RFR: 8342530: Specifying "@Nx" scaling level in ImageStorage should only load that specific level

[John Hendrikx]

On Thu, 15 May 2025 11:27:21 GMT, Lukasz Kostyra <lkostyra at openjdk.org> wrote:

> This follow-up change finishes the earlier changes to `ImageStorage.loadAll()` and adds support for loading specific scale requested in the input.
> 
> `loadAll()` will now first check if the input path ends with a scaling level specified, and if that is the case it will attempt creating a Stream. If requested resource does not exist it will throw an Exception, skipping the rest of the load process. If the resource does _not_ have a scaled name in its path, it will continue loading as normal - looking for all scale levels, trying to load the main resource and falling back to trying to load "@1x" variant.
> 
> Added tests to check the new `ImageTools.hasScaledName()` method + new behavior.

Changes requested by jhendrikx (Reviewer).

modules/javafx.graphics/src/main/java/com/sun/javafx/iio/common/ImageTools.java line 166:

> 164:         return true;
> 165:     }
> 166: 

1. Is looking for a slash going to be compatible on all platforms?  Where is the path string coming from?
2. Catching `NumberFormatException` to "check" if something is a number is bad form
3. It will allow `@0x` and `@-1x` etc...
4. Consider using a regular expression, it is much more concise and intended for this kind of matching

Here's a regular expression for this:

    Pattern SCALED_PATTERN = Pattern.compile(".*@[1-9][0-9]?x(\.[^\.]+)?");
    
The above will match any path that ends with `@` followed by a number from 1 to 99, followed by an `x`, optionally followed by an extension that does not contain a dot.  No need to check for slashes.

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PR Review: https://git.openjdk.org/jfx/pull/1809#pullrequestreview-2844864600
PR Review Comment: https://git.openjdk.org/jfx/pull/1809#discussion_r2091889766