test_text_lengthAdjust.html

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https://bugzilla.mozilla.org/show_bug.cgi?id=569722

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  <meta charset=UTF-8>

  <title>Test for Bug 569722</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />

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<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=569722">Mozilla Bug 569722</a>

<p id="display"></p>

<div id="content">

  <svg width="400" height="200">

    <text x="0" y="100" style="font: 16px sans-serif">aaa</text>

  </svg>

</div>

<pre id="test">

<script class="testbody" type="application/javascript">

SimpleTest.waitForExplicitFinish();

function close(x, y, message) {

  ok(Math.abs(x - y) < 1e-4, message);

function runTest() {

  var text = document.querySelector("text");

  // get the original length

  var length = text.getComputedTextLength();

  // get the original glyph positions

  var startPositions = [],

      endPositions = [],

      extents = [];

  for (let i = 0; i < 3; i++) {

    startPositions.push(text.getStartPositionOfChar(i));

    endPositions.push(text.getEndPositionOfChar(i));

    extents.push(text.getExtentOfChar(i));

  // widths should all be the same

  is(extents[0].width, extents[1].width);

  is(extents[0].width, extents[2].width);

  var checkCharNumAtPosition = function(x, y, i) {

    var p = document.querySelector("svg").createSVGPoint();

    p.x = x;

    p.y = y;

    is(text.getCharNumAtPosition(p), i, "getCharNumAtPosition(" + i + ")");

};

  var checkPositions = function(start, end, width) {

    for (let i = 0; i < 3; i++) {

      // check their positions

      close(text.getStartPositionOfChar(i).x, start[i], "start position of glyph " + i);

      close(text.getEndPositionOfChar(i).x, end[i], "end position of glyph " + i);

      close(text.getExtentOfChar(i).x, start[i], "left edge of extent of glyph " + i);

      close(text.getExtentOfChar(i).width, width, "width of glyph " + i);

      checkCharNumAtPosition((start[i] + end[i]) / 2, 100, i);

};

  var w = extents[0].width;

  var doLengthAdjustSpacingTest = function() {

    // getComputedTextLength should return the sum of the advances, and since

    // we are just changing the positions of the glyphs, it should be the same

    // as without a textLength="" attribute

    close(text.getComputedTextLength(), length, "getComputedTextLength when lengthAdjust=\"spacing\"");

    // expected start and end positions of the glyphs

    var start = [0, 50 - w / 2, 100 - w];

    var end = [w, 50 + w / 2, 100];

    checkPositions(start, end, w);

};

  // switch to adjust glyph positions, using the default value of lengthAdjust=""

  text.setAttribute("textLength", "100");

  doLengthAdjustSpacingTest();

  // then with an explicit lengthAdjust="spacing"

  text.setAttribute("lengthAdjust", "spacing");

  doLengthAdjustSpacingTest();

  // now test with lengthAdjust="spacingAndGlyphs"

  text.setAttribute("lengthAdjust", "spacingAndGlyphs");

  // now that each glyph is stretched, the total advance should be the textLength

  close(text.getComputedTextLength(), 100, "getComputedTextLength when lengthAdjust=\"spacingAndGlyphs\"");

  // expected start and end positions of the glyphs

  var start = [0, 33.3333, 66.6666];

  var end = [33.3333, 66.6666, 100];

  checkPositions(start, end, 33.3333);

  SimpleTest.finish();

window.addEventListener("load", runTest);

</script>

</pre>

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