RFR: 7093691: Nimbus LAF: disabled JComboBox using renderer has bad font color [v6]

[Damon Nguyen]

On Tue, 14 Feb 2023 19:11:20 GMT, Damon Nguyen <dnguyen at openjdk.org> wrote:

>> Before the fix, a JComboBox in Nimbus L&F would have normal black text even when the JComboBox was disabled if SynthComboBoxRenderer was replaced with a DefaultListCellRenderer. This text should be greyed out like in other L&F's. When looking into the defaults for Nimbus L&F files for attributes and states of a JComboBox, it confirm that the intention for disabled JComboBoxes is nimbusDisabledText (which is grey text).
>> 
>> SynthComboBoxes have an additional check in its default SynthComboBoxRenderer that enables/disables the renderer itself. The SynthComboBoxRenderer inherits its enabled state from the parent ComboBox. Since the renderer with DefaultListCellRenderer is in a separate class without a reference to the comboBox, a listener was added to SynthComboBoxUI.
>> 
>> An additional issue occurred in DefaultListCellRenderer because the renderer overrode the listener's re-assigned enabled state. In testing, setting the enabled state in DefaultListCellRenderer is redundant for all L&F's and is not needed here. However, instead of removing it altogether, a conditional was added specifically to allow ComboBoxes to skip setting enabled state here.
>> 
>> After the fix, the Nimbus JComboBox with DLCR set matches the appearance of a normal Nimbus JComboBox. I can enable/disable the JComboBoxes in the test, and the UI elements behave and appear as expected.
>
> Damon Nguyen has updated the pull request incrementally with four additional commits since the last revision:
> 
>  - Remove extra bufferedImage
>  - Fix crlf
>  - Add automated test. Cycle thru all LAF
>  - Add testing for other LAFs

> extends DefaultListCellRenderer.UIResource

I tried implementing this after your suggestion, but it doesn't achieve the wanted result. This makes sense from my understanding because with a new comboBox set to using a new DefaultListCellRenderer, the SynthComboBoxRenderer wouldn't be used. Changing what is extended for SynthComboBoxRenderer would only affect the normal comboBox using the default Synth renderer. The listener is the way around this because the comboBox with a DLCR still is a SynthComboBox but does not rely on the SynthComboBoxRenderer.

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PR: https://git.openjdk.org/jdk/pull/12390