Class ShapeWriter

Hierarchy: Object , ShapeWriter

public class ShapeWriter

Writes Geometrys into Java2D Shape objects of the appropriate type. This supports rendering geometries using Java2D. The ShapeWriter allows supplying a PointTransformation class, to transform coordinates from model space into view space. This is useful if a client is providing its own transformation logic, rather than relying on Java2D AffineTransforms.

The writer supports removing duplicate consecutive points (via the setRemoveDuplicatePoints(boolean) method) as well as true decimation (via the setDecimation(double) method. Enabling one of these strategies can substantially improve rendering speed for large geometries. It is only necessary to enable one strategy. Using decimation is preferred, but this requires determining a distance below which input geometry vertices can be considered unique (which may not always be feasible). If neither strategy is enabled, all vertices of the input Geometry will be represented in the output Shape.

public ShapeWriter(PointTransformation pointTransformer, PointShapeFactory pointFactory)

Creates a new ShapeWriter with a specified point transformation and point shape factory.

Parameters:: pointTransformer - pointTransformer a transformation from model to view space to use; pointFactory - pointFactory the PointShapeFactory to use

public ShapeWriter(PointTransformation pointTransformer)

Creates a new ShapeWriter with a specified point transformation and the default point shape factory.

Parameters:: pointTransformer - pointTransformer a transformation from model to view space to use

public ShapeWriter()

Creates a new ShapeWriter with the default (identity) point transformation.

public void setRemoveDuplicatePoints(boolean doRemoveDuplicatePoints)

Sets whether duplicate consecutive points should be eliminated. This can reduce the size of the generated Shapes and improve rendering speed, especially in situations where a transform reduces the extent of the geometry.

The default is false.

Parameters:: doDecimation - doDecimation whether decimation is to be used

public void setDecimation(double decimationDistance)

Sets the decimation distance used to determine whether vertices of the input geometry are considered to be duplicate and thus removed. The distance is axis distance, not Euclidean distance. The distance is specified in the input geometry coordinate system (NOT the transformed output coordinate system).

When rendering to a screen image, a suitably small distance should be used to avoid obvious rendering defects. A distance equivalent to the equivalent of 1.5 pixels or less is recommended (and perhaps even smaller to avoid any chance of visible artifacts).

The default distance is 0.0, which disables decimation.

Parameters:: decimationDistance - decimationDistance the distance below which vertices are considered to be duplicates

public Shape toShape(Geometry geometry)

Creates a Shape representing a Geometry, according to the specified PointTransformation and PointShapeFactory (if relevant).

Note that Shapes do not preserve information about which elements in heterogeneous collections are 1D and which are 2D. For example, a GeometryCollection containing a ring and a disk will render as two disks if Graphics.fill is used, or as two rings if Graphics.draw is used. To avoid this issue use separate shapes for the components.

Parameters:: geometry - geometry the geometry to convert

Returns:: a Shape representing the geometry