Class: CanvasLayer

CanvasLayer

A layer with a HTML5 2D canvas context.
CanvasLayer provides some interface methods for canvas context operations.
You can use it directly, but can't serialize/deserialize a CanvasLayer with JSON in this way.
It is more recommended to extend it with a subclass and implement canvas paintings inside the subclass.

new CanvasLayer(id, options) [source] 

var layer = new CanvasLayer('canvas');

 layer.prepareToDraw = function (context) {
     var size = map.getSize();
     return [size.width, size.height]
 };

 layer.draw = function (context, width, height) {
     context.fillStyle = "#f00";
     context.fillRect(0, 0, w, h);
 };
 layer.addTo(map);
Parameter Type Description
id String | Number layer's id
options Object options defined in options
Extends:
Fires:

Members

  • (constant) options

    • Properties:
    Name Type Description
    options Object configuration options
    Properties
    Name Type Default Description
    doubleBuffer opt Boolean false layer is rendered with doubleBuffer
    animation opt Boolean false if the layer is an animated layer
    fps opt Boolean 1000 / 16 animation fps
    attribution opt String null the attribution of this layer, you can specify company or other information of this layer.
    minZoom opt Number -1 the minimum zoom to display the layer, set to -1 to unlimit it.
    maxZoom opt Number -1 the maximum zoom to display the layer, set to -1 to unlimit it.
    visible opt Boolean true whether to display the layer.
    opacity opt Number 1 opacity of the layer, from 0 to 1.
    zIndex opt Number z index of the layer
    hitDetect opt Boolean true Whether to enable hit detection for layers for cursor styles on this map, disable it to improve performance.
    renderer opt String canvas renderer type, "canvas" in default.
    globalCompositeOperation opt String null (Only for layer rendered with CanvasRenderer) globalCompositeOperation of layer's canvas 2d context.
    debugOutline opt String '#0f0' debug outline's color.
    cssFilter opt String null css filter apply to canvas context's filter
    forceRenderOnMoving opt Boolean false force to render layer when map is moving
    forceRenderOnZooming opt Boolean false force to render layer when map is zooming
    forceRenderOnRotating opt Boolean false force to render layer when map is Rotating
    Overrides:
    Source:

    Methods

  • prepareToDraw(context) [source]

    • An optional interface function called only once before the first draw, useful for preparing your canvas operations.
    Parameter Type Description
    context CanvasRenderingContext2D CanvasRenderingContext2D of the layer canvas.
    Returns:
    Array.<Object>: objects that will be passed to function draw(context, ..) as parameters.

  • draw(context) [source]

    • The required interface function to draw things on the layer canvas.
    Parameter Type Description
    context CanvasRenderingContext2D CanvasRenderingContext2D of the layer canvas.
    params.. * parameters returned by function prepareToDraw(context).

  • redraw() [source]

    • Redraw the layer
    Returns:
    CanvasLayer: this

  • play() [source]

    • Start animation
    Returns:
    CanvasLayer: this

  • pause() [source]

    • Pause the animation
    Returns:
    CanvasLayer: this

  • isPlaying() [source]

    • If the animation is playing
    Returns:
    Boolean:

  • clearCanvas() [source]

    • Clear layer's canvas
    Returns:
    CanvasLayer: this

  • requestMapToRender() [source]

    • Ask the map to redraw the layer canvas without firing any event.
    Returns:
    CanvasLayer: this

  • completeRender() [source]

    • Ask the map to redraw the layer canvas and fire layerload event
    Returns:
    CanvasLayer: this

  • onCanvasCreate() [source]

    • Callback function when layer's canvas is created.
    Override it to do anything needed.

  • onZoomStart(param) [source]

    • The event callback for map's zoomstart event.
    Parameter Type Description
    param Object event parameter

  • onZooming(param) [source]

    • The event callback for map's zooming event.
    Parameter Type Description
    param Object event parameter

  • onZoomEnd(param) [source]

    • The event callback for map's zoomend event.
    Parameter Type Description
    param Object event parameter

  • onMoveStart(param) [source]

    • The event callback for map's movestart event.
    Parameter Type Description
    param Object event parameter

  • onMoving(param) [source]

    • The event callback for map's moving event.
    Parameter Type Description
    param Object event parameter

  • onMoveEnd(param) [source]

    • The event callback for map's moveend event.
    Parameter Type Description
    param Object event parameter

  • onResize(param) [source]

    • The event callback for map's resize event.
    Parameter Type Description
    param Object event parameter

  • doubleBuffer(bufferContext, context) [source]

    • The callback function to double buffer.
    In default, it just draws and return, and you can override it if you need to process the canvas image before drawn.
    Parameter Type Description
    bufferContext CanvasRenderingContext2D CanvasRenderingContext2D of double buffer of the layer canvas.
    context CanvasRenderingContext2D CanvasRenderingContext2D of the layer canvas.

