1 files changed, 50 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/canvas/offscreen/text/2d.text.drawing.style.letterSpacing.measure.worker.js b/testing/web-platform/tests/html/canvas/offscreen/text/2d.text.drawing.style.letterSpacing.measure.worker.js
new file mode 100644
index 0000000000..630bf1d486
--- /dev/null
+++ b/testing/web-platform/tests/html/canvas/offscreen/text/2d.text.drawing.style.letterSpacing.measure.worker.js
@@ -0,0 +1,50 @@
+// 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
+// Description:Testing letter spacing with different length units
+// Note:
+
+importScripts("/resources/testharness.js");
+importScripts("/html/canvas/resources/canvas-tests.js");
+
+var t = async_test("Testing letter spacing with different length units");
+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'");
+  var width_normal = ctx.measureText('Hello World').width;
+
+  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,
+  // note that unit such as 1cm/1mm doesn't map to an exact pixel value.
+  test_cases = [['3px', 33, 0.1],
+               ['5px', 55, 0.1],
+               ['-2px', -22, 0.1],
+               ['1em', 110, 0.1],
+               ['-0.1em', -11, 0.1],
+               ['1in', 1056, 0.1],
+               ['-0.1cm', -41.65, 0.2],
+               ['-0.6mm', -24,95, 0.2]]
+
+  for (const test_case of test_cases) {
+    test_letter_spacing(test_case[0], test_case[1], test_case[2]);
+  }
+  t.done();
+});
+done();