https://openjdk.java.net/ 
/*
 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * 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).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.awt;

import java.beans.ConstructorProperties;

import java.lang.annotation.Native;


The BasicStroke class defines a basic set of rendering attributes for the outlines of graphics primitives, which are rendered with a Graphics2D object that has its Stroke attribute set to this BasicStroke. The rendering attributes defined by BasicStroke describe the shape of the mark made by a pen drawn along the outline of a Shape and the decorations applied at the ends and joins of path segments of the Shape. These rendering attributes include: 


width

The pen width, measured perpendicularly to the pen trajectory.

end caps

The decoration applied to the ends of unclosed subpaths and dash segments. Subpaths that start and end on the same point are still considered unclosed if they do not have a CLOSE segment. See SEG_CLOSE for more information on the CLOSE segment. The three different decorations are: CAP_BUTT, CAP_ROUND, and CAP_SQUARE. 
line joins

The decoration applied at the intersection of two path segments and at the intersection of the endpoints of a subpath that is closed using SEG_CLOSE. The three different decorations are: JOIN_BEVEL, JOIN_MITER, and JOIN_ROUND. 
miter limit

The limit to trim a line join that has a JOIN_MITER decoration.
A line join is trimmed when the ratio of miter length to stroke
width is greater than the miterlimit value.  The miter length is
the diagonal length of the miter, which is the distance between
the inside corner and the outside corner of the intersection.
The smaller the angle formed by two line segments, the longer
the miter length and the sharper the angle of intersection.  The
default miterlimit value of 10.0f causes all angles less than
11 degrees to be trimmed.  Trimming miters converts
the decoration of the line join to bevel.

dash attributes

The definition of how to make a dash pattern by alternating
between opaque and transparent sections.

 All attributes that specify measurements and distances controlling the shape of the returned outline are measured in the same coordinate system as the original unstroked Shape argument. When a Graphics2D object uses a Stroke object to redefine a path during the execution of one of its draw methods, the geometry is supplied in its original form before the Graphics2D transform attribute is applied. Therefore, attributes such as the pen width are interpreted in the user space coordinate system of the Graphics2D object and are subject to the scaling and shearing effects of the user-space-to-device-space transform in that particular Graphics2D. For example, the width of a rendered shape's outline is determined not only by the width attribute of this BasicStroke, but also by the transform attribute of the Graphics2D object. Consider this code: 

     // sets the Graphics2D object's Transform attribute
     g2d.scale(10, 10);
     // sets the Graphics2D object's Stroke attribute
     g2d.setStroke(new BasicStroke(1.5f));

