lang/pysideex/ MouseEventsExample001

This simply fills the window with a colour that is changed by clicking and dragging. It logs the mouse position and delta (x,y distance to point where mouse was pressed) to the console.

# widget that dumps mousemove events

import sys
from PySide6.QtCore import *
from PySide6.QtGui import *
from PySide6.QtWidgets import *
from PySide6.QtNetwork import *

def clamp(x,m,M):
  if x < m:
    return m
  if x > M:
    return M
  return x
class MyWidget(QWidget):
  def __init__(self,*xs,**kw):
    self.h = 0
    self.s = 255
    self.v = 0
    self.h0 = 0
    self.v0 = 0
    self.brush = QBrush()
    self.brush.setColor(QColor.fromHsv(self.h,self.s,self.v))
    super().__init__(*xs,**kw)
  def mousePressEvent(self,event):
    self.previous_pos = event.position().toPoint()
    x0 = self.previous_pos.x()
    y0 = self.previous_pos.y()
    print(f"Press at ({x0},{y0})")
    return super().mousePressEvent(event)
  def mouseMoveEvent(self,event):
    current_pos = event.position().toPoint()
    x0 = self.previous_pos.x()
    y0 = self.previous_pos.y()
    x = current_pos.x()
    y = current_pos.y()
    dx = x - x0
    dy = y - y0
    self.h = (self.h0 + dx) % 360
    self.v = clamp((self.v0 + dy),0,255)
    self.brush.setColor(QColor.fromHsv(self.h,self.s,self.v))
    print(f"Move ({x0},{y0}) => ({x},{y}) delta ({dx},{dy})")
    self.update()
    return super().mouseMoveEvent(event)
  def mouseReleaseEvent(self, event) -> None:
    current_pos = event.position().toPoint()
    x0 = self.previous_pos.x()
    y0 = self.previous_pos.y()
    x = current_pos.x()
    y = current_pos.y()
    dx = x - x0
    dy = y - y0
    self.h0 = (self.h0 + dx) % 360
    self.v0 = clamp((self.v0 + dy),0,255)
    self.h = self.h0
    self.v = self.v0
    self.brush.setColor(QColor.fromHsv(self.h,self.s,self.v))
    self.previous_pos = event.position().toPoint()
    x0 = self.previous_pos.x()
    y0 = self.previous_pos.y()

    print(f"Release at ({x0},{y0})")
    return super().mouseReleaseEvent(event)
  def paintEvent(self, event) -> None:
    with QPainter(self) as painter:
      rect = self.rect()
      print(f"rect {rect}")
      painter.fillRect(rect,QColor.fromHsv(self.h,self.s,self.v))
    return super().paintEvent(event)

app = QApplication(sys.argv)
win = QMainWindow()
w = MyWidget()
win.setCentralWidget(w)
win.show()
exit(app.exec())