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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>第 20 章 图形开发</title><link rel="stylesheet" type="text/css" href="docbook.css" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><meta name="keywords" content="php,pear,pecl,phar, python, , " /><link rel="home" href="index.html" title="Netkiller Python 手札" /><link rel="up" href="index.html" title="Netkiller Python 手札" /><link rel="prev" href="LangChain/ch19s04.html" title="19.4. 相似度搜索" /><link rel="next" href="graphviz.html" title="20.2. graphviz" /></head><body><a xmlns="" href="//www.netkiller.cn/">Home</a> | <a xmlns="" href="//netkiller.github.io/">简体中文</a> | <a xmlns="" href="http://netkiller.sourceforge.net/">繁体中文</a> | <a xmlns="" href="/journal/index.html">杂文</a>
| <a xmlns="" href="https://github.com/netkiller">Github</a> | <a xmlns="" href="https://zhuanlan.zhihu.com/netkiller">知乎专栏</a> | <a xmlns="" href="https://www.facebook.com/bg7nyt">Facebook</a> | <a xmlns="" href="http://cn.linkedin.com/in/netkiller/">Linkedin</a> | <a xmlns="" href="https://www.youtube.com/user/bg7nyt/videos">Youtube</a> | <a xmlns="" href="//www.netkiller.cn/home/donations.html">打赏(Donations)</a> | <a xmlns="" href="//www.netkiller.cn/home/about.html">About</a><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">第 20 章 图形开发</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="LangChain/ch19s04.html">上一页</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="graphviz.html">下一页</a></td></tr></table><hr /></div><table xmlns=""><tr><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&repo=netkiller.github.io&type=watch&count=true&size=large" height="30" width="170" frameborder="0" scrolling="0" style="width:170px; height: 30px;" allowTransparency="true"></iframe></td><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&repo=netkiller.github.io&type=fork&count=true&size=large" height="30" width="170" frameborder="0" scrolling="0" style="width:170px; height: 30px;" allowTransparency="true"></iframe></td><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&type=follow&count=true&size=large" height="30" width="240" frameborder="0" scrolling="0" style="width:240px; height: 30px;" allowTransparency="true"></iframe></td><td></td><td><a href="https://zhuanlan.zhihu.com/netkiller"><img src="/images/logo/zhihu-card-default.svg" height="25" /></a></td><td valign="middle"><a href="https://zhuanlan.zhihu.com/netkiller">知乎专栏</a></td><td></td><td></td><td></td><td></td></tr></table><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a id="graphics"></a>第 20 章 图形开发</h1></div></div></div><div class="toc"><p><strong>目录</strong></p><dl class="toc"><dt><span class="section"><a href="graphics.html#qrcode">20.1. 二维码</a></span></dt><dd><dl><dt><span class="section"><a href="graphics.html#id1237">20.1.1. qrcode</a></span></dt><dt><span class="section"><a href="graphics.html#MyQR">20.1.2. MyQR</a></span></dt><dt><span class="section"><a href="graphics.html#id1238">20.1.3. 从图片识别二维码</a></span></dt><dt><span class="section"><a href="graphics.html#id1239">20.1.4. 从摄像头识别二维码</a></span></dt></dl></dd><dt><span class="section"><a href="graphviz.html">20.2. graphviz</a></span></dt><dd><dl><dt><span class="section"><a href="graphviz.html#id1240">20.2.1. 安装 graphviz 环境</a></span></dt><dt><span class="section"><a href="graphviz.html#id1241">20.2.2. 例子</a></span></dt></dl></dd><dt><span class="section"><a href="pyro.html">20.3. Pyro - Pyro is short for PYthon Remote Objects</a></span></dt><dt><span class="section"><a href="python-imaging.html">20.4. Python Imaging Library</a></span></dt><dt><span class="section"><a href="opencv/index.html">20.5. OpenCV</a></span></dt><dd><dl><dt><span class="section"><a href="opencv/index.html#id1242">20.5.1. 安装 OpenCV</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1243">20.5.2. 显示图片</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1244">20.5.3. 将BGR图像转为RGB</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1245">20.5.4. uint8 格式</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1246">20.5.5. 应用Canny边缘检测</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1247">20.5.6. 摄像头捕捉图像</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1248">20.5.7. imread()</a></span></dt><dt><span class="section"><a href="opencv/index.html#opencv.channel]">20.5.8. 通道拆分/合并</a></span></dt><dt><span class="section"><a href="opencv/index.html#opencv.hsv">20.5.9. HSV 色彩识别</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1249">20.5.10. 色阶调整</a></span></dt><dt><span class="section"><a href="opencv/index.html#id1250">20.5.11. 