[prev in list] [next in list] [prev in thread] [next in thread] 

List:       html5-help
Subject:    Re: [html5] Absolute Pixels in HTML 5
From:       Geoffrey Sneddon <foolistbar () googlemail ! com>
Date:       2009-05-25 17:45:03
Message-ID: F6A515C3-1284-46A6-A592-CBE3615E665D () googlemail ! com
[Download RAW message or body]


On 25 May 2009, at 17:24, Sean B. Palmer wrote:

> HTML 5 currently says that img/@width and so forth use CSS 2.1 pixel
> values. Pixel values in CSS 2.1 are of course a relative rather than
> an absolute unit. In other words, CSS px is a non-linear alias for
> radians; 675.522px, for example, is a quarter of a radian.
>
> But non-vector image formats like JPG and PNG have discrete pixels,
> and screens have pixel displays with certain ppi values. So has
> anybody looked at whether browsers actually implement px as a relative
> unit? And how do they render images? I'm presuming that they don't
> resample to fit the relative measurement.
>
>>
> From the point of view of an author, I'm mainly concerned with, for
> example, setting widths for figures. If I'm not giving any height or
> width attributes for an <img> and my browser is rendering the image
> absolutely, I don't then want to set a relative width for the figure.

What HTML 5 defines is what browsers currently do, but it's also true  
that all desktop browsers set 1 CSS pixel = 1 physical pixel, so the  
issue doesn't really come up, though the definition matches what  
happens in cases where 1 CSS pixel does not equal 1 physical pixel.


--
Geoffrey Sneddon
<http://gsnedders.com/>

_______________________________________________
Help mailing list
Help@lists.whatwg.org
http://lists.whatwg.org/listinfo.cgi/help-whatwg.org
[prev in list] [next in list] [prev in thread] [next in thread]