摘要：這篇文章是在上測(cè)試和運(yùn)行的的下的安裝和配置請(qǐng)移步到這里應(yīng)用程序進(jìn)程樹默認(rèn)啟動(dòng)時(shí)初始化個(gè)用于處理圖片的工作進(jìn)程首先安裝需要的工具包使用的版本而不是系統(tǒng)自帶的創(chuàng)建項(xiàng)目模塊圖像處理獲取寬高把原始的二進(jìn)制圖片數(shù)據(jù)轉(zhuǎn)換為把轉(zhuǎn)換為的圖

這篇文章是在OSX上測(cè)試和運(yùn)行的的, Ubuntu下的安裝和配置請(qǐng)移步到這里

應(yīng)用程序進(jìn)程樹, 默認(rèn)啟動(dòng) Poolboy 時(shí), 初始化10個(gè)用于處理圖片的 Python 工作進(jìn)程(Worker)

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew install python
brew tap homebrew/science
brew install opencv
sudo pip install numpy
sudo pip install matplotlib

使用 Homebrew 的 Python 版本, 而不是 Mac OS X 系統(tǒng)自帶的 Python

alias python="/usr/local/bin/python"

?  mix new opencv_thumbnail_server --sup
* creating README.md
* creating .gitignore
* creating mix.exs
* creating config
* creating config/config.exs
* creating lib
* creating lib/opencv_thumbnail_server.ex
* creating test
* creating test/test_helper.exs
* creating test/opencv_thumbnail_server_test.exs

Your Mix project was created successfully.
You can use "mix" to compile it, test it, and more:

    cd opencv_thumbnail_server
    mix test

Run "mix help" for more commands.

Elixir 模塊

require Logger
defmodule OpencvThumbnailServer do
  use Application
  def start(_type, _args) do
    Logger.info "Start opencv thumbnail server"
    OpencvThumbnailServer.Supervisor.start_link()
  end
end

defmodule OpencvThumbnailServer.Supervisor do
  use Supervisor

  @config Application.get_env :opencv_thumbnail_server, :settings

  def start_link() do
    Supervisor.start_link(__MODULE__, [], name: {:global,__MODULE__})
  end

  def init([]) do
    pool_options = @config[:poolboy]
    {_, name} = pool_options[:name]
    children = [
      :poolboy.child_spec(name, pool_options, @config[:module_name])
    ]
    supervise(children, strategy: :one_for_all, max_restarts: 1000, max_seconds: 3600)
  end
end

defmodule OpencvThumbnailServer.Worker do
  use GenServer
  @config Application.get_env(:opencv_thumbnail_server, :settings)

  def start_link(python_module) do
    GenServer.start_link(__MODULE__, python_module, [])
  end

  def call_python(worker, function, args) do
    GenServer.call(worker, {:call_python, function, args}, 10_000)
  end

  def init(python_module) do
    IO.puts "Start worker"
    {:ok, pid} = :python.start_link([
      {:python_path, @config[:python_path]},
      {:python, @config[:python]}
    ])
    state = {python_module, pid}
    {:ok, state}
  end

  def handle_call({:call_python, function, args}, _from, state) do
    {module, pid} = state
    result = :python.call(pid, module, function, args)
    reply = {:ok, result}
    {:reply, reply, state}
  end

  def handle_call(_request, _from, state) do
    {:stop, :error, :bad_call, state}
  end

  def handle_info(_msg, {module,py_pid}) do
    {:stop, :error, {module,py_pid}}
  end

  def terminate(_reason, {_, py_pid}) do
    :python.stop(py_pid)
    :ok
  end
end

獲取寬高

# -*- coding: utf-8 -*-

import urllib2 as urllib
import numpy as np
import cv2


def load_image_url(url):
    resp = urllib.urlopen(url)
    buf = resp.read()
    return buf


def load_image_file(filename):
    image = cv2.imdecode(filename, cv2.IMREAD_COLOR)
    return image

def get_photo_sizes():
    return [
        [160, 160],
        [320, 320],
        [640, 640],
        [1060, 1060],
        [1280, 1280]
    ]
def show(buf):
    # print buf
    # x = cv2.imdecode(image, cv2.IMREAD_COLOR)
    # d = cv2.cvtColor(c, cv2.COLOR_RGB2BGR)
    np_ndarray = np.fromstring(buf, dtype=np.uint8)
    x = cv2.imdecode(np_ndarray, cv2.IMREAD_UNCHANGED)
    return cv2.imshow("NBA Image", x)

def write(buf):
    nparray = np.fromstring(buf, dtype=np.uint8)
    img = cv2.imdecode(nparray, cv2.IMREAD_UNCHANGED)
    return cv2.imwrite("/tmp/imwrite.png", img)

