/*
* 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.kaola.qrcodescanner.qrcode.view;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.widget.FrameLayout;
import android.widget.RelativeLayout;
import com.kaola.qrcodescanner.R;
import com.kaola.qrcodescanner.qrcode.utils.ScreenUtils;
/**
* 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.
*/
public final class QrCodeFinderView extends RelativeLayout {
private static final int[] SCANNER_ALPHA = { 0, 64, 128, 192, 255, 192, 128, 64 };
private static final long ANIMATION_DELAY = 100L;
private static final int OPAQUE = 0xFF;
private Paint mPaint;
private int mScannerAlpha;
private int mMaskColor;
private int mFrameColor;
private int mLaserColor;
private int mTextColor;
private Rect mFrameRect;
private int mFocusThick;
private int mAngleThick;
private int mAngleLength;
public QrCodeFinderView(Context context) {
this(context, null);
}
public QrCodeFinderView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public QrCodeFinderView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mPaint = new Paint();
Resources resources = getResources();
mMaskColor = resources.getColor(R.color.qr_code_finder_mask);
mFrameColor = resources.getColor(R.color.qr_code_finder_frame);
mLaserColor = resources.getColor(R.color.qr_code_finder_laser);
mTextColor = resources.getColor(R.color.qr_code_white);
mFocusThick = 1;
mAngleThick = 8;
mAngleLength = 40;
mScannerAlpha = 0;
init(context);
}
private void init(Context context) {
if (isInEditMode()) {
return;
}
// 需要调用下面的方法才会执行onDraw方法
setWillNotDraw(false);
LayoutInflater inflater = LayoutInflater.from(context);
RelativeLayout relativeLayout = (RelativeLayout) inflater.inflate(R.layout.layout_qr_code_scanner, this);
FrameLayout frameLayout = (FrameLayout) relativeLayout.findViewById(R.id.qr_code_fl_scanner);
mFrameRect = new Rect();
RelativeLayout.LayoutParams layoutParams = (LayoutParams) frameLayout.getLayoutParams();
mFrameRect.left = (ScreenUtils.getScreenWidth() - layoutParams.width) / 2;
mFrameRect.top = layoutParams.topMargin;
mFrameRect.right = mFrameRect.left + layoutParams.width;
mFrameRect.bottom = mFrameRect.top + layoutParams.height;
}
@Override
public void onDraw(Canvas canvas) {
if (isInEditMode()) {
return;
}
Rect frame = mFrameRect;
if (frame == null) {
return;
}
int width = canvas.getWidth();
int height = canvas.getHeight();
// 绘制焦点框外边的暗色背景
mPaint.setColor(mMaskColor);
canvas.drawRect(0, 0, width, frame.top, mPaint);
canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, mPaint);
canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, mPaint);
canvas.drawRect(0, frame.bottom + 1, width, height, mPaint);
drawFocusRect(canvas, frame);
drawAngle(canvas, frame);
drawText(canvas, frame);
drawLaser(canvas, frame);
// Request another update at the animation interval, but only repaint the laser line,
// not the entire viewfinder mask.
postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top, frame.right, frame.bottom);
}
/**
* 画聚焦框，白色的
*
* @param canvas
* @param rect
*/
private void drawFocusRect(Canvas canvas, Rect rect) {
// 绘制焦点框（黑色）
mPaint.setColor(mFrameColor);
// 上
canvas.drawRect(rect.left + mAngleLength, rect.top, rect.right - mAngleLength, rect.top + mFocusThick, mPaint);
// 左
canvas.drawRect(rect.left, rect.top + mAngleLength, rect.left + mFocusThick, rect.bottom - mAngleLength,
mPaint);
// 右
canvas.drawRect(rect.right - mFocusThick, rect.top + mAngleLength, rect.right, rect.bottom - mAngleLength,
mPaint);
// 下
canvas.drawRect(rect.left + mAngleLength, rect.bottom - mFocusThick, rect.right - mAngleLength, rect.bottom,
mPaint);
}
/**
* 画粉色的四个角
*
* @param canvas
* @param rect
*/
private void drawAngle(Canvas canvas, Rect rect) {
mPaint.setColor(mLaserColor);
mPaint.setAlpha(OPAQUE);
mPaint.setStyle(Paint.Style.FILL);
mPaint.setStrokeWidth(mAngleThick);
int left = rect.left;
int top = rect.top;
int right = rect.right;
int bottom = rect.bottom;
// 左上角
canvas.drawRect(left, top, left + mAngleLength, top + mAngleThick, mPaint);
canvas.drawRect(left, top, left + mAngleThick, top + mAngleLength, mPaint);
// 右上角
canvas.drawRect(right - mAngleLength, top, right, top + mAngleThick, mPaint);
canvas.drawRect(right - mAngleThick, top, right, top + mAngleLength, mPaint);
// 左下角
canvas.drawRect(left, bottom - mAngleLength, left + mAngleThick, bottom, mPaint);
canvas.drawRect(left, bottom - mAngleThick, left + mAngleLength, bottom, mPaint);
// 右下角
canvas.drawRect(right - mAngleLength, bottom - mAngleThick, right, bottom, mPaint);
canvas.drawRect(right - mAngleThick, bottom - mAngleLength, right, bottom, mPaint);
}
private void drawText(Canvas canvas, Rect rect) {
int margin = 40;
mPaint.setColor(mTextColor);
mPaint.setTextSize(getResources().getDimension(R.dimen.text_size_13sp));
String text = getResources().getString(R.string.qr_code_auto_scan_notification);
Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
float fontTotalHeight = fontMetrics.bottom - fontMetrics.top;
float offY = fontTotalHeight / 2 - fontMetrics.bottom;
float newY = rect.bottom + margin + offY;
float left = (ScreenUtils.getScreenWidth() - mPaint.getTextSize() * text.length()) / 2;
canvas.drawText(text, left, newY, mPaint);
}
private void drawLaser(Canvas canvas, Rect rect) {
// 绘制焦点框内固定的一条扫描线（红色）
mPaint.setColor(mLaserColor);
mPaint.setAlpha(SCANNER_ALPHA[mScannerAlpha]);
mScannerAlpha = (mScannerAlpha + 1) % SCANNER_ALPHA.length;
int middle = rect.height() / 2 + rect.top;
canvas.drawRect(rect.left + 2, middle - 1, rect.right - 1, middle + 2, mPaint);
}
}
