MOUSE_OVER & ROLL_OVER

本文通过一个小实验对比了MouseOver与RollOver两种鼠标事件的区别。MouseOver事件具备冒泡机制,即当鼠标移过一个对象及其子对象时都会触发该事件;而RollOver事件不具备冒泡机制,只有当鼠标移过对象本身时才会触发。

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MOUSE_OVER & ROLL_OVER
2009年7月17日 | 标签:
转:http://www.youyee.org/viewpoint/article_view.php?topic_id=90

在某种意义上。RollOver和MouseOver是一样的,他们都是监听鼠标在DisplayObject上的触发事件,很多时候大家都可以互换使用。正如RollOut和MouseOut一样,但是有人便开始问了,如果一样为什么还要存在两个这样的事件呢?不是多此一举了吗?

实际上RollOver和MouseOver是有微妙的差别的。

假设现在存在一个Sprite姑且命名其为father,然后Sprite里面有一个背景(DisplayObject)和一个按钮(SimpleButton),背景面积比按钮要大且处于最低层(index = 0),按钮处于背景的正中处于背景的上一层(index = 1),那么此时如果我们先开始对father监听MouseEvent.MouseOver事件:

1st.鼠标移到背景上,但还没有触碰到按钮,这个时候father发出了一个MouseEvent.MOUSE_OVER事件。

2nd.接着把鼠标继续移到按钮上,此时father又会发出一个MouseEvent.MOUSE_OVER事件。

然后我们继续对father监听MouseEvent.ROLL_OVER事件:

1st.鼠标移到背景上,但还没有触碰到按钮,这个时候father发出了一个MouseEvent.ROLL_OVER事件。

2nd.接着把鼠标继续移到按钮上,此时father并没有发出MouseEvent.ROLL_OVER事件。

从上面的小实验应该能够大体区分出两个事件的微妙与不同了,相信有经验的朋友也一定猜出来其中的缘由了,之所以造成两个事件不同的本质因素就是冒泡机制 (Bubble),ROLL_OVER明显不具备冒泡属性,而MOUSE_OVER则有,所以即便是子元素(Child)的鼠标事件也会一层层的冒出来被addEventListener接收到。从而也可以解释MouseEvent.MOUSE_OUT和MouseEvent.ROLL_OVER之间的微妙差别了
本文转自jiahuafu博客园博客,原文链接http://www.cnblogs.com/jiahuafu/archive/2010/12/01/1892605.html如需转载请自行联系原作者

