Android Shape 形状

Shape继承体系：

Shape (android.graphics.drawable.shapes)
----PathShape (android.graphics.drawable.shapes)
----RectShape (android.graphics.drawable.shapes)
--------ArcShape (android.graphics.drawable.shapes)
--------OvalShape (android.graphics.drawable.shapes)
--------RoundRectShape (android.graphics.drawable.shapes)

RectShape

RectShape rectShape = new RectShape();
ShapeDrawable drawable = new ShapeDrawable(rectShape);
drawable.getPaint().setColor(Color.RED);
drawable.getPaint().setStyle(Paint.Style.FILL); //填充
view.setBackgroundDrawable(drawable);

 矩形

RoundRectShape

float[] outerRadii = {20, 20, 40, 40, 60, 60, 80, 80};//外矩形 左上、右上、右下、左下 圆角半径
//float[] outerRadii = {20, 20, 20, 20, 20, 20, 20, 20};//外矩形 左上、右上、右下、左下 圆角半径
RectF inset = new RectF(100, 100, 200, 200);//内矩形距外矩形，左上角x,y距离。 右下角x,y距离
float[] innerRadii = {20, 20, 20, 20, 20, 20, 20, 20};//内矩形 圆角半径
//RoundRectShape roundRectShape = new RoundRectShape(outerRadii, inset, innerRadii);
RoundRectShape roundRectShape = new RoundRectShape(outerRadii, null, innerRadii); //无内矩形

ShapeDrawable drawable = new ShapeDrawable(roundRectShape);
drawable.getPaint().setColor(Color.MAGENTA);
drawable.getPaint().setAntiAlias(true);
drawable.getPaint().setStyle(Paint.Style.STROKE);//描边
view.setBackground(drawable);

 无内矩形的圆角矩形  带内矩形的圆角矩形

OvalShape

OvalShape ovalShape = new OvalShape();
ShapeDrawable drawable = new ShapeDrawable(ovalShape);
drawable.getPaint().setColor(Color.RED);
drawable.getPaint().setStyle(Paint.Style.FILL_AND_STROKE);
view.setBackgroundDrawable(drawable);

 椭圆。 而当View的宽高相等时，就绘出了圆

ArcShape

ArcShape arcShape = new ArcShape(45, 270); //顺时针  開始角度45。 扫描的角度270   扇形
ShapeDrawable drawable = new ShapeDrawable(arcShape);
drawable.getPaint().setColor(Color.RED);
drawable.getPaint().setStyle(Paint.Style.FILL);

// Bitmap bitmap =  ((BitmapDrawable)getResources().getDrawable(R.drawable.aa)).getBitmap();
// BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.MIRROR, Shader
//                .TileMode.REPEAT);
// Matrix matrix = new Matrix();
// matrix.preScale(600.00f / bitmap.getWidth(), 600.00f / bitmap.getHeight());//view:w=600,h=600
// bitmapShader.setLocalMatrix(matrix);
// drawable.getPaint().setShader(bitmapShader);

view.setBackgroundDrawable(drawable);

 扇形图

 结合BitmapShader

PathShape

Path path = new Path();
path.moveTo(50, 0);
path.lineTo(0, 50);
path.lineTo(50, 100);
path.lineTo(100, 50);
path.lineTo(50, 0);
PathShape pathShape = new PathShape(path, 200, 100);
ShapeDrawable drawable = new ShapeDrawable(pathShape);
drawable.getPaint().setColor(Color.RED);
drawable.getPaint().setStyle(Paint.Style.FILL);
imageView.setBackgroundDrawable(drawable);

以Path路径对象，来设定图形。

PathShape的构造函数：PathShape(path, stdWidth, stdHeight);

   stdWidth：标准宽度

   stdHeight：标准高度

 在构造PathShape对象时，设置了宽高的标准。

内部函数 

protected void onResize(float width, float height) {
    mScaleX = width / mStdWidth;
    mScaleY = height / mStdHeight;
}

public void draw(Canvas canvas, Paint paint) {
    canvas.save();
    canvas.scale(mScaleX, mScaleY);
    canvas.drawPath(mPath, paint);
    canvas.restore();
}

  Shape基类中有函数 resize()，当中调用了onResize()。ShapeDrawable中会调用resize()。

  有了设定的标准宽高。再算出实际宽高与标准宽高的比率，最后在绘制时，画布canvas缩放。

  造成的效果： path中的(x,y)坐标值 乘以 比率值，即是 终于呈现出的坐标值(实际内部是缩放的canvas)

  比方，这里view的 w=400。 h=400

  假设标准宽高都等于400，那么canvas终于不缩放，即1:1。

  PathShape pathShape = new PathShape(path, 400, 400);

    stdx=400, stdy=400

PathShape pathShape = new PathShape(path, 100, 100);

 stdx=100, stdy=100  

PathShape pathShape = new PathShape(path, 200, 100);

 stdx=200, stdy=100