Java example source code file (RenderingEngine.java)
The RenderingEngine.java Java example source code/*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package sun.java2d.pipe;
import java.awt.Shape;
import java.awt.BasicStroke;
import java.awt.geom.PathIterator;
import java.awt.geom.AffineTransform;
import java.security.PrivilegedAction;
import java.security.AccessController;
import java.util.ServiceLoader;
import sun.security.action.GetPropertyAction;
import sun.awt.geom.PathConsumer2D;
/**
* This class abstracts a number of features for which the Java 2D
* implementation relies on proprietary licensed software libraries.
* Access to those features is now achieved by retrieving the singleton
* instance of this class and calling the appropriate methods on it.
* The 3 primary features abstracted here include:
* <dl>
* <dt>Shape createStrokedShape(Shape, [BasicStroke attributes]);
* <dd>This method implements the functionality of the method of the
* same name on the {@link BasicStroke} class.
* <dt>void strokeTo(Shape, [rendering parameters], PathConsumer2D);
* <dd>This method performs widening of the source path on the fly
* and sends the results to the given {@link PathConsumer2D} object.
* This procedure avoids having to create an intermediate Shape
* object to hold the results of the {@code createStrokedShape} method.
* The main user of this method is the Java 2D non-antialiasing renderer.
* <dt>AATileGenerator getAATileGenerator(Shape, [rendering parameters]);
* <dd>This method returns an object which can iterate over the
* specified bounding box and produce tiles of coverage values for
* antialiased rendering. The details of the operation of the
* {@link AATileGenerator} object are explained in its class comments.
* </dl>
* Additionally, the following informational method supplies important
* data about the implementation.
* <dl>
* <dt>float getMinimumAAPenSize()
* <dd>This method provides information on how small the BasicStroke
* line width can get before dropouts occur. Rendering with a BasicStroke
* is defined to never allow the line to have breaks, gaps, or dropouts
* even if the width is set to 0.0f, so this information allows the
* {@link SunGraphics2D} class to detect the "thin line" case and set
* the rendering attributes accordingly.
* </dl>
* At startup the runtime will load a single instance of this class.
* It searches the classpath for a registered provider of this API
* and returns either the last one it finds, or the instance whose
* class name matches the value supplied in the System property
* {@code sun.java2d.renderer}.
* Additionally, a runtime System property flag can be set to trace
* all calls to methods on the {@code RenderingEngine} in use by
* setting the sun.java2d.renderer.trace property to any non-null value.
* <p>
* Parts of the system that need to use any of the above features should
* call {@code RenderingEngine.getInstance()} to obtain the properly
* registered (and possibly trace-enabled) version of the RenderingEngine.
*/
public abstract class RenderingEngine {
private static RenderingEngine reImpl;
/**
* Returns an instance of {@code RenderingEngine} as determined
* by the installation environment and runtime flags.
* <p>
* A specific instance of the {@code RenderingEngine} can be
* chosen by specifying the runtime flag:
* <pre>
* java -Dsun.java2d.renderer=<classname>
* </pre>
*
* If no specific {@code RenderingEngine} is specified on the command
* or Ductus renderer is specified, it will attempt loading the
* sun.dc.DuctusRenderingEngine class using Class.forName as a fastpath;
* if not found, use the ServiceLoader.
* If no specific {@code RenderingEngine} is specified on the command
* line then the last one returned by enumerating all subclasses of
* {@code RenderingEngine} known to the ServiceLoader is used.
