Curve demo 1ΒΆ

../_images/curvedemo1.png

import numpy as np

from qtpy.QtWidgets import QFrame
from qtpy.QtGui import QPen, QBrush, QFont, QPainter
from qtpy.QtCore import QSize, Qt
from qwt import QwtSymbol, QwtPlotCurve, QwtPlotItem, QwtScaleMap


class CurveDemo1(QFrame):
    def __init__(self, *args):
        QFrame.__init__(self, *args)

        self.xMap = QwtScaleMap()
        self.xMap.setScaleInterval(-0.5, 10.5)
        self.yMap = QwtScaleMap()
        self.yMap.setScaleInterval(-1.1, 1.1)

        # frame style
        self.setFrameStyle(QFrame.Box | QFrame.Raised)
        self.setLineWidth(2)
        self.setMidLineWidth(3)

        # calculate values
        self.x = np.arange(0, 10.0, 10.0 / 27)
        self.y = np.sin(self.x) * np.cos(2 * self.x)

        # make curves with different styles
        self.curves = []
        self.titles = []
        # curve 1
        self.titles.append("Style: Sticks, Symbol: Ellipse")
        curve = QwtPlotCurve()
        curve.setPen(QPen(Qt.red))
        curve.setStyle(QwtPlotCurve.Sticks)
        curve.setSymbol(
            QwtSymbol(QwtSymbol.Ellipse, QBrush(Qt.yellow), QPen(Qt.blue), QSize(5, 5))
        )
        self.curves.append(curve)
        # curve 2
        self.titles.append("Style: Lines, Symbol: None")
        curve = QwtPlotCurve()
        curve.setPen(QPen(Qt.darkBlue))
        curve.setStyle(QwtPlotCurve.Lines)
        self.curves.append(curve)
        # curve 3
        self.titles.append("Style: Lines, Symbol: None, Antialiased")
        curve = QwtPlotCurve()
        curve.setPen(QPen(Qt.darkBlue))
        curve.setStyle(QwtPlotCurve.Lines)
        curve.setRenderHint(QwtPlotItem.RenderAntialiased)
        self.curves.append(curve)
        # curve 4
        self.titles.append("Style: Steps, Symbol: None")
        curve = QwtPlotCurve()
        curve.setPen(QPen(Qt.darkCyan))
        curve.setStyle(QwtPlotCurve.Steps)
        self.curves.append(curve)
        # curve 5
        self.titles.append("Style: NoCurve, Symbol: XCross")
        curve = QwtPlotCurve()
        curve.setStyle(QwtPlotCurve.NoCurve)
        curve.setSymbol(
            QwtSymbol(QwtSymbol.XCross, QBrush(), QPen(Qt.darkMagenta), QSize(5, 5))
        )
        self.curves.append(curve)

        # attach data, using Numeric
        for curve in self.curves:
            curve.setData(self.x, self.y)

    def shiftDown(self, rect, offset):
        rect.translate(0, offset)

    def paintEvent(self, event):
        QFrame.paintEvent(self, event)
        painter = QPainter(self)
        painter.setClipRect(self.contentsRect())
        self.drawContents(painter)

    def drawContents(self, painter):
        # draw curves
        r = self.contentsRect()
        dy = int(r.height() / len(self.curves))
        r.setHeight(dy)
        for curve in self.curves:
            self.xMap.setPaintInterval(r.left(), r.right())
            self.yMap.setPaintInterval(r.top(), r.bottom())
            painter.setRenderHint(
                QPainter.Antialiasing,
                curve.testRenderHint(QwtPlotItem.RenderAntialiased),
            )
            curve.draw(painter, self.xMap, self.yMap, r)
            self.shiftDown(r, dy)
        # draw titles
        r = self.contentsRect()
        r.setHeight(dy)
        painter.setFont(QFont("Helvetica", 8))
        painter.setPen(Qt.black)
        for title in self.titles:
            painter.drawText(
                0,
                r.top(),
                r.width(),
                painter.fontMetrics().height(),
                Qt.AlignTop | Qt.AlignHCenter,
                title,
            )
            self.shiftDown(r, dy)


if __name__ == "__main__":
    from qwt import tests

    tests.test_widget(CurveDemo1, size=(300, 600), options=False)