On Wed, 26 May 2021 16:55:04 GMT, Jose Pereda <jper...@openjdk.org> wrote:
>> This PR adds style themes as a first-class concept to OpenJFX. A style theme
>> is a collection of stylesheets and the logic that governs them. Style themes
>> can respond to OS notifications and update their stylesheets dynamically.
>> This PR also re-implements Caspian and Modena as style themes.
>>
>> ### New APIs in `javafx.graphics`
>> The new theming-related APIs in `javafx.graphics` provide a basic framework
>> to support application-wide style themes. Higher-level theming concepts (for
>> example, "dark mode" detection or accent coloring) are not a part of this
>> basic framework, because any API invented here might soon be out of date.
>> Implementations can build on top of this framework to add useful
>> higher-level features.
>> #### 1. StyleTheme
>> A style theme is an implementation of the `javafx.css.StyleTheme` interface:
>>
>> /**
>> * {@code StyleTheme} is a collection of stylesheets that specify the
>> appearance of UI controls and other
>> * nodes in the application. Like a user-agent stylesheet, a {@code
>> StyleTheme} is implicitly used by all
>> * JavaFX nodes in the scene graph.
>> * <p>
>> * The list of stylesheets that comprise a {@code StyleTheme} can be
>> modified while the application is running,
>> * enabling applications to create dynamic themes that respond to changing
>> user preferences.
>> * <p>
>> * In the CSS subsystem, stylesheets that comprise a {@code StyleTheme} are
>> classified as
>> * {@link StyleOrigin#USER_AGENT} stylesheets, but have a higher precedence
>> in the CSS cascade
>> * than a stylesheet referenced by {@link
>> Application#userAgentStylesheetProperty()}.
>> */
>> public interface StyleTheme {
>> /**
>> * Gets the list of stylesheet URLs that comprise this {@code
>> StyleTheme}.
>> * <p>
>> * If the list of stylesheets that comprise this {@code StyleTheme} is
>> changed at runtime, this
>> * method must return an {@link ObservableList} to allow the CSS
>> subsystem to subscribe to list
>> * change notifications.
>> *
>> * @implNote Implementations of this method that return an {@link
>> ObservableList} are encouraged
>> * to minimize the number of subsequent list change
>> notifications that are fired by the
>> * list, as each change notification causes the CSS subsystem
>> to re-apply the referenced
>> * stylesheets.
>> */
>> List<String> getStylesheets();
>> }
>>
>>
>> A new `styleTheme` property is added to `javafx.application.Application`,
>> and `userAgentStylesheet` is promoted to a JavaFX property (currently, this
>> is just a getter/setter pair):
>>
>> public class Application {
>> ...
>> /**
>> * Specifies the user-agent stylesheet of the application.
>> * <p>
>> * A user-agent stylesheet is a global stylesheet that can be specified
>> in addition to a
>> * {@link StyleTheme} and that is implicitly used by all JavaFX nodes in
>> the scene graph.
>> * It can be used to provide default styling for UI controls and other
>> nodes.
>> * A user-agent stylesheets has the lowest precedence in the CSS cascade.
>> * <p>
>> * Before JavaFX 20, built-in themes were selectable using the special
>> user-agent stylesheet constants
>> * {@link #STYLESHEET_CASPIAN} and {@link #STYLESHEET_MODENA}. For
>> backwards compatibility, the meaning
>> * of these special constants is retained: setting the user-agent
>> stylesheet to either {@code STYLESHEET_CASPIAN}
>> * or {@code STYLESHEET_MODENA} will also set the value of the {@link
>> #styleThemeProperty() styleTheme}
>> * property to a new instance of the corresponding theme class.
>> * <p>
>> * Note: this property must only be modified on the JavaFX application
>> thread.
>> */
>> public static StringProperty userAgentStylesheetProperty();
>> public static String getUserAgentStylesheet();
>> public static void setUserAgentStylesheet(String url);
>>
>> /**
>> * Specifies the {@link StyleTheme} of the application.
>> * <p>
>> * {@code StyleTheme} is a collection of stylesheets that define the
>> appearance of the application.
>> * Like a user-agent stylesheet, a {@code StyleTheme} is implicitly used
>> by all JavaFX nodes in the
>> * scene graph.
>> * <p>
>> * Stylesheets that comprise a {@code StyleTheme} have a higher
>> precedence in the CSS cascade than a
>> * stylesheet referenced by the {@link #userAgentStylesheetProperty()
>> userAgentStylesheet} property.
