150 lines
4.6 KiB
JavaScript
150 lines
4.6 KiB
JavaScript
/**
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* @module ol/renderer/canvas/IntermediateCanvas
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*/
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import {inherits, nullFunction} from '../../index.js';
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import _ol_coordinate_ from '../../coordinate.js';
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import {createCanvasContext2D} from '../../dom.js';
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import {containsExtent, intersects} from '../../extent.js';
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import _ol_renderer_canvas_Layer_ from '../canvas/Layer.js';
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import _ol_transform_ from '../../transform.js';
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/**
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* @constructor
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* @abstract
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* @extends {ol.renderer.canvas.Layer}
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* @param {ol.layer.Layer} layer Layer.
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*/
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var _ol_renderer_canvas_IntermediateCanvas_ = function(layer) {
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_ol_renderer_canvas_Layer_.call(this, layer);
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/**
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* @protected
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* @type {ol.Transform}
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*/
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this.coordinateToCanvasPixelTransform = _ol_transform_.create();
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/**
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* @private
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* @type {CanvasRenderingContext2D}
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*/
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this.hitCanvasContext_ = null;
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};
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inherits(_ol_renderer_canvas_IntermediateCanvas_, _ol_renderer_canvas_Layer_);
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/**
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* @inheritDoc
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*/
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_ol_renderer_canvas_IntermediateCanvas_.prototype.composeFrame = function(frameState, layerState, context) {
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this.preCompose(context, frameState);
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var image = this.getImage();
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if (image) {
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// clipped rendering if layer extent is set
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var extent = layerState.extent;
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var clipped = extent !== undefined &&
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!containsExtent(extent, frameState.extent) &&
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intersects(extent, frameState.extent);
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if (clipped) {
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this.clip(context, frameState, /** @type {ol.Extent} */ (extent));
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}
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var imageTransform = this.getImageTransform();
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// for performance reasons, context.save / context.restore is not used
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// to save and restore the transformation matrix and the opacity.
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// see http://jsperf.com/context-save-restore-versus-variable
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var alpha = context.globalAlpha;
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context.globalAlpha = layerState.opacity;
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// for performance reasons, context.setTransform is only used
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// when the view is rotated. see http://jsperf.com/canvas-transform
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var dx = imageTransform[4];
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var dy = imageTransform[5];
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var dw = image.width * imageTransform[0];
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var dh = image.height * imageTransform[3];
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context.drawImage(image, 0, 0, +image.width, +image.height,
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Math.round(dx), Math.round(dy), Math.round(dw), Math.round(dh));
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context.globalAlpha = alpha;
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if (clipped) {
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context.restore();
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}
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}
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this.postCompose(context, frameState, layerState);
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};
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/**
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* @abstract
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* @return {HTMLCanvasElement|HTMLVideoElement|Image} Canvas.
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*/
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_ol_renderer_canvas_IntermediateCanvas_.prototype.getImage = function() {};
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/**
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* @abstract
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* @return {!ol.Transform} Image transform.
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*/
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_ol_renderer_canvas_IntermediateCanvas_.prototype.getImageTransform = function() {};
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/**
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* @inheritDoc
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*/
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_ol_renderer_canvas_IntermediateCanvas_.prototype.forEachFeatureAtCoordinate = function(coordinate, frameState, hitTolerance, callback, thisArg) {
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var layer = this.getLayer();
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var source = layer.getSource();
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var resolution = frameState.viewState.resolution;
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var rotation = frameState.viewState.rotation;
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var skippedFeatureUids = frameState.skippedFeatureUids;
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return source.forEachFeatureAtCoordinate(
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coordinate, resolution, rotation, hitTolerance, skippedFeatureUids,
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/**
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* @param {ol.Feature|ol.render.Feature} feature Feature.
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* @return {?} Callback result.
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*/
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function(feature) {
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return callback.call(thisArg, feature, layer);
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});
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};
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/**
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* @inheritDoc
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*/
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_ol_renderer_canvas_IntermediateCanvas_.prototype.forEachLayerAtCoordinate = function(coordinate, frameState, callback, thisArg) {
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if (!this.getImage()) {
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return undefined;
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}
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if (this.getLayer().getSource().forEachFeatureAtCoordinate !== nullFunction) {
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// for ImageCanvas sources use the original hit-detection logic,
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// so that for example also transparent polygons are detected
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return _ol_renderer_canvas_Layer_.prototype.forEachLayerAtCoordinate.apply(this, arguments);
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} else {
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var pixel = _ol_transform_.apply(this.coordinateToCanvasPixelTransform, coordinate.slice());
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_ol_coordinate_.scale(pixel, frameState.viewState.resolution / this.renderedResolution);
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if (!this.hitCanvasContext_) {
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this.hitCanvasContext_ = createCanvasContext2D(1, 1);
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}
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this.hitCanvasContext_.clearRect(0, 0, 1, 1);
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this.hitCanvasContext_.drawImage(this.getImage(), pixel[0], pixel[1], 1, 1, 0, 0, 1, 1);
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var imageData = this.hitCanvasContext_.getImageData(0, 0, 1, 1).data;
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if (imageData[3] > 0) {
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return callback.call(thisArg, this.getLayer(), imageData);
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} else {
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return undefined;
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}
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}
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};
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export default _ol_renderer_canvas_IntermediateCanvas_;
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