 Assuming there are no other scaling transforms added to the Graphics2D object, the resulting line will be approximately 15 pixels wide. As the example code demonstrates, a floating-point line offers better precision, especially when large transforms are used with a Graphics2D object. When a line is diagonal, the exact width depends on how the rendering pipeline chooses which pixels to fill as it traces the theoretical widened outline. The choice of which pixels to turn on is affected by the antialiasing attribute because the antialiasing rendering pipeline can choose to color partially-covered pixels. 
 For more information on the user space coordinate system and the rendering process, see the Graphics2D class comments. 
Author:Jim Graham
See Also:
/**
 * The {@code BasicStroke} class defines a basic set of rendering
 * attributes for the outlines of graphics primitives, which are rendered
 * with a {@link Graphics2D} object that has its Stroke attribute set to
 * this {@code BasicStroke}.
 * The rendering attributes defined by {@code BasicStroke} describe
 * the shape of the mark made by a pen drawn along the outline of a
 * {@link Shape} and the decorations applied at the ends and joins of
 * path segments of the {@code Shape}.
 * These rendering attributes include:
 * <dl>
 * <dt><i>width</i>
 * <dd>The pen width, measured perpendicularly to the pen trajectory.
 * <dt><i>end caps</i>
 * <dd>The decoration applied to the ends of unclosed subpaths and
 * dash segments.  Subpaths that start and end on the same point are
 * still considered unclosed if they do not have a CLOSE segment.
 * See {@link java.awt.geom.PathIterator#SEG_CLOSE SEG_CLOSE}
 * for more information on the CLOSE segment.
 * The three different decorations are: {@link #CAP_BUTT},
 * {@link #CAP_ROUND}, and {@link #CAP_SQUARE}.
 * <dt><i>line joins</i>
 * <dd>The decoration applied at the intersection of two path segments
 * and at the intersection of the endpoints of a subpath that is closed
 * using {@link java.awt.geom.PathIterator#SEG_CLOSE SEG_CLOSE}.
 * The three different decorations are: {@link #JOIN_BEVEL},
 * {@link #JOIN_MITER}, and {@link #JOIN_ROUND}.
 * <dt><i>miter limit</i>
 * <dd>The limit to trim a line join that has a JOIN_MITER decoration.
 * A line join is trimmed when the ratio of miter length to stroke
 * width is greater than the miterlimit value.  The miter length is
 * the diagonal length of the miter, which is the distance between
 * the inside corner and the outside corner of the intersection.
 * The smaller the angle formed by two line segments, the longer
 * the miter length and the sharper the angle of intersection.  The
 * default miterlimit value of 10.0f causes all angles less than
 * 11 degrees to be trimmed.  Trimming miters converts
 * the decoration of the line join to bevel.
 * <dt><i>dash attributes</i>
 * <dd>The definition of how to make a dash pattern by alternating
 * between opaque and transparent sections.
 * </dl>
 * All attributes that specify measurements and distances controlling
 * the shape of the returned outline are measured in the same
 * coordinate system as the original unstroked {@code Shape}
 * argument.  When a {@code Graphics2D} object uses a
 * {@code Stroke} object to redefine a path during the execution
 * of one of its {@code draw} methods, the geometry is supplied
 * in its original form before the {@code Graphics2D} transform
 * attribute is applied.  Therefore, attributes such as the pen width
 * are interpreted in the user space coordinate system of the
 * {@code Graphics2D} object and are subject to the scaling and
 * shearing effects of the user-space-to-device-space transform in that
 * particular {@code Graphics2D}.
 * For example, the width of a rendered shape's outline is determined
 * not only by the width attribute of this {@code BasicStroke},
 * but also by the transform attribute of the
 * {@code Graphics2D} object.  Consider this code:
 * <blockquote><pre>{@code
 *      // sets the Graphics2D object's Transform attribute
 *      g2d.scale(10, 10);
 *      // sets the Graphics2D object's Stroke attribute
 *      g2d.setStroke(new BasicStroke(1.5f));
 * }</pre></blockquote>
 * Assuming there are no other scaling transforms added to the
 * {@code Graphics2D} object, the resulting line
 * will be approximately 15 pixels wide.
 * As the example code demonstrates, a floating-point line
 * offers better precision, especially when large transforms are
 * used with a {@code Graphics2D} object.
 * When a line is diagonal, the exact width depends on how the
 * rendering pipeline chooses which pixels to fill as it traces the
 * theoretical widened outline.  The choice of which pixels to turn
 * on is affected by the antialiasing attribute because the
 * antialiasing rendering pipeline can choose to color
 * partially-covered pixels.
 * <p>
 * For more information on the user space coordinate system and the
 * rendering process, see the {@code Graphics2D} class comments.
 * @see Graphics2D
 * @author Jim Graham
 */
public class BasicStroke implements Stroke {

    
Joins path segments by extending their outside edges until
they meet.

/**
     * Joins path segments by extending their outside edges until
     * they meet.
     */
    @Native public static final int JOIN_MITER = 0;

    
Joins path segments by rounding off the corner at a radius
of half the line width.

/**
     * Joins path segments by rounding off the corner at a radius
     * of half the line width.
     */
    @Native public static final int JOIN_ROUND = 1;

    
Joins path segments by connecting the outer corners of their
wide outlines with a straight segment.

/**
     * Joins path segments by connecting the outer corners of their
     * wide outlines with a straight segment.
     */
    @Native public static final int JOIN_BEVEL = 2;

    
Ends unclosed subpaths and dash segments with no added
decoration.

/**
     * Ends unclosed subpaths and dash segments with no added
     * decoration.
     */
    @Native public static final int CAP_BUTT = 0;

    
Ends unclosed subpaths and dash segments with a round
decoration that has a radius equal to half of the width
of the pen.

/**
     * Ends unclosed subpaths and dash segments with a round
     * decoration that has a radius equal to half of the width
     * of the pen.
     */
    @Native public static final int CAP_ROUND = 1;

    
Ends unclosed subpaths and dash segments with a square
projection that extends beyond the end of the segment
to a distance equal to half of the line width.

