Examples

The test launcher

A lot of examples are available in the guiqwt test module

from guiqwt import tests
tests.run()

The two lines above execute the guiqwt test launcher:

Curve plotting

Basic curve plotting

from guidata.qt.QtGui import QFont

from guiqwt.plot import CurveDialog
from guiqwt.builder import make

def plot(*items):
    win = CurveDialog(edit=False, toolbar=True, wintitle="CurveDialog test",
                      options=dict(title="Title", xlabel="xlabel",
                                   ylabel="ylabel"))
    plot = win.get_plot()
    for item in items:
        plot.add_item(item)
    plot.set_axis_font("left", QFont("Courier"))
    win.get_itemlist_panel().show()
    plot.set_items_readonly(False)
    win.show()
    win.exec_()

def test():
    """Test"""
    # -- Create QApplication
    import guidata
    _app = guidata.qapplication()
    # --
    from numpy import linspace, sin
    x = linspace(-10, 10, 200)
    dy = x/100.
    y = sin(sin(sin(x)))    
    x2 = linspace(-10, 10, 20)
    y2 = sin(sin(sin(x2)))
    plot(make.curve(x, y, color="b"),
         make.curve(x2, y2, color="g", curvestyle="Sticks"),
         make.curve(x, sin(2*y), color="r"),
         make.merror(x, y/2, dy),
         make.label("Relative position <b>outside</b>",
                    (x[0], y[0]), (-10, -10), "BR"),
         make.label("Relative position <i>inside</i>",
                    (x[0], y[0]), (10, 10), "TL"),
         make.label("Absolute position", "R", (0, 0), "R"),
         make.legend("TR"),
         make.marker(position=(5., .8), label_cb=lambda x, y: "A = %.2f" % x,
                     markerstyle="|", movable=False)
         )

if __name__ == "__main__":
    test()

Computations on curves

from guiqwt.plot import CurveDialog
from guiqwt.builder import make

def plot( *items ):
    win = CurveDialog(edit=False, toolbar=True)
    plot = win.get_plot()
    for item in items:
        plot.add_item(item)
    win.show()
    win.exec_()


def test():
    """Test"""
    # -- Create QApplication
    import guidata
    _app = guidata.qapplication()
    # --
    from numpy import linspace, sin, trapz
    x = linspace(-10, 10, 1000)
    y = sin(sin(sin(x)))

    curve = make.curve(x, y, "ab", "b")
    range = make.range(-2, 2)
    disp0 = make.range_info_label(range, 'BR', "x = %.1f ± %.1f cm",
                                  title="Range infos")

    disp1 = make.computation(range, "BL", "trapz=%g",
                             curve, lambda x, y: trapz(y, x))

    disp2 = make.computations(range, "TL",
                              [(curve, "min=%.5f", lambda x, y: y.min()),
                               (curve, "max=%.5f", lambda x, y: y.max()),
                               (curve, "avg=%.5f", lambda x, y: y.mean())])
    legend = make.legend("TR")
    plot( curve, range, disp0, disp1, disp2, legend)

if __name__ == "__main__":
    test()

Curve fitting

import numpy as np

from guiqwt.widgets.fit import FitParam, guifit

def test():
    x = np.linspace(-10, 10, 1000)
    y = np.cos(1.5*x)+np.random.rand(x.shape[0])*.2
    
    def fit(x, params):
        a, b = params
        return np.cos(b*x)+a
    
    a = FitParam("Offset", 1., 0., 2.)
    b = FitParam("Frequency", 2., 1., 10., logscale=True)
    params = [a, b]
    values = guifit(x, y, fit, params, xlabel="Time (s)", ylabel="Power (a.u.)")
    
    print(values)
    print([param.value for param in params])

if __name__ == "__main__":
    test()

Image visualization

Image contrast adjustment

import os.path as osp

from guiqwt.plot import ImageDialog
from guiqwt.builder import make

def test():
    """Test"""
    # -- Create QApplication
    import guidata
    _app = guidata.qapplication()
    # --    
    filename = osp.join(osp.dirname(__file__), "brain.png")
    image = make.image(filename=filename, title="Original", colormap='gray')
    
    win = ImageDialog(edit=False, toolbar=True, wintitle="Contrast test",
                      options=dict(show_contrast=True))
    plot = win.get_plot()
    plot.add_item(image)
    win.resize(600, 600)
    win.show()
    try:
        plot.save_widget('contrast.png')
    except IOError:
        # Skipping this part of the test 
        # because user has no write permission on current directory
        pass
    win.exec_()

if __name__ == "__main__":
    test()

