Notebook/OneNote-Clone/frontend/canvas.py

import json
from PyQt6.QtWidgets import QWidget, QVBoxLayout, QHBoxLayout, QPushButton, QColorDialog, QSpinBox, QLabel
from PyQt6.QtCore import Qt, QPoint, pyqtSignal
from PyQt6.QtGui import QPainter, QPen, QColor

class DrawingCanvas(QWidget):
    changed = pyqtSignal()

    def __init__(self):
        super().__init__()
        self.setMinimumHeight(400)
        self.setAttribute(Qt.WidgetAttribute.WA_StaticContents)
        
        self.paths = [] # Liste de dictionnaires: {"points": [], "color": str, "width": int}
        self.current_path = None
        self.pen_color = QColor("#000000")
        self.pen_width = 3
        
        self.setStyleSheet("background-color: white; border: 1px solid #3c3c3c;")

    def mousePressEvent(self, event):
        if event.button() == Qt.MouseButton.LeftButton:
            self.current_path = {
                "points": [(event.position().x(), event.position().y())],
                "color": self.pen_color.name(),
                "width": self.pen_width
            }
            self.paths.append(self.current_path)
            self.update()

    def mouseMoveEvent(self, event):
        if (event.buttons() & Qt.MouseButton.LeftButton) and self.current_path:
            self.current_path["points"].append((event.position().x(), event.position().y()))
            self.update()

    def mouseReleaseEvent(self, event):
        if event.button() == Qt.MouseButton.LeftButton:
            self.current_path = None
            self.changed.emit()

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.RenderHint.Antialiasing)
        
        for path in self.paths:
            pen = QPen(QColor(path["color"]), path["width"], Qt.PenStyle.SolidLine, Qt.PenCapStyle.RoundCap, Qt.PenJoinStyle.RoundJoin)
            painter.setPen(pen)
            
            points = path["points"]
            if len(points) > 1:
                for i in range(len(points) - 1):
                    p1 = QPoint(int(points[i][0]), int(points[i][1]))
                    p2 = QPoint(int(points[i+1][0]), int(points[i+1][1]))
                    painter.drawLine(p1, p2)

    def clear(self):
        self.paths = []
        self.update()
        self.changed.emit()

    def get_data(self):
        return json.dumps(self.paths)

    def set_data(self, json_data):
        try:
            self.paths = json.loads(json_data) if json_data and json_data != 'null' else []
            self.update()
        except Exception as e:
            print(f"Error loading canvas data: {e}")
            self.paths = []
            self.update()