# 下載範例程式
~$ wget http://max543.com/debugger/class/python02/人臉辨識與物體辨識/code/ch5.zip
~$ unzip ch5.zip



### Lab5-1 ###

# 啟動 RTSP Server
~$ raspivid -o - -t 0 -hf --rotation 180 -w 320 -h 240 -fps 15 | cvlc -vvv stream:///dev/stdin --sout '#rtp{sdp=rtsp://:8554}' :demux=h264



# 找出佔用的 Port Number 的　PID　
~$ sudo netstat -lpn |grep 8554

# 刪除佔用的 PID
~$ sudo kill -9 PID



### Lab5-2 ###

# VLC media player
https://get.videolan.org/vlc/3.0.14/win64/vlc-3.0.14-win64.exe



### Lab5-3 ###

# 安裝輕量級的 RTSP Server
~$ cd ~
~$ git clone https://github.com/mpromonet/h264_v4l2_rtspserver.git
~$ sudo apt-get install liblivemedia-dev libv4l-dev cmake
~$ cd h264_v4l2_rtspserver
~/h264_v4l2_rtspserver$ cmake .
~/h264_v4l2_rtspserver$ make -j4
~/h264_v4l2_rtspserver$ sudo ./v4l2rtspserver -F 15 -W 800 -H 600 -P 8554 /dev/video0



# 沒有支援旋轉鏡頭參數的指令，也可以用以下的指令：
~$ v4l2-ctl --set-ctrl vertical_flip=1



### Lab5-4 ###

~$ pip install Flask



### Lab5-5 (app.py) ###

from flask import Flask

app = Flask(__name__)		# Flask 類別初始化時傳入的 __name__ 參數，代表當前模組的名稱。是固定用法，以便讓 Flask 知道在哪裡尋找資源 (template__folder 或 static_folder 資料夾位置)
 
@app.route('/')			# 定義路由路徑，告訴 Flask，哪個 URL 應該觸發我們的函式。/ 指的是 web root (URL) (又稱為 Controller)
def hello_world():		# 定義一個接著要觸發的函式
    return 'Hello, World!'	# 函式回傳的文字字串 (又稱為 View)	


### Lab5-6 (5-1-app-hello.py) ###

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
   return 'Hello Flask'

if __name__ == '__main__':	# 是直接運行的才會執行 app.run() 這個方法
    app.run(host = '0.0.0.0', port = 80, debug = True)



### Lab5-7 ###

# 查找哪一個 python 程序正在執行中
$ ps -fA | grep python

# 刪除 root 占用的程序
$ sudo kill -9 PID



### Lab5-8 ###

# 新增一個資料夾 templates，與一個網頁檔 link.html
~$ mkdir templates && cd templates
~/templates$ nano link.html

# link.html 的內容
<h1>Hello Template</h1>
<a href="{{ url_for('foo') }}">foo</a>

# 再新增一個 bar.html
~/templates$ nano bar.html

# bar.html 的內容
<ul>
{% for ext in extns %}		# 走訪容器
<li>{{ ext }}</li>
{% endfor %}
</ul>



### Lab5-9 (5-2-app-route.py) ###

from flask import Flask, render_template, Response	# render_template 用來使用 html

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('link.html')			# View 可由自訂的樣板產生

@app.route('/foo')
def foo():
    extns = ['Flask', 'Jinja2', 'Awesome']		# 樣板內可塞變數
    return render_template('bar.html', extns = extns)		# View 的超連結，並顯示變數

if __name__ == '__main__':
    app.run(host = '0.0.0.0', port = 80, debug = True)



### Lab5-10 (stream_pi.py) ###

from time import time			

class Camera(object):
    def __init__(self):
        self.frames = [open('static/' + f + '.jpg', 'rb').read() for f in ['1', '2', '3']]

    def get_frame(self):		# get_frame 每三秒讀取一張圖片，並回傳該張 frame
        return self.frames[int(time()) % 3]