  • (inherited) load() [source]

    • load the tile layer, can't be overrided by sub-classes
    Inherited From:

  • (inherited) getId() [source]

    • Get the layer id
    Inherited From:
    Returns:
    String: id

  • (inherited) setId(id) [source]

    • Set a new id to the layer
    Parameter Type Description
    id String new layer id
    Inherited From:
    Fires:
    Returns:
    Layer: this

  • (inherited) addTo(map) [source]

    • Adds itself to a map.
    Parameter Type Description
    map Map map added to
    Inherited From:
    Returns:
    Layer: this

  • (inherited) setZIndex(zIndex) [source]

    • Set a z-index to the layer
    Parameter Type Description
    zIndex Number layer's z-index
    Inherited From:
    Returns:
    Layer: this

  • (inherited) getZIndex() [source]

    • Get the layer's z-index
    Inherited From:
    Returns:
    Number:

  • (inherited) getMinZoom() [source]

    • Get Layer's minZoom to display
    Inherited From:
    Returns:
    Number:

  • (inherited) getMaxZoom() [source]

    • Get Layer's maxZoom to display
    Inherited From:
    Returns:
    Number:

  • (inherited) getOpacity() [source]

    • Get layer's opacity
    Inherited From:
    Returns:
    Number:

  • (inherited) setOpacity(opacity) [source]

    • Set opacity to the layer
    Parameter Type Description
    opacity Number layer's opacity
    Inherited From:
    Returns:
    Layer: this

  • (protected) (inherited) isCanvasRender() [source]

    • If the layer is rendered by HTML5 Canvas.
    Returns:
    Boolean:

  • (inherited) getMap() [source]

    • Get the map that the layer added to
    Inherited From:
    Returns:
    Map:

  • (inherited) getProjection() [source]

    • Get projection of layer's map
    Inherited From:
    Returns:
    Object:

  • (inherited) bringToFront() [source]

    • Brings the layer to the top of all the layers
    Inherited From:
    Returns:
    Layer: this

  • (inherited) bringToBack() [source]

    • Brings the layer under the bottom of all the layers
    Inherited From:
    Returns:
    Layer: this

  • (inherited) show() [source]

    • Show the layer
    Inherited From:
    Returns:
    Layer: this

  • (inherited) hide() [source]

    • Hide the layer
    Inherited From:
    Returns:
    Layer: this

  • (inherited) isVisible() [source]

    • Whether the layer is visible now.
    Inherited From:
    Returns:
    Boolean:

  • (inherited) remove() [source]

    • Remove itself from the map added to.
    Inherited From:
    Returns:
    Layer: this

  • (inherited) getMask() [source]

    • Get the mask geometry of the layer
    Inherited From:
    Returns:
    Geometry:

  • (inherited) setMask(mask) [source]

    • Set a mask geometry on the layer, only the area in the mask will be displayed.
    Parameter Type Description
    mask Geometry mask geometry, can only be a Marker with vector symbol, a Polygon or a MultiPolygon
    Inherited From:
    Returns:
    Layer: this

  • (inherited) removeMask() [source]

    • Remove the mask
    Inherited From:
    Returns:
    Layer: this

  • (protected) (inherited) onLoad() [source]

    • Prepare Layer's loading, this is a method intended to be overrided by subclasses.
    Inherited From:
    Returns:
    Boolean: true to continue loading, false to cease.

  • (inherited) isLoaded() [source]

    • Whether the layer is loaded
    Inherited From:
    Returns:
    Boolean:

  • (inherited) on(eventsOn, handler, contextopt) [source]

    • Register a handler function to be called whenever this event is fired. 
    foo.on('mousedown mousemove mouseup', onMouseEvent, foo);
    Parameter Type Default Description
    eventsOn String event types to register, seperated by space if more than one.
    handler function handler function to be called
    context opt Object null the context of the handler
    Mixes From:
    Inherited From:
    Returns:
    Any: this

  • (inherited) addEventListener(eventTypes, handler, contextopt) [source]

    • Alias for on
    Parameter Type Default Description
    eventTypes String event types to register, seperated by space if more than one.
    handler function handler function to be called
    context opt Object null the context of the handler
    Mixes From:
    Inherited From:
    Returns:
    : this

  • (inherited) once(eventTypes, handler, contextopt) [source]

    • Same as on, except the listener will only get fired once and then removed. 
    foo.once('mousedown mousemove mouseup', onMouseEvent, foo);
    Parameter Type Default Description
    eventTypes String event types to register, seperated by space if more than one.
    handler function listener handler
    context opt Object null the context of the handler
    Mixes From:
    Inherited From:
    Returns:
    : this

  • (inherited) off(eventsOff, handler, contextopt) [source]