/**
     * Ends unclosed subpaths and dash segments with a square
     * projection that extends beyond the end of the segment
     * to a distance equal to half of the line width.
     */
    @Native public static final int CAP_SQUARE = 2;

    float width;

    int join;
    int cap;
    float miterlimit;

    float[] dash;
    float dash_phase;

    
Constructs a new BasicStroke with the specified attributes. 
Params:
  • width – the width of this BasicStroke. The width must be greater than or equal to 0.0f. If width is set to 0.0f, the stroke is rendered as the thinnest possible line for the target device and the antialias hint setting.
  • cap – the decoration of the ends of a BasicStroke
  • join – the decoration applied where path segments meet
  • miterlimit – the limit to trim the miter join.  The miterlimit
       must be greater than or equal to 1.0f.
  • dash – the array representing the dashing pattern
  • dash_phase – the offset to start the dashing pattern
Throws:
/**
     * Constructs a new {@code BasicStroke} with the specified
     * attributes.
     * @param width the width of this {@code BasicStroke}.  The
     *         width must be greater than or equal to 0.0f.  If width is
     *         set to 0.0f, the stroke is rendered as the thinnest
     *         possible line for the target device and the antialias
     *         hint setting.
     * @param cap the decoration of the ends of a {@code BasicStroke}
     * @param join the decoration applied where path segments meet
     * @param miterlimit the limit to trim the miter join.  The miterlimit
     *        must be greater than or equal to 1.0f.
     * @param dash the array representing the dashing pattern
     * @param dash_phase the offset to start the dashing pattern
     * @throws IllegalArgumentException if {@code width} is negative
     * @throws IllegalArgumentException if {@code cap} is not either
     *         CAP_BUTT, CAP_ROUND or CAP_SQUARE
     * @throws IllegalArgumentException if {@code miterlimit} is less
     *         than 1 and {@code join} is JOIN_MITER
     * @throws IllegalArgumentException if {@code join} is not
     *         either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER
     * @throws IllegalArgumentException if {@code dash_phase}
     *         is negative and {@code dash} is not {@code null}
     * @throws IllegalArgumentException if the length of
     *         {@code dash} is zero
     * @throws IllegalArgumentException if dash lengths are all zero.
     */
    @ConstructorProperties({ "lineWidth", "endCap", "lineJoin", "miterLimit", "dashArray", "dashPhase" })
    public BasicStroke(float width, int cap, int join, float miterlimit,
                       float[] dash, float dash_phase) {
        if (width < 0.0f) {
            throw new IllegalArgumentException("negative width");
        }
        if (cap != CAP_BUTT && cap != CAP_ROUND && cap != CAP_SQUARE) {
            throw new IllegalArgumentException("illegal end cap value");
        }
        if (join == JOIN_MITER) {
            if (miterlimit < 1.0f) {
                throw new IllegalArgumentException("miter limit < 1");
            }
        } else if (join != JOIN_ROUND && join != JOIN_BEVEL) {
            throw new IllegalArgumentException("illegal line join value");
        }
        if (dash != null) {
            if (dash_phase < 0.0f) {
                throw new IllegalArgumentException("negative dash phase");
            }
            boolean allzero = true;
            for (int i = 0; i < dash.length; i++) {
                float d = dash[i];
                if (d > 0.0) {
                    allzero = false;
                } else if (d < 0.0) {
                    throw new IllegalArgumentException("negative dash length");
                }
            }
            if (allzero) {
                throw new IllegalArgumentException("dash lengths all zero");
            }
        }
        this.width      = width;
        this.cap        = cap;
        this.join       = join;
        this.miterlimit = miterlimit;
        if (dash != null) {
            this.dash = dash.clone();
        }
        this.dash_phase = dash_phase;
    }

    
Constructs a solid BasicStroke with the specified attributes. 
Params:
  • width – the width of the BasicStroke
  • cap – the decoration of the ends of a BasicStroke
  • join – the decoration applied where path segments meet
  • miterlimit – the limit to trim the miter join
Throws:
/**
     * Constructs a solid {@code BasicStroke} with the specified
     * attributes.
     * @param width the width of the {@code BasicStroke}
     * @param cap the decoration of the ends of a {@code BasicStroke}
     * @param join the decoration applied where path segments meet
     * @param miterlimit the limit to trim the miter join
     * @throws IllegalArgumentException if {@code width} is negative
     * @throws IllegalArgumentException if {@code cap} is not either
     *         CAP_BUTT, CAP_ROUND or CAP_SQUARE
     * @throws IllegalArgumentException if {@code miterlimit} is less
     *         than 1 and {@code join} is JOIN_MITER
     * @throws IllegalArgumentException if {@code join} is not
     *         either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER
     */
    public BasicStroke(float width, int cap, int join, float miterlimit) {
        this(width, cap, join, miterlimit, null, 0.0f);
    }

