def _calc_size(self):
realSize = self.realsize
canvaswidth = self.canvas.width()
mapunitsperpixel = abs(self.canvas.mapUnitsPerPixel())
mapunits = self.canvas.mapUnits()
prefered_units = roam.config.settings.get("prefer_units", "meters")
newunits = Qgis.fromLiteral(prefered_units, Qgis.Meters)
mapunitsperpixel *= Qgis.fromUnitToUnitFactor(mapunits, newunits)
mapunits = newunits
# Convert the real distance into pixels
barwidth = realSize / mapunitsperpixel
if barwidth < 30:
barwidth = canvaswidth / 4
while barwidth > canvaswidth / 3:
barwidth /= 3
realSize = barwidth * mapunitsperpixel
# Round
powerof10 = math.floor(math.log10(realSize))
scaler = math.pow(10.0, powerof10)
realSize = round(realSize / scaler) * scaler
barwidth = realSize / mapunitsperpixel
label, realSize = self._label_size(mapunits, realSize)
metrics = QFontMetrics(self.font)
fontwidth = metrics.width(label)
fontheight = metrics.height()
sizelabel = QLocale.system().toString(realSize)
sizelabel = "{} {}".format(sizelabel, label)
barwidth = self._adjust_bar_size(barwidth, mapunits)
barwidth = barwidth + fontwidth
return barwidth, realSize, sizelabel, (fontwidth, fontheight)
