Steffen Becker
29d82ee657
An EMF is replayed into SVG (import/emf.ts): window/viewport plus world transform, a DC stack, pens/brushes/fonts, the poly and path records, EXTTEXTOUT and embedded DIBs. It rides the lazy pre-pass both importers already use for TIFF, so a document without one pays nothing. a fixture fixture's seven MATLAB plots arrive as pictures now.
86 lines
3.1 KiB
TypeScript
86 lines
3.1 KiB
TypeScript
// A Windows metafile drawn as SVG (import/emf.ts): the records a plot consists of —
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// a pen, a polyline, a label — and the signature check that rejects anything else.
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import { describe, it, expect } from 'vitest';
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import { emfToSvg } from '../../src/lib/import/emf';
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function record(type: number, body: Uint8Array): Uint8Array {
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const out = new Uint8Array(8 + body.length);
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const v = new DataView(out.buffer);
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v.setUint32(0, type, true);
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v.setUint32(4, out.length, true);
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out.set(body, 8);
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return out;
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}
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const body = (bytes: number, fill: (v: DataView) => void) => {
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const b = new Uint8Array(bytes);
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fill(new DataView(b.buffer));
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return b;
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};
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function header(): Uint8Array {
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return body(88, (v) => {
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v.setUint32(0, 1, true);
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v.setUint32(4, 88, true);
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[0, 0, 199, 99].forEach((n, i) => v.setInt32(8 + i * 4, n, true)); // rclBounds
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v.setUint32(40, 0x464d4520, true);
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});
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}
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function metafile(...records: Uint8Array[]): Uint8Array {
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const parts = [header(), ...records];
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const out = new Uint8Array(parts.reduce((n, p) => n + p.length, 0));
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let at = 0;
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for (const p of parts) { out.set(p, at); at += p.length; }
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return out;
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}
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const createPen = (handle: number, color: number) => record(0x26, body(20, (v) => {
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v.setUint32(0, handle, true);
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v.setUint32(4, 0, true); // PS_SOLID
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v.setInt32(8, 2, true); // width
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v.setUint32(16, color, true); // 0x00bbggrr
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}));
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const selectObject = (handle: number) => record(0x25, body(4, (v) => v.setUint32(0, handle, true)));
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const polyline16 = (points: [number, number][]) => record(0x57, body(20 + points.length * 4, (v) => {
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v.setUint32(16, points.length, true);
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points.forEach(([x, y], i) => { v.setInt16(20 + i * 4, x, true); v.setInt16(22 + i * 4, y, true); });
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}));
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const extTextOutW = (x: number, y: number, text: string) => record(0x54, body(68 + text.length * 2, (v) => {
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v.setInt32(28, x, true); // EmrText.Reference
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v.setInt32(32, y, true);
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v.setUint32(36, text.length, true);
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v.setUint32(40, 76, true); // offString, from the record's own start
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[...text].forEach((c, i) => v.setUint16(68 + i * 2, c.charCodeAt(0), true));
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}));
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const svgOf = (bytes: Uint8Array) => {
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const svg = emfToSvg(bytes);
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expect(svg).toBeTruthy();
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expect(new DOMParser().parseFromString(svg!, 'image/svg+xml').getElementsByTagName('parsererror').length).toBe(0);
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return svg!;
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};
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describe('a metafile', () => {
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it('draws a polyline in its pen’s colour, sized by the header bounds', () => {
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const svg = svgOf(metafile(createPen(1, 0x0000ff), selectObject(1), polyline16([[0, 0], [50, 60]])));
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expect(svg).toContain('width="200" height="100"');
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expect(svg).toContain('stroke="#ff0000"'); // COLORREF is 0x00bbggrr
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expect(svg).toContain('M 0 0 L 50 60');
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});
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it('writes out a label at its reference point', () => {
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const svg = svgOf(metafile(extTextOutW(10, 40, 'Coherence')));
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expect(svg).toContain('>Coherence<');
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expect(svg).toContain('x="10"');
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});
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it('declines bytes that are not a metafile', () => {
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expect(emfToSvg(new Uint8Array(200))).toBeNull();
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expect(emfToSvg(new Uint8Array([1, 2, 3]))).toBeNull();
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});
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});
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