layoutEngine

Example Python program layoutEngine.py Python version 3.x or newer. To check the Python version use:

python --version

Modules

• from defcon import LayoutEngine
• from PyQt5.QtCore import pyqtSignal, Qt
• from PyQt5.QtWidgets import QComboBox, QGridLayout, QGroupBox, QLineEdit, QRadioButton, QVBoxLayout, QWidget

Classes

• class OpenTypeControls(QWidget):
• class PreviewWindow(QWidget):

Methods

• def init(self, parent=None):
• def updateFromEngine(self, engine):
• def init(self, parent=None):
• def updateView(self, text):

Code

Example Python PyQt program :

from defcon import LayoutEngine
from PyQt5.QtCore import pyqtSignal, Qt
from PyQt5.QtWidgets import QComboBox, QGridLayout, QGroupBox, QLineEdit, QRadioButton, QVBoxLayout, QWidget

class OpenTypeControls(QWidget):
    controlsChanged = pyqtSignal()

    def __init__(self, parent=None):
        super().__init__(parent)

        # writing direction
        ltrBox = QRadioButton("LTR", self)
        ltrBox.toggled.connect(self.controlsChanged)
        rtlBox = QRadioButton("RTL", self)
        directionGroupBox = QGroupBox("Writing direction", self)
        directionLayout = QVBoxLayout(self)
        directionLayout.addWidget(ltrBox)
        directionLayout.addWidget(rtlBox)
        directionGroupBox.setLayout(directionLayout)
        directionGroupBox.toggled.connect(self.controlsChanged)
        # script & language
        self.scriptBox = QComboBox(self)
        self.scriptBox.currentTextChanged.connect(self.controlsChanged)
        self.languageBox = QComboBox(self)
        self.languageBox.currentTextChanged.connect(self.controlsChanged)
        # feature list
        featGroupBox = QGroupBox("Feature list", self)
        featGroupBox.setFlat(True)
        self.groupBoxLayout = QVBoxLayout(self)
        featGroupBox.setLayout(self.groupBoxLayout)
        featGroupBox.toggled.connect(self.controlsChanged)

        layout = QVBoxLayout(self)
        layout.addWidget(directionGroupBox)
        layout.addWidget(self.scriptBox)
        layout.addWidget(self.languageBox)
        layout.addWidget(featGroupBox)
        self.setLayout(layout)

    def updateFromEngine(self, engine):
        # script & language
        currentText = self.scriptBox.currentText()
        self.scriptBox.clear()
        self.scriptBox.addItems(engine.getScriptList())
        self.scriptBox.setCurrentText(currentText)
        currentText = self.languageBox.currentText()
        self.languageBox.clear()
        self.languageBox.addItems(engine.getLanguageList())
        self.languageBox.setCurrentText(currentText)
        # destroy current checkboxes
        for checkBox in self.groupBoxLayout.children():
            checkBox.setParent(None)
        # populate features
        for feature in engine.getFeatureList():
            box = QCheckBox(feature, self.groupBoxLayout)
            box.setChecked(engine.getFeatureState(feature))
            #self.groupBoxLayout.addWidget(box)



class PreviewWindow(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent, Qt.Window)
        self._font = CurrentFont()
        self._layoutEngine = LayoutEngine(self._font)

        otControls = OpenTypeControls(self)
        inputLine = QLineEdit(self)
        inputLine.textChanged.connect(self.updateView)
        canvas = QWidget(self)

        layout = QGridLayout()
        layout.addWidget(inputLine, 0, 0, 1, 2)
        layout.addWidget(otControls, 1, 0)
        layout.addWidget(canvas, 1, 1)
        self.setLayout(layout)

    def updateView(self, text):
        rec = self._layoutEngine.process(text)
        print(rec)

window = PreviewWindow()
window.show()

Useful Links

• Articles: https://python-commandments.org/
• PyQt: https://pythonpyqt.com/
• Tutorial: https://pythonprogramminglanguage.com/