* <p>
* Runtime tracing of the actions of the {@code RenderingEngine}
* can be enabled by specifying the runtime flag:
* <pre>
* java -Dsun.java2d.renderer.trace=<any string>
* </pre>
* @return an instance of {@code RenderingEngine}
* @since 1.7
*/
public static synchronized RenderingEngine getInstance() {
if (reImpl != null) {
return reImpl;
}
reImpl =
AccessController.doPrivileged(new PrivilegedAction<RenderingEngine>() {
public RenderingEngine run() {
final String ductusREClass = "sun.dc.DuctusRenderingEngine";
String reClass =
System.getProperty("sun.java2d.renderer", ductusREClass);
if (reClass.equals(ductusREClass)) {
try {
Class<?> cls = Class.forName(ductusREClass);
return (RenderingEngine) cls.newInstance();
} catch (ReflectiveOperationException ignored) {
// not found
}
}
ServiceLoader<RenderingEngine> reLoader =
ServiceLoader.loadInstalled(RenderingEngine.class);
RenderingEngine service = null;
for (RenderingEngine re : reLoader) {
service = re;
if (re.getClass().getName().equals(reClass)) {
break;
}
}
return service;
}
});
if (reImpl == null) {
throw new InternalError("No RenderingEngine module found");
}
GetPropertyAction gpa =
new GetPropertyAction("sun.java2d.renderer.trace");
String reTrace = AccessController.doPrivileged(gpa);
if (reTrace != null) {
reImpl = new Tracer(reImpl);
}
return reImpl;
}
/**
* Create a widened path as specified by the parameters.
* <p>
* The specified {@code src} {@link Shape} is widened according
* to the specified attribute parameters as per the
* {@link BasicStroke} specification.
*
* @param src the source path to be widened
* @param width the width of the widened path as per {@code BasicStroke}
* @param caps the end cap decorations as per {@code BasicStroke}
* @param join the segment join decorations as per {@code BasicStroke}
* @param miterlimit the miter limit as per {@code BasicStroke}
* @param dashes the dash length array as per {@code BasicStroke}
* @param dashphase the initial dash phase as per {@code BasicStroke}
* @return the widened path stored in a new {@code Shape} object
* @since 1.7
*/
public abstract Shape createStrokedShape(Shape src,
float width,
int caps,
int join,
float miterlimit,
float dashes[],
float dashphase);
/**
* Sends the geometry for a widened path as specified by the parameters
* to the specified consumer.
* <p>
* The specified {@code src} {@link Shape} is widened according
* to the parameters specified by the {@link BasicStroke} object.
* Adjustments are made to the path as appropriate for the
* {@link VALUE_STROKE_NORMALIZE} hint if the {@code normalize}
* boolean parameter is true.
* Adjustments are made to the path as appropriate for the
* {@link VALUE_ANTIALIAS_ON} hint if the {@code antialias}
* boolean parameter is true.
* <p>
* The geometry of the widened path is forwarded to the indicated
* {@link PathConsumer2D} object as it is calculated.
*
* @param src the source path to be widened
* @param bs the {@code BasicSroke} object specifying the
* decorations to be applied to the widened path
* @param normalize indicates whether stroke normalization should
* be applied
* @param antialias indicates whether or not adjustments appropriate
* to antialiased rendering should be applied
* @param consumer the {@code PathConsumer2D} instance to forward
* the widened geometry to
* @since 1.7
*/
public abstract void strokeTo(Shape src,
AffineTransform at,
BasicStroke bs,
boolean thin,
boolean normalize,
boolean antialias,
PathConsumer2D consumer);
/**
* Construct an antialiased tile generator for the given shape with
* the given rendering attributes and store the bounds of the tile
* iteration in the bbox parameter.
* The {@code at} parameter specifies a transform that should affect
* both the shape and the {@code BasicStroke} attributes.
* The {@code clip} parameter specifies the current clip in effect
* in device coordinates and can be used to prune the data for the
* operation, but the renderer is not required to perform any
* clipping.
* If the {@code BasicStroke} parameter is null then the shape
* should be filled as is, otherwise the attributes of the
* {@code BasicStroke} should be used to specify a draw operation.
* The {@code thin} parameter indicates whether or not the
* transformed {@code BasicStroke} represents coordinates smaller
* than the minimum resolution of the antialiasing rasterizer as
* specified by the {@code getMinimumAAPenWidth()} method.
