Files
openlayers/src/ol/style/AtlasManager.js

253 lines
8.1 KiB
JavaScript

/**
* @module ol/style/AtlasManager
*/
import {MAX_TEXTURE_SIZE as WEBGL_MAX_TEXTURE_SIZE} from '../webgl.js';
import {VOID} from '../functions.js';
import Atlas from './Atlas.js';
/**
* @typedef {Object} Options
* @property {number} [initialSize=256] The size in pixels of the first atlas image.
* @property {number} [maxSize] The maximum size in pixels of atlas images. Default is
* `webgl/MAX_TEXTURE_SIZE` or 2048 if WebGL is not supported.
* @property {number} [space=1] The space in pixels between images.
*/
/**
* Provides information for an image inside an atlas manager.
* `offsetX` and `offsetY` is the position of the image inside
* the atlas image `image` and the position of the hit-detection image
* inside the hit-detection atlas image `hitImage`.
* @typedef {Object} AtlasManagerInfo
* @property {number} offsetX
* @property {number} offsetY
* @property {HTMLCanvasElement} image
* @property {HTMLCanvasElement} hitImage
*/
/**
* The size in pixels of the first atlas image.
* @type {number}
*/
const INITIAL_ATLAS_SIZE = 256;
/**
* The maximum size in pixels of atlas images.
* @type {number}
*/
const MAX_ATLAS_SIZE = -1;
/**
* @classdesc
* Manages the creation of image atlases.
*
* Images added to this manager will be inserted into an atlas, which
* will be used for rendering.
* The `size` given in the constructor is the size for the first
* atlas. After that, when new atlases are created, they will have
* twice the size as the latest atlas (until `maxSize` is reached).
*
* If an application uses many images or very large images, it is recommended
* to set a higher `size` value to avoid the creation of too many atlases.
* @api
*/
class AtlasManager {
/**
* @param {Options=} opt_options Options.
*/
constructor(opt_options) {
const options = opt_options || {};
/**
* The size in pixels of the latest atlas image.
* @private
* @type {number}
*/
this.currentSize_ = options.initialSize !== undefined ?
options.initialSize : INITIAL_ATLAS_SIZE;
/**
* The maximum size in pixels of atlas images.
* @private
* @type {number}
*/
this.maxSize_ = options.maxSize !== undefined ?
options.maxSize : MAX_ATLAS_SIZE != -1 ?
MAX_ATLAS_SIZE : WEBGL_MAX_TEXTURE_SIZE !== undefined ?
WEBGL_MAX_TEXTURE_SIZE : 2048;
/**
* The size in pixels between images.
* @private
* @type {number}
*/
this.space_ = options.space !== undefined ? options.space : 1;
/**
* @private
* @type {Array<import("./Atlas.js").default>}
*/
this.atlases_ = [new Atlas(this.currentSize_, this.space_)];
/**
* The size in pixels of the latest atlas image for hit-detection images.
* @private
* @type {number}
*/
this.currentHitSize_ = this.currentSize_;
/**
* @private
* @type {Array<import("./Atlas.js").default>}
*/
this.hitAtlases_ = [new Atlas(this.currentHitSize_, this.space_)];
}
/**
* @param {string} id The identifier of the entry to check.
* @return {?AtlasManagerInfo} The position and atlas image for the
* entry, or `null` if the entry is not part of the atlas manager.
*/
getInfo(id) {
/** @type {?import("./Atlas.js").AtlasInfo} */
const info = this.getInfo_(this.atlases_, id);
if (!info) {
return null;
}
const hitInfo = /** @type {import("./Atlas.js").AtlasInfo} */ (this.getInfo_(this.hitAtlases_, id));
return this.mergeInfos_(info, hitInfo);
}
/**
* @private
* @param {Array<import("./Atlas.js").default>} atlases The atlases to search.
* @param {string} id The identifier of the entry to check.
* @return {?import("./Atlas.js").AtlasInfo} The position and atlas image for the entry,
* or `null` if the entry is not part of the atlases.