Image cross-sections

import os.path as osp, numpy as np

from guiqwt.plot import ImageDialog
from guiqwt.builder import make

def create_window():
    win = ImageDialog(edit=False, toolbar=True, wintitle="Cross sections test",
                      options=dict(show_xsection=True, show_ysection=True))
    win.resize(600, 600)
    return win

def test():
    """Test"""
    # -- Create QApplication
    import guidata
    _app = guidata.qapplication()
    # --
    filename = osp.join(osp.dirname(__file__), "brain.png")
    win = create_window()
    image = make.image(filename=filename, colormap="bone")
    data2 = np.array(image.data.T[200:], copy=True)
    image2 = make.image(data2, title="Modified", alpha_mask=True)
    plot = win.get_plot()
    plot.add_item(image)
    plot.add_item(image2, z=1)
    win.exec_()

if __name__ == "__main__":
    test()

Transformable images

Affine transforms example on 3000x3000 images (real-time transforms):

from guidata.qt.QtCore import QRectF
from guidata.qt.QtGui import QImage

import numpy as np

from guiqwt.image import assemble_imageitems
from guiqwt.plot import ImageDialog
from guiqwt.builder import make
from guiqwt import io

DEFAULT_CHARS = "".join([chr(c) for c in range(32, 256)])

def get_font_array(sz, chars=DEFAULT_CHARS):
    from guidata.qt.QtGui import QFont, QPainter, QColor
    font = QFont()
    font.setFixedPitch(True)
    font.setPixelSize(sz)
    font.setStyleStrategy(QFont.NoAntialias)
    dummy = QImage(10, 10, QImage.Format_ARGB32)
    pnt = QPainter(dummy)
    pnt.setFont(font)
    metric = pnt.fontMetrics()
    rct = metric.boundingRect(chars)
    pnt.end()
    h = rct.height()
    w = rct.width()
    img = QImage(w, h, QImage.Format_ARGB32)
    paint = QPainter()
    paint.begin(img)
    paint.setFont(font)
    paint.setBrush( QColor(255, 255, 255) )
    paint.setPen( QColor(255, 255, 255) )
    paint.drawRect(0, 0, w+1, h+1)
    paint.setPen( QColor(0, 0, 0))
    paint.setBrush( QColor(0, 0, 0) )
    paint.drawText(0, paint.fontMetrics().ascent(), chars)
    paint.end()
    try:
        data = img.bits().asstring(img.numBytes())
    except SystemError:
        # Python 3
        return
    npy = np.frombuffer(data, np.uint8)
    npy.shape = img.height(), img.bytesPerLine()/4, 4
    return npy[:,:, 0]

def txtwrite(data, x, y, sz, txt, range=None):
    arr = get_font_array(sz, txt)
    if arr is None:
        return
    if range is None:
        m, M = data.min(), data.max()
    else:
        m, M = range
    z = (float(M)-float(m))*np.array(arr, float)/255.+m
    arr = np.array(z, data.dtype)
    dy, dx = arr.shape
    data[y:y+dy, x:x+dx] = arr


def imshow(items, title=""):
    gridparam = make.gridparam(background="black", minor_enabled=(False, False),
                               major_style=(".", "gray", 1))
    win = ImageDialog(edit=False, toolbar=True, wintitle=title,
                      options=dict(gridparam=gridparam))
    nc = int(np.sqrt(len(items))+1.0)
    maxy = 0
    y = 0
    x = 0
    w = None
    plot = win.get_plot()
    print("-"*80)
    for i, item in enumerate(items):
        h = item.boundingRect().height()
        if i%nc==0:
            x = 0
            y += maxy
            maxy = h
        else:
            x += w
            maxy = max(maxy, h)
        w = item.boundingRect().width()

        item.set_transform(x, y, 0.0)
        print("Adding item #%d..." % i, end=' ')
        plot.add_item(item)
        print("Done")
    win.show()
    win.exec_()

def compute_image(NX, NY):
    BX, BY = 40, 40
    img = np.random.normal(0, 100, size=(BX, BY))
    timg = np.fft.fftshift(np.fft.fft2(img))
    print(timg.shape)
    cx = NX/2
    cy = NY/2
    bx2 = BX/2
    by2 = BY/2
    z=np.zeros( (NX, NY), np.complex64)
    z[cx-bx2:cx-bx2+BX, cy-by2:cy-by2+BY] = timg
    z = np.fft.ifftshift(z)
    rev = np.fft.ifft2(z)
    return np.abs(rev)

