Hi guys,
I finally closed DIRSTUDIO_1038. We now dispose all the
org.eclipse.swt.graphics.* elements.
For the upcoming developemnts, I'd like to give a bit of guidelines :
Font
----
Font must be disposed. It's then easier to use a FontRegistry to avoid
creating a font everytime it's needed. One way to do that is :
FontData[] fontData =
Display.getDefault().getSystemFont().getFontData();
FontData fontDataBoldItalic = new FontData(
fontData[0].getName(), fontData[0].getHeight(), SWT.BOLD | SWT.ITALIC );
FontRegistry fontRegistry = new FontRegistry(
getWorkbench().getDisplay() );
if ( !fontRegistry.hasValueFor( fontData[0].toString() ) )
{
fontRegistry.put( fontData[0].toString(), fontData );
}
Font newFont = fontRegistry.get( fontData[0].toString() );
GC
--
Not frequently used. One exemple :
GC gc = new GC( control );
try
{
gc.setFont( JFaceResources.getDialogFont() );
FontMetrics fontMetrics = gc.getFontMetrics();
int width = Dialog.convertHorizontalDLUsToPixels(
fontMetrics, IDialogConstants.BUTTON_WIDTH );
return width;
}
finally
{
gc.dispose();
}
The disposal is done in a finally clause, to be sure we dispose the GC,
no matter what
Image
-----
Even simpler : when you create an Image, be sure to call the dispose()
method when done. Otherwise, each plugin activator (ie the class which
extends AbstractUIPlugin) has a method getImage( String ) :
/**
* Use this method to get SWT images. A ImageRegistry is used
* to manage the the path->Image mapping.
* <p>
* Note: Don't dispose the returned SWT Image. It is disposed
* automatically when the plugin is stopped.
*
* @param path the path
* @return The SWT Image or null
*/
public Image getImage( String path )
{
Image image = getImageRegistry().get( path );
if ( image == null )
{
ImageDescriptor id = getImageDescriptor( path );
if ( id != null )
{
image = id.createImage();
getImageRegistry().put( path, image );
}
}
return image;
}
Color
-----
Colors are quite frequently used. Hopefully, we mostly used quite common
colors, like Red, Black, or various greys. I have moved all the Color
creations and disposals into the CommonUiConstants/CommonUiPlugins classes :
// To see the world in black and white
public static final RGB BLACK = new RGB( 0, 0, 0 );
public static Color BLACK_COLOR;
public static final RGB WHITE = new RGB( 255, 255, 255 );
public static Color WHITE_COLOR;
// 7 shade of greys... From dark to light, with combinaisons
public static final RGB BD_GREY = new RGB( 31, 31, 31 ); // Black
Dark grey
public static Color BD_GREY_COLOR;
public static final RGB D_GREY = new RGB( 63, 63, 63 ); // Dark grey
public static Color D_GREY_COLOR;
public static final RGB MD_GREY = new RGB( 95, 95, 95 ); //
Medium Dark grey
public static Color MD_GREY_COLOR;
public static final RGB M_GREY = new RGB( 127, 127, 127 ); // Grey
public static Color M_GREY_COLOR;
public static final RGB ML_GREY = new RGB( 159, 159, 159 ); //
Medium Light grey
public static Color ML_GREY_COLOR;
public static final RGB L_GREY = new RGB( 191, 191, 191 ); // Light
grey
public static Color L_GREY_COLOR;
public static final RGB WL_GREY = new RGB( 224, 224, 224 ); // White
Light grey
public static Color WL_GREY_COLOR;
// Red
public static final RGB M_RED = new RGB( 127, 0, 0 ); //
Medium red
public static Color M_RED_COLOR;
public static final RGB ML_RED = new RGB( 159, 0, 0 ); //
Medium light red
public static Color ML_RED_COLOR;
public static final RGB RED = new RGB( 255, 0, 0 ); // Full red
public static Color RED_COLOR;
// Green
public static final RGB M_GREEN = new RGB( 0, 127, 0 ); //
Medium green
public static Color M_GREEN_COLOR;
public static final RGB ML_GREEN = new RGB( 0, 159, 0 ); //
Medium Light green
public static Color ML_GREEN_COLOR;
public static final RGB GREEN = new RGB( 0, 255, 0 ); // Full
green
public static Color GREEN_COLOR;
// Blue
public static final RGB M_BLUE = new RGB( 0, 0, 127 ); //
Medium blue
public static Color M_BLUE_COLOR;
public static final RGB L_BLUE = new RGB( 0, 0, 191 ); // Light
blue
public static Color L_BLUE_COLOR;
public static final RGB BLUE = new RGB( 0, 0, 255 ); // Full blue
public static Color BLUE_COLOR;
// Purple
public static final RGB M_PURPLE = new RGB( 127, 0, 127 ); //
Middle purple
public static Color M_PURPLE_COLOR;
public static final RGB PURPLE = new RGB( 255, 0, 255 ); // Full
purple
public static Color PURPLE_COLOR;
// Other colors
public static final RGB R0_G127_B255 = new RGB( 0, 127, 255 );
public static Color R0_G127_B255_COLOR;
public static final RGB R95_G63_B159 = new RGB( 95, 63, 159 );
public static Color R95_G63_B159_COLOR;
public static final RGB R63_G127_B63 = new RGB( 63, 127, 63 );
public static Color R63_G127_B63_COLOR;
Each color is declared as a RGB instance, and a Color instance is
created in the CommonUIPlugins class start's method :
public void start( BundleContext context ) throws Exception
{
super.start( context );
// Create the colors we use
CommonUIConstants.BLACK_COLOR = new Color( null,
CommonUIConstants.BLACK );
CommonUIConstants.WHITE_COLOR = new Color( null,
CommonUIConstants.WHITE );
...
and the dispose() method is called in the stop method :
public void stop( BundleContext context ) throws Exception
{
plugin = null;
// Dispose the colors
CommonUIConstants.BLACK_COLOR.dispose();
CommonUIConstants.WHITE_COLOR.dispose();
Would you want to create a new color, it's enough to add the RGB
instance and declare the Color instance in the CommonUiConstants class,
and to instanciate it and dispose it in the CommonUIPlugins class.
Comments ?
