1 files changed, 47 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/canvas/offscreen/text/2d.text.drawing.style.letterSpacing.measure.relative.worker.js b/testing/web-platform/tests/html/canvas/offscreen/text/2d.text.drawing.style.letterSpacing.measure.relative.worker.js
new file mode 100644
index 0000000000..59d17ef82c
--- /dev/null
+++ b/testing/web-platform/tests/html/canvas/offscreen/text/2d.text.drawing.style.letterSpacing.measure.relative.worker.js
@@ -0,0 +1,47 @@
+// DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py.
+// OffscreenCanvas test in a worker:2d.text.drawing.style.letterSpacing.measure.relative
+// Description:Testing letter spacing with font-relative length
+// Note:
+
+importScripts("/resources/testharness.js");
+importScripts("/html/canvas/resources/canvas-tests.js");
+
+var t = async_test("Testing letter spacing with font-relative length");
+var t_pass = t.done.bind(t);
+var t_fail = t.step_func(function(reason) {
+    throw reason;
+});
+t.step(function() {
+
+var canvas = new OffscreenCanvas(100, 50);
+var ctx = canvas.getContext('2d');
+
+_assertSame(ctx.letterSpacing, '0px', "ctx.letterSpacing", "'0px'");
+_assertSame(ctx.wordSpacing, '0px', "ctx.wordSpacing", "'0px'");
+ctx.font = "10px monospace";
+var width_normal = ctx.measureText('Hello World').width;
+var ch_width = width_normal / 11;
+
+function test_letter_spacing(value, difference_spacing, epsilon) {
+  ctx.letterSpacing = value;
+  _assertSame(ctx.letterSpacing, value, "ctx.letterSpacing", "value");
+  _assertSame(ctx.wordSpacing, '0px', "ctx.wordSpacing", "'0px'");
+  width_with_letter_spacing = ctx.measureText('Hello World').width;
+  assert_approx_equals(width_with_letter_spacing, width_normal + difference_spacing, epsilon, "letter spacing doesn't work.");
+}
+
+// The first value is the letter Spacing to be set, the second value the
+// change in length of string 'Hello World', note that there are 11 letters
+// in 'hello world', so the length difference is always letterSpacing * 11.
+// and the third value is the acceptable differencee for the length change.
+test_cases = [['1em', 110, 0.1],
+              ['-0.1em', -11, 0.1],
+              ['1ch', 11 * ch_width, 0.1]]
+
+for (const test_case of test_cases) {
+  test_letter_spacing(test_case[0], test_case[1], test_case[2]);
+}
+t.done();
+
+});
+done();