class View(Subject, QMainWindow):
"""Main window class, and the View of the MVC pattern.
Attributes:
model: The model of the MVC pattern.
menu_bar: A menu bar derived from QMenuBar.
tool_bar: A tool bar derived from QToolBar.
exif_area: The widget containing any available EXIF data.
image_area: The widget containing the displayed image.
status_bar: A status bar derived from QStatusBar.
about: The classic "About" informative widget (actually a new, separate window).
"""
def __init__(self, model):
"""Inits the class."""
Subject.__init__(self)
QMainWindow.__init__(self)
# Set model
self.model = model
# Create interface elements
self.menu_bar = MenuBar(self)
self.tool_bar = ToolBar(self)
self.exif_area = ExifWidget(self)
self.image_area = ImageWidget(self)
self.status_bar = StatusBar()
about_text = 'IEViewer 1.0' \
'<br><br>' \
'Copyright © 2021 by' \
'<br>' \
'Paula Mihalcea' \
'<br>' \
'<a href="mailto:[email protected]">[email protected]</a>' \
'<br><br>' \
'This program uses PyQt5, a comprehensive set of Python bindings for Qt v5. Qt is a set of cross-platform C++ libraries that implement high-level APIs for accessing many aspects of modern desktop and mobile systems.\n' \
'<br><br>' \
'PyQt5 is copyright © Riverbank Computing Limited. Its homepage is <a href="https://www.riverbankcomputing.com/software/pyqt/">https://www.riverbankcomputing.com/software/pyqt/</a>.' \
'<br><br>' \
'No genasi were harmed in the making of this application. <a href="https://www.dndbeyond.com/races/genasi#WaterGenasi">#GenasiLivesMatter#NereisThalian</a>'
self.about = AboutWidget('About IEViewer',
about_text,
image_path='icons/about_img.png')
# Disable GUI elements that are unavailable when no image is opened
self.menu_bar.disable_widgets()
self.exif_area.hide()
# Set layout
self.setCentralWidget(Layout(self).central_widget)
# Set window properties
self.set_window_properties()
# Install additional event filters
self.image_area.installEventFilter(self)
def set_window_properties(self):
"""Sets some main window properties."""
self.statusBar()
self.setStatusTip('Ready.')
self.setWindowTitle(
'IEViewer') # Window title (the one in the title bar)
self.resize(
512,
256) # These default dimensions should be fine for most displays
def get_open_file_dialog(self, caption, filter):
"""Opens an "Open File" dialog and returns a file path. If no file has been selected and the user has pressed "Cancel" or closed the dialog, then it returns None."""
file_path, _ = QFileDialog.getOpenFileName(caption=caption,
directory='',
filter=filter)
if file_path == '':
return None
else:
return file_path
def get_save_file_dialog(self, caption, filter):
"""Opens a "Save As" dialog and returns a file path and format. If no name has been entered and the user has pressed "Cancel" or closed the dialog, then it returns None."""
file_path, format = QFileDialog.getSaveFileName(
caption=caption, directory='', filter=filter
) # By omitting the directory argument (empty string, ''), the dialog should remember the last directory (depends on operating system)
if file_path == '':
return None, None
else:
format = format.split(' ')
return file_path, format[0]
def show_message_box(self, title, text, icon=QMessageBox.Information):
"""Opens a simple message box window, with some text and a customizable icon."""
info_box = QMessageBox(self)
if icon is not None:
info_box.setIcon(icon)
info_box.setWindowTitle(title)
info_box.setText(text)
info_box.show()
def event(self, e):
"""Defines the default status bar message (when nothing else is displayed)."""
if e.type() == QEvent.StatusTip:
if e.tip() == '':
e = QStatusTipEvent('Ready.')
return super().event(e)
def open(self):
"""Only needed to notify observers (i.e. the controller) that they should load an image."""
self.set_state('open')
def load_image(self):
"""Displays the image contained in the model."""
