If I am developing a skinned UI and I provide a set of 20 images for various parts of the controls and then hand off to my graphic designer to create the DPI variants for all of the images, it is much easier for me to tell them to name all of the images with suffixes for the DPI variants and then load them all with:

    getImage("buttoncorner.png", <list of suffixes>);

than it is to do:

    for (String suffix : mylistofsuffixes) {
       array[i] = "buttoncorner" + suffix+".png";
    }
    getImage("buttoncorner.png", array);

for every image in the UI.

So, the list of suffixes in some form has value. As to whether or not delineating the scales along with the suffixes is needed, that's another question...

                        ...jim

On 9/22/16 10:56 AM, Philip Race wrote:
The method getImageUsingNamingSchemes(String fileName, 
MediaResolutionNamingScheme...
 namingSchemes) works for any scheme not only for the default one.

I'm sure it does. My point is that we don't need it.
No one will care or use it. They just want to list their image files.

The naming scheme is only important for the cases when people
are NOT supplying an explicit list of images to getImage.
So public API for the naming schema - or the float scale - is completely 
unnecessary
bloat and complication.

-phil.

On 9/22/16, 10:23 AM, Alexandr Scherbatiy wrote:
On 9/21/2016 9:47 PM, Philip Race wrote:
Hi,

When the application is specifying the set of images from which
to build the MRI you ask the app to specify a "schema" (probably not the
right name given that it is per-file), and a floating point scale.

I don't see why we need to ask the app to name the files
in accordance with our schema in this case .. it should just be
able to list the set of files. It looks redundant to an app developer
to say "150pct" is scale "1.5".

   The method getImageUsingNamingSchemes(String fileName, 
MediaResolutionNamingScheme... namingSchemes) works for any
scheme not only for the default one.
   For example call
   Image image = toolkit.getImageUsingNamingSchemes(url,
           new Toolkit.MediaResolutionNamingScheme("-144dpi", 1.5f),
           new Toolkit.MediaResolutionNamingScheme("-192dpi", 2f)
   );
   loads resolution variants image-144dpi.png and image-192dpi.png for the base 
image.png image.

   If it is necessary I can add a method like 
Toolkit.loadImageWithScales(String fileName, float... scales) which
loads resolution variants for the given scales using the default scheme.

  Thanks,
  Alexandr.

Obviously the ideal is the image is exactly what the naming convention
implies it is, but what if it is not ?

This issue does exist already even in JDK 8 .. if the
@2x image is really 1.5X the @1 image

Consider what happens if this contradicts the floating point scale ?
It appears to me that as implemented, in practice, the app could call it "@XXX",
and once @XXX has been used to find the file, the only thing that actually
matters is the floating point scale.

So the naming schema is not important when they provide the scale.

But we still have the issue that the *actual* image size may not be
what they said it was  - either explicitly or by convention.

Supposing what is claimed to be a 1.5x1.5 scale image is actually
1.0x2.0 times the size of the base image ? It is not even uniform.

Ultimately what needs to "win" is the w:h ratio of the base image
and we generally would want to pick whichever image best works
for the actual device scale, based on the *real* dimensions of
the hi-res image, don't we ?

In which case, I'd expect us to work out the scale automatically.
It is WID_HIRES/WID_BASE x HGT_HIRES/HGT_BASE

At which point why do we even need the app to tell us anything
except the (full) names of the files where to get the set of images,
with the first one being the base .. or perhaps it should always
be the "smallest".

Otherwise if any are in fact smaller (or the same as) BASE .. do we just 
discard them ?

-phil.

On 9/19/16, 12:03 PM, Alexander Scherbatiy wrote:
Hello,

Could you review the updated fix:
  http://cr.openjdk.java.net/~alexsch/8163854/webrev.01

The fix includes support for resolution variants loading by getImage() method 
for built-in toolkits using the
following media resolution naming scheme (qualifier, scale): ("@125pct", 1.25), 
("@150pct", 1.5), ("@200pct" or
"@2x", 2), ("@250pct", 2.5), ("@300pct" or "@3x", 3).

Thanks,
Alexandr.

On 25/08/16 05:39, Philip Race wrote:
FWIW I think the most important image loading use case
is that some generic resource loading code - perhaps JDK code - will get a URL 
for where
the resources are and go hunting. It is never going to call this API .. so
it had better be an optimisation and not a necessity

-phil.


On 8/24/16, 5:24 PM, Philip Race wrote:
Alexander,

Were  the existing Toolkit.getImage(String/URL) APIs not enhanced to
do this for you automatically ? I suppose I thought they were but
they can't be since you are using getImage(String) here.

IMO that would be more important than this.

And in any case I don't see why this is solved only for local files.

I am *not* asking for that right now. I am asking if the existing Toolkit APIs
can load a multi-res image and if not, why not  and can we fix that instead ..

-phil.

On 8/24/16, 9:36 AM, Alexander Scherbatiy wrote:

Hello,

Could you review the fix:
  bug: https://bugs.openjdk.java.net/browse/JDK-8163854
  webrev: http://cr.openjdk.java.net/~alexsch/8163854/webrev.00

  The public API which allows to load an image with resolution variants based 
on the provided media resolution
naming scheme is added:
  - Toolkit.MediaResolutionNamingScheme class
  - Toolkit.getImageUsingNamingSchemes(String fileName, 
MediaResolutionNamingScheme... namingSchemes)

  A simple example for images which use naming scheme @150pct for scale 1.5 and 
@2x for scale 2 is:
    image_name.ext
    image_n...@150pct.ext
    image_n...@2x.ext

    Toolkit toolkit = Toolkit.getDefaultToolkit();
    Image image = toolkit.getImageUsingNamingSchemes(fileName,
            new Toolkit.MediaResolutionNamingScheme(“@150pct”, 1.5f),
            new Toolkit.MediaResolutionNamingScheme(“@2x", 2f)
    );

  Thanks,
  Alexandr.



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