PyQt5 styleSheet Animation
I am using PyQt5 to build an app with multiple buttons. What I am trying to accomplish is to create a blinking background color (yellow-red) for some of my buttons.
btn1.setStyleSheet("background-color: green; color: red; font-weight: 800; font-size: 22")
tobyte = 'styleSheet'
a = bytearray(tobyte, 'utf-8')
animation = QtCore.QPropertyAnimation(' + 'btn' + str(yy) + ', a)
animation.setDuration(1000)
animation.setLoopCount(1000)
animation.setStartValue("background-color: yellow; color: red; font-weight: 800; font-size: 22")
animation.setEndValue("background-color: red; color: red; font-weight: 800; font-size: 22")
animation.start()
The animation starts (it removes the predefined, green background), but it doesn't change the background color of the button to yellow or red.
Any ideas?
Answer
You ought not to animate stylesheets because there are the vagueness which specifically value must be animated (interpolated). There are not internal parser of stylesheet into PyQt5 classes. Nevertheless there are ways to solve the problem. Below is working example for animated QLabel (background-color of QLabel).
Main idea consists in using the custom QtCore.QPropertyAnimation. In this case its name is zcolor. Also you ought to create property QtCore.pyqtProperty in class derived from QLabel (and any other class).
Moreover you can use several animation in your class, in example you can switch between three types of animation (No animation, type 1, type 2).
Of course some params of some widgets can be animated via QtGui.QPalette.Window without parse of ss (see three strings in comment starting with # pal = self.palette()), however the way via stylesheets is more flexible IMHO.
import sys
import re
from PyQt5.QtWidgets import (QApplication, QFormLayout, QLabel, QDialog, QLineEdit, QPushButton)
from PyQt5 import QtCore, QtGui
class AnimatedLabel(QLabel):
def __init__(self):
QLabel.__init__(self)
color1 = QtGui.QColor(255, 0, 0)
color2 = QtGui.QColor(255, 144, 0)
color3 = QtGui.QColor(255, 255, 0)
color4 = QtGui.QColor(224, 192, 192)
color5 = QtGui.QColor(192, 224, 192)
color6 = QtGui.QColor(192, 192, 192)
color7 = QtGui.QColor(212, 208, 200)
self.co_get = 0
self.co_set = 0
byar = QtCore.QByteArray()
byar.append('zcolor')
self.color_anim = QtCore.QPropertyAnimation(self, byar)
self.color_anim.setStartValue(color4)
self.color_anim.setKeyValueAt(0.15, color1)
self.color_anim.setKeyValueAt(0.3, color2)
self.color_anim.setKeyValueAt(0.5, color3)
self.color_anim.setKeyValueAt(0.75, color2)
self.color_anim.setEndValue(color4)
self.color_anim.setDuration(2000)
self.color_anim.setLoopCount(1)
self.color_anim_ok = QtCore.QPropertyAnimation(self, byar)
self.color_anim_ok.setStartValue(color5)
self.color_anim_ok.setKeyValueAt(0.5, color6)
self.color_anim_ok.setEndValue(color7)
self.color_anim_ok.setDuration(1000)
self.color_anim_ok.setLoopCount(-1)
self.custom_anim = QtCore.QPropertyAnimation(self, byar)
def parseStyleSheet(self):
ss = self.styleSheet()
sts = [s.strip() for s in ss.split(';') if len(s.strip())]
return sts
def getBackColor(self):
self.co_get += 1
# print(fuin(), self.co_get)
return self.palette().color(self.pal_ele)
def setBackColor(self, color):
self.co_set += 1
sss = self.parseStyleSheet()
bg_new = 'background-color: rgba(%d,%d,%d,%d);' % (color.red(), color.green(), color.blue(), color.alpha())
for k, sty in enumerate(sss):
if re.search('\Abackground-color:', sty):
sss[k] = bg_new
break
else:
sss.append(bg_new)
# pal = self.palette()
# pal.setColor(self.pal_ele, color)
# self.setPalette(pal)
self.setStyleSheet('; '.join(sss))
pal_ele = QtGui.QPalette.Window
zcolor = QtCore.pyqtProperty(QtGui.QColor, getBackColor, setBackColor)
# this class is only for test
class SomeDia2(QDialog):
def __init__(self, parent=None):
"""Sets up labels in form"""
QDialog.__init__(self, parent)
self.co_press = 0
self.setModal(True)
self.setWindowTitle('Animation Example')
self.edit_pad = QLineEdit('-1')
self.edit_rad = QLineEdit('-1')
self._mapHeight = QLineEdit('0')
self.layout = QFormLayout()
self.lab_pad = QLabel('Padding (px):')
self.lab_rad = QLabel('Radius (px):' )
self.layout.addRow(self.lab_pad, self.edit_pad)
self.layout.addRow(self.lab_rad, self.edit_rad)
self.anila = AnimatedLabel()
self.anila.setText('Label for animation:')
# self.anila.setStyleSheet('padding: 0 4px; border-radius: 4px;')
self.layout.addRow(self.anila, self._mapHeight)
self.ok = QPushButton()
self.ok.setText('OK -- change animation')
self.ok.clicked.connect(self._okPress)
self.layout.addRow(self.ok)
self.layout.setLabelAlignment(QtCore.Qt.AlignRight)
self.setLayout(self.layout)
self.set_initial_data()
def set_initial_data(self):
pad_vali = QtGui.QIntValidator(0, 20)
rad_vali = QtGui.QIntValidator(0, 10)
self.edit_pad.setValidator(pad_vali)
self.edit_rad.setValidator(rad_vali)
pad, rad = 4, 4
self.edit_pad.setText(str(pad))
self.edit_rad.setText(str(rad))
self.set_ss(pad,rad)
# slots
self.edit_pad.textChanged.connect(self.change_padrad)
self.edit_rad.textChanged.connect(self.change_padrad)
def set_ss(self, pad, rad):
self.anila.setStyleSheet('padding: 0 %dpx; border-radius: %dpx;' % (pad, rad))
for lab in [self.lab_rad, self.lab_pad]:
lab.setStyleSheet('padding: 0 %dpx;' % pad)
def change_padrad(self):
try:
pad = int(self.edit_pad.text())
rad = int(self.edit_rad.text())
# print(pad, rad)
self.set_ss(pad, rad)
except Exception as ex:
print(type(ex).__name__)
def _okPress(self, flag):
# print('OK PRESS', flag)
self.co_press += 1
typ = self.co_press % 3
if 0 == typ:
print('Animation NO')
self.anila.color_anim.stop()
self.anila.color_anim_ok.stop()
elif 1 == typ:
print('Animation type 1')
self.anila.color_anim_ok.stop()
self.anila.color_anim.start()
elif 2 == typ:
print('Animation type 2')
self.anila.color_anim.stop()
self.anila.color_anim_ok.start()
if __name__ == "__main__":
app = QApplication(sys.argv)
dia = SomeDia2()
dia.show()
app.exec_()