PolylineCollection - CesiumJS API 文档

new Cesium.PolylineCollection(options)

一种可转换的多线集.

Example polylines

Polylines are added and removed from the collection using PolylineCollection#add 和 PolylineCollection#remove .

Performance:

For best performance, prefer a few collections, each with many polylines, to 许多收藏,每个只有几条多线. 组织收藏以便多线同一更新频率的集合中为 i.e .,不包含的多线更改应该在一个集合中;改变每个框架的多线应该在另一个集合中收藏; 等.

Name Type Description

options

object

optional 下列属性的对象 :

Name	Type	Default	Description
`modelMatrix`	Matrix4	`Matrix4.IDENTITY`	optional The 4x4 transformation matrix that transforms each polyline from model to world coordinates.
`debugShowBoundingVolume`	boolean	`false`	optional For debugging only. Determines if this primitive's commands' bounding spheres are shown.
`show`	boolean	`true`	optional Determines if the polylines in the collection will be shown.

Example:

// Create a polyline collection with two polylines
const polylines = new Cesium.PolylineCollection();
polylines.add({
  positions : Cesium.Cartesian3.fromDegreesArray([
    -75.10, 39.57,
    -77.02, 38.53,
    -80.50, 35.14,
    -80.12, 25.46]),
  width : 2
});

polylines.add({
  positions : Cesium.Cartesian3.fromDegreesArray([
    -73.10, 37.57,
    -75.02, 36.53,
    -78.50, 33.14,
    -78.12, 23.46]),
  width : 4
});

See:

Members

debugShowBoundingVolume : boolean

此属性仅用于调试;不用于生产,也不优化.

绘制原始中每个绘图命令的边框.

Default Value: false

length : number

返回此收藏中的多行数。这通常用于 PolylineCollection#get to iterate over all the polylines 在收藏中.

modelMatrix : Matrix4

4x4变换矩阵,将本集合中的每个聚线从模型变为世界坐标. 当这是身份矩阵时, 聚线被绘制在世界坐标中, . i.e−., 地球的 WGS84−坐标. 本地参考框架可以通过提供不同的变换矩阵来使用, 如返回的变换矩阵 by Transforms.eastNorthUpToFixedFrame.

Default Value: Matrix4.IDENTITY

show : boolean

确定是否显示此收藏中的多线 .

Default Value: true

Methods

add(options) → Polyline

在收藏中创建和添加带有指定初始属性的多线. 添加的多线被返回,以便日后可以修改或从收藏中移除.

Performance:

After calling add, PolylineCollection#update is called and 收藏的顶点缓冲器被重写 - 一个 O(n) 操作,它也导致 CPU 到 GPU % 管理. 对于最佳性能,在拨打 NT 0 update NT 1 前,请加入尽可能多的多线.

Name	Type	Description
`options`	object	optional A template describing the polyline's properties as shown in Example 1.

Returns:

收藏中加入的多线.

Throws:

DeveloperError : This object was destroyed, i.e., destroy() was called.

Example:

// Example 1:  Add a polyline, specifying all the default values.
const p = polylines.add({
  show : true,
  positions : ellipsoid.cartographicArrayToCartesianArray([
           Cesium.Cartographic.fromDegrees(-75.10, 39.57),
           Cesium.Cartographic.fromDegrees(-77.02, 38.53)]),
  width : 1
});

See:

contains(polyline) → boolean

确定此收藏是否包含指定的多线 .

Name	Type	Description
`polyline`	Polyline	要检查的多线.

Returns:

如果此收藏包含多线, 则不正确 .

See:

PolylineCollection#get

destroy()

Destroys the WebGL resources held by this object. Destroying an object allows for deterministic 释放 WebGL 资源,而不是依赖垃圾收集器来摧毁此对象.

Once an object is destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception. Therefore, assign the return value (undefined) to the object as done in the example.

Throws:

DeveloperError : This object was destroyed, i.e., destroy() was called.

Example:

polylines = polylines && polylines.destroy();

See:

PolylineCollection#isDestroyed

get(index) → Polyline

在指定的索引中返回收藏中的多线。指数为零并随着多线的增加而增加。删除多线在之后所有多线在左边,改变他们的指数。此函数通常用于 PolylineCollection#length to iterate over all the polylines 在收藏中.

Performance:

If polylines were removed from the collection and PolylineCollection#update was not called, an implicit O(n) 操作完成.

Name	Type	Description
`index`	number	多线的零基指数.

Returns:

指定指数下的多线 .

Throws:

DeveloperError : This object was destroyed, i.e., destroy() was called.

Example:

// Toggle the show property of every polyline in the collection
const len = polylines.length;
for (let i = 0; i < len; ++i) {
  const p = polylines.get(i);
  p.show = !p.show;
}

See:

PolylineCollection#length

isDestroyed() → boolean

如果此对象被销毁, 返回真实; 否则, 错误 .

If this object was destroyed, it should not be used; calling any function other than isDestroyed will result in a DeveloperError exception.

Returns:

true if this object was destroyed; otherwise, false.

See:

PolylineCollection#destroy

remove(polyline) → boolean

从收藏中删除多线.

Performance:

After calling remove, PolylineCollection#update is called and 收藏的顶点缓冲器被重写 - 一个 O(n) 操作,它也导致 CPU 到 GPU % 管理. 为了达到最佳性能,请在拨打 NT 0 update NT 1 前,尽可能删除多条多线. 如果你打算暂时隐藏一条多线,通常更高效的呼叫 Polyline#show 而不是去除和重新添加多线.

Name	Type	Description
`polyline`	Polyline	要删除的多线.

Returns:

true if the polyline was removed; false if the polyline was not found in the collection.

Throws:

DeveloperError : This object was destroyed, i.e., destroy() was called.

Example:

const p = polylines.add(...);
polylines.remove(p);  // Returns true

See:

removeAll()

从收藏中删除所有多行.

Performance:

O(n). It is more efficient to remove all the polylines 从收藏开始,然后添加新收藏,而不是完全创建新收藏.

Throws:

DeveloperError : This object was destroyed, i.e., destroy() was called.

Example:

polylines.add(...);
polylines.add(...);
polylines.removeAll();

See:

update()

Called when Viewer or CesiumWidget render the scene to 获得使这个原始化所需的绘图命令.

不要直接调用此函数。记录下来的只是列出场景拍摄时可能宣传的例外情况:

Throws:

RuntimeError : Vertex texture fetch support is required to render primitives with per-instance attributes. The maximum number of vertex texture image units must be greater than zero.