自定义 相机 及取景框 绘制
在相机预览组件上覆盖一层 自定义ImageView 重写 IamgeView的 ondraw() 方法。2.要实现第一步 首先要的到矩形框 左上角的 坐标（全屏下是marginLeft（左） marjinTop（上）-忽略单位） 还有 宽（width） 长（height） 来得到矩形区域 。就是 重写ondraw（）了 要用到 画布canvas 的方法 画矩形 drawRect 来完成 画出矩形 还需要 画笔Paint 来设置 属性 及 颜色 透明等等。 下面上代码
/* * Copyright (c) - Founder Ltd. All Rights Reserved. * *zhx for org* * */package org.zhx.view.camera.widget;import org.zhx.view.camera.util.DisplayUtil;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Paint.Style;import android.graphics.Point;import android.graphics.Rect;import android.util.AttributeSet;import android.util.Log;import android.widget.ImageView;/*** * 希望有一天可以开源出来 org.zhx* * @version 1.0, -11-15 下午7:11:49* @author zhx*/public class OverlayerView extends ImageView {private static final String TAG = OverlayerView.class.getSimpleName();private Paint mLinePaint;private Paint mAreaPaint;private Rect mCenterRect = null;private Context mContext;private Paint paint;private int widthScreen, heightScreen;public OverlayerView(Context context, AttributeSet attrs) {super(context, attrs);// TODO Auto-generated constructor stubinitPaint();mContext = context;// 获取屏幕px值 组装成一个 point对象Point p = DisplayUtil.getScreenMetrics(mContext);widthScreen = p.x;heightScreen = p.y;}private void initPaint() {// 绘制中间透明区域矩形边界的PaintmLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);mLinePaint.setColor(Color.BLUE);mLinePaint.setStyle(Style.STROKE);mLinePaint.setStrokeWidth(5f);// 值不为0 那么透明取景框 周围就会有线 看需求 修改值就行 我的项目部需要 线 所以透明mLinePaint.setAlpha(0);// 绘制四周阴影区域 的画笔mAreaPaint = new Paint(Paint.ANTI_ALIAS_FLAG);mAreaPaint.setColor(Color.GRAY);mAreaPaint.setStyle(Style.FILL);mAreaPaint.setAlpha(100);paint = new Paint();}@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubLog.i(TAG, "onDraw...");if (mCenterRect == null)return;// 绘制阴影区域 2 为 4个角上短线的 高度canvas.drawRect(0, 0, widthScreen, mCenterRect.top - 2, mAreaPaint);canvas.drawRect(0, mCenterRect.bottom + 2, widthScreen, heightScreen,mAreaPaint);canvas.drawRect(0, mCenterRect.top - 2, mCenterRect.left - 2,mCenterRect.bottom + 2, mAreaPaint);canvas.drawRect(mCenterRect.right + 2, mCenterRect.top - 2,widthScreen, mCenterRect.bottom + 2, mAreaPaint);// 短线的颜色 和透明度paint.setColor(Color.WHITE);paint.setAlpha(150);// 50为 4角短线的长度canvas.drawRect(mCenterRect.left - 2, mCenterRect.bottom,mCenterRect.left + 50, mCenterRect.bottom + 2, paint);// 左下 底部canvas.drawRect(mCenterRect.left - 2, mCenterRect.bottom - 50,mCenterRect.left, mCenterRect.bottom, paint);// 左下 左侧canvas.drawRect(mCenterRect.right - 50, mCenterRect.bottom,mCenterRect.right + 2, mCenterRect.bottom + 2, paint);// 右下 右侧canvas.drawRect(mCenterRect.right, mCenterRect.bottom - 50,mCenterRect.right + 2, mCenterRect.bottom, paint);// 右下 底部canvas.drawRect(mCenterRect.left - 2, mCenterRect.top - 2,mCenterRect.left + 50, mCenterRect.top, paint);// 左上 顶部canvas.drawRect(mCenterRect.left - 2, mCenterRect.top,mCenterRect.left, mCenterRect.top + 50, paint);// 左上 侧边canvas.drawRect(mCenterRect.right - 50, mCenterRect.top - 2,mCenterRect.right + 2, mCenterRect.top, paint);// 右上 顶部canvas.drawRect(mCenterRect.right, mCenterRect.top,mCenterRect.right + 2, mCenterRect.top + 50, paint);// 右上 右侧// 绘制目标透明区域canvas.drawRect(mCenterRect, mLinePaint);super.onDraw(canvas);}public Rect getmCenterRect() {return mCenterRect;}/*** 设置 取景框 的矩形框 。* * @param value* 矩形取景框* @return* @throws Exception* @author zhx*/public void setmCenterRect(Rect mCenterRect) {this.mCenterRect = mCenterRect;postInvalidate();}}
辅助类
package org.zhx.view.camera.util;import android.content.Context;import android.graphics.Point;import android.graphics.Rect;import android.util.DisplayMetrics;import android.util.Log;/*** * 希望有一天可以开源出来 org.zhx* * @version 1.0, -11-15 下午5:23:57* @author zhx*/public class DisplayUtil {private static final String TAG = DisplayUtil.class.getSimpleName();public static int dip2px(Context context, float dipValue) {final float scale = context.getResources().getDisplayMetrics().density;return (int) (dipValue * scale + 0.5f);}/*** * @param value* @return int* @throws Exception* @author zhx*/public static int px2dip(Context context, float pxValue) {final float scale = context.getResources().getDisplayMetrics().density;return (int) (pxValue / scale + 0.5f);}/*** * @param value* @return* @throws Exception* @author zhx*/public static Point getScreenMetrics(Context context) {DisplayMetrics dm = context.getResources().getDisplayMetrics();int w_screen = dm.widthPixels;int h_screen = dm.heightPixels;Log.i(TAG, "Screen---Width = " + w_screen + " Height = " + h_screen+ " densityDpi = " + dm.densityDpi);return new Point(w_screen, h_screen);}/*** * @param value* @return* @throws Exception* @author zhx*/public static float getScreenRate(Context context) {Point P = getScreenMetrics(context);float H = P.y;float W = P.x;return (H / W);}/*** * @param value* @return* @throws Exception* @author zhx*/public static Rect createCenterScreenRect(Context context, Rect rect) {int x1 = DisplayUtil.dip2px(context, rect.left);int y1 = DisplayUtil.dip2px(context, rect.top);int x2 = DisplayUtil.getScreenMetrics(context).x- DisplayUtil.dip2px(context, rect.right);int y2 = DisplayUtil.getScreenMetrics(context).y- DisplayUtil.dip2px(context, rect.bottom);Log.i(TAG, x1 + "@" + y1 + "@" + x2 + "@" + y2);return new Rect(x1, y1, x2, y2);}}
源码 提github 维护 下载地址：/zhoulinxue/ZCamera.git
