Fixed css precedence ordering - Githubissues

afonsolage / bevy_ecss

Bevy crate which uses a subset of CSS to update Bevy ECS components

Apache License 2.0

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Fixed css precedence ordering #40

Closed afonsolage closed 1 year ago

afonsolage commented 1 year ago

Fixes #21

Added an weight on Selector which is based on Specificity by Mozilla.

In short terms, we compute a sum based weight for each element on rule, where:

Component names, since they are more broad, just add 1;
Class names are a bit more specific, so add 10;
Names are very specific, so add 100;
PseudoClass adds the same as Class, so 10;

In that way:

.ui-bg text would have a total weight of 11;
.ui-bg text:hover would have a total weight of 21;
#alert.ui-bg text:hover would have a total weight of 121;

Low weight rules are applied first so they got overwritten by high weight rules.