Piccasso图片圆角及圆形图片实现

在开发中我们会经常遇到对图片进行圆角处理，以及现在流行的头像等将图片处理成圆形，Piccasso提供了transform这个机制，我们可以利用这个机制，在图片展示之前对图片进行处理，处理方式只需要实现
Transformation 接口即可，下面我们来看一下实现代码。

图片圆角

public class RoundedTransform implements Transformation {

    private final int radius;
    private final int margin;

    public RoundedTransform(final int radius, final int margin) {
        this.radius = radius;
        this.margin = margin;
    }

    @Override
    public Bitmap transform(Bitmap source) {
        final Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setShader(new BitmapShader(source, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
        Bitmap output = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        canvas.drawRoundRect(new RectF(margin, margin, source.getWidth() - margin, source.getHeight() - margin), radius, radius, paint);

        if (source != output) {
            source.recycle();
        }

        return output;
    }

    @Override
    public String key() {
        return "rounded(radius=" + radius + ", margin=" + margin + ")";
    }
}

圆形图片

public class CircleTransform implements Transformation {
  @Override
  public Bitmap transform(Bitmap source) {
      int size = Math.min(source.getWidth(), source.getHeight());

      int x = (source.getWidth() - size) / 2;
      int y = (source.getHeight() - size) / 2;

      Bitmap squaredBitmap = Bitmap.createBitmap(source, x, y, size, size);
      if (squaredBitmap != source) {
          source.recycle();
      }

      Bitmap bitmap = Bitmap.createBitmap(size, size, source.getConfig());

      Canvas canvas = new Canvas(bitmap);
      Paint paint = new Paint();
      BitmapShader shader = new BitmapShader(squaredBitmap, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP);
      paint.setShader(shader);
      paint.setAntiAlias(true);

      float r = size / 2f;
      canvas.drawCircle(r, r, r, paint);

      squaredBitmap.recycle();
      return bitmap;
  }

  @Override
  public String key() {
      return "circle";
  }
}