[webkit-dev] Removing target-densitydpi (was Re: Device and page scaling)

Konrad Piascik kpiascik at rim.com
Mon Jun 4 15:55:57 PDT 2012

it would still be useful for ports to set their own target density. I know currently 160 is what the auto value is and all content is scaled to this DPI it would be nice to have the option to not scale content, even if it is for just the embedder to decide.

We want this on BlackBerry, and I'm sure that there are others who may find this useful.
Sent from my BlackBerry on the Rogers Wireless Network

----- Original Message -----
From: Adam Barth [mailto:abarth at webkit.org]
Sent: Friday, June 01, 2012 01:54 PM
To: Konrad Piascik
Cc: Maciej Stachowiak <mjs at apple.com>; kenneth at webkit.org <kenneth at webkit.org>; webkit-dev at lists.webkit.org <webkit-dev at lists.webkit.org>
Subject: Removing target-densitydpi (was Re: [webkit-dev] Device and page scaling)

I think folks agree that these are important use cases.  The
disagreement is about how to address them.  For example, another
approach is to use responsive images (e.g., srcset and image-set)
together with device units in CSS.  Now that WebKit has support for
subpixel layout, we can provide a high quality implementation of these

By contrast, target-densitydpi does not have broad support from
implementors, and there are concerns about the quality of the current
implementation and its maintainability.


On Fri, Jun 1, 2012 at 9:15 AM, Konrad Piascik <kpiascik at rim.com> wrote:
> Reposting comment from Bug 88047
> After discussing this internally we believe that while the current implementation of target-densitydpi is not ideal it's ability to allow you scale your viewport to a given target density as well as to allow you to not scale (deviceDPI) are both desired features of this API that we'd like to have available to developers.
> This is useful for 2 cases:
> 1) automatically scaling content to the AutoValue (ie 160) DPI, which is what most mobile optimized sites do
> 2) allowing the user to have pixel perfect rendering on a given device.
> -Konrad
> ________________________________________
> From: webkit-dev-bounces at lists.webkit.org [webkit-dev-bounces at lists.webkit.org] on behalf of Adam Barth [abarth at webkit.org]
> Sent: Friday, June 01, 2012 2:21 AM
> To: Maciej Stachowiak
> Cc: kenneth at webkit.org; webkit-dev at lists.webkit.org
> Subject: Re: [webkit-dev] Device and page scaling
> I've posted a patch to remove target-densitydpi:
> https://bugs.webkit.org/show_bug.cgi?id=88047
> There's some concern that target-densitydpi is used by some apps that
> are bundled with Android, but folks appear willing to deprecate the
> feature and to migrate those apps to using other mechanisms, such as
> responsive images and CSS device units.
> Once that patch lands, I'll start to unwind the complexity introduced
> by the feature.
> Thanks,
> Adam

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