Method encode

src/core/qrcode/encoder/Encoder.ts:83–167

(content: string,
        ecLevel: ErrorCorrectionLevel,
        hints: Map<EncodeHintType, any> = null)

    // }

    public static encode(content: string,
        ecLevel: ErrorCorrectionLevel,
        hints: Map<EncodeHintType, any> = null): QRCode /*throws WriterException*/ {

        // Determine what character encoding has been specified by the caller, if any
        let encoding: string = Encoder.DEFAULT_BYTE_MODE_ENCODING;
        const hasEncodingHint: boolean = hints !== null && undefined !== hints.get(EncodeHintType.CHARACTER_SET);
        if (hasEncodingHint) {
            encoding = hints.get(EncodeHintType.CHARACTER_SET).toString();
        }

        // Pick an encoding mode appropriate for the content. Note that this will not attempt to use
        // multiple modes / segments even if that were more efficient. Twould be nice.
        const mode: Mode = this.chooseMode(content, encoding);

        // This will store the header information, like mode and
        // length, as well as "header" segments like an ECI segment.
        const headerBits = new BitArray();

        // Append ECI segment if applicable
        if (mode === Mode.BYTE && (hasEncodingHint || Encoder.DEFAULT_BYTE_MODE_ENCODING !== encoding)) {
            const eci = CharacterSetECI.getCharacterSetECIByName(encoding);
            if (eci !== undefined) {
                this.appendECI(eci, headerBits);
            }
        }

        // (With ECI in place,) Write the mode marker
        this.appendModeInfo(mode, headerBits);

        // Collect data within the main segment, separately, to count its size if needed. Don't add it to
        // main payload yet.
        const dataBits = new BitArray();
        this.appendBytes(content, mode, dataBits, encoding);

        let version: Version;
        if (hints !== null && undefined !== hints.get(EncodeHintType.QR_VERSION)) {
            const versionNumber = Number.parseInt(hints.get(EncodeHintType.QR_VERSION).toString(), 10);
            version = Version.getVersionForNumber(versionNumber);
            const bitsNeeded = this.calculateBitsNeeded(mode, headerBits, dataBits, version);
            if (!this.willFit(bitsNeeded, version, ecLevel)) {
                throw new WriterException('Data too big for requested version');
            }
        } else {
            version = this.recommendVersion(ecLevel, mode, headerBits, dataBits);
        }

        const headerAndDataBits = new BitArray();
        headerAndDataBits.appendBitArray(headerBits);
        // Find "length" of main segment and write it
        const numLetters = mode === Mode.BYTE ? dataBits.getSizeInBytes() : content.length;
        this.appendLengthInfo(numLetters, version, mode, headerAndDataBits);
        // Put data together into the overall payload
        headerAndDataBits.appendBitArray(dataBits);

        const ecBlocks: ECBlocks = version.getECBlocksForLevel(ecLevel);
        const numDataBytes = version.getTotalCodewords() - ecBlocks.getTotalECCodewords();