<AWT Dev> [OpenJDK 2D-Dev] [9] Review request for 8073320 Windows HiDPI Graphics support

Philip Race philip.race at oracle.com
Sat Oct 24 17:31:20 UTC 2015

We don't even support EXIF or TIFF at all yet (hope to have it in 9) and 
that does
have EXIF data processing support but we would be talking an incredibly
heavyweight process to determine that and figure out how it maps to what
image you want. Being able to tell from the filename is probably 100,000 
times faster.
And I really don't know who would want to start to have to add that 
information to images they design.
Also I don't know how you would apply it to PNG which is the most common
format people use here. JPEG is lossy and probably not an ideal choice 
for some of these uses.


On 10/23/15, 10:53 PM, Hendrik Schreiber wrote:
> Hey Jim,
> I had assumed the code was for still for MRI. And in that context EXIF would have made more sense. My bad. Sorry for the noise.
> -hendrik
>> On Oct 24, 2015, at 02:29, Jim Graham<james.graham at oracle.com>  wrote:
>> Hi Hendrik,
>> The comment I was making was on the format of the command line arguments we use to override DPI scaling and has nothing to do with image loading.
>> You are correct that we don't really deal with the EXIF tags currently, but I am not sure that they represent something we should be dealing with here.  The current effort is to normalize the size of UI elements on various displays of different display resolution, but EXIF resolution tag processing would be more of a pre-press feature of an image display and layout editor.  That goes a bit beyond the current effort...
>> 			...jim
>> On 10/22/2015 11:56 PM, Hendrik Schreiber wrote:
>>>> The reason for this is both to have an explicit token for the regular scale factor and also so that this matches with the default image suffix of "@2x" so that we can add more ways to provide alternate media such as "@120dpi" which are consistent with the values we use here.
>>>> BTW, we need to discuss ways to automate loading alternate media beyond @2x at some point…
>>> I’m not sure it’s practical, but has anybody every thought about using existing EXIF tags to determine image resolution?
>>> AFAIK, both JPEG and TIFF support EXIF tags (http://www.w3.org/2003/12/exif/) and thus embedding of resolution metadata (Labels: resolution, xResolution, yResolution, resolutionUnit).
>>> There could be another special tag @exif (or @native, to avoid being tied down to one particular way of embedding info), which basically means: check the embedded resolution info.
>>> -hendrik

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