@cantoo/pdf-lib/es/core/embedders/CMap.js

Create and modify PDF files with JavaScript

import { toHexString, toHexStringOfMinLength } from '../../utils/index.js';
import { hasSurrogates, highSurrogate, isWithinBMP, lowSurrogate, } from '../../utils/unicode.js';
/** `glyphs` should be an array of unique glyphs */
export const createCmap = (glyphs, glyphId) => {
    const bfChars = new Array(glyphs.length);
    for (let idx = 0, len = glyphs.length; idx < len; idx++) {
        const glyph = glyphs[idx];
        const id = cmapHexFormat(cmapHexString(glyphId(glyph)));
        const unicode = cmapHexFormat(...glyph.codePoints.map(cmapCodePointFormat));
        bfChars[idx] = [id, unicode];
    }
    return fillCmapTemplate(bfChars);
};
/* =============================== Templates ================================ */
const fillCmapTemplate = (bfChars) => `\
/CIDInit /ProcSet findresource begin
12 dict begin
begincmap
/CIDSystemInfo <<
  /Registry (Adobe)
  /Ordering (UCS)
  /Supplement 0
>> def
/CMapName /Adobe-Identity-UCS def
/CMapType 2 def
1 begincodespacerange
<0000><ffff>
endcodespacerange
${bfChars.length} beginbfchar
${bfChars.map(([glyphId, codePoint]) => `${glyphId} ${codePoint}`).join('\n')}
endbfchar
endcmap
CMapName currentdict /CMap defineresource pop
end
end\
`;
/* =============================== Utilities ================================ */
const cmapHexFormat = (...values) => `<${values.join('')}>`;
const cmapHexString = (value) => toHexStringOfMinLength(value, 4);
const cmapCodePointFormat = (codePoint) => {
    if (isWithinBMP(codePoint))
        return cmapHexString(codePoint);
    if (hasSurrogates(codePoint)) {
        const hs = highSurrogate(codePoint);
        const ls = lowSurrogate(codePoint);
        return `${cmapHexString(hs)}${cmapHexString(ls)}`;
    }
    const hex = toHexString(codePoint);
    const msg = `0x${hex} is not a valid UTF-8 or UTF-16 codepoint.`;
    throw new Error(msg);
};
//# sourceMappingURL=CMap.js.map