/*
* Copyright (C) 2008 ZXing authors
*
* 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.barcode.view;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.View;
import com.barcode.camera.CameraManager;
import com.google.zxing.ResultPoint;
import com.ttj.R;
/**
* This view is overlaid on top of the camera preview. It adds the viewfinder
* rectangle and partial transparency outside it, as well as the laser scanner
* animation and result points.
*
* <br/>
* <br/>
* 该视图是覆盖在相机的预览视图之上的一层视图。扫描区构成原理，其实是在预览视图上画四块遮罩层，
* 中间留下的部分保持透明，并画上一条激光线，实际上该线条就是展示而已，与扫描功能没有任何关系。
*
* @author dswitkin@google.com (Daniel Switkin)
*/
public final class ViewfinderView extends View {
/**
* 刷新界面的时间
*/
private static final long ANIMATION_DELAY = 10L;
private static final int OPAQUE = 0xFF;
/**
* 四个绿色边角对应的长度
*/
private int ScreenRate;
/**
* 四个绿色边角对应的宽度
*/
private static final int CORNER_WIDTH = 6;
private static final int L_WIDTH = 1;
/**
* 扫描框中的中间线的宽度
*/
private static final int MIDDLE_LINE_WIDTH = 15;
/**
* 中间那条线每次刷新移动的距离
*/
private static final int SPEEN_DISTANCE = 8;
/**
* 手机的屏幕密度
*/
private static float density;
/**
* 画笔对象的引用
*/
private Paint paint;
/**
* 中间滑动线的最顶端位置
*/
private int slideTop;
private boolean isFirst;
private static final int MAX_RESULT_POINTS = 20;
private CameraManager cameraManager;
private Bitmap resultBitmap;
private final int maskColor;
private final int resultColor;
private final int resultPointColor;
private List<ResultPoint> possibleResultPoints;
private List<ResultPoint> lastPossibleResultPoints;
// This constructor is used when the class is built from an XML resource.
public ViewfinderView(Context context, AttributeSet attrs) {
super(context, attrs);
// Initialize these once for performance rather than calling them every
// time in onDraw().
density = context.getResources().getDisplayMetrics().density;
// 将像素转换成dp
ScreenRate = (int) (20 * density);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
Resources resources = getResources();
maskColor = resources.getColor(R.color.viewfinder_mask);
resultColor = resources.getColor(R.color.result_view);
resultPointColor = resources.getColor(R.color.possible_result_points);
possibleResultPoints = new ArrayList<ResultPoint>(5);
lastPossibleResultPoints = null;
}
public void setCameraManager(CameraManager cameraManager) {
this.cameraManager = cameraManager;
}
@SuppressLint("DrawAllocation")
@Override
public void onDraw(Canvas canvas) {
if (cameraManager == null) {
return; // not ready yet, early draw before done configuring
}
Rect frame = cameraManager.getFramingRect();
Rect previewFrame = cameraManager.getFramingRectInPreview();
if (frame == null || previewFrame == null) {
return;
}
// 初始化中间线滑动的最上边和最下边
if (!isFirst) {
isFirst = true;
slideTop = frame.top - 5;
}
int width = canvas.getWidth();
int height = canvas.getHeight();
// Draw the exterior (i.e. outside the framing rect) darkened
/*
* 预览界面的绘制
*/
paint.setColor(resultBitmap != null ? resultColor : maskColor);
canvas.drawRect(0, 0, width, frame.top - 1, paint);
canvas.drawRect(0, frame.top - 1, frame.left - 1, frame.bottom + 1,
paint);
canvas.drawRect(frame.right + 1, frame.top - 1, width,
frame.bottom + 1, paint);
canvas.drawRect(0, frame.bottom + 1, width, height, paint);
if (resultBitmap != null) {
// Draw the opaque result bitmap over the scanning rectangle
paint.setAlpha(OPAQUE);
// canvas.drawBitmap(resultBitmap, null, frame, paint);
canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint);
} else {
// 画扫预览灰线框，共4个部分
paint.setColor(Color.GRAY);
canvas.drawRect(frame.left, frame.top, frame.right, frame.top
+ L_WIDTH, paint);
canvas.drawRect(frame.left, frame.top, frame.left + L_WIDTH,
frame.bottom, paint);
canvas.drawRect(frame.left, frame.bottom - L_WIDTH, frame.right,
frame.bottom, paint);
canvas.drawRect(frame.right - L_WIDTH, frame.top, frame.right,
frame.bottom, paint);
// 画扫描框边上的角，总共8个部分
paint.setColor(Color.GREEN);
canvas.drawRect(frame.left, frame.top, frame.left + ScreenRate,
frame.top + CORNER_WIDTH, paint);
canvas.drawRect(frame.left, frame.top, frame.left + CORNER_WIDTH,
frame.top + ScreenRate, paint);
canvas.drawRect(frame.right - ScreenRate, frame.top, frame.right,
frame.top + CORNER_WIDTH, paint);
canvas.drawRect(frame.right - CORNER_WIDTH, frame.top, frame.right,
frame.top + ScreenRate, paint);
canvas.drawRect(frame.left, frame.bottom - CORNER_WIDTH, frame.left
+ ScreenRate, frame.bottom, paint);
canvas.drawRect(frame.left, frame.bottom - ScreenRate, frame.left
+ CORNER_WIDTH, frame.bottom, paint);
canvas.drawRect(frame.right - ScreenRate, frame.bottom
- CORNER_WIDTH, frame.right, frame.bottom, paint);
canvas.drawRect(frame.right - CORNER_WIDTH, frame.bottom
- ScreenRate, frame.right, frame.bottom, paint);
// 绘制中间的线,每次刷新界面，中间的线往下移动SPEEN_DISTANCE
slideTop += SPEEN_DISTANCE;
if (slideTop >= frame.bottom - 10) {
slideTop = frame.top - 5;
}
Rect lineRect = new Rect();
lineRect.left = frame.left;
lineRect.right = frame.right;
lineRect.top = slideTop;
lineRect.bottom = slideTop + MIDDLE_LINE_WIDTH;// 扫描线的宽度15
canvas.drawBitmap(((BitmapDrawable) (getResources()
.getDrawable(R.drawable.qrcode_scan_line))).getBitmap(),
null, lineRect, paint);
paint.setColor(Color.WHITE);
paint.setTextSize(15 * density);
paint.setAlpha(0xee);
paint.setTypeface(Typeface.create("System", Typeface.BOLD));
List<ResultPoint> currentPossible = possibleResultPoints;
Collection<ResultPoint> currentLast = lastPossibleResultPoints;
if (currentPossible.isEmpty()) {
lastPossibleResultPoints = null;
} else {
possibleResultPoints = new ArrayList<ResultPoint>(5);
lastPossibleResultPoints = currentPossible;
paint.setAlpha(OPAQUE);
paint.setColor(resultPointColor);
for (ResultPoint point : currentPossible) {
canvas.drawCircle(frame.left + point.getX(), frame.top
+ point.getY(), 6.0f, paint);
}
}
if (currentLast != null) {
paint.setAlpha(OPAQUE / 2);
paint.setColor(resultPointColor);
for (ResultPoint point : currentLast) {
canvas.drawCircle(frame.left + point.getX(), frame.top
+ point.getY(), 3.0f, paint);
}
}
// 刷新界面区域
postInvalidateDelayed(ANIMATION_DELAY, 0, 0, width, height);
}
}
public void drawViewfinder() {
Bitmap resultBitmap = this.resultBitmap;
this.resultBitmap = null;
if (resultBitmap != null) {
resultBitmap.recycle();
}
invalidate();
}
/**
* Draw a bitmap with the result points highlighted instead of the live
* scanning display.
*
* @param barcode
* An image of the decoded barcode.
*/
public void drawResultBitmap(Bitmap barcode) {
resultBitmap = barcode;
invalidate();
}
public void addPossibleResultPoint(ResultPoint point) {
List<ResultPoint> points = possibleResultPoints;
synchronized (points) {
points.add(point);
int size = points.size();
if (size > MAX_RESULT_POINTS) {
// trim it
points.subList(0, size - MAX_RESULT_POINTS / 2).clear();
}
}
}
}