Files
openlayers/src/ol/source/IIIF.js
Lutz Helm 58efe1f850 Limit IIIF tile source percentages to 10 decimals max
IIIF Image API versions 1 and 2 recommend limiting the number of
decimals digits to 10 at most.
2019-05-09 18:00:18 +02:00

249 lines
9.6 KiB
JavaScript

/**
* @module ol/source/IIIF
*/
import {DEFAULT_TILE_SIZE} from '../tilegrid/common.js';
import {getTopLeft} from '../extent.js';
import {CustomTile} from './Zoomify.js';
import {Versions} from '../format/IIIFInfo.js';
import {assert} from '../asserts.js';
import TileGrid from '../tilegrid/TileGrid.js';
import TileImage from './TileImage.js';
/**
* @typedef {Object} Options
* @property {import("./Source.js").AttributionLike} [attributions] Attributions.
* @property {boolean} [attributionsCollapsible=true] Attributions are collapsible.
* @property {number} [cacheSize]
* @property {null|string} [crossOrigin]
* @property {import("../proj.js").ProjectionLike} [projection]
* @property {number} [tilePixelRatio]
* @property {number} [reprojectionErrorThreshold=0.5]
* @property {string} [url] Base URL of the IIIF Image service.
* This shoulf be the same as the IIIF Image @id.
* @property {import("../size.js").Size} [size] Size of the image [width, height].
* @property {import("../size.js").Size[]} [sizes] Supported scaled image sizes.
* Content of the IIIF info.json 'sizes' property, but as array of Size objects.
* @property {import("../extent.js").Extent} [extent=[0, -height, width, 0]]
* @property {number} [transition]
* @property {number|import("../size.js").Size} [tileSize] Tile size.
* Same tile size is used for all zoom levels. If tile size is a number,
* a square tile is assumed. If the IIIF image service supports arbitrary
* tiling (sizeByH, sizeByW or sizeByPct as well as regionByPx and regionByPct
* are supported), the default tilesize is 256.
* @property {boolean} [wrapX=false]
*/
function formatPercentage(percentage) {
return percentage.toLocaleString('en', {maximumFractionDigits: 10});
}
/**
* @classdesc
* Layer source for tile data in IIIF format.
* @api
*/
class IIIF extends TileImage {
constructor(opt_options) {
const options = opt_options || {};
let baseUrl = options.url || '';
baseUrl = baseUrl + (baseUrl.lastIndexOf('/') === baseUrl.length - 1 || baseUrl === '' ? '' : '/');
const version = options.version || Versions.VERSION2;
const sizes = options.sizes || [];
const size = options.size;
// TODO Appropriate error code
assert(size != undefined && Array.isArray(size) && size.length == 2 &&
!isNaN(size[0]) && size[0] > 0 && !isNaN(size[1] && size[1] > 0), 999);
const width = size[0];
const height = size[1];
const tileSize = options.tileSize;
const format = options.format || 'jpg';
const quality = options.quality || (options.version == Versions.VERSION1 ? 'native' : 'default');
let resolutions = options.resolutions || [];
const features = options.features || [];
const extent = options.extent || [0, -height, width, 0];
const supportsListedSizes = sizes != undefined && Array.isArray(sizes) && sizes.length > 0;
const supportsListedTiles = tileSize != undefined && (Number.isInteger(tileSize) && tileSize > 0 || Array.isArray(tileSize) && tileSize.length > 0);
const supportsArbitraryTiling = features != undefined && Array.isArray(features) &&
(features.includes('regionByPx') || features.includes('regionByPct')) &&
(features.includes('sizeByWh') || features.includes('sizeByH') ||
features.includes('sizeByW') || features.includes('sizeByPct'));
let tileWidth,
tileHeight,
maxZoom;
resolutions.sort(function(a, b) {
return b - a;
});
if (supportsListedTiles || supportsArbitraryTiling) {
if (tileSize != undefined) {
if (Number.isInteger(tileSize) && tileSize > 0) {
tileWidth = tileSize;
tileHeight = tileSize;
} else if (Array.isArray(tileSize) && tileSize.length > 0) {
if (tileSize.length == 1 || tileSize[1] == undefined && Number.isInteger(tileSize[0])) {
tileWidth = tileSize[0];
tileHeight = tileSize[0];
}
if (tileSize.length == 2) {
if (Number.isInteger(tileSize[0]) && Number.isInteger(tileSize[1])) {
tileWidth = tileSize[0];
tileHeight = tileSize[1];
} else if (tileSize[0] == undefined && Number.isInteger(tileSize[1])) {
tileWidth = tileSize[1];
tileHeight = tileSize[1];
}
}
}
}
if (tileWidth === undefined || tileHeight === undefined) {
tileWidth = DEFAULT_TILE_SIZE;
tileHeight = DEFAULT_TILE_SIZE;
}
if (resolutions.length == 0) {
maxZoom = Math.max(
Math.ceil(Math.log(width / tileWidth) / Math.LN2),
Math.ceil(Math.log(height / tileHeight) / Math.LN2)
);
for (let i = maxZoom; i >= 0; i--) {
resolutions.push(Math.pow(2, i));
}
} else {
const maxScaleFactor = Math.max([...resolutions]);
// TODO maxScaleFactor might not be a power to 2
maxZoom = Math.round(Math.log(maxScaleFactor) / Math.LN2);
}
} else {
// No tile support.
tileWidth = width;
tileHeight = height;
resolutions = [];
if (supportsListedSizes) {
/*
* 'sizes' provided. Use full region in different resolutions. Every
* resolution has only one tile.
