在一些特殊的业务场景中，我们需要一次性提取一张图片中的色卡信息，并且需要使用十六进制的颜色表示方法进行展示。

今天得空做了一个小工具，用来自定义的提取某一张图片中的色卡信息，需要提取某张图片中的色卡可以自行选择。

实现过程就是比较简单的，主要是通过extcolors的python非标准库来实现的。

另外的python非标准库就是PyQt5的使用，还有os、sys等系统或文件操作模块。

没有安装上述几个python非标准库的话，我们直接使用pip的方式安装一下即可。

pip install PyQt5 -i https://pypi.tuna.tsinghua.edu.cn/simple/

pip install extcolors -i https://pypi.tuna.tsinghua.edu.cn/simple/

在安装完成相关的模块之后，将我们需要的python模块导入到开发的代码块中。

# It's a module that allows you to print the stack trace of an exception.
import traceback

# It's a module that allows you to print the stack trace of an exception.
import extcolors

# It's importing all the classes from the QtWidgets module.
from PyQt5.QtWidgets import *

# It's importing all the classes from the QtGui module.
from PyQt5.QtGui import *

# It's importing all the classes from the QtCore module.
from PyQt5.QtCore import *

# It's importing the sys module.
import sys

# It's importing the os module.
import os

在代码块中创建ColorUI作为UI组件及布局的使用类，将UI相关的操作和槽函数全部放到这个类中进行处理。

class ColorUI(QWidget):
    def __init__(self):
        """
        A constructor. It is called when an object is created from a class and it allows the class to initialize the
        attributes of a class.
        """
        super(ColorUI, self).__init__()
        self.init_ui()

    def init_ui(self):
        """
        This function initializes the UI.
        """
        self.setWindowTitle('图片颜色提取器 公众号：Python 集中营')
        self.setWindowIcon(QIcon('color.ico'))
        self.resize(500, 300)

        self.image_label = QLabel()
        self.image_label.setMinimumWidth(300)
        self.image_label.setMaximumHeight(300)
        self.image_label.setText('公众号：Python 集中营')
        self.image_label.setAlignment(Qt.AlignCenter)
        self.image_label.setStyleSheet('font-size:20px;color:blue;')
        self.image_label.setScaledContents(True)

        self.image_path_in = QLineEdit()
        self.image_path_in.setPlaceholderText('源图片路径')
        self.image_path_in.setReadOnly(True)

        self.image_path_btn = QPushButton()
        self.image_path_btn.setText('加载源图片')
        self.image_path_btn.clicked.connect(self.image_path_btn_click)

        self.set_color_num_label = QLabel()
        self.set_color_num_label.setText('设置提取色卡数量：')

        self.set_color_num_in = QLineEdit()
        self.set_color_num_in.setPlaceholderText('例如：10')

        self.start_btn = QPushButton()
        self.start_btn.setText('开始提取颜色')
        self.start_btn.clicked.connect(self.start_btn_click)

        self.brower = QTextBrowser()
        self.brower.setReadOnly(True)
        self.brower.setFont(QFont('宋体', 8))
        self.brower.setPlaceholderText('日志处理过程区域...')
        self.brower.ensureCursorVisible()

        hbox = QHBoxLayout()

        left_box = QVBoxLayout()
        right_box = QVBoxLayout()

        left_box.addWidget(self.image_label)
        right_form_box = QFormLayout()
        right_form_box.addRow(self.image_path_in, self.image_path_btn)
        right_form_box.addRow(self.set_color_num_label, self.set_color_num_in)
        right_form_box.addRow(self.start_btn)
        right_box.addLayout(right_form_box)
        right_box.addWidget(self.brower)

        hbox.addLayout(left_box)
        hbox.addLayout(right_box)

        self.thread_ = ColorWork(self)
        self.thread_.message.connect(self.show_message)

        self.setLayout(hbox)

    def show_message(self, text):
        """
        It shows a message

        :param text: The text to be displayed
        """
        cursor = self.brower.textCursor()
        cursor.movePosition(QTextCursor.End)
        self.brower.append(text)
        self.brower.setTextCursor(cursor)
        self.brower.ensureCursorVisible()

    def start_btn_click(self):
        """
        A function that is called when the start button is clicked.
        """
        self.thread_.start()

    def image_path_btn_click(self):
        """
        It opens a file dialog box to select the image file.
        """
        path = QFileDialog.getOpenFileName(self, "选取文件", os.getcwd(), "Image File (*.jpg);;Image File (*.png)")
        self.image_path_in.setText(path[0])
        pixmap = QPixmap(path[0])
        self.image_label.clear()
        self.image_label.setPixmap(pixmap)

创建一个ColorWork类，继承自子线程QThread，将提取色卡的业务操作写到这个类中，和UI主线程分开处理保证不影响主线程的逻辑处理。

class ColorWork(QThread):
    message = pyqtSignal(str)

    def __init__(self, parent=None):
        """
        A constructor that initializes the class.

        :param parent: The parent widget
        """
        super(ColorWork, self).__init__(parent)
        self.working = True
        self.parent = parent

    def __del__(self):
        """
        A destructor. It is called when the object is destroyed.
        """
        self.working = False

    def run(self):
        """
        *|CURSOR_MARCADOR|*
        """
        try:
            image_path_in = self.parent.image_path_in.text().strip()
            set_color_num_in = self.parent.set_color_num_in.text().strip()
            if image_path_in == '' or set_color_num_in == '':
                self.message.emit('系统参数设置不能为空，请检查参数设置！')
                return
            colors_x = extcolors.extract_from_path(image_path_in, tolerance=12, limit=int(set_color_num_in))

            for turple_ in colors_x[0]:
                rgb_ = turple_[0]
                color_16 = ('{:02X}' * 3).format(rgb_[0], rgb_[1], rgb_[2])
                color_16 = ('#' + color_16)
                self.message.emit(color_16)
        except:
            traceback.print_exc()
            self.message.emit('系统运行出现错误，请检查相关参数是否正确！')

最后，我们按照main的标准处理方式，将整个页面应用启动起来就大功告成啦！

if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = ColorUI()
    main.show()
    sys.exit(app.exec_())

下面使用一个动态图片简单演示一下提取色卡信息的处理过程。

色卡提取器应用color-catch.zip已打包成exe文件，公众号内回复 ‘色卡提取器’ 获取百度网盘的下载链接。