PolygonDrawingUtil

A compact Android utility for constructing and drawing rounded regular polygons.

Consumers can specify:

• number of sides (≥ 3);
• center coordinates;
• outer radius (center to vertex);
• corner rounding radius;
• polygon rotation;
• (optional) fill/stroke Paint;
• (optional) target Path instance.

Demo

This video was captured using the sample application in this repository. It provides convenient controls for exploring PolygonDrawingUtil’s capabilities.

Getting Started

1. Specify PolygonDrawingUtil as a dependency in your build.gradle file:

   dependencies {
     implementation "com.stkent:polygondrawingutil:1.2.0"
   }
   

2. Create a new PolygonDrawingUtil instance and assign it to a property in your custom view class:

   private val polygonDrawingUtil = PolygonDrawingUtil()
   

3. Call polygonDrawUtil.drawPolygon in your onDraw method:

   override fun onDraw(canvas: Canvas) {
       super.onDraw(canvas)
   
       polygonDrawingUtil.drawPolygon(
           canvas,
           numberOfSides,
           centerX,
           centerY,
           polygonRadius,
           cornerRadius,
           rotation,
           polygonPaint
       )
   }
   

   Alternately, you can supply your own Path instance and ask PolygonDrawingUtil to fill it with a polygon:

   private val myPath = Path()
   
   polygonDrawingUtil.constructPolygonPath(
       myPath,
       numberOfSides,
       centerX,
       centerY,
       polygonRadius,
       cornerRadius,
       rotation
   )
   

   This allows you to perform post-processing on the Path before drawing to a Canvas.

License

Copyright 2019 Stuart Kent

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.