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Re: [css-masking] 'mask: none' clear all masking operations

From: Dirk Schulze <dschulze@adobe.com>
Date: Wed, 5 Jun 2013 23:40:12 -0700
To: fantasai <fantasai.lists@inkedblade.net>
CC: www-style list <www-style@w3.org>
Message-ID: <87AD0178-7C3B-4C30-B726-7D96C9CD5851@adobe.com>

On Jun 5, 2013, at 2:06 AM, fantasai <fantasai.lists@inkedblade.net> wrote:

> On 05/29/2013 09:01 PM, Dirk Schulze wrote:
>> Hi,
>> 
>> During the WG meeting today, there was a question if 'mask: none;' can clear all masking operations on an element.
>> 
>> As an introduction, the CSS Masking spec defines three main properties: mask, mask-box-image and clip-path where some are shorthands for a couple of longhand properties:
>> 
>> mask
>>     * mask-image, mask-source-type, mask-repeat, mask-position, mask-clip, mask-size
>> 
>> mask-box-image:
>>     * mask-box-image-source, mask-box-image-slice, mask-box-image-width, mask-box-image-outset, mask-box-image-repeat
>> 
>> While the 'mask*' properties are similar to the 'background*' properties,
>> the 'mask-box-image*' properties are similar to the 'border-image*' properties.
>> 
>> Since 'mask' and 'mask-box-image' are two shorthands, it seems to be impossible
>> to disable all masking operations with 'mask: none'.
> 
> That's because of the way the shorthands have been defined.
> That can be changed to be more like the way 'border'
> interacts with 'border-image'.

Ok, now I understand you. However, this still leads to the following questions:

1) Has "mask-image: none;" any affect on mask-box-image? Or is it just the mask shorthand that can reset mask-box-image?
2) What about "mask: none, url('image.png')" or even "mask: none, none;"  (notice: there are two masking layer defined)? Does this setting for the both examples affect mask-box-image?
3) Can the mask shorthand be restricted to just reset 'mask-box-image' if it is explicitly set to "none"?

Greetings,
Dirk

> 
>> The biggest problem is that the initial value for 'mask-image' is 'none' and
>> therefore would always disable 'mask-box-image' as well.
> 
> This is an invalid issue. Shorthands don't have initial values
> and don't reset anything unless they're explicitly specified.
> (That declaration then gets expanded into the relevant longhands.)
> 
>> I added a note to the 'mask' property, that 'mask: none' will just disable
>> masking by the 'mask*' properties, but not for 'mask-box-image*' properties.
>> If there are no objections, I will remove the issue 1
> 
> I object to removing the issue without thinking through potential solutions
> and concluding that it's in fact not a good idea to have a master shorthand
> for masking.
> 
> ~fantasai
Received on Thursday, 6 June 2013 06:40:53 UTC

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