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Add relative move and rotate to rel plugin (#794)

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The relative position in rel plugin is currently based on the world coordinate. So for the same effect, like fly in from the right-hand side, we must use different `data-rel-x/y/z` value. Why not let the plugin do the hard part?

So I introduce a `data-rel-position`, when set to `relative`, all relative attribute is based on the position and rotation of previous slide. So no matter the rotation of previous slide, data-rel-x="1000" always looks like fly in from the right-hand side. We can change the position and rotation of one slide, and the position of all following slides will be changed too.

When `data-rel-position` is set to `relative`, relative rotation has a clear meaning. It describes the relative rotations between slides. We don't need to set rotations for all slide, setting the key slides is enough. If `data-rel-position` is not relative, the effect of `data-rel-rotate-x/y/z` is not clear, so they're only used when `data-rel-position="relative"`.

After the introduction of relative rotation, there're 6 attribute that will inherit from previous slide. If we want to set a relative X move, we have to set all other 5 attributes to 0. It's boring. So a `data-rel-clear` is used to set all 6 attributes to 0, and then the value specified in current slide is applied. 

The `examples/3D-positions/index.html` shows some usage. As you can see, the html code of two slide ring is the same, and slides except for the first two in a ring has no position attributes. It work by inheriting the previous one.

This PR invokes a lot math calculations. Basically, the rotation of a slide is translated into the coordinate describing the directions of X/Y/Z axes. And `data-rel-x/y/z` can be easily calculated by that. The rotations is the hard part, I mainly use the algorithm in the Quaternions and spatial rotation - Wikipedia to compose two and more rotations.  I'm not a math guy, hope I don't make much mistakes.
This commit is contained in:
thawk
2022-04-25 02:37:50 +08:00
committed by GitHub
parent d3760dfa0a
commit 629f7686f3
18 changed files with 10537 additions and 101 deletions
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4
qunit_test_runner.html
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@@ -13,6 +13,7 @@
<div id="qunit"></div>
<div id="qunit-fixture"></div>
<script src="node_modules/qunit/qunit/qunit.js"></script>
<script src="node_modules/qunit-assert-close/qunit-assert-close.js"></script>
<!-- The QUnit tests. -->
<script src="test/helpers.js"></script>
<!-- Core tests -->
@@ -21,5 +22,8 @@
<!-- Plugins -->
<script src="src/plugins/navigation/navigation_tests.js"></script>
<script src="test/plugins/rel/relative_to_screen_size_tests.js"></script>
<script src="test/plugins/rel/rotation_tests.js"></script>
<script src="test/plugins/rel/padding_tests.js"></script>
<script src="test/plugins/rel/rel_to_tests.js"></script>
</body>
</html>