/* * Copyright (C) 2008 The Android Open Source Project * * 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. */package com.example.android.apis.graphics;import android.app.Activity;import android.content.Context;import android.graphics.*;import android.os.Bundle;import android.view.View;public class Regions extends GraphicsActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(new SampleView(this));    }        private static class SampleView extends View {        private final Paint mPaint = new Paint();        private final Rect  mRect1 = new Rect();        private final Rect  mRect2 = new Rect();        public SampleView(Context context) {            super(context);            setFocusable(true);                        mPaint.setAntiAlias(true);            mPaint.setTextSize(16);            mPaint.setTextAlign(Paint.Align.CENTER);                        mRect1.set(10, 10, 100, 80);            mRect2.set(50, 50, 130, 110);        }        private void drawOriginalRects(Canvas canvas, int alpha) {            mPaint.setStyle(Paint.Style.STROKE);            mPaint.setColor(Color.RED);            mPaint.setAlpha(alpha);            drawCentered(canvas, mRect1, mPaint);            mPaint.setColor(Color.BLUE);            mPaint.setAlpha(alpha);            drawCentered(canvas, mRect2, mPaint);                        // restore style            mPaint.setStyle(Paint.Style.FILL);        }                private void drawRgn(Canvas canvas, int color, String str, Region.Op op) {            if (str != null) {                mPaint.setColor(Color.BLACK);                canvas.drawText(str, 80, 24, mPaint);            }                        Region rgn = new Region();            rgn.set(mRect1);            rgn.op(mRect2, op);                        mPaint.setColor(color);            RegionIterator iter = new RegionIterator(rgn);            Rect r = new Rect();                        canvas.translate(0, 30);            mPaint.setColor(color);            while (iter.next(r)) {                canvas.drawRect(r, mPaint);            }            drawOriginalRects(canvas, 0x80);        }                private static void drawCentered(Canvas c, Rect r, Paint p) {            float inset = p.getStrokeWidth() * 0.5f;            if (inset == 0) {   // catch hairlines                inset = 0.5f;            }            c.drawRect(r.left + inset, r.top + inset,                       r.right - inset, r.bottom - inset, p);        }                @Override protected void onDraw(Canvas canvas) {            canvas.drawColor(Color.GRAY);                        canvas.save();            canvas.translate(80, 5);            drawOriginalRects(canvas, 0xFF);            canvas.restore();                        mPaint.setStyle(Paint.Style.FILL);                        canvas.save();            canvas.translate(0, 140);            drawRgn(canvas, Color.RED, "Union", Region.Op.UNION);            canvas.restore();                        canvas.save();            canvas.translate(0, 280);            drawRgn(canvas, Color.BLUE, "Xor", Region.Op.XOR);            canvas.restore();                        canvas.save();            canvas.translate(160, 140);            drawRgn(canvas, Color.GREEN, "Difference", Region.Op.DIFFERENCE);            canvas.restore();                        canvas.save();            canvas.translate(160, 280);            drawRgn(canvas, Color.WHITE, "Intersect", Region.Op.INTERSECT);            canvas.restore();        }    }}