jiahuafu

// A simple demo of 3D Tiles feature picking with hover and select behavior // Building data courtesy of NYC OpenData portal: http://www1.nyc.gov/site/doitt/initiatives/3d-building.page const viewer = new Cesium.Viewer(“cesiumContainer”, { terrain: Cesium.Terrain.fromWorldTerrain(), }); viewer.scene.globe.depthTestAgainstTerrain = true; // Set the initial camera view to look at Manhattan const initialPosition = Cesium.Cartesian3.fromDegrees( -74.01881302800248, 40.69114333714821, 753, ); const initialOrientation = new Cesium.HeadingPitchRoll.fromDegrees( 21.27879878293835, -21.34390550872461, 0.0716951918898415, ); viewer.scene.camera.setView({ destination: initialPosition, orientation: initialOrientation, endTransform: Cesium.Matrix4.IDENTITY, }); // Load the NYC buildings tileset try { const tileset = await Cesium.Cesium3DTileset.fromIonAssetId(75343); viewer.scene.primitives.add(tileset); } catch (error) { console.log(Error loading tileset: ${error}); } // HTML overlay for showing feature name on mouseover const nameOverlay = document.createElement(“div”); viewer.container.appendChild(nameOverlay); nameOverlay.className = “backdrop”; nameOverlay.style.display = “none”; nameOverlay.style.position = “absolute”; nameOverlay.style.bottom = “0”; nameOverlay.style.left = “0”; nameOverlay.style[“pointer-events”] = “none”; nameOverlay.style.padding = “4px”; nameOverlay.style.backgroundColor = “black”; // Information about the currently selected feature const selected = { feature: undefined, originalColor: new Cesium.Color(), }; // An entity object which will hold info about the currently selected feature for infobox display const selectedEntity = new Cesium.Entity(); // Get default left click handler for when a feature is not picked on left click const clickHandler = viewer.screenSpaceEventHandler.getInputAction( Cesium.ScreenSpaceEventType.LEFT_CLICK, ); // Update the ‘nameOverlay’ for the given picked feature, // at the given (screen) position. function updateNameOverlay(pickedFeature, position) { if (!Cesium.defined(pickedFeature)) { nameOverlay.style.display = “none”; return; } // A feature was picked, so show its overlay content nameOverlay.style.display = “block”; nameOverlay.style.bottom = ${viewer.canvas.clientHeight - position.y}px; nameOverlay.style.left = ${position.x}px; const name = pickedFeature.getProperty(“BIN”); nameOverlay.textContent = name; } // Create the HTML that will be put into the info box that shows // information about the currently selected feature function createPickedFeatureDescription(pickedFeature) { const description = ${ '<table class="cesium-infoBox-defaultTable"><tbody>' + "<tr><th>BIN</th><td>" }${pickedFeature.getProperty("BIN")}</td></tr> + <tr><th>DOITT ID</th><td>${pickedFeature.getProperty( "DOITT_ID", )}</td></tr> + <tr><th>SOURCE ID</th><td>${pickedFeature.getProperty( "SOURCE_ID", )}</td></tr> + <tr><th>Longitude</th><td>${pickedFeature.getProperty( "Longitude", )}</td></tr> + <tr><th>Latitude</th><td>${pickedFeature.getProperty( "Latitude", )}</td></tr> + <tr><th>Height</th><td>${pickedFeature.getProperty("Height")}</td></tr> + <tr><th>Terrain Height (Ellipsoid)</th><td>${pickedFeature.getProperty( "TerrainHeight", )}</td></tr> + </tbody></table>; return description; } // If silhouettes are supported, silhouette features in blue on mouse over and silhouette green on mouse click. // If silhouettes are not supported, change the feature color to yellow on mouse over and green on mouse click. if (Cesium.PostProcessStageLibrary.isSilhouetteSupported(viewer.scene)) { // Silhouettes are supported const silhouetteBlue = Cesium.PostProcessStageLibrary.createEdgeDetectionStage(); silhouetteBlue.uniforms.color = Cesium.Color.BLUE; silhouetteBlue.uniforms.length = 0.01; silhouetteBlue.selected = []; const silhouetteGreen = Cesium.PostProcessStageLibrary.createEdgeDetectionStage(); silhouetteGreen.uniforms.color = Cesium.Color.LIME; silhouetteGreen.uniforms.length = 0.01; silhouetteGreen.selected = []; viewer.scene.postProcessStages.add( Cesium.PostProcessStageLibrary.createSilhouetteStage([ silhouetteBlue, silhouetteGreen, ]), ); // Silhouette a feature blue on hover. viewer.screenSpaceEventHandler.setInputAction(function onMouseMove(movement) { // If a feature was previously highlighted, undo the highlight silhouetteBlue.selected = []; // Pick a new feature const pickedFeature = viewer.scene.pick(movement.endPosition); updateNameOverlay(pickedFeature, movement.endPosition); if (!Cesium.defined(pickedFeature)) { return; } // Highlight the feature if it's not already selected. if (pickedFeature !