Added a method for extracting the transform matrix.

src/main/java/pythagoras/d/AffineTransform.java

@@ -114,6 +114,13 @@ public class AffineTransform extends AbstractTransform
         return this.ty;
     }
 
+    @Override // from Transform
+    public void transform (double[] matrix) {
+        matrix[0] = m00; matrix[1] = m01;
+        matrix[2] = m10; matrix[3] = m11;
+        matrix[4] =  tx; matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setUniformScale (double scale) {
         return setScale(scale, scale);

src/main/java/pythagoras/d/IdentityTransform.java

@@ -42,6 +42,13 @@ public class IdentityTransform extends AbstractTransform
         return 0;
     }
 
+    @Override // from Transform
+    public void transform (double[] matrix) {
+        matrix[0] = 1; matrix[1] = 0;
+        matrix[2] = 0; matrix[3] = 1;
+        matrix[4] = 0; matrix[5] = 0;
+    }
+
     @Override // from Transform
     public Transform invert () {
         return this;

src/main/java/pythagoras/d/NonUniformTransform.java

@@ -63,6 +63,14 @@ public class NonUniformTransform extends AbstractTransform
         return ty;
     }
 
+    @Override // from Transform
+    public void transform (double[] matrix) {
+        double sina = Math.sin(rotation), cosa = Math.cos(rotation);
+        matrix[0] = cosa * scaleX;  matrix[1] = sina * scaleY;
+        matrix[2] = -sina * scaleX; matrix[3] = cosa * scaleY;
+        matrix[4] = tx;             matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setUniformScale (double scale) {
         setScaleX(scale);

src/main/java/pythagoras/d/RigidTransform.java

@@ -58,6 +58,14 @@ public class RigidTransform extends AbstractTransform
         return ty;
     }
 
+    @Override // from Transform
+    public void transform (double[] matrix) {
+        double sina = Math.sin(rotation), cosa = Math.cos(rotation);
+        matrix[0] = cosa;  matrix[1] = sina;
+        matrix[2] = -sina; matrix[3] = cosa;
+        matrix[4] = tx;    matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setRotation (double angle) {
         this.rotation = angle;

src/main/java/pythagoras/d/Transform.java

@@ -39,6 +39,10 @@ public interface Transform
     /** Returns the y-coordinate of the translation component. */
     double ty ();
 
+    /** Copies the affine transform matrix into the supplied array.
+     * @param matrix the array which receives {@code m00, m01, m10, m11, tx, ty}. */
+    void transform (double[] matrix);
+
     /** Sets the uniform scale of this transform.
      * @return this instance, for chaining.
      * @throws IllegalArgumentException if the supplied scale is zero.

src/main/java/pythagoras/d/UniformTransform.java

@@ -63,6 +63,14 @@ public class UniformTransform extends AbstractTransform
         return ty;
     }
 
+    @Override // from Transform
+    public void transform (double[] matrix) {
+        double sina = Math.sin(rotation), cosa = Math.cos(rotation);
+        matrix[0] = cosa * scale;  matrix[1] = sina * scale;
+        matrix[2] = -sina * scale; matrix[3] = cosa * scale;
+        matrix[4] = tx;            matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setUniformScale (double scale) {
         if (scale == 0) throw new IllegalArgumentException("Scale must be non-zero.");

src/main/java/pythagoras/f/AffineTransform.java

@@ -114,6 +114,13 @@ public class AffineTransform extends AbstractTransform
         return this.ty;
     }
 
+    @Override // from Transform
+    public void transform (float[] matrix) {
+        matrix[0] = m00; matrix[1] = m01;
+        matrix[2] = m10; matrix[3] = m11;
+        matrix[4] =  tx; matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setUniformScale (float scale) {
         return setScale(scale, scale);

src/main/java/pythagoras/f/IdentityTransform.java

@@ -42,6 +42,13 @@ public class IdentityTransform extends AbstractTransform
         return 0;
     }
 
+    @Override // from Transform
+    public void transform (float[] matrix) {
+        matrix[0] = 1; matrix[1] = 0;
+        matrix[2] = 0; matrix[3] = 1;
+        matrix[4] = 0; matrix[5] = 0;
+    }
+
     @Override // from Transform
     public Transform invert () {
         return this;

src/main/java/pythagoras/f/NonUniformTransform.java

@@ -63,6 +63,14 @@ public class NonUniformTransform extends AbstractTransform
         return ty;
     }
 
+    @Override // from Transform
+    public void transform (float[] matrix) {
+        float sina = FloatMath.sin(rotation), cosa = FloatMath.cos(rotation);
+        matrix[0] = cosa * scaleX;  matrix[1] = sina * scaleY;
+        matrix[2] = -sina * scaleX; matrix[3] = cosa * scaleY;
+        matrix[4] = tx;             matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setUniformScale (float scale) {
         setScaleX(scale);

src/main/java/pythagoras/f/RigidTransform.java

@@ -58,6 +58,14 @@ public class RigidTransform extends AbstractTransform
         return ty;
     }
 
+    @Override // from Transform
+    public void transform (float[] matrix) {
+        float sina = FloatMath.sin(rotation), cosa = FloatMath.cos(rotation);
+        matrix[0] = cosa;  matrix[1] = sina;
+        matrix[2] = -sina; matrix[3] = cosa;
+        matrix[4] = tx;    matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setRotation (float angle) {
         this.rotation = angle;

src/main/java/pythagoras/f/Transform.java

@@ -39,6 +39,10 @@ public interface Transform
     /** Returns the y-coordinate of the translation component. */
     float ty ();
 
+    /** Copies the affine transform matrix into the supplied array.
+     * @param matrix the array which receives {@code m00, m01, m10, m11, tx, ty}. */
+    void transform (float[] matrix);
+
     /** Sets the uniform scale of this transform.
      * @return this instance, for chaining.
      * @throws IllegalArgumentException if the supplied scale is zero.

src/main/java/pythagoras/f/UniformTransform.java

@@ -63,6 +63,14 @@ public class UniformTransform extends AbstractTransform
         return ty;
     }
 
+    @Override // from Transform
+    public void transform (float[] matrix) {
+        float sina = FloatMath.sin(rotation), cosa = FloatMath.cos(rotation);
+        matrix[0] = cosa * scale;  matrix[1] = sina * scale;
+        matrix[2] = -sina * scale; matrix[3] = cosa * scale;
+        matrix[4] = tx;            matrix[5] = ty;
+    }
+
     @Override // from Transform
     public Transform setUniformScale (float scale) {
         if (scale == 0) throw new IllegalArgumentException("Scale must be non-zero.");