RFR: 7175396: The text on label is not painted red for Nimbus LaF. [v3]

[Alexey Ivanov]

On Tue, 13 Sep 2022 07:49:38 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> Label.foreground UIProperty is not honored by Nimbus L&F.
>> Added support for setting JLabel foreground color for Nimbus L&F
>
> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Get color once during init

src/java.desktop/share/classes/javax/swing/plaf/synth/SynthLabelUI.java line 222:

> 220:             if (fgColor != null) {
> 221:                 label.setForeground(fgColor);
> 222:             }

Why is the color set to the `label` component during paint?

Shouldn't it be `g.setColor(fgColor)`? And the above code which uses the `context` should be skipped if `fgColor != null`.

test/jdk/javax/swing/plaf/nimbus/TestNimbusLabel.java line 48:

> 46:     private static JLabel label;
> 47:     private static JFrame frame;
> 48:     private static boolean passed = false;

`passed` could be local variable in `main`.

`label` could also be local variable inside the lambda expression which creates the UI.

test/jdk/javax/swing/plaf/nimbus/TestNimbusLabel.java line 75:

> 73:                 frame = new JFrame();
> 74:                 UIManager.getDefaults().put("Label.foreground",
> 75:                                             java.awt.Color.red);

You import `Color` class, there's no need to specify the full class name. You should use `RED` as constants are in upper case.

test/jdk/javax/swing/plaf/nimbus/TestNimbusLabel.java line 97:

> 95:                     System.out.println("color(" + x + "," + y + ")=" +
> 96:                                         robot.getPixelColor(x, y));
> 97:                     Color color = robot.getPixelColor(x, y);

Suggestion:

                    Color color = robot.getPixelColor(x, y);
                    System.out.println("color(" + x + "," + y + ")=" +
                                        color);

test/jdk/javax/swing/plaf/nimbus/TestNimbusLabel.java line 98:

> 96:                                         robot.getPixelColor(x, y));
> 97:                     Color color = robot.getPixelColor(x, y);
> 98:                     if (checkPixel(color)) {

I wonder if disabling text antialiasing would yield a simpler code in `checkPixel`? However, it cannot be disabled on macOS which still uses grayscale antialiasing. But for Windows and Linux, it should help. Or the test could be limited to Windows and Linux.

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PR: https://git.openjdk.org/jdk/pull/9900