    • Unregister the event handler for the specified event types. 
    foo.off('mousedown mousemove mouseup', onMouseEvent, foo);
    Parameter Type Default Description
    eventsOff String event types to unregister, seperated by space if more than one.
    handler function listener handler
    context opt Object null the context of the handler
    Mixes From:
    Inherited From:
    Returns:
    : this

  • (inherited) removeEventListener(eventTypes, handler, contextopt) [source]

    • Alias for off
    Parameter Type Default Description
    eventTypes String event types to unregister, seperated by space if more than one.
    handler function listener handler
    context opt Object null the context of the handler
    Mixes From:
    Inherited From:
    Returns:
    : this

  • (inherited) listens(eventType, hanlderopt, contextopt) [source]

    • Returns listener's count registered for the event type.
    Parameter Type Default Description
    eventType String an event type
    hanlder opt function null listener function
    context opt Object null the context of the handler
    Mixes From:
    Inherited From:
    Returns:
    Number:

  • (inherited) copyEventListeners(target) [source]

    • Copy all the event listener to the target object
    Parameter Type Description
    target Object target object to copy to.
    Mixes From:
    Inherited From:
    Returns:
    : this

  • (inherited) fire(eventType, param) [source]

    • Fire an event, causing all handlers for that event name to run.
    Parameter Type Description
    eventType String an event type to fire
    param Object parameters for the listener function.
    Mixes From:
    Inherited From:
    Returns:
    : this

  • (inherited) registerJSONType(type) [source]

    • It is a static method.
    Register layer for JSON serialization and assign a JSON type.
    Parameter Type Description
    type String JSON type
    Mixes From:
    Inherited From:

  • (inherited) getJSONClass(type) [source]

    • It is a static method.
    Get class of input JSON type
    Parameter Type Description
    type String JSON type
    Mixes From:
    Inherited From:
    Returns:
    Class: Class

  • (inherited) getJSONType() [source]

    • Get object's JSON Type
    Mixes From:
    Inherited From:
    Returns:
    String:

  • (inherited) registerRenderer(name, clazz) [source]

    • Register a renderer class with the given name.
    Parameter Type Description
    name String renderer's register key
    clazz function renderer's class, a function (not necessarily a Class).
    Mixes From:
    Inherited From:
    Returns:
    *: this

  • (inherited) getRendererClass(name) [source]

    • Get the registered renderer class by the given name
    Parameter Type Description
    name String renderer's register key
    Mixes From:
    Inherited From:
    Returns:
    function: renderer's class

  • (inherited) callInitHooks() [source]

    • Visit and call all the init hooks defined on Class and its parents.
    Inherited From:
    Returns:
    Class: this

  • (inherited) setOptions(options) [source]

    • Merges options with the default options of the object.
    Parameter Type Description
    options Object options to set
    Inherited From:
    Returns:
    Class: this

  • (inherited) config(conf) [source]

    • 1. Return object's options if no parameter is provided.
    2. update an option and enable/disable the handler if a handler with the same name existed. 
    // Get marker's options;
var options = marker.config();
// Set map's option "draggable" to false and disable map's draggable handler.
map.config('draggable', false);
// You can update more than one options like this:
map.config({
    'scrollWheelZoom' : false,
    'doubleClickZoom' : false
});
    Parameter Type Description
    conf Object config to update
    Inherited From:
    Returns:
    Class: this

  • (inherited) onConfig() [source]

    • Default callback when config is called
    Inherited From:

    Events

  • (inherited) idchange [source]

    • idchange event.
    Inherited From:
    Properties:
    Name Type Description
    type String idchange
    target Layer the layer fires the event
    old String value of the old id
    new String value of the new id
    Inherited From:
    Source:

  • (inherited) renderercreate [source]

    • renderercreate event, fired when renderer is created.
    Inherited From:
    Properties:
    Name Type Description
    type String renderercreate
    target Layer the layer fires the event
    renderer Any renderer of the layer
    Inherited From:
    Source:

  • (inherited) resourceload [source]

    • resourceload event, fired when external resources of the layer complete loading.
    Inherited From:
    Properties:
    Name Type Description
    type String resourceload
    target Layer layer
    Inherited From:
    Source:

  • (inherited) canvascreate [source]

    • canvascreate event, fired when canvas created.
    Inherited From:
    Properties:
    Name Type Description
    type String canvascreate
    target Layer layer
    context CanvasRenderingContext2D canvas's context
    gl WebGLRenderingContext2D canvas's webgl context
    Inherited From:
    Source:

  • (inherited) renderstart [source]

    • renderstart event, fired when layer starts to render.
    Inherited From:
    Properties:
    Name Type Description
    type String renderstart
    target Layer layer
    context CanvasRenderingContext2D canvas's context
    Inherited From:
    Source:

  • (inherited) renderend [source]

    • renderend event, fired when layer ends rendering.
    Inherited From:
    Properties:
    Name Type Description
    type String renderend
    target Layer layer
    context CanvasRenderingContext2D canvas's context
    Inherited From:
    Source: