Curve demo 1ΒΆ

../_images/curvedemo1.png

import numpy as np

from qtpy.QtWidgets import QFrame
from qtpy.QtGui import QPen, QBrush, QFont, QPainter, QPaintEngine
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.tests import test_widget

    app = test_widget(CurveDemo1, size=(300, 600), options=False)