def get_bbox(items):
    r = QRectF()
    for it in items:
        r = r.united(it.boundingRect())
    return r

def save_image(name, data):
    io.imwrite(name+".u16.tif", data, dtype=np.uint16, max_range=True)
    io.imwrite(name+".u8.png", data, dtype=np.uint8, max_range=True)

def build_image(items):
    r = get_bbox(items)
    x, y, w, h = r.getRect()
    print("Assemble test1:", w, "x", h)
    dest = assemble_imageitems(items, r, w, h)
    print("saving...")
    save_image("test1.png", dest)
    
    print("Assemble test2:", w/4, "x", h/4)
    dest = assemble_imageitems(items, r, w/4, h/4)
    save_image("test2.png", dest)

def test():
    """Test"""
    N = 500
    data = compute_image(N, N)
    m = data.min()
    M = data.max()
    items = [make.trimage(data, alpha_mask=True, colormap="jet")]
    for type in (np.uint8, np.uint16, np.int8, np.int16):
        info = np.iinfo(type().dtype)
        s = float((info.max-info.min))
        a1 = s*(data-m)/(M-m)
        img = np.array(a1+info.min, type)
        txtwrite(img, 0, 0, N/15., str(type))
        items.append(make.trimage(img, colormap="jet"))
    imshow(items, title="Transform test (%dx%d images)" % (N, N))
    return items

if __name__ == "__main__":
    # -- Create QApplication
    import guidata
    _app = guidata.qapplication()
    # --    
    items = test()
    build_image(items)

Image rectangular filter

from scipy.ndimage import gaussian_filter

from guiqwt.plot import ImageDialog
from guiqwt.builder import make

def imshow(x, y, data, filter_area, yreverse=True):
    win = ImageDialog(edit=False, toolbar=True, wintitle="Image filter demo",
                      options=dict(xlabel="x (cm)", ylabel="y (cm)",
                                   yreverse=yreverse))
    image = make.xyimage(x, y, data)
    plot = win.get_plot()
    plot.add_item(image)
    xmin, xmax, ymin, ymax = filter_area
    flt = make.imagefilter(xmin, xmax, ymin, ymax, image,
                           filter=lambda x, y, data: gaussian_filter(data, 5))
    plot.add_item(flt, z=1)
    plot.replot()
    win.show()
    win.exec_()

def test():
    """Test"""
    # -- Create QApplication
    import guidata
    _app = guidata.qapplication()
    # --
    from guiqwt.tests.imagexy import compute_image
    x, y, data = compute_image()
    imshow(x, y, data, filter_area=(-3., -1., 0., 2.), yreverse=False)
    # --
    import os.path as osp, numpy as np
    from guiqwt import io
    filename = osp.join(osp.dirname(__file__), "brain.png")
    data = io.imread(filename, to_grayscale=True)
    x = np.linspace(0, 30., data.shape[1])
    y = np.linspace(0, 30., data.shape[0])
    imshow(x, y, data, filter_area=(10, 20, 5, 15))

if __name__ == "__main__":
    test()

Histograms

2-D histogram

from numpy import random, array, dot, concatenate

from guiqwt.plot import ImageDialog
from guiqwt.builder import make
from guiqwt.config import _

def hist2d(X, Y):
    win = ImageDialog(edit=True, toolbar=True,
                      wintitle="2-D Histogram X0=(0,1), X1=(-1,-1)")
    hist2d = make.histogram2D(X, Y, 200, 200)
    curve = make.curve(X[::50], Y[::50],
                       linestyle='', marker='+', title=_("Markers"))
    plot = win.get_plot()
    plot.set_aspect_ratio(lock=False)
    plot.set_antialiasing(False)
    plot.add_item(hist2d)
    plot.add_item(curve)
    plot.set_item_visible(curve, False)
    win.show()
    win.exec_()

if __name__ == "__main__":
    import guidata
    _app = guidata.qapplication()
    N = 150000
    m = array([[ 1., .2], [-.2, 3.]])
    X1 = random.normal(0, .3, size=(N, 2))
    X2 = random.normal(0, .3, size=(N, 2))
    X = concatenate((X1+[0, 1.], dot(X2, m)+[-1, -1.])) 
    hist2d(X[:, 0], X[:, 1])