# def get_dimension():
#     url = "http://img1.gtimg.com/16/1601/160106/16010642_1200x1000_0.jpg"
#     resp = urllib.urlopen(url)
#     buf = resp.read()
#     x = np.fromstring(buf, dtype=np.uint8)
#     img = cv2.imdecode(x, cv2.IMREAD_UNCHANGED)
#     # height = np.size(img, 0)
#     # width = np.size(img, 1)
#     height, width = image.shape[:2]
#     return (width, height)

def get_dimension(buffer):
    # 把原始的二進(jìn)制圖片數(shù)據(jù)轉(zhuǎn)換為NpArray
    nparray = np.fromstring(buffer, dtype=np.uint8)
    # 把 nparray 轉(zhuǎn)換為 opencv 的圖像格式
    image = cv2.imdecode(nparray, cv2.IMREAD_UNCHANGED)
    height, width = image.shape[:2]
    return (width, height)

def convert_color():
    url = "http://ww3.sinaimg.cn/mw690/6941baebgw1epzcuv9vmxj20me0hy0u1.jpg"
    resp = urllib.urlopen(url)
    buf = resp.read()
    x = np.fromstring(buf, dtype=np.uint8)
    img = cv2.imdecode(x, cv2.IMREAD_UNCHANGED)

if __name__ == "__main__":
    get_dimension()

Erlang 的binary()數(shù)據(jù)類型和 Python 之間的映射關(guān)系, 在Python 2.x 中二進(jìn)制數(shù)據(jù)類型為 str() 表示, Python 3.x 中為 bytes()

buf = resp.read(), 其中變量 buf 的類型為

在 Elixir 我們看到變量 buf 的值為:

{:ok, <<255, 216, 255, 224, 0, 16, 74, 70, 73, 70, 0, 1, 1, 1, 0, 72, 
      0, 72, 0, 0, 255, 219, 0, 67, 0, 8, 6, 6, 7, 6, 5, 8, 7, 7, 7, 
      9, 9, 8, 10, 12, 20, 13, 12, 11, 11, 12, 25, 18, 19, ...>>}

{:ok, data} = OpencvThumbnailServer.Api.load_image_url("https://segmentfault.com/img/bVwhAW")
OpencvThumbnailServer.Api.get_dimension(data) 
{:ok, {800, 431}}

之前的 Python 圖像處理模塊可以組織到一個(gè)項(xiàng)目中多帶帶維護(hù). 這里使用工具 cookiecutter 創(chuàng)建 Python 一個(gè)基本的項(xiàng)目骨架, 用于實(shí)現(xiàn)縮略圖的功能

cookiecutter 可以通過多種方式安裝, 包括pip, easy_install, conda, brew

pip install cookiecutter
easy_install cookiecutter
conda install -c https://conda.binstar.org/pydanny cookiecutter
brew install cookiecutter(Mac OS X)

目錄結(jié)構(gòu)

?  opencv_thumbnail git:(master) tree
.
├── AUTHORS.rst
├── CONTRIBUTING.rst
├── HISTORY.rst
├── LICENSE
├── MANIFEST.in
├── Makefile
├── README.rst
├── build
│?? ├── bdist.macosx-10.11-x86_64
│?? └── lib
│??     └── opencv_thumbnail
│??         ├── __init__.py
│??         └── opencv_thumbnail.py
├── dist
│?? └── opencv_thumbnail-0.1.0-py2.7.egg
├── docs
│?? ├── Makefile
│?? ├── authors.rst
│?? ├── conf.py
│?? ├── contributing.rst
│?? ├── history.rst
│?? ├── index.rst
│?? ├── installation.rst
│?? ├── make.bat
│?? ├── readme.rst
│?? └── usage.rst
├── opencv_thumbnail
│?? ├── __init__.py
│?? ├── __init__.pyc
│?? ├── opencv_thumbnail.py
│?? └── opencv_thumbnail.pyc
├── opencv_thumbnail.egg-info
│?? ├── PKG-INFO
│?? ├── SOURCES.txt
│?? ├── dependency_links.txt
│?? ├── not-zip-safe
│?? └── top_level.txt
├── requirements_dev.txt
├── setup.cfg
├── setup.py
├── tests
│?? ├── __init__.py
│?? └── test_opencv_thumbnail.py
├── tox.ini
└── travis_pypi_setup.py

9 directories, 36 files

調(diào)用需要從 Poolboy 池中取出一個(gè)工作進(jìn)程, 并調(diào)用工作進(jìn)程的call_python, 進(jìn)程使用完成后返還給 Poolboy 進(jìn)程池, 這里對(duì)調(diào)用過程封裝一下, 以簡(jiǎn)化使用.

defmodule OpencvThumbnailServer.Api do
  alias OpencvThumbnailServer.Worker

  def get_dimension(data) do
    worker = :poolboy.checkout(:opencv_thumbnail_server_pool)
    {w, h} = Worker.call_python(worker, :get_dimension, [data])
    :poolboy.checkin(:opencv_thumbnail_server_pool, worker)
    {w, h}
  end

  def load_image_url(url) do
    worker = :poolboy.checkout(:opencv_thumbnail_server_pool)
    image_bin = Worker.call_python(worker, :load_image_url, [url])
    :poolboy.checkin(:opencv_thumbnail_server_pool, worker)
    image_bin
  end
end

https://github.com/developerworks/opencv_thumbnail_server

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