android 放大镜ShapeDrawable妙用分享

float scale = 1.2f;

int cx = 224;
int cy = 357;
int r = 200;

// 指定形状创建一个ShapeDrawable 
ShapeDrawable shape=new ShapeDrawable(new OvalShape());
Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.bg1);
BitmapShader bs = new BitmapShader(bm, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

Matrix m = new Matrix();
m.setTranslate(r-cx, r-cy);
m.postScale(scale, scale);
bs.setLocalMatrix(m);   // 图形变换可以在这里实现，包括区域指定 

// 为ShapeDrawable设置Shader 
shape.getPaint().setShader(bs);

// 指定描画目标位置 
shape.setBounds((int)(cx-r*scale),(int)(cy-r*scale),(int)(cx+r*scale),(int)(cy+r*scale));
canvas.drawBitmap(bm, 0, 0, null);
shape.draw(canvas);

float scale = 1.2f;

int cx = 224;
int cy = 357;
int r = 200;

// 指定形状创建一个ShapeDrawable
ShapeDrawable shape=new ShapeDrawable(new OvalShape());
Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.bg1);
BitmapShader bs = new BitmapShader(bm, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

Matrix m = new Matrix();
m.setTranslate(r-cx, r-cy);
m.postScale(scale, scale);
bs.setLocalMatrix(m); // 图形变换可以在这里实现，包括区域指定

// 为ShapeDrawable设置Shader
shape.getPaint().setShader(bs);

// 指定描画目标位置
shape.setBounds((int)(cx-r*scale),(int)(cy-r*scale),(int)(cx+r*scale),(int)(cy+r*scale));
canvas.drawBitmap(bm, 0, 0, null);
shape.draw(canvas);