# Get original image dimensions
width = self.model.image.width()
height = self.model.image.height()
# Recalculate image dimensions so as to have a maximum dimension (height or width) of 512 pixels
if width >= height and width > 512:
w = 512
h = int(512 * height / width)
elif height >= width and height > 512:
w = int(512 * width / height)
h = 512
else:
w = width
h = height
# Generate and set a pixmap from the image
self.image_area.set_image(self.model.image, w, h)
# Resize the window and pixmap (generated from the image),
# so as to display correctly the window title, menu bar and image (actually, its pixmap)
#
# The diff parameter is another piece of PyQt5 magic.
# Without it, an image larger than 512 pixels might be displayed smaller
# than the maximum 512 that it has been resized to
# (despite having been resized to 512 pixels).
diff = 130 # This value is good for both Windows 10 and Ubuntu 20.04
if w < 280: # Again, this should suffice for both OSs
self.resize(280, h + diff)
else:
self.resize(w, h + diff)
self.image_area.pixmap.scaled(w, h)
# Add EXIF data from the model
self.exif_area.load_exif()
# Update window title
self.setWindowTitle('IEViewer - ' + self.model.filename)
# Enable menus
self.menu_bar.enable_widgets()
def save(self):
"""Saves the modified image. Uses the stored original image, not the modified version currently displayed in the window."""
self.model.set_image(
self.model.image.transformed(
QTransform().rotate(self.image_area.rot),
Qt.SmoothTransformation))
self.set_state('save')
def saveas(self):
"""Saves the modified image with another name. Uses the stored original image, not the modified version currently displayed in the window."""
self.model.set_image(
self.model.image.transformed(
QTransform().rotate(self.image_area.rot),
Qt.SmoothTransformation))
self.set_state('saveas')
def eventFilter(self, widget, event):
"""Adds new behavior for certain events."""
# Resize event
# Or what should happen to the image widget when the user resizes the main window
if event.type(
) == QEvent.Resize and widget is self.image_area and self.image_area.pixmap is not None:
self.image_area.setPixmap(
QPixmap.fromImage(self.model.modified_image).scaled(
self.image_area.width(),
self.image_area.height(),
aspectRatioMode=Qt.KeepAspectRatio,
transformMode=Qt.SmoothTransformation))
# Update new dimensions for later use
self.image_area.w = self.image_area.width()
self.image_area.h = self.image_area.height()
return True
return QMainWindow.eventFilter(self, widget, event)
def close(self):
"""Closes an image."""
self.set_state('close')
# Clear image area widget and adjust layout
self.image_area.clear_image()
self.exif_area = ExifWidget(self)
self.setCentralWidget(Layout(self).central_widget)
# Disable unavailable menus
self.menu_bar.disable_widgets()
# Hide EXIF area (if visible) and show blank image widget
self.exif_area.hide()
self.image_area.show()
# Update window title
self.setWindowTitle('IEViewer')
def exit(self):
"""Only needed to notify observers (i.e. the controller) that they should exit the application."""
self.set_state('exit')
def rotate(self, degree):
"""Base function for rotation.
Subsequent rotation functions are only needed as hooks for menu actions; actual rotations happen here.
Here, the View directly changes the Model. Arguably, this is a violation of the MVC pattern. It happens that, for some reason, returning a reference to the rotated image to the Controller in order to have the Controller itself change the Model does not work, probably because it only returns a reference and not a copy of the rotated image. PyQt5 does not allow deep copies of its objects, so the following seems to be the only way to make it work.
"""
self.model.set_modified_image(
self.model.image.transformed(
QTransform().rotate(self.image_area.rot + degree),
Qt.SmoothTransformation)) # Rotate image
self.image_area.set_image(self.model.modified_image, self.image_area.w,
self.image_area.h) # Display rotated image
self.image_area.rot += degree # Update rotation history
def rotate180(self):
"""Rotate the displayed image by 180 degrees."""
self.rotate(180)
def rotate90c(self):
"""Rotate the displayed image by 90 degrees clock wise."""
self.rotate(90)
def rotate90cc(self):
"""Rotate the displayed image by 90 degrees clock wise."""
self.rotate(-90)
def reset_image(self):
"""Reset the displayed image to its original orientation."""
self.rotate(-self.image_area.rot)
def show_exif(self):
"""Display EXIF data (and at the same time hide the image)."""
if self.exif_area.isHidden():
self.image_area.hide()
self.exif_area.show()
else:
self.image_area.show()
self.exif_area.hide()
def about(self):
"""Display info about the program."""
self.about.show()
