fonteditor-core/src/ttf/table/table.js

fonts (ttf, woff, woff2, eot, svg, otf) parse, write, transform, glyph adjust.

/**
 * @file ttf表基类
 * @author mengke01(kekee000@gmail.com)
 */

import struct from './struct';
import error from '../error';
/* eslint-disable no-invalid-this */
/**
 * 读取表结构
 *
 * @param {Reader} reader reader对象
 * @return {Object} 当前对象
 */
function read(reader) {

    const offset = this.offset;

    if (undefined !== offset) {
        reader.seek(offset);
    }

    const me = this;

    this.struct.forEach((item) => {
        const name = item[0];
        const type = item[1];
        let typeName = null;
        switch (type) {
        case struct.Int8:
        case struct.Uint8:
        case struct.Int16:
        case struct.Uint16:
        case struct.Int32:
        case struct.Uint32:
            typeName = struct.names[type];
            me[name] = reader.read(typeName);
            break;

        case struct.Fixed:
            me[name] = reader.readFixed();
            break;

        case struct.LongDateTime:
            me[name] = reader.readLongDateTime();
            break;

        case struct.Bytes:
            me[name] = reader.readBytes(reader.offset, item[2] || 0);
            break;

        case struct.Char:
            me[name] = reader.readChar();
            break;

        case struct.String:
            me[name] = reader.readString(reader.offset, item[2] || 0);
            break;

        default:
            error.raise(10003, name, type);
        }
    });

    return this.valueOf();
}

/**
 * 写表结构
 *
 * @param {Object} writer writer对象
 * @param {Object} ttf 已解析的ttf对象
 *
 * @return {Writer} 返回writer对象
 */
function write(writer, ttf) {
    const table = ttf[this.name];

    if (!table) {
        error.raise(10203, this.name);
    }

    this.struct.forEach((item) => {
        const name = item[0];
        const type = item[1];
        let typeName = null;
        switch (type) {
        case struct.Int8:
        case struct.Uint8:
        case struct.Int16:
        case struct.Uint16:
        case struct.Int32:
        case struct.Uint32:
            typeName = struct.names[type];
            writer.write(typeName, table[name]);
            break;

        case struct.Fixed:
            writer.writeFixed(table[name]);
            break;

        case struct.LongDateTime:
            writer.writeLongDateTime(table[name]);
            break;

        case struct.Bytes:
            writer.writeBytes(table[name], item[2] || 0);
            break;

        case struct.Char:
            writer.writeChar(table[name]);
            break;

        case struct.String:
            writer.writeString(table[name], item[2] || 0);
            break;

        default:
            error.raise(10003, name, type);
        }
    });

    return writer;
}

/**
 * 获取ttf表的size大小
 *
 * @param {string} name 表名
 * @return {number} 表大小
 */
function size() {

    let sz = 0;
    this.struct.forEach((item) => {
        const type = item[1];
        switch (type) {
        case struct.Int8:
        case struct.Uint8:
            sz += 1;
            break;

        case struct.Int16:
        case struct.Uint16:
            sz += 2;
            break;

        case struct.Int32:
        case struct.Uint32:
        case struct.Fixed:
            sz += 4;
            break;

        case struct.LongDateTime:
            sz += 8;
            break;

        case struct.Bytes:
            sz += item[2] || 0;
            break;

        case struct.Char:
            sz += 1;
            break;

        case struct.String:
            sz += item[2] || 0;
            break;

        default:
            error.raise(10003, name, type);
        }
    });

    return sz;
}

/**
 * 获取对象的值
 *
 * @return {*} 当前对象的值
 */
function valueOf() {
    const val = {};
    const me = this;
    this.struct.forEach(item => {
        val[item[0]] = me[item[0]];
    });

    return val;
}

export default {
    read,
    write,
    size,
    valueOf,

    /**
     * 创建一个表结构
     *
     * @param {string} name 表名
     * @param {Array<[string, number]>} struct 表结构
     * @param {Object} proto 原型
     * @return {Function} 表构造函数
     */
    create(name, struct, proto) {
        class Table {
            constructor(offset) {
                this.name = name;
                this.struct = struct;
                this.offset = offset;
            }
        }

        Table.prototype.read = read;
        Table.prototype.write = write;
        Table.prototype.size = size;
        Table.prototype.valueOf = valueOf;
        Object.assign(Table.prototype, proto);
        return Table;
    }
};