### Lab5-11 (5-3-app-stream.py) ###

from flask import Flask, render_template, Response
from stream_pi import Camera

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('stream.html')

def gen(camera):
    while True:
        frame = camera.get_frame()			# Camera 類別
        yield (b'--frame\r\n'
               b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n\r\n')

@app.route('/video_feed')
def video_feed():
    return Response(gen(Camera()),			# 回傳內容
                    mimetype = 'multipart/x-mixed-replace; boundary = frame')

if __name__ == '__main__':
    app.run(host = '0.0.0.0', port = 80, debug = True)



### Lab5-12 ###

# 新增一個 stream.html
$ nano templates/stream.html

# stream.html 的內容
<h1>Hello Stream</h1>
<img id="bg" src="{{ url_for('video_feed') }}">



### Lab5-13 ###

import cv2

class Camera(object):
    def __init__(self):
        self.video = cv2.VideoCapture(0)			# 開啟 /dev/videoX，預設的 camera 是 0
    
    def __del__(self):
        self.video.release()
    
    def get_frame(self):
        success, image = self.video.read()		# V4L2 的 API
        ret, jpeg = cv2.imencode('.jpg', image)
        return jpeg.tostring()



### Lab5-14 (5-4-app-camera.py) ###

from flask import Flask, render_template, Response
from camera_pi import Camera

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('stream.html')

def gen(camera):
    while True:
        frame = camera.get_frame()
        yield (b'--frame\r\n'
               b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n\r\n')

@app.route('/video_feed')
def video_feed():
    return Response(gen(Camera()),
                    mimetype = 'multipart/x-mixed-replace; boundary = frame')

if __name__ == '__main__':
    app.run(host = '0.0.0.0', port = 80, debug = True)



### Lab5-15 ###

~$ sudo pip install numpy==1.21.4
~$ sudo pip install opencv-python==4.5.4.60
~$ sudo pip install opencv-contrib-python==4.5.4.60


### Lab5-16 (camera_pi_v2.py) ###

import cv2

class Camera(object):
    def __init__(self):
        if cv2.__version__.startswith('2'):					# 若是 OpenCV 是 2.X 的版本
            PROP_FRAME_WIDTH = cv2.cv.CV_CAP_PROP_FRAME_WIDTH
            PROP_FRAME_HEIGHT = cv2.cv.CV_CAP_PROP_FRAME_HEIGHT
        elif cv2.__version__.startswith('3'):					# 若是 OpenCV 是 3.X 的版本
            PROP_FRAME_WIDTH = cv2.CAP_PROP_FRAME_WIDTH
            PROP_FRAME_HEIGHT = cv2.CAP_PROP_FRAME_HEIGHT
        else:										# 若是 OpenCV 是其他的版本
            PROP_FRAME_WIDTH = cv2.CAP_PROP_FRAME_WIDTH
            PROP_FRAME_HEIGHT = cv2.CAP_PROP_FRAME_HEIGHT

        self.video = cv2.VideoCapture(0)
        #self.video = cv2.VideoCapture(1)
        #self.video.set(PROP_FRAME_WIDTH, 640)
        #self.video.set(PROP_FRAME_HEIGHT, 480)
        self.video.set(PROP_FRAME_WIDTH, 320)		# 改變視窗的寬
        self.video.set(PROP_FRAME_HEIGHT, 240)		# 改變視窗的高
    
    def __del__(self):
        self.video.release()
    
    def get_frame(self):
        success, image = self.video.read()
        ret, jpeg = cv2.imencode('.jpg', image)		# 調整 JPG 壓縮品質
        return jpeg.tostring()



### Lab5-17 ###

~$ cd ~/ch05/project_opencv
~/project_opencv$ sudo python3 app-opencv.py



### Lab5-18 ###

~$ cd ~/ch05/project_opencv+line
~/project_opencv+line$ sudo python3 app-opencv+line.py