When the initial value of a styleable property is not specified in a
stylesheet, no transition is started:
.button {
transition: -fx-opacity 1s;
}
.button:hover {
-fx-opacity: 0.5;
}
The expected behavior is that a transition is started in this case, since the
default value of `-fx-opacity` is 1.
The reason for this bug is that `StyleableProperty` implementations do not
start a CSS transition when the value is applied for the first time. The
intention behind this is that a node that is added to the scene graph should
not start transitions. CSS transitions should only be started _after_ the node
has been shown for the first time.
The logic to detect this situation is currently as follows:
// If this.origin == null, we're setting the value for the first time.
// No transition should be started in this case.
TransitionDefinition transition = this.origin != null && getBean()
instanceof Node node ?
NodeHelper.findTransitionDefinition(node, getCssMetaData()) : null;
However, this does not work. When no initial style is specified in the
stylesheet, `this.origin` will not be set, and thus no transition will be
started even after the node has been shown. The new logic works like this:
A `Node.initialCssState` flag is added. Initially, this is `true`. Manually
calling `applyCss` or similar methods will not clear this flag, as we consider
all manual CSS processing to be part of the "initial CSS state". Only at the
end of `Scene.doCSSPass` will this flag be cleared on all nodes that have
expressed their interest. This mechanism ensures that a node will be eligible
for CSS transitions only after the following conditions have been satisfied:
1. The node was added to a scene graph
2. CSS processing was completed for a scene pulse
-------------
Commit messages:
- start transitions only when not in initial CSS state
Changes: https://git.openjdk.org/jfx/pull/1607/files
Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1607&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8342703
Stats: 178 lines in 13 files changed: 152 ins; 8 del; 18 mod
Patch: https://git.openjdk.org/jfx/pull/1607.diff
Fetch: git fetch https://git.openjdk.org/jfx.git pull/1607/head:pull/1607
PR: https://git.openjdk.org/jfx/pull/1607
