自定義 相機 及取景框 繪製
- 在相機預覽組件上覆蓋一層 自定義ImageView 重寫 IamgeView的 ondraw() 方法。
2.要實現第一步 首先要的到矩形框 左上角的 座標（全屏下是marginLeft（左） marjinTop（上）-忽略單位） 還有 寬（width） 長（height） 來獲得矩形區域 。
- 就是 重寫ondraw（）了 要用到 畫布canvas 的方法 畫矩形 drawRect 來完成 畫出矩形 還須要 畫筆Paint 來設置 屬性 及 顏色 透明等等。 下面上代碼
/*
* Copyright (c) 2015-2020 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;
/**
*
* 但願有一天能夠開源出來 org.zhx
*
* @version 1.0, 2015-11-15 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 stub
initPaint();
mContext = context;
// 獲取屏幕px值 組裝成一個 point對象
Point p = DisplayUtil.getScreenMetrics(mContext);
widthScreen = p.x;
heightScreen = p.y;
}
private void initPaint() {
// 繪製中間透明區域矩形邊界的Paint
mLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mLinePaint.setColor(Color.BLUE);
mLinePaint.setStyle(Style.STROKE);
mLinePaint.setStrokeWidth(5f);
// 值不爲0 那麼透明取景框 周圍就會有線 看需求 修改值就行 個人項目部須要 線 因此透明
mLinePaint.setAlpha(0);
// 繪製四周陰影區域 的畫筆
mAreaPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mAreaPaint.setColor(Color.GRAY);
mAreaPaint.setStyle(Style.FILL);
mAreaPaint.setAlpha(100);
paint = new Paint();
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
Log.i(TAG, "onDraw...");
if (mCenterRect == null)
return;
// 繪製陰影區域 2 爲 4個角上短線的 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);
// 短線的顏色 和透明度
paint.setColor(Color.WHITE);
paint.setAlpha(150);
// 50爲 4角短線的長度
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 左側
canvas.drawRect(mCenterRect.right - 50, mCenterRect.bottom,
mCenterRect.right + 2, mCenterRect.bottom + 2, paint);// 右下 右側
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 頂部
canvas.drawRect(mCenterRect.left - 2, mCenterRect.top,
mCenterRect.left, mCenterRect.top + 50, paint);// 左上 側邊
canvas.drawRect(mCenterRect.right - 50, mCenterRect.top - 2,
mCenterRect.right + 2, mCenterRect.top, paint);// 右上 頂部
canvas.drawRect(mCenterRect.right, mCenterRect.top,
mCenterRect.right + 2, mCenterRect.top + 50, paint);// 右上 右側
// 繪製目標透明區域
canvas.drawRect(mCenterRect, mLinePaint);
super.onDraw(canvas);
}
public Rect getmCenterRect() {
return mCenterRect;
}
/**
* 設置 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();
}
}
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;
/**
*
* 但願有一天能夠開源出來 org.zhx
*
* @version 1.0, 2015-11-15 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);
}
}