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Re: DnD vs CnP (was Copy/Paste Events)

From: Ian Hickson <ian@hixie.ch>
Date: Sat, 22 Aug 2009 05:51:36 +0000 (UTC)
To: Paul Libbrecht <paul@activemath.org>
Cc: "public-webapps@w3.org Group WG" <public-webapps@w3.org>, Sebastian Markbåge <sebastian@calyptus.eu>
Message-ID: <Pine.LNX.4.62.0908220543000.13789@hixie.dreamhostps.com>
On Thu, 13 Aug 2009, Paul Libbrecht wrote:
> > 
> > The drag and drop model allows the user to drag to the clipboard and 
> > paste from the clipboard. This is exactly what copy-and- paste 
> > simulates. I don't see why this is a problem. If the drag-and-drop 
> > code doesn't support dragging to another app, then that's a problem 
> > with the drag-and-drop code, and providing a second API to work around 
> > that problem just for copy-and-paste doesn't help the people using the 
> > drag-and-drop feature in that fashion
> 
> To me it is a problem to confuse the two operations:
> 
> - drag and drop allows a precise visual target identification thus may 
> be considered safer (and this is actually implemented so: you can faster 
> drag-and-drop URLs than copy and paste them). Copying, however, is 
> simpler and better understood as long as the selection model is clear.

I agree that the UI is different. But that doesn't mean that they're not 
the same operation. Double clicking on an application icon and running the 
application from the command line are also the same operation with 
different UI. It's all the same.


> - copy-and-paste is aimed at long term storage: if you write to the 
> clipboard you have to write all the flavours you think a recipient would 
> ever make use of! The clipboard often survives computer-restarts.

Drag-and-drop can also be for long-term storage -- drag whatever it is you 
were going to copy to your clipboard to your clipboard... same result. And 
with the DND model in HTML5, you have to "write all the flavours you think 
a recipient would ever make use of" in the same way as you describe for 
copy-and-paste.


> - drag-and-drop is aimed at direct negotiations: generally, only at the 
> end of the drag is the actual data produced. In case this is running 
> over a network-based conversion this is significant I feel.

DND in HTML5 generates the data at drag time, not drop time.


> So I would insist to split the two set of events while keeping common, 
> of course, some of the interfaces to denote what can be transferred.

I see no reason to split them.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Saturday, 22 August 2009 05:51:31 GMT

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