*
* * The Context should be created using a cairo {@link Surface}. The * operators don't seem to work correctly when a * {@link org.gnome.gdk.Drawable Drawable} is used instead of a cairo * Surface. * *
* The example images shown below were generated with the following code: * *
* cr.rectangle(0, 0, 75, 75); * cr.setSource(0.7, 0, 0, 0.8); * cr.fill(); * * cr.setOperator(Operator.FOO); * * cr.rectangle(40, 40, 75, 75); * cr.setSource(0, 0, 0.9, 0.4); * cr.fill(); ** *
* The drawing operations in cairo are said to be bounded and * unbounded with reguards to the Surface to be drawn to. * *
* When an operator is said to be bounded any cairo mask present determines * where the operation is applied. * *
* When an operator is said to be unbounded the operation is applied ignoring
* any present mask. Note: Clipping can still limit an unbounded
* operator.
*
* @author Andrew Cowie
* @author Kenneth Prugh
* @author Zak Fenton
* @since 4.0.7
*/
public class Operator extends Constant
{
private Operator(int ordinal, String nickname) {
super(ordinal, nickname);
}
/**
* Clear a surface to all transparent.
*
*
* This operator is bounded.
*
* @since 4.0.7
*/
public static final Operator CLEAR = new Operator(CairoOperator.CLEAR, "CLEAR");
/**
* Draw over existing pixels as if they were not present. 
*
*
* This operator is bounded. * *
* As an example, you could set up the object to be drawn over: * *
* cr.setSource(0.7, 0, 0, 0.8);
* cr.rectangle(15, 10, 50, 50);
* cr.fill();
*
*
* Now set up the source object that will draw over the area beneath it:
*
*
* cr.setSource(0, 0, 0.9, 0.4);
* cr.rectangle(35, 35, 50, 50);
* cr.setOperator(Operator.SOURCE);
* cr.fill();
*
*
* @since 4.0.16
*/
public static final Operator SOURCE = new Operator(CairoOperator.SOURCE, "SOURCE");
/**
* Draws the specified source object over the underlying object as if both
* objects were two overlapping panels of transparent glass. This only
* applies to objects that have an alpha channel; if the objects do not
* have an alpha channel, the source object simply paints over the
* underlying object. 
*
* * This is the default operator. * *
* This operator has the same effect for bounded and unbounded.
*
* @since 4.0.10
*/
public static final Operator OVER = new Operator(CairoOperator.OVER, "OVER");
/**
* Draw only where existing pixels are, clearing the rest of the surface.
* 
*
*
* This operator is unbounded.
*
* @since 4.0.16
*/
public static final Operator IN = new Operator(CairoOperator.IN, "IN");
/**
* Draw only where existing pixels are not present, leaving a shadow
* behind where the two overlapped due to transparency. 
*
*
* This operator is unbounded.
*
* @since 4.0.16
*/
public static final Operator OUT = new Operator(CairoOperator.OUT, "OUT");
/**
* Draw only where existing pixels are, mixing the color of the
* overlapping region. 
*
*
* This operator has the same effect for bounded and unbounded.
*
* @since 4.0.16
*/
public static final Operator ATOP = new Operator(CairoOperator.ATOP, "ATOP");
/**
* Any existing pixels are left untouched, while the current drawing is
* discarded. 
*
*
* This operator has the same effect for bounded and unbounded.
*
* @since 4.0.16
*/
public static final Operator DEST = new Operator(CairoOperator.DEST, "DEST");
/**
* Draw below any existing pixels with similar results to the
* {@link #OVER OVER} operator. 
*
*
* This operator has the same effect for bounded and unbounded.
*
* @since 4.0.16
*/
public static final Operator DEST_OVER = new Operator(CairoOperator.DEST_OVER, "DEST_OVER");
/**
* Draw below the overlapping region, clearing everything outside the
* region similar to the {@link #IN IN} Operator. 
*
*
* This operator is unbounded.
*
* @since 4.0.16
*/
public static final Operator DEST_IN = new Operator(CairoOperator.DEST_IN, "DEST_IN");
/**
* Reduce the visibility of the overlapping region. 
*
*
* This operator has the same effect for bounded and unbounded.
*
* @since 4.0.16
*/
public static final Operator DEST_OUT = new Operator(CairoOperator.DEST_OUT, "DEST_OUT");
/**
* Draw and clear any existing pixels outside the overlapping region, the
* color of the overlapping region is mixed similar to the {@link #ATOP
* ATOP} Operator. 
*
*
* This operator is unbounded.
*
* @since 4.0.16
*/
public static final Operator DEST_ATOP = new Operator(CairoOperator.DEST_ATOP, "DEST_ATOP");
/**
* XOR the colors of the overlapping region. 
*
*
* This operator has the same effect for bounded and unbounded.
*
* @since 4.0.16
*/
public static final Operator XOR = new Operator(CairoOperator.XOR, "XOR");
/**
* Add the colors of the overlapping region. 
*
*
* This operator has the same effect for bounded and unbounded.
*
* @since 4.0.16
*/
public static final Operator ADD = new Operator(CairoOperator.ADD, "ADD");
/**
* Saturate the colors of the overlapping region. 
*
*
* This operator has the same effect for bounded and unbounded. * * @since 4.0.16 */ public static final Operator SATURATE = new Operator(CairoOperator.SATURATE, "SATURATE"); }