From eb3bd6beb1f3f1fbac11a1763aaf8b2c136ac356 Mon Sep 17 00:00:00 2001
From: Chris Mills <chrisdavidmills@gmail.com>
Date: Thu, 28 Dec 2023 11:25:15 +0000
Subject: [PATCH] fix: descriptions of discrete animation behavior between
 visible and hidden (#690)
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### Description

In https://github.com/mdn/data/pull/688, part of the work was to add
descriptions of the new specific animation behavior of certain
"discrete" animated properties — `display`, `content-visibility`, and
`overlay` — when animating from a hidden state or a visible state.
However, on talking to some Chrome engineering folks about this, I
realized that some of my descriptions were not quite right.

This PR aims to fix those descriptions.

The description I was sent by the Chrome engineering folk is as follows:

"The idea behind "p = 1" is that during transitions between certain
values for certain properties which we consider invisible to visible or
vice versa, the browser will automatically choose the "visible" option
for the duration of the animation it creates.
For example, if you transition from "display:none" to "display:block",
the element will be "display:block" for the entire animation created by
the transition.
And likewise if you transition from "display:block" to "display:none",
the element will be "display:block" for the entire animation created by
the transition.
However, if you transition from "display:flex" to "display:block", the
element's display value will switch halfway through the animation.
This behavior is applied to content-visibility:hidden, display:none,
visibility:hidden, and overlay:none."

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### Motivation

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### Additional details

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### Related issues and pull requests

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---
 css/properties.json        |  6 +++---
 css/properties.schema.json |  5 ++---
 l10n/css.json              | 11 ++++-------
 3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/css/properties.json b/css/properties.json
index 0334ff3c..451bc12d 100644
--- a/css/properties.json
+++ b/css/properties.json
@@ -4483,7 +4483,7 @@
     "syntax": "visible | auto | hidden",
     "media": "all",
     "inherited": false,
-    "animationType": "discreteHiddenSwapAt0",
+    "animationType": "discreteButVisibleForDurationWhenAnimatedHidden",
     "percentages": "no",
     "groups": [
       "CSS Containment"
@@ -4582,7 +4582,7 @@
     "syntax": "[ <display-outside> || <display-inside> ] | <display-listitem> | <display-internal> | <display-box> | <display-legacy>",
     "media": "all",
     "inherited": false,
-    "animationType": "discreteNoneSwapAt0",
+    "animationType": "discreteButVisibleForDurationWhenAnimatedNone",
     "percentages": "no",
     "groups": [
       "CSS Display"
@@ -7619,7 +7619,7 @@
     "syntax": "none | auto",
     "media": "visual",
     "inherited": false,
-    "animationType": "discreteSwapAt1",
+    "animationType": "discreteButVisibleForDurationWhenAnimatedNone",
     "percentages": "no",
     "groups": [
       "CSS Positioning"
diff --git a/css/properties.schema.json b/css/properties.schema.json
index e29479e9..cebf15ff 100644
--- a/css/properties.schema.json
+++ b/css/properties.schema.json
@@ -21,9 +21,8 @@
         "byComputedValueTypeNormalAnimatesAsObliqueZeroDeg",
         "color",
         "discrete",
-        "discreteHiddenSwapAt0",
-        "discreteNoneSwapAt0",
-        "discreteSwapAt1",
+        "discreteButVisibleForDurationWhenAnimatedHidden",
+        "discreteButVisibleForDurationWhenAnimatedNone",
         "eachOfShorthandPropertiesExceptUnicodeBiDiAndDirection",
         "filterList",
         "fontStretch",
diff --git a/l10n/css.json b/l10n/css.json
index c60b62f1..ef895f86 100644
--- a/l10n/css.json
+++ b/l10n/css.json
@@ -654,14 +654,11 @@
     "fr": "discrète",
     "ja": "離散値"
   },
-  "discreteHiddenSwapAt0": {
-    "en-US": "Discrete behavior but when animating from <code>hidden</code> swaps to end value at progress > 0 rather than 0.5"
+  "discreteButVisibleForDurationWhenAnimatedHidden": {
+    "en-US": "Discrete behavior except when animating to or from <code>hidden</code> is visible for the entire duration"
   },
-  "discreteNoneSwapAt0": {
-    "en-US": "Discrete behavior but when animating from <code>none</code> swaps to end value at progress > 0 rather than 0.5"
-  },
-  "discreteSwapAt1": {
-    "en-US": "Discrete behavior but swaps to end value at progress 1 rather than 0.5"
+  "discreteButVisibleForDurationWhenAnimatedNone": {
+    "en-US": "Discrete behavior except when animating to or from <code>none</code> is visible for the entire duration"
   },
   "eachOfShorthandPropertiesExceptUnicodeBiDiAndDirection": {
     "de": "wie jede der Kurzschreibweisen Eigenschaften (alle Eigenschaften außer {{cssxref(\"unicode-bidi\")}} und {{cssxref(\"direction\")}})",