* <p>
* Upon returning, this method will fill the {@code bbox} parameter
* with 4 values indicating the bounds of the iteration of the
* tile generator.
* The iteration order of the tiles will be as specified by the
* pseudo-code:
* <pre>
* for (y = bbox[1]; y < bbox[3]; y += tileheight) {
* for (x = bbox[0]; x < bbox[2]; x += tilewidth) {
* }
* }
* </pre>
* If there is no output to be rendered, this method may return
* null.
*
* @param s the shape to be rendered (fill or draw)
* @param at the transform to be applied to the shape and the
* stroke attributes
* @param clip the current clip in effect in device coordinates
* @param bs if non-null, a {@code BasicStroke} whose attributes
* should be applied to this operation
* @param thin true if the transformed stroke attributes are smaller
* than the minimum dropout pen width
* @param normalize true if the {@code VALUE_STROKE_NORMALIZE}
* {@code RenderingHint} is in effect
* @param bbox returns the bounds of the iteration
* @return the {@code AATileGenerator} instance to be consulted
* for tile coverages, or null if there is no output to render
* @since 1.7
*/
public abstract AATileGenerator getAATileGenerator(Shape s,
AffineTransform at,
Region clip,
BasicStroke bs,
boolean thin,
boolean normalize,
int bbox[]);
/**
* Construct an antialiased tile generator for the given parallelogram
* store the bounds of the tile iteration in the bbox parameter.
* The parallelogram is specified as a starting point and 2 delta
* vectors that indicate the slopes of the 2 pairs of sides of the
* parallelogram.
* The 4 corners of the parallelogram are defined by the 4 points:
* <ul>
* <li> {@code x}, {@code y}
* <li> {@code x+dx1}, {@code y+dy1}
* <li> {@code x+dx1+dx2}, {@code y+dy1+dy2}
* <li> {@code x+dx2}, {@code y+dy2}
* </ul>
* The {@code lw1} and {@code lw2} parameters provide a specification
* for an optionally stroked parallelogram if they are positive numbers.
* The {@code lw1} parameter is the ratio of the length of the {@code dx1},
* {@code dx2} delta vector to half of the line width in that same
* direction.
* The {@code lw2} parameter provides the same ratio for the other delta
* vector.
* If {@code lw1} and {@code lw2} are both greater than zero, then
* the parallelogram figure is doubled by both expanding and contracting
* each delta vector by its corresponding {@code lw} value.
* If either (@code lw1) or {@code lw2} are also greater than 1, then
* the inner (contracted) parallelogram disappears and the figure is
* simply a single expanded parallelogram.
* The {@code clip} parameter specifies the current clip in effect
* in device coordinates and can be used to prune the data for the
* operation, but the renderer is not required to perform any
* clipping.
* <p>
* Upon returning, this method will fill the {@code bbox} parameter
* with 4 values indicating the bounds of the iteration of the
* tile generator.
* The iteration order of the tiles will be as specified by the
* pseudo-code:
* <pre>
* for (y = bbox[1]; y < bbox[3]; y += tileheight) {
* for (x = bbox[0]; x < bbox[2]; x += tilewidth) {
* }
* }
* </pre>
* If there is no output to be rendered, this method may return
* null.
*
* @param x the X coordinate of the first corner of the parallelogram
* @param y the Y coordinate of the first corner of the parallelogram
* @param dx1 the X coordinate delta of the first leg of the parallelogram
* @param dy1 the Y coordinate delta of the first leg of the parallelogram
* @param dx2 the X coordinate delta of the second leg of the parallelogram
* @param dy2 the Y coordinate delta of the second leg of the parallelogram
* @param lw1 the line width ratio for the first leg of the parallelogram
* @param lw2 the line width ratio for the second leg of the parallelogram
* @param clip the current clip in effect in device coordinates
* @param bbox returns the bounds of the iteration
* @return the {@code AATileGenerator} instance to be consulted
* for tile coverages, or null if there is no output to render
* @since 1.7
*/
public abstract AATileGenerator getAATileGenerator(double x, double y,
double dx1, double dy1,
double dx2, double dy2,
double lw1, double lw2,
Region clip,
int bbox[]);
/**
* Returns the minimum pen width that the antialiasing rasterizer
* can represent without dropouts occurring.