== selected.feature) { silhouetteBlue.selected = [pickedFeature]; } }, Cesium.ScreenSpaceEventType.MOUSE_MOVE); // Silhouette a feature on selection and show metadata in the InfoBox. viewer.screenSpaceEventHandler.setInputAction(function onLeftClick(movement) { // If a feature was previously selected, undo the highlight silhouetteGreen.selected = []; // Pick a new feature const pickedFeature = viewer.scene.pick(movement.position); if (!Cesium.defined(pickedFeature)) { clickHandler(movement); return; } // Select the feature if it's not already selected if (silhouetteGreen.selected[0] === pickedFeature) { return; } // Save the selected feature's original color const highlightedFeature = silhouetteBlue.selected[0]; if (pickedFeature === highlightedFeature) { silhouetteBlue.selected = []; } // Highlight newly selected feature silhouetteGreen.selected = [pickedFeature]; // Set feature infobox description viewer.selectedEntity = selectedEntity; selectedEntity.description = createPickedFeatureDescription(pickedFeature); }, Cesium.ScreenSpaceEventType.LEFT_CLICK); } else { // Silhouettes are not supported. Instead, change the feature color. // Information about the currently highlighted feature const highlighted = { feature: undefined, originalColor: new Cesium.Color(), }; // Color a feature yellow on hover. viewer.screenSpaceEventHandler.setInputAction(function onMouseMove(movement) { // If a feature was previously highlighted, undo the highlight if (Cesium.defined(highlighted.feature)) { highlighted.feature.color = highlighted.originalColor; highlighted.feature = undefined; } // Pick a new feature const pickedFeature = viewer.scene.pick(movement.endPosition); updateNameOverlay(pickedFeature, movement.endPosition); if (!Cesium.defined(pickedFeature)) { return; } // Highlight the feature if it's not already selected. if (pickedFeature !== selected.feature) { highlighted.feature = pickedFeature; Cesium.Color.clone(pickedFeature.color, highlighted.originalColor); pickedFeature.color = Cesium.Color.YELLOW; } }, Cesium.ScreenSpaceEventType.MOUSE_MOVE); // Color a feature on selection and show metadata in the InfoBox. viewer.screenSpaceEventHandler.setInputAction(function onLeftClick(movement) { // If a feature was previously selected, undo the highlight if (Cesium.defined(selected.feature)) { selected.feature.color = selected.originalColor; selected.feature = undefined; } // Pick a new feature const pickedFeature = viewer.scene.pick(movement.position); if (!Cesium.defined(pickedFeature)) { clickHandler(movement); return; } // Select the feature if it’s not already selected if (selected.feature === pickedFeature) { return; } selected.feature = pickedFeature; // Save the selected feature’s original color if (pickedFeature === highlighted.feature) { Cesium.Color.clone(highlighted.originalColor, selected.originalColor); highlighted.feature = undefined; } else { Cesium.Color.clone(pickedFeature.color, selected.originalColor); } // Highlight newly selected feature pickedFeature.color = Cesium.Color.LIME; // Set feature infobox description viewer.selectedEntity = selectedEntity; selectedEntity.description = createPickedFeatureDescription(pickedFeature); }, Cesium.ScreenSpaceEventType.LEFT_CLICK); 1 <style> 2 @import url(…/templates/bucket.css); 3 </style> 4 <div id=“cesiumContainer” class=“fullSize”></div> 5 <div id=“loadingOverlay”><h1>Loading…</h1></div> 6 <div id=“toolbar”></div> 7 结合这些代码做出《结合Cesium实现 3dtile 数据的拾取》 项目目标 通过本实验,需完成以下目标: 安装、配置并使用Cesium进行三维地球。 添加 3dtile 类型的模型数据,实现 3dtile模型数据的可视化。 实现 3dtile 数据的点击拾取查询,返回模型的属性信息 网页上通过按钮添加 3dtile 数据,点击拾取按钮实现点击查询要素信息 项目环境 编程语言:JavaScript 开发工具:Visual Studio Code 注意事项 Cesium配置:确保Cesium的静态资源正确加载,避免页面显示问题,要求将cesium加载纽约建筑改为武汉建筑的代码,摄像头视角改到武汉
06-12
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