BasicStroke (Java Platform SE 8 )
Keywords: java.awt.BasicStroke class
Date: 2026-08-19

java.awt

## Class BasicStroke

- java.lang.Object
- - java.awt.BasicStroke

- All Implemented Interfaces:
    Stroke

      public class BasicStroke
      extends Object
      implements Stroke

  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.

  See Also:
    `Graphics2D`

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `CAP_BUTT` Ends unclosed subpaths and dash segments with no added decoration.
    `static int` | `CAP_ROUND` Ends unclosed subpaths and dash segments with a round decoration that has a radius equal to half of the width of the pen.
    `static int` | `CAP_SQUARE` 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.
    `static int` | `JOIN_BEVEL` Joins path segments by connecting the outer corners of their wide outlines with a straight segment.
    `static int` | `JOIN_MITER` Joins path segments by extending their outside edges until they meet.
    `static int` | `JOIN_ROUND` Joins path segments by rounding off the corner at a radius of half the line width.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `BasicStroke()` Constructs a new `BasicStroke` with defaults for all attributes.
    `BasicStroke(float width)` Constructs a solid `BasicStroke` with the specified line width and with default values for the cap and join styles.
    `BasicStroke(float width, int cap, int join)` Constructs a solid `BasicStroke` with the specified attributes.
    `BasicStroke(float width, int cap, int join, float miterlimit)` Constructs a solid `BasicStroke` with the specified attributes.
    `BasicStroke(float width, int cap, int join, float miterlimit, float[] dash, float dash_phase)` Constructs a new `BasicStroke` with the specified attributes.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Shape` | `createStrokedShape(Shape s)` Returns a `Shape` whose interior defines the stroked outline of a specified `Shape`.
    `boolean` | `equals(Object obj)` 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`.
    `float[]` | `getDashArray()` Returns the array representing the lengths of the dash segments.
    `float` | `getDashPhase()` Returns the current dash phase.
    `int` | `getEndCap()` Returns the end cap style.
    `int` | `getLineJoin()` Returns the line join style.
    `float` | `getLineWidth()` Returns the line width.
    `float` | `getMiterLimit()` Returns the limit of miter joins.
    `int` | `hashCode()` Returns the hashcode for this stroke.

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### JOIN_MITER

          @Native
          public static final int JOIN_MITER

      Joins path segments by extending their outside edges until they meet.
      See Also:
        Constant Field Values

    - #### JOIN_ROUND

          @Native
          public static final int JOIN_ROUND

      Joins path segments by rounding off the corner at a radius of half the line width.
      See Also:
        Constant Field Values

    - #### JOIN_BEVEL

          @Native
          public static final int JOIN_BEVEL

      Joins path segments by connecting the outer corners of their wide outlines with a straight segment.
      See Also:
        Constant Field Values

    - #### CAP_BUTT

          @Native
          public static final int CAP_BUTT

      Ends unclosed subpaths and dash segments with no added decoration.
      See Also:
        Constant Field Values

    - #### CAP_ROUND

          @Native
          public static final int CAP_ROUND

      Ends unclosed subpaths and dash segments with a round decoration that has a radius equal to half of the width of the pen.
      See Also:
        Constant Field Values

    - #### CAP_SQUARE

          @Native
          public static final int CAP_SQUARE

      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.
      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### BasicStroke

          @ConstructorProperties(value={"lineWidth","endCap","lineJoin","miterLimit","dashArray","dashPhase"})
          public BasicStroke(float width,
                                                                                                                                  int cap,
                                                                                                                                  int join,
                                                                                                                                  float miterlimit,
                                                                                                                                  float[] dash,
                                                                                                                                  float dash_phase)

      Constructs a new `BasicStroke` with the specified attributes.
      Parameters:
        `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:
        `IllegalArgumentException` - if `width` is negative
        `IllegalArgumentException` - if `cap` is not either CAP_BUTT, CAP_ROUND or CAP_SQUARE
        `IllegalArgumentException` - if `miterlimit` is less than 1 and `join` is JOIN_MITER
        `IllegalArgumentException` - if `join` is not either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER
        `IllegalArgumentException` - if `dash_phase` is negative and `dash` is not `null`
        `IllegalArgumentException` - if the length of `dash` is zero
        `IllegalArgumentException` - if dash lengths are all zero.

    - #### BasicStroke

          public BasicStroke(float width,
                             int cap,
                             int join,
                             float miterlimit)

      Constructs a solid `BasicStroke` with the specified attributes.
      Parameters:
        `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:
        `IllegalArgumentException` - if `width` is negative
        `IllegalArgumentException` - if `cap` is not either CAP_BUTT, CAP_ROUND or CAP_SQUARE
        `IllegalArgumentException` - if `miterlimit` is less than 1 and `join` is JOIN_MITER
        `IllegalArgumentException` - if `join` is not either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER

    - #### BasicStroke

          public BasicStroke(float width,
                             int cap,
                             int join)

      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.
      Parameters:
        `width` - the width of the `BasicStroke`
        `cap` - the decoration of the ends of a `BasicStroke`
        `join` - the decoration applied where path segments meet
      Throws:
        `IllegalArgumentException` - if `width` is negative
        `IllegalArgumentException` - if `cap` is not either CAP_BUTT, CAP_ROUND or CAP_SQUARE
        `IllegalArgumentException` - if `join` is not either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER

    - #### BasicStroke

          public BasicStroke(float width)

      Constructs a solid `BasicStroke` with the specified line width and with default values for the cap and join styles.
      Parameters:
        `width` - the width of the `BasicStroke`
      Throws:
        `IllegalArgumentException` - if `width` is negative

    - #### BasicStroke

          public BasicStroke()

      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.

  - ### Method Detail

    - #### createStrokedShape

          public Shape createStrokedShape(Shape s)

      Returns a `Shape` whose interior defines the stroked outline of a specified `Shape`.
      Specified by:
        `createStrokedShape` in interface `Stroke`
      Parameters:
        `s` - the `Shape` boundary be stroked
      Returns:
        the `Shape` of the stroked outline.

    - #### getLineWidth

          public float getLineWidth()

      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.
      Returns:
        the line width of this `BasicStroke`.
      See Also:
        `Graphics2D`

    - #### getEndCap

          public int getEndCap()

      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.

    - #### getLineJoin

          public int getLineJoin()

      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.

    - #### getMiterLimit

          public float getMiterLimit()

      Returns the limit of miter joins.
      Returns:
        the limit of miter joins of the `BasicStroke`.

    - #### getDashArray

          public float[] getDashArray()

      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.

    - #### getDashPhase

          public float getDashPhase()

      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.

    - #### hashCode

          public int hashCode()

      Returns the hashcode for this stroke.
      Overrides:
        `hashCode` in class `Object`
      Returns:
        a hash code for this stroke.
      See Also:
        `Object.equals(java.lang.Object)`, `System.identityHashCode(java.lang.Object)`

    - #### equals

          public boolean equals(Object obj)

      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`.
      Overrides:
        `equals` in class `Object`
      Parameters:
        `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.
      See Also:
        `Object.hashCode()`, `HashMap`

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