* @since 1.7
*/
public abstract float getMinimumAAPenSize();
/**
* Utility method to feed a {@link PathConsumer2D} object from a
* given {@link PathIterator}.
* This method deals with the details of running the iterator and
* feeding the consumer a segment at a time.
*/
public static void feedConsumer(PathIterator pi, PathConsumer2D consumer) {
float coords[] = new float[6];
while (!pi.isDone()) {
switch (pi.currentSegment(coords)) {
case PathIterator.SEG_MOVETO:
consumer.moveTo(coords[0], coords[1]);
break;
case PathIterator.SEG_LINETO:
consumer.lineTo(coords[0], coords[1]);
break;
case PathIterator.SEG_QUADTO:
consumer.quadTo(coords[0], coords[1],
coords[2], coords[3]);
break;
case PathIterator.SEG_CUBICTO:
consumer.curveTo(coords[0], coords[1],
coords[2], coords[3],
coords[4], coords[5]);
break;
case PathIterator.SEG_CLOSE:
consumer.closePath();
break;
}
pi.next();
}
}
static class Tracer extends RenderingEngine {
RenderingEngine target;
String name;
public Tracer(RenderingEngine target) {
this.target = target;
name = target.getClass().getName();
}
public Shape createStrokedShape(Shape src,
float width,
int caps,
int join,
float miterlimit,
float dashes[],
float dashphase)
{
System.out.println(name+".createStrokedShape("+
src.getClass().getName()+", "+
"width = "+width+", "+
"caps = "+caps+", "+
"join = "+join+", "+
"miter = "+miterlimit+", "+
"dashes = "+dashes+", "+
"dashphase = "+dashphase+")");
return target.createStrokedShape(src,
width, caps, join, miterlimit,
dashes, dashphase);
}
public void strokeTo(Shape src,
AffineTransform at,
BasicStroke bs,
boolean thin,
boolean normalize,
boolean antialias,
PathConsumer2D consumer)
{
System.out.println(name+".strokeTo("+
src.getClass().getName()+", "+
at+", "+
bs+", "+
(thin ? "thin" : "wide")+", "+
(normalize ? "normalized" : "pure")+", "+
(antialias ? "AA" : "non-AA")+", "+
consumer.getClass().getName()+")");
target.strokeTo(src, at, bs, thin, normalize, antialias, consumer);
}
public float getMinimumAAPenSize() {
System.out.println(name+".getMinimumAAPenSize()");
return target.getMinimumAAPenSize();
}
public AATileGenerator getAATileGenerator(Shape s,
AffineTransform at,
Region clip,
BasicStroke bs,
boolean thin,
boolean normalize,
int bbox[])
{
System.out.println(name+".getAATileGenerator("+
s.getClass().getName()+", "+
at+", "+
clip+", "+
bs+", "+
(thin ? "thin" : "wide")+", "+
(normalize ? "normalized" : "pure")+")");
return target.getAATileGenerator(s, at, clip,
bs, thin, normalize,
bbox);
}
public AATileGenerator getAATileGenerator(double x, double y,
double dx1, double dy1,
double dx2, double dy2,
double lw1, double lw2,
Region clip,
int bbox[])
{
System.out.println(name+".getAATileGenerator("+
x+", "+y+", "+
dx1+", "+dy1+", "+
dx2+", "+dy2+", "+
lw1+", "+lw2+", "+
clip+")");
return target.getAATileGenerator(x, y,
dx1, dy1,
dx2, dy2,
lw1, lw2,
clip, bbox);
}
}
}
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