    
Constructs a solid BasicStroke with the specified attributes. The miterlimit parameter is unnecessary in cases where the default is allowable or the line joins are not specified as JOIN_MITER. 
Params:
  • width – the width of the BasicStroke
  • cap – the decoration of the ends of a BasicStroke
  • join – the decoration applied where path segments meet
Throws:
/**
     * Constructs a solid {@code BasicStroke} with the specified
     * attributes.  The {@code miterlimit} parameter is
     * unnecessary in cases where the default is allowable or the
     * line joins are not specified as JOIN_MITER.
     * @param width the width of the {@code BasicStroke}
     * @param cap the decoration of the ends of a {@code BasicStroke}
     * @param join the decoration applied where path segments meet
     * @throws IllegalArgumentException if {@code width} is negative
     * @throws IllegalArgumentException if {@code cap} is not either
     *         CAP_BUTT, CAP_ROUND or CAP_SQUARE
     * @throws IllegalArgumentException if {@code join} is not
     *         either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER
     */
    public BasicStroke(float width, int cap, int join) {
        this(width, cap, join, 10.0f, null, 0.0f);
    }

    
Constructs a solid BasicStroke with the specified line width and with default values for the cap and join styles. 
Params:
  • width – the width of the BasicStroke
Throws:
/**
     * Constructs a solid {@code BasicStroke} with the specified
     * line width and with default values for the cap and join
     * styles.
     * @param width the width of the {@code BasicStroke}
     * @throws IllegalArgumentException if {@code width} is negative
     */
    public BasicStroke(float width) {
        this(width, CAP_SQUARE, JOIN_MITER, 10.0f, null, 0.0f);
    }

    
Constructs a new BasicStroke with defaults for all attributes. The default attributes are a solid line of width 1.0, CAP_SQUARE, JOIN_MITER, a miter limit of 10.0. 
/**
     * Constructs a new {@code BasicStroke} with defaults for all
     * attributes.
     * The default attributes are a solid line of width 1.0, CAP_SQUARE,
     * JOIN_MITER, a miter limit of 10.0.
     */
    public BasicStroke() {
        this(1.0f, CAP_SQUARE, JOIN_MITER, 10.0f, null, 0.0f);
    }


    
Returns a Shape whose interior defines the stroked outline of a specified Shape. 
Params:
  • s – the Shape boundary be stroked
Returns:the Shape of the stroked outline.
/**
     * Returns a {@code Shape} whose interior defines the
     * stroked outline of a specified {@code Shape}.
     * @param s the {@code Shape} boundary be stroked
     * @return the {@code Shape} of the stroked outline.
     */
    public Shape createStrokedShape(Shape s) {
        sun.java2d.pipe.RenderingEngine re =
            sun.java2d.pipe.RenderingEngine.getInstance();
        return re.createStrokedShape(s, width, cap, join, miterlimit,
                                     dash, dash_phase);
    }

    
Returns the line width. Line width is represented in user space, which is the default-coordinate space used by Java 2D. See the Graphics2D class comments for more information on the user space coordinate system. 
See Also:
Returns:the line width of this BasicStroke.
/**
     * Returns the line width.  Line width is represented in user space,
     * which is the default-coordinate space used by Java 2D.  See the
     * {@code Graphics2D} class comments for more information on
     * the user space coordinate system.
     * @return the line width of this {@code BasicStroke}.
     * @see Graphics2D
     */
    public float getLineWidth() {
        return width;
    }

    
Returns the end cap style.

Returns:the end cap style of this BasicStroke as one of the static int values that define possible end cap styles.
/**
     * Returns the end cap style.
     * @return the end cap style of this {@code BasicStroke} as one
     * of the static {@code int} values that define possible end cap
     * styles.
     */
    public int getEndCap() {
        return cap;
    }

    
Returns the line join style.

