Source code for NanoVNASaver.Charts.VSWR

#  NanoVNASaver
#
#  A python program to view and export Touchstone data from a NanoVNA
#  Copyright (C) 2019, 2020  Rune B. Broberg
#  Copyright (C) 2020ff NanoVNA-Saver Authors
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <https://www.gnu.org/licenses/>.
import math
import logging

from PyQt6 import QtGui

from NanoVNASaver.RFTools import Datapoint
from NanoVNASaver.Charts.Chart import Chart
from NanoVNASaver.Charts.Frequency import FrequencyChart

logger = logging.getLogger(__name__)


[docs]class VSWRChart(FrequencyChart): def __init__(self, name=""): super().__init__(name) self.maxDisplayValue = 25 self.minDisplayValue = 1 self.maxVSWR = 3 self.span = 2
[docs] def logarithmicYAllowed(self) -> bool: return True
[docs] def drawValues(self, qp: QtGui.QPainter): if not self.data and not self.reference: return if self.fixedSpan: fstart = self.minFrequency fstop = self.maxFrequency elif len(self.data) > 0: fstart = self.data[0].freq fstop = self.data[len(self.data) - 1].freq else: fstart = self.reference[0].freq fstop = self.reference[len(self.reference) - 1].freq self.fstart = fstart self.fstop = fstop # Draw bands if required if self.bands.enabled: self.drawBands(qp, fstart, fstop) # Find scaling if self.fixedValues: minVSWR = max(1, self.minDisplayValue) maxVSWR = self.maxDisplayValue else: minVSWR = 1 maxVSWR = 3 for d in self.data: vswr = d.vswr if vswr > maxVSWR: maxVSWR = vswr try: maxVSWR = min(self.maxDisplayValue, math.ceil(maxVSWR)) except OverflowError: maxVSWR = self.maxDisplayValue self.maxVSWR = maxVSWR self.span = (maxVSWR - minVSWR) or 0.01 target_ticks = math.floor(self.dim.height / 60) if self.logarithmicY: for i in range(target_ticks): y = int(self.topMargin + (i / target_ticks) * self.dim.height) vswr = self.valueAtPosition(y)[0] qp.setPen(Chart.color.text) if vswr != 0: digits = max( 0, min(2, math.floor(3 - math.log10(abs(vswr)))) ) v_text = f"{round(vswr, digits)}" if digits else "0" qp.drawText(3, y + 3, v_text) qp.setPen(QtGui.QPen(Chart.color.foreground)) qp.drawLine( self.leftMargin - 5, y, self.leftMargin + self.dim.width, y ) qp.drawLine( self.leftMargin - 5, self.topMargin + self.dim.height, self.leftMargin + self.dim.width, self.topMargin + self.dim.height, ) qp.setPen(Chart.color.text) digits = max(0, min(2, math.floor(3 - math.log10(abs(minVSWR))))) v_text = f"{round(minVSWR, digits)}" if digits else "0" qp.drawText(3, self.topMargin + self.dim.height, v_text) else: for i in range(target_ticks): vswr = minVSWR + i * self.span / target_ticks y = self.getYPositionFromValue(vswr) qp.setPen(Chart.color.text) if vswr != 0: digits = max( 0, min(2, math.floor(3 - math.log10(abs(vswr)))) ) vswrstr = f"{round(vswr, digits)}" if digits else "0" qp.drawText(3, y + 3, vswrstr) qp.setPen(QtGui.QPen(Chart.color.foreground)) qp.drawLine( self.leftMargin - 5, y, self.leftMargin + self.dim.width, y ) qp.drawLine( self.leftMargin - 5, self.topMargin, self.leftMargin + self.dim.width, self.topMargin, ) qp.setPen(Chart.color.text) digits = max(0, min(2, math.floor(3 - math.log10(abs(maxVSWR))))) v_text = f"{round(maxVSWR, digits)}" if digits else "0" qp.drawText(3, 35, v_text) qp.setPen(Chart.color.swr) for vswr in self.swrMarkers: y = self.getYPositionFromValue(vswr) qp.drawLine(self.leftMargin, y, self.leftMargin + self.dim.width, y) qp.drawText(self.leftMargin + 3, y - 1, str(vswr)) self.drawFrequencyTicks(qp) self.drawData(qp, self.data, Chart.color.sweep) self.drawData(qp, self.reference, Chart.color.reference) self.drawMarkers(qp)
[docs] def getYPositionFromValue(self, vswr) -> int: if self.logarithmicY: min_val = self.maxVSWR - self.span if self.maxVSWR > 0 and min_val > 0 and vswr > 0: span = math.log(self.maxVSWR) - math.log(min_val) else: return -1 return self.topMargin + int( (math.log(self.maxVSWR) - math.log(vswr)) / span * self.dim.height ) try: return self.topMargin + int( (self.maxVSWR - vswr) / self.span * self.dim.height ) except OverflowError: return self.topMargin
[docs] def getYPosition(self, d: Datapoint) -> int: return self.getYPositionFromValue(d.vswr)
[docs] def valueAtPosition(self, y) -> list[float]: absy = y - self.topMargin if self.logarithmicY: min_val = self.maxVSWR - self.span if self.maxVSWR > 0 and min_val > 0: span = math.log(self.maxVSWR) - math.log(min_val) step = span / self.dim.height val = math.exp(math.log(self.maxVSWR) - absy * step) else: val = -1 else: val = -1 * ((absy / self.dim.height * self.span) - self.maxVSWR) return [val]
[docs] def resetDisplayLimits(self): self.maxDisplayValue = 25 super().resetDisplayLimits()