*/
getInfo_(atlases, id) {
for (let i = 0, ii = atlases.length; i < ii; ++i) {
const atlas = atlases[i];
const info = atlas.get(id);
if (info) {
return info;
}
}
return null;
}
/**
* @private
* @param {import("./Atlas.js").AtlasInfo} info The info for the real image.
* @param {import("./Atlas.js").AtlasInfo} hitInfo The info for the hit-detection
* image.
* @return {?AtlasManagerInfo} The position and atlas image for the
* entry, or `null` if the entry is not part of the atlases.
*/
mergeInfos_(info, hitInfo) {
return (
/** @type {AtlasManagerInfo} */ ({
offsetX: info.offsetX,
offsetY: info.offsetY,
image: info.image,
hitImage: hitInfo.image
})
);
}
/**
* Add an image to the atlas manager.
*
* If an entry for the given id already exists, the entry will
* be overridden (but the space on the atlas graphic will not be freed).
*
* If `renderHitCallback` is provided, the image (or the hit-detection version
* of the image) will be rendered into a separate hit-detection atlas image.
*
* @param {string} id The identifier of the entry to add.
* @param {number} width The width.
* @param {number} height The height.
* @param {function(CanvasRenderingContext2D, number, number): void} renderCallback
* Called to render the new image onto an atlas image.
* @param {function(CanvasRenderingContext2D, number, number)=} opt_renderHitCallback Called to render a hit-detection image onto a hit
* detection atlas image.
* @param {Object=} opt_this Value to use as `this` when executing
* `renderCallback` and `renderHitCallback`.
* @return {?AtlasManagerInfo} The position and atlas image for the
* entry, or `null` if the image is too big.
*/
add(id, width, height, renderCallback, opt_renderHitCallback, opt_this) {
if (width + this.space_ > this.maxSize_ ||
height + this.space_ > this.maxSize_) {
return null;
}
/** @type {?import("./Atlas.js").AtlasInfo} */
const info = this.add_(false, id, width, height, renderCallback, opt_this);
if (!info) {
return null;
}
// even if no hit-detection entry is requested, we insert a fake entry into
// the hit-detection atlas, to make sure that the offset is the same for
// the original image and the hit-detection image.
const renderHitCallback = opt_renderHitCallback !== undefined ?
opt_renderHitCallback : VOID;
const hitInfo = /** @type {import("./Atlas.js").AtlasInfo} */ (this.add_(true,
id, width, height, renderHitCallback, opt_this));
return this.mergeInfos_(info, hitInfo);
}
/**
* @private
* @param {boolean} isHitAtlas If the hit-detection atlases are used.
* @param {string} id The identifier of the entry to add.
* @param {number} width The width.
* @param {number} height The height.
* @param {function(CanvasRenderingContext2D, number, number): void} renderCallback
* Called to render the new image onto an atlas image.
* @param {Object=} opt_this Value to use as `this` when executing
* `renderCallback` and `renderHitCallback`.
* @return {?import("./Atlas.js").AtlasInfo} The position and atlas image for the entry,
* or `null` if the image is too big.
*/
add_(isHitAtlas, id, width, height, renderCallback, opt_this) {
const atlases = (isHitAtlas) ? this.hitAtlases_ : this.atlases_;
let atlas, info, i, ii;
for (i = 0, ii = atlases.length; i < ii; ++i) {
atlas = atlases[i];
info = atlas.add(id, width, height, renderCallback, opt_this);
if (info) {
return info;
} else if (!info && i === ii - 1) {
// the entry could not be added to one of the existing atlases,
// create a new atlas that is twice as big and try to add to this one.
let size;
if (isHitAtlas) {
size = Math.min(this.currentHitSize_ * 2, this.maxSize_);
this.currentHitSize_ = size;
} else {
size = Math.min(this.currentSize_ * 2, this.maxSize_);
this.currentSize_ = size;
}
atlas = new Atlas(size, this.space_);
atlases.push(atlas);
// run the loop another time
++ii;
}
}
return null;
}
}
export default AtlasManager;