>> * <p>
>> * Note: this property must only be modified on the JavaFX application
>> thread.
>> */
>> public static ObjectProperty<StyleTheme> styleThemeProperty();
>> public static StyleTheme getStyleTheme();
>> public static void setStyleTheme(StyleTheme theme);
>> ...
>> }
>>
>>
>> `styleTheme` and `userAgentStylesheet` are correlated to preserve backwards
>> compatibility: setting `userAgentStylesheet` to the magic values "CASPIAN"
>> or "MODENA" will implicitly set `styleTheme` to a new instance of the
>> `CaspianTheme` or `ModenaTheme` class. Aside from these magic values,
>> `userAgentStylesheet` can be set independently from `styleTheme`. In the CSS
>> cascade, `userAgentStylesheet` has a lower precedence than `styleTheme`.
>>
>> #### 2. PlatformPreferences
>> `javafx.application.PlatformPreferences` can be used to query UI-related
>> information about the current platform to allow theme implementations to
>> adapt to the operating system. The interface extends `Map` and adds several
>> useful methods, as well as the option to register a listener for change
>> notifications:
>>
>> /**
>> * Contains UI preferences of the current platform.
>> * <p>
>> * {@code PlatformPreferences} implements {@link Map} to expose platform
>> preferences as key-value pairs.
>> * For convenience, {@link #getString}, {@link #getBoolean} and {@link
>> #getColor} are provided as typed
>> * alternatives to the untyped {@link #get} method.
>> * <p>
>> * The preferences that are reported by the platform may be dependent on the
>> operating system version.
>> * Applications should always test whether a preference is available, or use
>> the {@link #getString(String, String)},
>> * {@link #getBoolean(String, boolean)} or {@link #getColor(String, Color)}
>> overloads that accept a fallback
>> * value if the preference is not available.
>> */
>> public interface PlatformPreferences extends Map<String, Object> {
>> String getString(String key);
>> String getString(String key, String fallbackValue);
>>
>> Boolean getBoolean(String key);
>> boolean getBoolean(String key, boolean fallbackValue);
>>
>> Color getColor(String key);
>> Color getColor(String key, Color fallbackValue);
>>
>> void addListener(PlatformPreferencesListener listener);
>> void removeListener(PlatformPreferencesListener listener);
>> }
>>
>> An instance of `PlatformPreferences` can be retrieved via
>> `Platform.getPreferences()`.
>>
>> ### Usage
>> In its simplest form, a style theme is just a static collection of
>> stylesheets:
>>
>> Application.setStyleTheme(() -> List.of("stylesheet1.css",
>> "stylesheet2.css");
>>
>> A dynamic theme can be created by returning an instance of `ObservableList`:
>>
>> public class MyCustomTheme implements StyleTheme {
>> private final ObservableList<String> stylesheets =
>> FXCollections.observableArrayList("colors-light.css",
>> "controls.css");
>>
>> @Override
>> public List<String> getStylesheets() {
>> return stylesheets;
>> }
>>
>> public void setDarkMode(boolean enabled) {
>> stylesheets.set(0, enabled ? "colors-dark.css" : "colors-light.css");
>> }
>> }
>>
>> `CaspianTheme` and `ModenaTheme` can be extended by prepending or appending
>> additional stylesheets:
>>
>> Application.setStyleTheme(new ModenaTheme() {
>> {
>> addFirst("stylesheet1.css");
>> addLast("stylesheet2.css");
>> }
>> });
>
> modules/javafx.graphics/src/main/native-glass/win/ThemeSupport.cpp line 44:
>
>> 42: }
>> 43:
>> 44: void ThemeSupport::queryHighContrastScheme(jobject properties)
>
> @mstr2 Do you think it is possible to use here
> `Windows.UI.ViewManagement.AccessibleSettings` instead, same as you do in
> `queryWindows10ThemeColors` with `Windows.UI.ViewManagement.UISettings`?
>
> I believe `Windows.UI.ViewManagement.AccessibleSettings.HighContrastScheme`
> contains a not localised string for the high contrast scheme, and that would
> allow solving https://bugs.openjdk.java.net/browse/JDK-8185447.
I just checked on Windows 10 v20H2 (build 19042.985), and unfortunately the
`Windows.UI.ViewManagement.AccessibleSettings.HighContrastScheme` contains a
localized name for the high contrast scheme.
-------------
PR: https://git.openjdk.org/jfx/pull/511