亮度调节</a></span></dt></dl></dd><dt><span class="section"><a href="pillow/index.html">20.6. PIL（Python Imaging Library）Python 图像处理库</a></span></dt><dd><dl><dt><span class="section"><a href="pillow/index.html#pillow.setup">20.6.1. 安装</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.resize">20.6.2. 缩放图像与尺寸修改</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.paste">20.6.3. 叠加图像</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.rotate">20.6.4. 图像旋转</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.width.height">20.6.5. 获取图片信息</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.new">20.6.6. 创建空图像</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.crop">20.6.7. 裁剪</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.convert">20.6.8. 彩色转灰度</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.merge">20.6.9. RGB 通道操作</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.pixel">20.6.10. 像素操作</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.text">20.6.11. 图像上加文字</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.point">20.6.12. 明暗调整</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.fromarray">20.6.13. PIL 与 Numpy 相互转换</a></span></dt><dt><span class="section"><a href="pillow/index.html#image.diff">20.6.14. 比较两张图片</a></span></dt></dl></dd><dt><span class="section"><a href="ch20s07.html">20.7. SVG 图形库</a></span></dt><dd><dl><dt><span class="section"><a href="ch20s07.html#svg.tag">20.7.1. SVG 标签</a></span></dt><dt><span class="section"><a href="ch20s07.html#drawsvg">20.7.2. drawsvg</a></span></dt><dt><span class="section"><a href="ch20s07.html#CairoSVG">20.7.3. CairoSVG - SVG 转换为 PNG/PDF/PS</a></span></dt></dl></dd><dt><span class="section"><a href="netkiller-chart.html">20.8. Netkiller SVG 图形库</a></span></dt><dd><dl><dt><span class="section"><a href="netkiller-chart.html#id1269">20.8.1. 安装</a></span></dt><dt><span class="section"><a href="netkiller-chart.html#id1285">20.8.2. SVG 图形库</a></span></dt><dt><span class="section"><a href="netkiller-chart.html#id1288">20.8.3. Gantt 甘特图</a></span></dt><dt><span class="section"><a href="netkiller-chart.html#id1289">20.8.4. 工作负载图</a></span></dt><dt><span class="section"><a href="netkiller-chart.html#id1290">20.8.5. 思维导图</a></span></dt><dt><span class="section"><a href="netkiller-chart.html#id1291">20.8.6. 石川鱼骨图</a></span></dt></dl></dd></dl></div>
<div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="qrcode"></a>20.1. 二维码</h2></div></div></div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="id1237"></a>20.1.1. qrcode</h3></div></div></div>
<p>安装</p>
<p>pip install qrcode</p>
<pre class="screen">
neo@MacBook-Pro-Neo ~ % pip install qrcode
Collecting qrcode
Downloading qrcode-6.1-py2.py3-none-any.whl (31 kB)
Requirement already satisfied: six in /usr/local/lib/python3.9/site-packages (from qrcode) (1.15.0)
Installing collected packages: qrcode
Successfully installed qrcode-6.1
</pre>
<p>常规二维码</p>
<pre class="programlisting">
import qrcode
img = qrcode.make('《Netkiller Python 手札》')
img.save("text.png")
img = qrcode.make('http://www.netkiller.cn')
img.save("url.png")
</pre>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1235"></a>20.1.1.1. 设置颜色</h4></div></div></div>
<p>颜色设置背景为白色，前景为绿色</p>
<pre class="programlisting">
import qrcode as qrcode
qr = qrcode.QRCode(version=1, box_size=10, border=2)
# 向二维码添加数据
qr.add_data("http://www.netkiller.cn")
qr.make(fit=True)
# 更改QR的背景为白色和绘画颜色为绿色
img = qr.make_image(fill_color="green", back_color="white")
img.save('green.png')
img.show() # 显示二维码
</pre>
<p>QRCode 参数</p>
<div class="literallayout"><p><br />
<br />
version: 范围为1到40整数（最小值是1，表示12×12的矩阵），如果想让程序自动生成，将值设置为 None 并使用 fit=True 参数即可。<br />
error_correction: 二维码的纠错范围，可以选择4个常量：<br />
1. ERROR_CORRECT_L 7%以下的错误会被纠正<br />
2. ERROR_CORRECT_M (default) 15%以下的错误会被纠正<br />
3. ERROR_CORRECT_Q 25 %以下的错误会被纠正<br />
4. ERROR_CORRECT_H. 30%以下的错误会被纠正<br />
boxsize: 每个点（方块）中的像素个数<br />
border: 二维码图像外围边框宽度，默认为4<br />
<br />
</p></div>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id1236"></a>20.1.1.2. qr - script to create QR codes at the command line</h4></div></div></div>
<pre class="screen">
NAME
qr - script to create QR codes at the command line
SYNOPSIS
qr [--help] [--factory=FACTORY] [--optimize=OPTIMIZE] [--error-correction=LEVEL]
[data]
DESCRIPTION
This script uses the python qrcode module. It can take data from stdin or from the
commandline and generate a QR code. Normally it will output the QR code as ascii
art to the terminal. If the output is piped to a file, it will output the image
(default type of PNG).
