### ch07 程式碼下載 ###
$ cd ~/Lab
$ wget https://max543.com/debugger/class/python02/PiCamera/Lab/code/ch07.zip
$ unzip ch07.zip



### ex7-1 ###

# 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



### ex7-2 ###

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



### ex7-3 ###

# 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
$ cmake .
$ make -j4
$ sudo ./v4l2rtspserver -F 15 --rotation 180 -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 



### ex7-4 (7-1-app-hello.py) ###

from flask import Flask

app = Flask(__name__)		# flask 才會知道你的 root 在何處

@app.route("/")			# 定義路由路徑，/ 指的是 web root (URL)
def index():			# 一個接著要執行的 function。
   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)



### ex7-5 ###

# 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



### ex7-6 (7-2-app-route.py) ###

from flask import Flask, render_template, Response

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)

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



### ex7-7 ###

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

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

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

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



### ex7-8 (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):
        return self.frames[int(time()) % 3]



### ex7-9 (7-3-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()
        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)



### ex7-10 ###

# 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') }}">



### ex7-11 (7-4-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)



### ex7-12 (camera_pi.py) ###

import cv2

class Camera(object):
    def __init__(self):
        if cv2.__version__.startswith('2'):
            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'):
            PROP_FRAME_WIDTH = cv2.CAP_PROP_FRAME_WIDTH
            PROP_FRAME_HEIGHT = cv2.CAP_PROP_FRAME_HEIGHT
        else:
            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)
        self.video.set(PROP_FRAME_HEIGHT, 240)
    
    def __del__(self):
        self.video.release()
    
    def get_frame(self):
        success, image = self.video.read()
        ret, jpeg = cv2.imencode('.jpg', image)
        return jpeg.tostring()