*/
sizes.sort(function(a, b) {
return a[0] - b[0];
});
for (let i = 0; i < sizes.length; i++) {
const resolution = width / sizes[i][0];
resolutions.push(resolution);
maxZoom = i;
}
} else {
// No useful image information at all. Try pseudo tile with full image.
resolutions.push(1);
sizes.push([width, height]);
maxZoom = 0;
}
}
const tileGrid = new TileGrid({
tileSize: [tileWidth, tileHeight],
extent: extent,
origin: getTopLeft(extent),
resolutions: resolutions
});
const tileUrlFunction = function(tileCoord, pixelRatio, projection) {
let regionParam,
sizeParam;
const zoom = tileCoord[0];
if (maxZoom < zoom) {
return;
}
const tileX = tileCoord[1],
tileY = tileCoord[2],
scale = resolutions[zoom];
if (tileX < 0 || Math.ceil(width / scale / tileWidth) <= tileX ||
tileY < 0 || Math.ceil(height / scale / tileHeight) <= tileY) {
return;
}
if (supportsArbitraryTiling || supportsListedTiles) {
const regionX = tileX * tileWidth * scale,
regionY = tileY * tileHeight * scale;
let regionW = tileWidth * scale,
regionH = tileHeight * scale,
sizeW = tileWidth,
sizeH = tileHeight;
if (regionX + regionW > width) {
regionW = width - regionX;
}
if (regionY + regionH > height) {
regionH = height - regionY;
}
if (regionX + tileWidth * scale > width) {
sizeW = Math.floor((width - regionX + scale - 1) / scale);
}
if (regionY + tileHeight * scale > height) {
sizeH = Math.floor((height - regionY + scale - 1) / scale);
}
const sizeHBySizeW = Math.round(sizeW / regionW * regionH),
sizeWBySizeH = Math.round(sizeH / regionH * regionW),
preferSizeByH = (sizeHBySizeW > sizeH) && (sizeW == sizeWBySizeH);
if (regionX == 0 && regionW == width && regionY == 0 && regionH == height) {
// canonical full image region parameter is 'full', not 'x,y,w,h'
regionParam = 'full';
} else if (!supportsArbitraryTiling || features.includes('regionByPx')) {
regionParam = regionX + ',' + regionY + ',' + regionW + ',' + regionH;
} else if (features.includes('regionByPct')) {
const pctX = formatPercentage(regionX / width * 100),
pctY = formatPercentage(regionY / height * 100),
pctW = formatPercentage(regionW / width * 100),
pctH = formatPercentage(regionH / height * 100);
regionParam = 'pct:' + pctX + ',' + pctY + ',' + pctW + ',' + pctH;
}
if (version == Versions.VERSION3 && (!supportsArbitraryTiling || features.includes('sizeByWh'))) {
sizeParam = sizeW + ',' + sizeH;
} else if (!supportsArbitraryTiling || features.includes('sizeByW') && (!preferSizeByH || !(features.includes('sizeByH')))) {
sizeParam = sizeW + ',';
} else if (features.includes('sizeByH')) {
sizeParam = ',' + sizeH;
} else if (features.includes('sizeByWh')) {
sizeParam = sizeW + ',' + sizeH;
} else if (features.includes('sizeByPct')) {
sizeParam = 'pct:' + formatPercentage(100 / scale);
}
} else {
regionParam = 'full';
if (supportsListedSizes) {
sizeParam = sizes[zoom][0] + ',' + (version == Versions.VERSION3 ? sizes[zoom][1] : '');
} else {
sizeParam = version == Versions.VERSION3 ? 'max' : 'full';
}
}
return baseUrl + regionParam + '/' + sizeParam + '/0/' + quality + '.' + format;
};
const IiifTileClass = CustomTile.bind(null, tileGrid);
super({
attributions: options.attributions,
attributionsCollapsible: options.attributionsCollapsible,
cacheSize: options.cacheSize,
crossOrigin: options.crossOrigin,
opaque: options.opaque,
projection: options.projection,
reprojectionErrorThreshold: options.reprojectionErrorThreshold,
state: options.state,
tileClass: IiifTileClass,
transition: options.transition,
wrapX: options.wrapX !== undefined ? options.wrapX : false,
tileGrid: tileGrid,
tilePixelRatio: options.tilePixelRatio,
tileUrlFunction: tileUrlFunction
});
}
}
export default IIIF;