import {startsWith, getFileExtension} from '../utils/string';
import {getUrlFromUri} from '../utils/uri';
import {getViewFromDOMImage} from '../image/domReader';
import {fileContentTypes} from './filesLoader';
import {urlContentTypes} from './urlsLoader';
/**
* Raw image loader.
*/
export class RawImageLoader {
/**
* if abort is triggered, all image.onload callbacks have to be cancelled
*
* @type {boolean}
*/
#aborted = false;
/**
* Set the loader options.
*
* @param {object} _opt The input options.
*/
setOptions(_opt) {
// does nothing
}
/**
* Is the load ongoing? TODO...
*
* @returns {boolean} True if loading.
*/
isLoading() {
return true;
}
/**
* Create a Data URI from an HTTP request response.
*
* @param {ArrayBuffer} response The HTTP request response.
* @param {string} dataType The data type.
* @returns {string} The data URI.
*/
#createDataUri(response, dataType) {
// image type
let imageType = dataType;
if (!imageType || imageType === 'jpg') {
imageType = 'jpeg';
}
// create uri
const file = new Blob([response], {type: 'image/' + imageType});
return window.URL.createObjectURL(file);
}
/**
* Load data.
*
* @param {ArrayBuffer|string} buffer The read data.
* @param {string|File} origin The data origin.
* @param {number} index The data index.
*/
load(buffer, origin, index) {
this.#aborted = false;
// create a DOM image
const image = new Image();
// triggered by ctx.drawImage
image.onload = (/*event*/) => {
try {
if (!this.#aborted) {
this.onprogress({
lengthComputable: true,
loaded: 100,
total: 100,
index: index,
source: origin
});
const data = getViewFromDOMImage(image, origin, index);
// only expecting one item
this.onloaditem(data);
this.onload(data);
}
} catch (error) {
this.onerror({
error: error,
source: origin
});
} finally {
this.onloadend({
source: origin
});
}
};
// storing values to pass them on
if (typeof buffer === 'string') {
// file case
image.src = buffer;
} else if (typeof origin === 'string') {
// url case
const ext = origin.split('.').pop().toLowerCase();
image.src = this.#createDataUri(buffer, ext);
}
}
/**
* Abort load.
*/
abort() {
this.#aborted = true;
this.onabort({});
this.onloadend({});
}
/**
* Check if the loader can load the provided file.
*
* @param {object} file The file to check.
* @returns {boolean} True if the file can be loaded.
*/
canLoadFile(file) {
return (typeof file.type !== 'undefined' &&
file.type.match('image.*'));
}
/**
* Check if the loader can load the provided url.
*
* @param {string} url The url to check.
* @param {object} [options] Optional url request options.
* @returns {boolean} True if the url can be loaded.
*/
canLoadUrl(url, options) {
// if there are options.requestHeaders, just base check on them
if (typeof options !== 'undefined' &&
typeof options.requestHeaders !== 'undefined') {
// starts with 'image/'
const isImage = function (element) {
return element.name === 'Accept' &&
startsWith(element.value, 'image/');
};
return typeof options.requestHeaders.find(isImage) !== 'undefined';
}
const urlObjext = getUrlFromUri(url);
// extension
const ext = getFileExtension(urlObjext.pathname);
const hasImageExt = (ext === 'jpeg') || (ext === 'jpg') ||
(ext === 'png') || (ext === 'gif');
// content type (for wado url)
const contentType = urlObjext.searchParams.get('contentType');
const hasContentType = contentType !== null &&
typeof contentType !== 'undefined';
const hasImageContentType = (contentType === 'image/jpeg') ||
(contentType === 'image/png') ||
(contentType === 'image/gif');
return hasContentType ? hasImageContentType : hasImageExt;
}
/**
* Check if the loader can load the provided memory object.
*
* @param {object} mem The memory object.
* @returns {boolean} True if the object can be loaded.
*/
canLoadMemory(mem) {
if (typeof mem.filename !== 'undefined') {
return this.canLoadFile({name: mem.filename});
}
return false;
}
/**
* Get the file content type needed by the loader.
*
* @returns {number} One of the 'fileContentTypes'.
*/
loadFileAs() {
return fileContentTypes.DataURL;
}
/**
* Get the url content type needed by the loader.
*
* @returns {number} One of the 'urlContentTypes'.
*/
loadUrlAs() {
return urlContentTypes.ArrayBuffer;
}
/**
* Handle a load start event.
* Default does nothing.
*
* @param {object} _event The load start event.
*/
onloadstart(_event) {}
/**
* Handle a progress event.
* Default does nothing.
*
* @param {object} _event The progress event.
*/
onprogress(_event) {}
/**
* Handle a load item event.
* Default does nothing.
*
* @param {object} _event The load item event fired
* when a file item has been loaded successfully.
*/
onloaditem(_event) {}
/**
* Handle a load event.
* Default does nothing.
*
* @param {object} _event The load event fired
* when a file has been loaded successfully.
*/
onload(_event) {}
/**
* Handle an load end event.
* Default does nothing.
*
* @param {object} _event The load end event fired
* when a file load has completed, successfully or not.
*/
onloadend(_event) {}
/**
* Handle an error event.
* Default does nothing.
*
* @param {object} _event The error event.
*/
onerror(_event) {}
/**
* Handle an abort event.
* Default does nothing.
*
* @param {object} _event The abort event.
*/
onabort(_event) {}
} // class RawImageLoader