 5, 14),
               'blocks': [
                   { 
                       className: "olwidgetPopupStemBL",
                       size: new OpenLayers.Size(20,20),
                       anchor: new OpenLayers.Bounds(null, null, 32, 4),
                       position: new OpenLayers.Pixel(0, 0)
                   }
               ]
           },
           "br": {
               'offset': new OpenLayers.Pixel(-44, 6),
               'padding': new OpenLayers.Bounds(5, 5, 5, 14),
               'blocks': [
                   { 
                       className: "olwidgetPopupStemBR",
                       size: new OpenLayers.Size(20, 20),
                       anchor: new OpenLayers.Bounds(32, null, null, 4),
                       position: new OpenLayers.Pixel(0, 0)
                   }
               ]
           }
       },
   
       initialize: function(id, lonlat, contentSize, contentHTML, anchor, closeBox,
                       closeBoxCallback, relativePosition, separator) {
           if (relativePosition && relativePosition != 'auto') {
               this.fixedRelativePosition = true;
               this.relativePosition = relativePosition;
           }
           if (separator === undefined) {
               this.separator = ' of ';
           } else {
               this.separator = separator;
           }
   
           this.olwidgetCloseBox = closeBox;
           this.olwidgetCloseBoxCallback = closeBoxCallback;
           this.page = 0;
           OpenLayers.Popup.Framed.prototype.initialize.apply(this, [id, lonlat,
               contentSize, contentHTML, anchor, false, null]);
       },
   
       /*
        * 构造popup内部容器。
        */
       setContentHTML: function(contentHTML) {
           if (contentHTML !== null && contentHTML !== undefined) {
               this.contentHTML = contentHTML;
           }
     
           if (this.contentDiv !== null)  {
               var popup = this; 
   
               // 清空旧数据
               this.contentDiv.innerHTML = "";
   
               // 创建内部容器
               var containerDiv = document.createElement("div");
               containerDiv.innerHTML = this.contentHTML;
               containerDiv.className = 'olwidgetPopupContent';
               this.contentDiv.appendChild(containerDiv);
   
               // 创建关闭按钮
               if (this.olwidgetCloseBox) {
                   var closeDiv = document.createElement("div");
                   closeDiv.className = "olwidgetPopupCloseBox";
                   closeDiv.innerHTML = "close";
                   closeDiv.onclick = function(event) {
                       popup.olwidgetCloseBoxCallback.apply(popup, arguments);
                   };
                   this.contentDiv.appendChild(closeDiv);
               }
               if (this.autoSize) {
                   this.registerImageListeners();
                   this.updateSize();
               }
           }
       },
   
       /*
        * 重写createBlocks：使用CSS样式而不是特定的img图片
        */
       createBlocks: function() {
           this.blocks = [];
   
           // since all positions contain the same number of blocks, we can
           // just pick the first position and use its blocks array to create
           // our blocks array
           var firstPosition = null;
           for(var key in this.positionBlocks) {
               firstPosition = key;
               break;
           }
   
           var position = this.positionBlocks[firstPosition];
           for (var i = 0; i < position.blocks.length; i++) {
   
               var block = {};
               this.blocks.push(block);
   
               var divId = this.id + '_FrameDecorationDiv_' + i;
               block.div = OpenLayers.Util.createDiv(divId,
                   null, null, null, "absolute", null, "hidden", null
               );
               this.groupDiv.appendChild(block.div);
           }
       },
       /*
        * 重写updateBlocks
        */
       updateBlocks: function() {
           if (!this.blocks) {
               this.createBlocks();
           }
           if (this.size && this.relativePosition) {
               var position = this.positionBlocks[this.relativePosition];
               for (var i = 0; i < position.blocks.length; i++) {
   
                   var positionBlock = position.blocks[i];
                   var block = this.blocks[i];
   
                   // adjust sizes
                   var l = positionBlock.anchor.left;
                   var b = positionBlock.anchor.bottom;
                   var r = positionBlock.anchor.right;
                   var t = positionBlock.anchor.top;
   
                   // note that we use the isNaN() test here because if the
                   // size object is initialized with a "auto" parameter, the
                   // size constructor calls parseFloat() on the string,
                   // which will turn it into NaN
                   //
                   var w = (isNaN(positionBlock.size.w)) ? this.size.w - (r + l)
                                                         : positionBlock.size.w;
   
                   var h = (isNaN(positionBlock.size.h)) ? this.size.h - (b + t)
                                                         : positionBlock.size.h;
   
                   block.div.style.width = (w < 0 ? 0 : w) + 'px';
                   block.div.style.height = (h < 0 ? 0 : h) + 'px';
   
                   block.div.style.left = (l !== null) ? l + 'px' : '';
                   block.div.style.bottom = (b !== null) ? b + 'px' : '';
                   block.div.style.right = (r !== null) ? r + 'px' : '';
                   block.div.style.top = (t !== null) ? t + 'px' : '';
   
                   block.div.className = positionBlock.className;
               }
   
               this.contentDiv.style.left = this.padding.left + "px";
               this.contentDiv.style.top = this.padding.top + "px";
           }
       },
       updateSize: function() {
           
               return OpenLayers.Popup.prototype.updateSize.apply(this, arguments);
       
       },
   
       CLASS_NAME: "OpenLayers.Popup.CSSFramedCloud"
   });

2. 然后是css样式：

   .olPopupContent {
       overflow: visible !important;
       padding: 0 !important;
   }
   .olPopup {
       z-index: 1005 !important;
   }
   .olwidgetPopupContent {
       background: none repeat scroll 0 0 #FFFFFF;
       border-radius: 1.2em 1.2em 1.2em 1.2em;
       box-shadow: 0 3px 14px rgba(0, 0, 0, 0.35);
       overflow: auto;
       padding: 10px 8px 8px;
   }
   .olwidgetPopupCloseBox {
       background: url("img/popup_icons.png") no-repeat scroll -80px 0 #FFFFFF;
       cursor: pointer;
       height: 0;
       overflow: hidden;
       padding-top: 16px;
       position: absolute;
       right: 10px;
       top: 10px;
       width: 16px;
   }
   .olwidgetPopupCloseBox:hover {
       background-position: -64px 0;
   }
   .olwidgetPopupStemTL,.olwidgetPopupStemTR {
       -moz-transform: rotate(45deg);
       -webkit-transform: rotate(45deg);
       -ms-transform: rotate(45deg);
       -o-transform: rotate(45deg);
       transform: rotate(45deg);
       background: none repeat scroll 0 0 #FFFFFF;
       z-index: 1;
   }
   
   .olwidgetPopupStemBL,.olwidgetPopupStemBR {
       -moz-transform: rotate(45deg);
       -webkit-transform: rotate(45deg);
       -ms-transform: rotate(45deg);
       -o-transform: rotate(45deg);
       transform: rotate(45deg);
       background: none repeat scroll 0 0 #FFFFFF;
       z-index: 1;
   }

   使用方法和OL自带的一样：

    function onFeatureSelect(feature) {
               selectedFeature = feature;
               popup = new OpenLayers.Popup.CSSFramedCloud("chicken", 
                                        feature.geometry.getBounds().getCenterLonLat(),
                                        null,
                                        "<div style='font-size:.8em'>Feature: " + feature.id +"<br>Area: " + feature.geometry.getArea()+"</div>",
                                        null, true, onPopupClose);
               feature.popup = popup;
               map.addPopup(popup);
           }

    源码：https://github.com/shitao1988/OL_CSSPopups

 在线示例：http://www.fenglgis.com/github/OL_CSSPopups/select-feature-openpopup.html