Other examples

Image plot tools

import os.path as osp

from guiqwt.plot import ImageDialog
from guiqwt.tools import (RectangleTool, EllipseTool, HRangeTool, PlaceAxesTool,
                          MultiLineTool, FreeFormTool, SegmentTool, CircleTool,
                          AnnotatedRectangleTool, AnnotatedEllipseTool,
                          AnnotatedSegmentTool, AnnotatedCircleTool, LabelTool,
                          AnnotatedPointTool,
                          VCursorTool, HCursorTool, XCursorTool,
                          ObliqueRectangleTool, AnnotatedObliqueRectangleTool)
from guiqwt.builder import make

def create_window():
    win = ImageDialog(edit=False, toolbar=True,
                      wintitle="All image and plot tools test")
    for toolklass in (LabelTool, HRangeTool,
                      VCursorTool, HCursorTool, XCursorTool,
                      SegmentTool, RectangleTool, ObliqueRectangleTool,
                      CircleTool, EllipseTool,
                      MultiLineTool, FreeFormTool, PlaceAxesTool,
                      AnnotatedRectangleTool, AnnotatedObliqueRectangleTool,
                      AnnotatedCircleTool, AnnotatedEllipseTool,
                      AnnotatedSegmentTool, AnnotatedPointTool):
        win.add_tool(toolklass)
    return win

def test():
    """Test"""
    # -- Create QApplication
    import guidata
    _app = guidata.qapplication()
    # --
    filename = osp.join(osp.dirname(__file__), "brain.png")
    win = create_window()
    image = make.image(filename=filename, colormap="bone")
    plot = win.get_plot()
    plot.add_item(image)
    win.exec_()

if __name__ == "__main__":
    test()

Real-time Mandelbrot plotting

import numpy as np

from guidata.qt.QtCore import QRectF, QPointF

from guiqwt.config import _
from guiqwt.plot import ImageDialog
from guiqwt.image import RawImageItem
from guiqwt.tools import ToggleTool
from guiqwt.mandelbrot import mandelbrot


class FullScale(ToggleTool):
    def __init__(self, parent, image):
        super(FullScale, self).__init__(parent, _("MAX resolution"), None)
        self.image = image
        self.minprec = image.IMAX
        self.maxprec = 5*image.IMAX
        
    def activate_command(self, plot, checked):
        if self.image.IMAX == self.minprec:
            self.image.IMAX = self.maxprec
        else:
            self.image.IMAX = self.minprec
        self.image.set_lut_range([0, self.image.IMAX])
        plot.replot()
        
    def update_status(self, plot):
        self.action.setChecked(self.image.IMAX == self.maxprec)

class MandelItem(RawImageItem):
    def __init__(self, xmin, xmax, ymin, ymax):
        super(MandelItem, self).__init__(np.zeros((1, 1), np.uint8))
        self.bounds = QRectF(QPointF(xmin, ymin),
                             QPointF(xmax, ymax))
        self.update_border()
        self.IMAX = 80
        self.set_lut_range([0, self.IMAX])
        
    #---- QwtPlotItem API ------------------------------------------------------
    def draw_image(self, painter, canvasRect, srcRect, dstRect, xMap, yMap):        
        x1, y1 = canvasRect.left(), canvasRect.top()
        x2, y2 = canvasRect.right(), canvasRect.bottom()
        i1, j1, i2, j2 = srcRect

        NX = x2-x1
        NY = y2-y1
        if self.data.shape != (NX, NY):
            self.data = np.zeros((NY, NX), np.uint8)
        mandelbrot(i1, j1, i2, j2, self.data, self.IMAX)
        
        srcRect = (0, 0, NX, NY)
        x1, y1, x2, y2 = canvasRect.getCoords()
        RawImageItem.draw_image(self, painter, canvasRect,
                                srcRect, (x1, y1, x2, y2), xMap, yMap)

def mandel():
    win = ImageDialog(edit=True, toolbar=True, wintitle="Mandelbrot",
                      options=dict(yreverse=False))
    mandel = MandelItem(-1.5, .5, -1., 1.)
    win.add_tool(FullScale, mandel)
    plot = win.get_plot()
    plot.set_aspect_ratio(lock=False)
    plot.add_item(mandel)
    plot.set_full_scale(mandel)
    win.show()
    win.exec_()

if __name__ == "__main__":
    import guidata
    _app = guidata.qapplication()
    mandel()

