114 lines
3.2 KiB
JavaScript
114 lines
3.2 KiB
JavaScript
'use strict'
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/*!
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* Canvas
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* Copyright (c) 2010 LearnBoost <tj@learnboost.com>
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* MIT Licensed
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*/
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const bindings = require('./bindings')
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const Canvas = module.exports = bindings.Canvas
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const Context2d = require('./context2d')
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const PNGStream = require('./pngstream')
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const PDFStream = require('./pdfstream')
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const JPEGStream = require('./jpegstream')
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const FORMATS = ['image/png', 'image/jpeg']
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const util = require('util')
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// TODO || is for Node.js pre-v6.6.0
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Canvas.prototype[util.inspect.custom || 'inspect'] = function () {
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return `[Canvas ${this.width}x${this.height}]`
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}
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Canvas.prototype.getContext = function (contextType, contextAttributes) {
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if (contextType == '2d') {
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const ctx = this._context2d || (this._context2d = new Context2d(this, contextAttributes))
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this.context = ctx
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ctx.canvas = this
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return ctx
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}
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}
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Canvas.prototype.pngStream =
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Canvas.prototype.createPNGStream = function (options) {
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return new PNGStream(this, options)
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}
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Canvas.prototype.pdfStream =
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Canvas.prototype.createPDFStream = function (options) {
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return new PDFStream(this, options)
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}
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Canvas.prototype.jpegStream =
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Canvas.prototype.createJPEGStream = function (options) {
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return new JPEGStream(this, options)
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}
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Canvas.prototype.toDataURL = function (a1, a2, a3) {
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// valid arg patterns (args -> [type, opts, fn]):
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// [] -> ['image/png', null, null]
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// [qual] -> ['image/png', null, null]
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// [undefined] -> ['image/png', null, null]
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// ['image/png'] -> ['image/png', null, null]
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// ['image/png', qual] -> ['image/png', null, null]
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// [fn] -> ['image/png', null, fn]
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// [type, fn] -> [type, null, fn]
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// [undefined, fn] -> ['image/png', null, fn]
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// ['image/png', qual, fn] -> ['image/png', null, fn]
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// ['image/jpeg', fn] -> ['image/jpeg', null, fn]
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// ['image/jpeg', opts, fn] -> ['image/jpeg', opts, fn]
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// ['image/jpeg', qual, fn] -> ['image/jpeg', {quality: qual}, fn]
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// ['image/jpeg', undefined, fn] -> ['image/jpeg', null, fn]
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// ['image/jpeg'] -> ['image/jpeg', null, fn]
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// ['image/jpeg', opts] -> ['image/jpeg', opts, fn]
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// ['image/jpeg', qual] -> ['image/jpeg', {quality: qual}, fn]
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let type = 'image/png'
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let opts = {}
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let fn
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if (typeof a1 === 'function') {
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fn = a1
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} else {
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if (typeof a1 === 'string' && FORMATS.includes(a1.toLowerCase())) {
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type = a1.toLowerCase()
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}
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if (typeof a2 === 'function') {
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fn = a2
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} else {
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if (typeof a2 === 'object') {
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opts = a2
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} else if (typeof a2 === 'number') {
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opts = { quality: Math.max(0, Math.min(1, a2)) }
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}
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if (typeof a3 === 'function') {
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fn = a3
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} else if (undefined !== a3) {
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throw new TypeError(`${typeof a3} is not a function`)
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}
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}
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}
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if (this.width === 0 || this.height === 0) {
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// Per spec, if the bitmap has no pixels, return this string:
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const str = 'data:,'
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if (fn) {
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setTimeout(() => fn(null, str))
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return
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} else {
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return str
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}
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}
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if (fn) {
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this.toBuffer((err, buf) => {
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if (err) return fn(err)
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fn(null, `data:${type};base64,${buf.toString('base64')}`)
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}, type, opts)
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} else {
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return `data:${type};base64,${this.toBuffer(type, opts).toString('base64')}`
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}
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}
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