Module: ol/render

ol/render


import * as olRender from 'ol/render';

Functions

getRenderPixel(event, pixel){Pixel}

import {getRenderPixel} from 'ol/render';

Gets the pixel of the event's canvas context from the map viewport's CSS pixel.

Name Type Description
event RenderEvent

Render event.

pixel Pixel

CSS pixel relative to the top-left corner of the map viewport.

Returns:
Pixel on the event's canvas context.

getVectorContext(event){CanvasImmediateRenderer}

import {getVectorContext} from 'ol/render';

Gets a vector context for drawing to the event's canvas.

Name Type Description
event RenderEvent

Render event.

Returns:
Vector context.

toContext(context, options){CanvasImmediateRenderer}

import {toContext} from 'ol/render';

Binds a Canvas Immediate API to a canvas context, to allow drawing geometries to the context's canvas.

The units for geometry coordinates are css pixels relative to the top left corner of the canvas element.

import {toContext} from 'ol/render';
import Fill from 'ol/style/Fill';
import Polygon from 'ol/geom/Polygon';

const canvas = document.createElement('canvas');
const render = toContext(
    canvas.getContext('2d'),
    {size: [100, 100]}
);
render.setFillStrokeStyle(new Fill({ color: blue }));
render.drawPolygon(
    new Polygon([[[0, 0], [100, 100], [100, 0], [0, 0]]])
);
Name Type Description
context CanvasRenderingContext2D

Canvas context.

options

Options.

Name Type Description
size Size | undefined

Desired size of the canvas in css pixels. When provided, both canvas and css size will be set according to the pixelRatio. If not provided, the current canvas and css sizes will not be altered.

pixelRatio number (defaults to window.devicePixelRatio)

Pixel ratio (canvas pixel to css pixel ratio) for the canvas.

Returns:
Canvas Immediate.

Type Definitions

OrderFunction()

A function to be used when sorting features before rendering. It takes two instances of Feature or RenderFeature and returns a {number}.

State{Object}

Properties:
Name Type Description
context CanvasRenderingContext2D

Canvas context that the layer is being rendered to.

feature FeatureLike

Feature.

geometry SimpleGeometry

Geometry.

pixelRatio number

Pixel ratio used by the layer renderer.

resolution number

Resolution that the render batch was created and optimized for. This is not the view's resolution that is being rendered.

rotation number

Rotation of the rendered layer in radians.

ToContextOptions{Object}

Properties:
Name Type Argument Default Description
size Size <optional>

Desired size of the canvas in css pixels. When provided, both canvas and css size will be set according to the pixelRatio. If not provided, the current canvas and css sizes will not be altered.

pixelRatio number <optional>
window.devicePixelRatio

Pixel ratio (canvas pixel to css pixel ratio) for the canvas.