Simple application

from guidata.qt.QtGui import QMainWindow, QMessageBox, QSplitter, QListWidget
from guidata.qt.QtCore import (QSize, QT_VERSION_STR, PYQT_VERSION_STR, Qt,
                               SIGNAL)
from guidata.qt.compat import getopenfilename

import sys, platform
import numpy as np

from guidata.dataset.datatypes import DataSet, GetAttrProp
from guidata.dataset.dataitems import (IntItem, FloatArrayItem, StringItem,
                                       ChoiceItem)
from guidata.dataset.qtwidgets import DataSetEditGroupBox
from guidata.configtools import get_icon
from guidata.qthelpers import create_action, add_actions, get_std_icon
from guidata.utils import update_dataset
from guidata.py3compat import to_text_string

from guiqwt.config import _
from guiqwt.plot import ImageWidget
from guiqwt.builder import make
from guiqwt.signals import SIG_LUT_CHANGED
from guiqwt import io

APP_NAME = _("Application example")
VERSION = '1.0.0'

class ImageParam(DataSet):
    _hide_data = False
    _hide_size = True
    title = StringItem(_("Title"), default=_("Untitled"))
    data = FloatArrayItem(_("Data")).set_prop("display",
                                              hide=GetAttrProp("_hide_data"))
    width = IntItem(_("Width"), help=_("Image width (pixels)"), min=1,
                    default=100).set_prop("display",
                                          hide=GetAttrProp("_hide_size"))
    height = IntItem(_("Height"), help=_("Image height (pixels)"), min=1,
                     default=100).set_prop("display",
                                           hide=GetAttrProp("_hide_size"))

class ImageParamNew(ImageParam):
    _hide_data = True
    _hide_size = False
    type = ChoiceItem(_("Type"),
                      (("rand", _("random")), ("zeros", _("zeros"))))

class ImageListWithProperties(QSplitter):
    def __init__(self, parent):
        QSplitter.__init__(self, parent)
        self.imagelist = QListWidget(self)
        self.addWidget(self.imagelist)
        self.properties = DataSetEditGroupBox(_("Properties"), ImageParam)
        self.properties.setEnabled(False)
        self.addWidget(self.properties)

class CentralWidget(QSplitter):
    def __init__(self, parent, toolbar):
        QSplitter.__init__(self, parent)
        self.setContentsMargins(10, 10, 10, 10)
        self.setOrientation(Qt.Vertical)
        
        imagelistwithproperties = ImageListWithProperties(self)
        self.addWidget(imagelistwithproperties)
        self.imagelist = imagelistwithproperties.imagelist
        self.connect(self.imagelist, SIGNAL("currentRowChanged(int)"),
                     self.current_item_changed)
        self.connect(self.imagelist, SIGNAL("itemSelectionChanged()"),
                     self.selection_changed)
        self.properties = imagelistwithproperties.properties
        self.connect(self.properties, SIGNAL("apply_button_clicked()"),
                     self.properties_changed)
        
        self.imagewidget = ImageWidget(self)
        self.connect(self.imagewidget.plot, SIG_LUT_CHANGED,
                     self.lut_range_changed)
        self.item = None # image item
        
        self.imagewidget.add_toolbar(toolbar, "default")
        self.imagewidget.register_all_image_tools()
        
        self.addWidget(self.imagewidget)

        self.images = [] # List of ImageParam instances
        self.lut_ranges = [] # List of LUT ranges

        self.setStretchFactor(0, 0)
        self.setStretchFactor(1, 1)
        self.setHandleWidth(10)
        self.setSizes([1, 2])
        
    def refresh_list(self):
        self.imagelist.clear()
        self.imagelist.addItems([image.title for image in self.images])
        
    def selection_changed(self):
        """Image list: selection changed"""
        row = self.imagelist.currentRow()
        self.properties.setDisabled(row == -1)
        
    def current_item_changed(self, row):
        """Image list: current image changed"""
        image, lut_range = self.images[row], self.lut_ranges[row]
        self.show_data(image.data, lut_range)
        update_dataset(self.properties.dataset, image)
        self.properties.get()
        
    def lut_range_changed(self):
        row = self.imagelist.currentRow()
        self.lut_ranges[row] = self.item.get_lut_range()
        
