Date: Tue, 15 Nov 2016 14:29:03 +0100
Subject: [PATCH] Port HTML note on zoom/accessibility
Ports the note warning/note recently added to
https://w3c.github.io/html/document-metadata.html#the-meta-element about
not suppressing/limiting user's ability to zoom, and the note that UAs
can ignore these directives anyway
---
css-device-adapt/Overview.bs | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/css-device-adapt/Overview.bs b/css-device-adapt/Overview.bs
index 9f0f1d8c168..eb0df9bc389 100644
--- a/css-device-adapt/Overview.bs
+++ b/css-device-adapt/Overview.bs
@@ -524,7 +524,9 @@ Computed value: auto, or a non-negative number or percentage as specified
Specifies the largest allowed zoom factor. It is used as input to the
constraining procedure to constrain
non-''zoom/auto'' 'zoom' values, but also to limit the allowed zoom factor
-that can be set through user interaction. The UA should also use this
+that can be set through user interaction. The UA may choose to ignore
+this limit for accessbility/usability reasons – see the relevant note in
+the 'user-zoom' section. The UA should also use this
value as a constraint when choosing an actual zoom factor when the
used value of 'zoom' is ''zoom/auto''.
@@ -578,6 +580,22 @@ Values have the following meanings:
+
+ Authors should not suppress (with user-zoom: fixed)
+ or limit (with max-zoom) the ability of users to resize
+ a document, as this causes accessibility and usability issues.
+
+ There may be specific use cases where preventing users from zooming
+ may be appropriate, such as map applications – where custom zoom
+ functionality is handled via scripting. However, in general this
+ practice should be avoided.
+
+ Most user agents now allow users to always zoom, regardless
+ of any restrictions specified by web content – either by default, or
+ as a setting/option (which may however not be immediately apparent
+ to users).
+
+
The 'orientation' descriptor