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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /devtools/shared/qrcode/index.js | |
parent | Initial commit. (diff) | |
download | firefox-esr-upstream.tar.xz firefox-esr-upstream.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'devtools/shared/qrcode/index.js')
-rw-r--r-- | devtools/shared/qrcode/index.js | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/devtools/shared/qrcode/index.js b/devtools/shared/qrcode/index.js new file mode 100644 index 0000000000..4dcc4f6598 --- /dev/null +++ b/devtools/shared/qrcode/index.js @@ -0,0 +1,116 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +"use strict"; + +// Lazily require encoder and decoder in case only one is needed +Object.defineProperty(this, "Encoder", { + get: () => + require("resource://devtools/shared/qrcode/encoder/index.js").Encoder, +}); +Object.defineProperty(this, "QRRSBlock", { + get: () => + require("resource://devtools/shared/qrcode/encoder/index.js").QRRSBlock, +}); +Object.defineProperty(this, "QRErrorCorrectLevel", { + get: () => + require("resource://devtools/shared/qrcode/encoder/index.js") + .QRErrorCorrectLevel, +}); +Object.defineProperty(this, "decoder", { + get: () => { + // Some applications don't ship the decoder, see moz.build + try { + return require("resource://devtools/shared/qrcode/decoder/index.js"); + } catch (e) { + return null; + } + }, +}); + +/** + * There are many "versions" of QR codes, which describes how many dots appear + * in the resulting image, thus limiting the amount of data that can be + * represented. + * + * The encoder used here allows for versions 1 - 10 (more dots for larger + * versions). + * + * It expects you to pick a version large enough to contain your message. Here + * we search for the mimimum version based on the message length. + * @param string message + * Text to encode + * @param string quality + * Quality level: L, M, Q, H + * @return integer + */ +exports.findMinimumVersion = function (message, quality) { + const msgLength = message.length; + const qualityLevel = QRErrorCorrectLevel[quality]; + for (let version = 1; version <= 10; version++) { + const rsBlocks = QRRSBlock.getRSBlocks(version, qualityLevel); + let maxLength = rsBlocks.reduce((prev, block) => { + return prev + block.dataCount; + }, 0); + // Remove two bytes to fit header info + maxLength -= 2; + if (msgLength <= maxLength) { + return version; + } + } + throw new Error("Message too large"); +}; + +/** + * Simple wrapper around the underlying encoder's API. + * @param string message + * Text to encode + * @param string quality (optional) + Quality level: L, M, Q, H + * @param integer version (optional) + * QR code "version" large enough to contain the message + * @return object with the following fields: + * * src: an image encoded a data URI + * * height: image height + * * width: image width + */ +exports.encodeToDataURI = function (message, quality, version) { + quality = quality || "H"; + version = version || exports.findMinimumVersion(message, quality); + const encoder = new Encoder(version, quality); + encoder.addData(message); + encoder.make(); + return encoder.createImgData(); +}; + +/** + * Simple wrapper around the underlying decoder's API. + * @param string URI + * URI of an image of a QR code + * @return Promise + * The promise will be resolved with a string, which is the data inside + * the QR code. + */ +exports.decodeFromURI = function (URI) { + if (!decoder) { + return Promise.reject(); + } + return new Promise((resolve, reject) => { + decoder.decodeFromURI(URI, resolve, reject); + }); +}; + +/** + * Decode a QR code that has been drawn to a canvas element. + * @param Canvas canvas + * <canvas> element to read from + * @return string + * The data inside the QR code + */ +exports.decodeFromCanvas = function (canvas) { + if (!decoder) { + throw new Error("Decoder not available"); + } + return decoder.decodeFromCanvas(canvas); +}; |