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// Helper for SVG WPT tests: assert that two SVGTransform objects are equal.
//
// Per SVG 2 §8.5, an SVGTransform's observable state is (type, angle,
// matrix.{a,b,c,d,e,f}); `angle` is 0 by spec for matrix/translate/scale.
//
// Default epsilon absorbs tan(45°) round-trip and 32-to-64-bit float
// conversions while still catching real divergence.
//
// Two ways to call it:
//
// // 1. With an SVGTransform built via the DOM API:
// const expected = svg.createSVGTransform();
// expected.setTranslate(50, 0);
// assert_svg_transform_equals(text.transform.animVal.getItem(0), expected);
//
// // 2. With a literal descriptor object (no createSVGTransform boilerplate):
// assert_svg_transform_equals(text.transform.animVal.getItem(0),
// {translate: [50, 0]});
function assert_svg_transform_equals(actual, expected, epsilon = 1e-6, description = '') {
if (!(expected instanceof SVGTransform)) {
expected = svg_transform_from_descriptor(expected);
}
const prefix = description ? description + ': ' : '';
assert_equals(actual.type, expected.type, prefix + 'type');
assert_approx_equals(actual.angle, expected.angle, epsilon, prefix + 'angle');
for (const matrix_component of ['a', 'b', 'c', 'd', 'e', 'f']) {
assert_approx_equals(actual.matrix[matrix_component], expected.matrix[matrix_component], epsilon,
prefix + 'matrix.' + matrix_component);
}
}
// Build an SVGTransform from a literal descriptor:
// {translate: [tx, ty?]} ty defaults to 0
// {scale: [sx, sy?]} sy defaults to sx
// {rotate: [angle, cx?, cy?]} cx/cy default to 0
// {skewX: angle} | {skewY: angle}
// {matrix: [a, b, c, d, e, f]}
function svg_transform_from_descriptor(d) {
const t = svg.createSVGTransform();
if ('translate' in d) {
const [tx, ty = 0] = d.translate;
t.setTranslate(tx, ty);
} else if ('scale' in d) {
const [sx, sy = sx] = d.scale;
t.setScale(sx, sy);
} else if ('rotate' in d) {
const [angle, cx = 0, cy = 0] = d.rotate;
t.setRotate(angle, cx, cy);
} else if ('skewX' in d) {
t.setSkewX(d.skewX);
} else if ('skewY' in d) {
t.setSkewY(d.skewY);
} else if ('matrix' in d) {
const m = svg.createSVGMatrix();
[m.a, m.b, m.c, m.d, m.e, m.f] = d.matrix;
t.setMatrix(m);
} else {
throw new Error('assert_svg_transform_equals: unknown descriptor ' +
JSON.stringify(d));
}
return t;
}