RFR: 6391806: JLabel and AbstractButton's imageUpdate method should be better specified [v5]

[Phil Race]

On Tue, 28 Jun 2022 11:15:41 GMT, Abhishek Kumar <duke at openjdk.org> wrote:

>> JLabel and AbstractButton's imageUpdate method description updated.
>
> Abhishek Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   passed in text added

The bug suggests
returns true if one of this JLabel's icon or disabled icon is derived from
ImageIcon and it's Image is equal to the image passed in; false
otherwise.

But looking at the code .. I don't think that is quite right either
////
  public boolean imageUpdate(Image img, int infoflags,
                               int x, int y, int w, int h) {
        // Don't use getDisabledIcon, will trigger creation of icon if icon
        // not set.
        if (!isShowing() ||
            !SwingUtilities.doesIconReferenceImage(getIcon(), img) &&
            !SwingUtilities.doesIconReferenceImage(disabledIcon, img)) {

            return false;
        }
        return super.imageUpdate(img, infoflags, x, y, w, h);
    }
///

So if they are the same what it actually does isn't return true - it returns whatever super does !
So the original text was in some ways better and its main problem was just referring to Icon
which is the interface that will only have an Image if the implementing class is ImageIcon
There's also the isShowing condition which nothing seems to cover.

So for JLabel we want something like
If the component is not showing, or either the icon or disabled icon is not
an {@code ImageIcon} with an {@code Image} equal to the passed in {@code Image}
this method will return false. Otherwise it will delegate to the super-class.

What do you think ?


AbstractButton may need something similar but I'll leave that to you to check

-------------

PR: https://git.openjdk.org/jdk/pull/9240