[platform-ui-dev] More from the colors and fonts front

[Kim Horne <Kim_Horne@xxxxxxxxxx>]

Theme support in eclipse moves ever
forward.  On the extension point side, definitions for colors, fonts
and gradients have been moved under the org.eclipse.ui.themes point.  The
old font extension point still exists for backwards compatibility and the
fonts it describes are first class citizens in the themes world.  The
themes point also allows for theme elements.  A theme is an identifiable
grouping of font, color and gradient overrides that is used to provide
alternate schemes for workbench usage.  In addition to these named
themes, there is also the default theme which contains all of the base
definitions.

The workbench has started using themes
for all of its color, font and gradient resolution.  We have introduced
getThemeManager() into IWorkbench.  IThemeManager allows you to get
and set  the currently active theme, get an arbitrary theme, and add
theme change listeners.  Clients who introduce their own definitions
or rely on the definitions of others should use the color, font and gradient
registries provided by the ITheme interface rather than the those supplied
by JFaceResources.  By doing so they can better integrate with a users
currently active theme.  You can change the currently active theme
by going to the appearance page and modifying the theme combo.  When
the current theme changes, the values in the Colors and Fonts preference
page change to reflect the new theme.  There are still some implementation
details to work out here (the workbench doesn't yet respect theme changes
in all cases and the preference page doesn't default to the correct values
for anything but the default theme) but it's something to play with.  These
issues should be addressed shortly.

Here is an example of a simple view
that responds to theme changes. Please note that the color IDs used here
don't actually exist in the workbench.  If you want to give this a
try you'll need to add some colorDefinitions and possibly a theme with
colorOverrides. 

public
class
ThemeDemo extends
ViewPart {

    static
final
String MYCOLORID1 = "scratch1";
    static
final
String MYCOLORID2 = "scratch2";

    private
Label control1;
    private
Label control2;

    private
IPropertyChangeListener valueChangeListener = new
IPropertyChangeListener() {

        public
void
propertyChange(PropertyChangeEvent event) {
         
  if
(event.getProperty().equals(IThemeManager.CHANGE_CURRENT_THEME)) {
         
      //
the current enabled theme has changed. refresh all colors
         
      //
and listeners
         
      ((ITheme) event.getOldValue()).getColorRegistry().removeListener(this);
         
      ((ITheme) event.getNewValue()).getColorRegistry().addListener(this);
         
              setControlColor(control1,
MYCOLORID1);
         
              setControlColor(control2,
MYCOLORID2);
         
  } else
if
(event.getProperty().equals(MYCOLORID1)) {
         
          //
the value of mycolor1 has changed in the current theme
         
      setControlColor(control1, MYCOLORID1);
         
  } else
if
(event.getProperty().equals(MYCOLORID2)) {
         
          //
the value of mycolor2 has changed in the current theme
         
      setControlColor(control2, MYCOLORID2);
         
  }
        }
    };

    /**
     *
@see
ViewPart#createPartControl
     */
    public
void
createPartControl(Composite parent) {
        control1
= new
Label(parent, SWT.NONE);
        control1.setText("Some
text");
        control2
= new
Label(parent, SWT.NONE);
        control2.setText("Some
more text");

        IThemeManager
themeManager = PlatformUI.getWorkbench().getThemeManager();
        //
listen for the default workbench theme to change.
        themeManager.addPropertyChangeListener(valueChangeListener);
        //
listen for changes to the current theme values
        themeManager.getCurrentTheme().getColorRegistry().addListener(valueChangeListener);
        setControlColor(control1,
MYCOLORID1);
        setControlColor(control2,
MYCOLORID2);
    }

    private
void
setControlColor(Control control, String colorKey) {
         
     if
(control != null
&& !control.isDisposed())
         
      control.setForeground(PlatformUI.getWorkbench().getThemeManager()
         
              .getCurrentTheme().getColorRegistry().get(colorKey));
    }
    
    public
void
setFocus() {}

    /*
     *
(non-Javadoc)
     *

     *
@see org.eclipse.ui.IWorkbenchPart#dispose()
     */
    public
void
dispose() {
        PlatformUI.getWorkbench().getThemeManager()
         
      .removePropertyChangeListener(valueChangeListener);
        PlatformUI.getWorkbench().getThemeManager().getCurrentTheme()
         
      .removePropertyChangeListener(valueChangeListener);
        super.dispose();
    }
}