Below is a solution, for a QLabel
, derived from the solution posted here: https://forum.qt.io/topic/36088/automatically-scale-text-in-qlabels/5.
This consists in a reimplementation of the resizeEvent
method where the font size of the QLabel
is updated according to the size of its contentRect
. Note that the sizePolicy
of the Qlabel has to be set to Ignored
for this to work properly.
import sys
from PyQt4 import QtGui
class myQLabel(QtGui.QLabel):
def __init__(self, *args, **kargs):
super(myQLabel, self).__init__(*args, **kargs)
self.setSizePolicy(QtGui.QSizePolicy(QtGui.QSizePolicy.Ignored,
QtGui.QSizePolicy.Ignored))
self.setMinSize(14)
def setMinSize(self, minfs):
f = self.font()
f.setPixelSize(minfs)
br = QtGui.QFontMetrics(f).boundingRect(self.text())
self.setMinimumSize(br.width(), br.height())
def resizeEvent(self, event):
super(myQLabel, self).resizeEvent(event)
if not self.text():
return
#--- fetch current parameters ----
f = self.font()
cr = self.contentsRect()
#--- find the font size that fits the contentsRect ---
fs = 1
while True:
f.setPixelSize(fs)
br = QtGui.QFontMetrics(f).boundingRect(self.text())
if br.height() <= cr.height() and br.width() <= cr.width():
fs += 1
else:
f.setPixelSize(max(fs - 1, 1)) # backtrack
break
#--- update font size ---
self.setFont(f)
class myApplication(QtGui.QWidget):
def __init__(self, parent=None):
super(myApplication, self).__init__(parent)
#---- Prepare a Layout ----
grid = QtGui.QGridLayout()
for i in range(3):
grid.addWidget(myQLabel('some text'), i, 0)
grid.setRowStretch(i, i+1)
grid.setRowMinimumHeight(i, 25)
self.setLayout(grid)
self.resize(500, 300)
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
instance = myApplication()
instance.show()
sys.exit(app.exec_())
Which results in:
Update - Optimization of resizeEvent :
Below is an optimized version of the resizeEvent
method that should yield better performances. It drastically reduces the number of iteration required to find the optimal value of the font size. I haven't tested it extensively though.
def resizeEvent(self, event):
super(myQLabel, self).resizeEvent(event)
if not self.text():
return
#--- fetch current parameters ----
f = self.font()
cr = self.contentsRect()
#--- iterate to find the font size that fits the contentsRect ---
dw = event.size().width() - event.oldSize().width() # width change
dh = event.size().height() - event.oldSize().height() # height change
fs = max(f.pixelSize(), 1)
while True:
f.setPixelSize(fs)
br = QtGui.QFontMetrics(f).boundingRect(self.text())
if dw >= 0 and dh >= 0: # label is expanding
if br.height() <= cr.height() and br.width() <= cr.width():
fs += 1
else:
f.setPixelSize(max(fs - 1, 1)) # backtrack
break
else: # label is shrinking
if br.height() > cr.height() or br.width() > cr.width():
fs -= 1
else:
break
if fs < 1: break
#--- update font size ---
self.setFont(f)
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