Returns:the line join style of the BasicStroke as one of the static int values that define possible line join styles.
/**
     * Returns the line join style.
     * @return the line join style of the {@code BasicStroke} as one
     * of the static {@code int} values that define possible line
     * join styles.
     */
    public int getLineJoin() {
        return join;
    }

    
Returns the limit of miter joins.

Returns:the limit of miter joins of the BasicStroke.
/**
     * Returns the limit of miter joins.
     * @return the limit of miter joins of the {@code BasicStroke}.
     */
    public float getMiterLimit() {
        return miterlimit;
    }

    
Returns the array representing the lengths of the dash segments. Alternate entries in the array represent the user space lengths of the opaque and transparent segments of the dashes. As the pen moves along the outline of the Shape to be stroked, the user space distance that the pen travels is accumulated. The distance value is used to index into the dash array. The pen is opaque when its current cumulative distance maps to an even element of the dash array and transparent otherwise. 
Returns:the dash array.
/**
     * Returns the array representing the lengths of the dash segments.
     * Alternate entries in the array represent the user space lengths
     * of the opaque and transparent segments of the dashes.
     * As the pen moves along the outline of the {@code Shape}
     * to be stroked, the user space
     * distance that the pen travels is accumulated.  The distance
     * value is used to index into the dash array.
     * The pen is opaque when its current cumulative distance maps
     * to an even element of the dash array and transparent otherwise.
     * @return the dash array.
     */
    public float[] getDashArray() {
        if (dash == null) {
            return null;
        }

        return dash.clone();
    }

    
Returns the current dash phase.
The dash phase is a distance specified in user coordinates that
represents an offset into the dashing pattern. In other words, the dash
phase defines the point in the dashing pattern that will correspond to
the beginning of the stroke.

Returns:the dash phase as a float value.
/**
     * Returns the current dash phase.
     * The dash phase is a distance specified in user coordinates that
     * represents an offset into the dashing pattern. In other words, the dash
     * phase defines the point in the dashing pattern that will correspond to
     * the beginning of the stroke.
     * @return the dash phase as a {@code float} value.
     */
    public float getDashPhase() {
        return dash_phase;
    }

    
Returns the hashcode for this stroke.

Returns:     a hash code for this stroke.
/**
     * Returns the hashcode for this stroke.
     * @return      a hash code for this stroke.
     */
    public int hashCode() {
        int hash = Float.floatToIntBits(width);
        hash = hash * 31 + join;
        hash = hash * 31 + cap;
        hash = hash * 31 + Float.floatToIntBits(miterlimit);
        if (dash != null) {
            hash = hash * 31 + Float.floatToIntBits(dash_phase);
            for (int i = 0; i < dash.length; i++) {
                hash = hash * 31 + Float.floatToIntBits(dash[i]);
            }
        }
        return hash;
    }

    /**
     * Returns true if this BasicStroke represents the same
     * stroking operation as the given argument.
     */
   
Tests if a specified object is equal to this BasicStroke by first testing if it is a BasicStroke and then comparing its width, join, cap, miter limit, dash, and dash phase attributes with those of this BasicStroke. 
Params:
  • obj – the specified object to compare to this BasicStroke
Returns:true if the width, join, cap, miter limit, dash, and dash phase are the same for both objects; false otherwise.
/**
    * Tests if a specified object is equal to this {@code BasicStroke}
    * by first testing if it is a {@code BasicStroke} and then comparing
    * its width, join, cap, miter limit, dash, and dash phase attributes with
    * those of this {@code BasicStroke}.
    * @param  obj the specified object to compare to this
    *              {@code BasicStroke}
    * @return {@code true} if the width, join, cap, miter limit, dash, and
    *            dash phase are the same for both objects;
    *            {@code false} otherwise.
    */
    public boolean equals(Object obj) {
        if (!(obj instanceof BasicStroke)) {
            return false;
        }

        BasicStroke bs = (BasicStroke) obj;
        if (width != bs.width) {
            return false;
        }

        if (join != bs.join) {
            return false;
        }

        if (cap != bs.cap) {
            return false;
        }

        if (miterlimit != bs.miterlimit) {
            return false;
        }

        if (dash != null) {
            if (dash_phase != bs.dash_phase) {
                return false;
            }

            if (!java.util.Arrays.equals(dash, bs.dash)) {
                return false;
            }
        }
        else if (bs.dash != null) {
            return false;
        }

        return true;
    }
}