    def show_data(self, data, lut_range=None):
        plot = self.imagewidget.plot
        if self.item is not None:
            self.item.set_data(data)
            if lut_range is None:
                lut_range = self.item.get_lut_range()
            self.imagewidget.set_contrast_range(*lut_range)
            self.imagewidget.update_cross_sections()
        else:
            self.item = make.image(data)
            plot.add_item(self.item, z=0)
        plot.replot()
        
    def properties_changed(self):
        """The properties 'Apply' button was clicked: updating image"""
        row = self.imagelist.currentRow()
        image = self.images[row]
        update_dataset(image, self.properties.dataset)
        self.refresh_list()
        self.show_data(image.data)
    
    def add_image(self, image):
        self.images.append(image)
        self.lut_ranges.append(None)
        self.refresh_list()
        self.imagelist.setCurrentRow(len(self.images)-1)
        plot = self.imagewidget.plot
        plot.do_autoscale()
    
    def add_image_from_file(self, filename):
        image = ImageParam()
        image.title = to_text_string(filename)
        image.data = io.imread(filename, to_grayscale=True)
        image.height, image.width = image.data.shape
        self.add_image(image)

class MainWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        self.setup()
        
    def setup(self):
        """Setup window parameters"""
        self.setWindowIcon(get_icon('python.png'))
        self.setWindowTitle(APP_NAME)
        self.resize(QSize(600, 800))
        
        # Welcome message in statusbar:
        status = self.statusBar()
        status.showMessage(_("Welcome to guiqwt application example!"), 5000)
        
        # File menu
        file_menu = self.menuBar().addMenu(_("File"))
        new_action = create_action(self, _("New..."),
                                   shortcut="Ctrl+N",
                                   icon=get_icon('filenew.png'),
                                   tip=_("Create a new image"),
                                   triggered=self.new_image)
        open_action = create_action(self, _("Open..."),
                                    shortcut="Ctrl+O",
                                    icon=get_icon('fileopen.png'),
                                    tip=_("Open an image"),
                                    triggered=self.open_image)
        quit_action = create_action(self, _("Quit"),
                                    shortcut="Ctrl+Q",
                                    icon=get_std_icon("DialogCloseButton"),
                                    tip=_("Quit application"),
                                    triggered=self.close)
        add_actions(file_menu, (new_action, open_action, None, quit_action))
        
        # Help menu
        help_menu = self.menuBar().addMenu("?")
        about_action = create_action(self, _("About..."),
                                     icon=get_std_icon('MessageBoxInformation'),
                                     triggered=self.about)
        add_actions(help_menu, (about_action,))
        
        main_toolbar = self.addToolBar("Main")
        add_actions(main_toolbar, (new_action, open_action, ))
        
        # Set central widget:
        toolbar = self.addToolBar("Image")
        self.mainwidget = CentralWidget(self, toolbar)
        self.setCentralWidget(self.mainwidget)
        
    #------?
    def about(self):
        QMessageBox.about( self, _("About ")+APP_NAME,
              """<b>%s</b> v%s<p>%s Pierre Raybaut
              <br>Copyright &copy; 2009-2010 CEA
              <p>Python %s, Qt %s, PyQt %s %s %s""" % \
              (APP_NAME, VERSION, _("Developped by"), platform.python_version(),
               QT_VERSION_STR, PYQT_VERSION_STR, _("on"), platform.system()) )
        
    #------I/O
    def new_image(self):
        """Create a new image"""
        imagenew = ImageParamNew(title=_("Create a new image"))
        if not imagenew.edit(self):
            return
        image = ImageParam()
        image.title = imagenew.title
        if imagenew.type == 'zeros':
            image.data = np.zeros((imagenew.width, imagenew.height))
        elif imagenew.type == 'rand':
            image.data = np.random.randn(imagenew.width, imagenew.height)
        self.mainwidget.add_image(image)
    
    def open_image(self):
        """Open image file"""
        saved_in, saved_out, saved_err = sys.stdin, sys.stdout, sys.stderr
        sys.stdout = None
        filename, _filter = getopenfilename(self, _("Open"), "",
                                            io.iohandler.get_filters('load'))
        sys.stdin, sys.stdout, sys.stderr = saved_in, saved_out, saved_err
        if filename:
            self.mainwidget.add_image_from_file(filename)
        
if __name__ == '__main__':
    from guidata import qapplication
    app = qapplication()
    window = MainWindow()
    window.show()
    app.exec_()