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Re: CSS Viewport proposal

From: Rune Lillesveen <rune@opera.com>
Date: Tue, 10 Aug 2010 10:45:02 +0200
To: "Kenneth Christiansen" <kenneth.christiansen@openbossa.org>
Cc: "www-style list" <www-style@w3.org>
Message-ID: <op.vg7rxcbr8isf1p@id-c1005.oslo.osa>
On Mon, 09 Aug 2010 19:02:23 +0200, Kenneth Christiansen  
<kenneth.christiansen@openbossa.org> wrote:

> Basically the ratio is calculated, and the default DPI is considered
> to be 160 which I guess is the DPI on the first iPhone and Android
> devices.
>
> With a DPI of 160 no scaling is needed. On the other hand if you have
> a device such as the newer Android devices or the Nokia N900, if no
> DPI is set, a scale of 1.5 is applied (Fennec does this on the N900 as
> well), due to the DPI of the device being 240.
>
> This is reflected via the -webkit-device-pixel-ratio media feature.
>
> Instead of doing the scaling, the web developer can set
> target-densitydpi to device-dpi (240 in the above case) in which no
> scale is applied. This means that a initial-scale of 1.0 is actually
> 1.0 and not 1.5 as if the target-densitydpi was left out.
>
> The list of options for target-densitydpi are as follows (copied from
> Android changelog):
>
> device-dpi:    Use the device's native dpi as target dpi.
> low-dpi:       120dpi
> medium-dpi:    160dpi, which is also the default as of today
> high-dpi:      240dpi
> <number>:      We take any number between 70 and 400 as a valid target  
> dpi.

I understand, I'm just a bit unsure about the use cases. Is it to  
compensate for missing/bad sub-pixel rendering?

-- 
Rune Lillesveen
Senior Core Developer / Architect
Opera Software ASA
Received on Tuesday, 10 August 2010 08:45:36 GMT

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