OPTIONS
-h, --help
Show a help message.
--factory=FACTORY
Full python path to the image factory class to create the image with. You can
use the following shortcuts to the built-in image factory classes: pil
(default), pymaging, svg, svg-fragment, svg-path.
--optimize=OPTIMIZE
Optimize the data by looking for chunks of at least this many characters that
could use a more efficient encoding method. Use 0 to turn off chunk optimiza-
tion.
--error-correction=LEVEL
The error correction level to use. Choices are L (7%), M (15%, default), Q
(25%), and H (30%).
data
The data from which the QR code will be generated.
SEE ALSO
https://github.com/lincolnloop/python-qrcode/
</pre>
<p>使用方法</p>
<pre class="screen">
neo@MacBook-Pro-Neo ~ % qr "Some text" > test.png
</pre>
</div>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="MyQR"></a>20.1.2. MyQR</h3></div></div></div>
<p>安装依赖包</p>
<pre class="screen">
pip install myqr
</pre>
<pre class="programlisting">
from MyQR import myqr
# myqr.run 参数:
# words：文本/链接，或者你想说的话(不支持中文，很不友好)
# picture：背景图
# colorsize：True 表示生成彩图
# save_name：生成的二维码文件名
myqr.run(words="http://www.netkiller.com",
picture="db.png", colorized=True,
save_name="netkiller.png")
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="id1238"></a>20.1.3. 从图片识别二维码</h3></div></div></div>
<p>安装依赖包</p>
<pre class="screen">
pip install pyzbar
</pre>
<p>pyzbar 是调用 zbar 共享库，所以还需要安装 zbar</p>
<pre class="screen">
brew install zbar
</pre>
<pre class="programlisting">
import numpy as np
from PIL import Image
import pyzbar.pyzbar as pyzbar
# 读取文件，转成数组
im = np.array(Image.open("netkiller.png"))
print(pyzbar.decode(im))
# 返回的信息
print('-' * 50)
# 读取内容
print(pyzbar.decode(im)[0].data.decode("utf-8"))
</pre>
<p>输出信息</p>
<pre class="screen">
[Decoded(data=b'http://www.netkiller.com', type='QRCODE', rect=Rect(left=36, top=36, width=297, height=297), polygon=[Point(x=36, y=36), Point(x=36, y=332), Point(x=333, y=333), Point(x=332, y=36)])]
--------------------------------------------------
http://www.netkiller.com
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="id1239"></a>20.1.4. 从摄像头识别二维码</h3></div></div></div>
<pre class="programlisting">
import cv2
import pyzbar.pyzbar as pyzbar
def decodeQrcode(image):
barcodes = pyzbar.decode(image)
for barcode in barcodes:
# 提取二维码数据
barcodeData = barcode.data.decode("utf-8")
barcodeType = barcode.type
# 打印调试信息
print("[INFO] Found {}: {}".format(barcodeType, barcodeData))
# 取出二维码在图像中的位置
(x, y, w, h) = barcode.rect
cv2.rectangle(image, (x, y), (x + w, y + h),
(255, 255, 255), cv2.BORDER_DEFAULT)
# 框出图像中的二维码
text = "{} ({})".format(barcodeData, barcodeType)
cv2.putText(image, text, (x, y - 10), cv2.FONT_HERSHEY_SIMPLEX,
.5, (225, 225, 225), 2)
return image
if __name__ == '__main__':
# 默认摄像头是0，如果读取不到，改为1试试
camera = cv2.VideoCapture(1)
while True:
# 从摄像头读取当前帧
ret, frame = camera.read()
# 转为灰度图像，转递给解码函数
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
im = decodeQrcode(gray)
cv2.waitKey(5)
cv2.imshow("camera", im)
# 设置退出按键，按下q跳出本次循环
if cv2.waitKey(5) & 0xFF == ord('q'):
break
camera.release()
cv2.destroyAllWindows()
</pre>
</div>
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