class PhotosViewer(QGraphicsView):
afterLeftClick = pyqtSignal(float, float)
afterLeftClickReleased = pyqtSignal(float, float)
afterDoubleClick = pyqtSignal(float, float)
def __init__(self, selfwindow):
QGraphicsView.__init__(self)
self.selfwindow = selfwindow
self.panSelect = False
self.zoomSelect = False
self.zoom_data = []
self.scene = QGraphicsScene()
self.setScene(self.scene)
self.setMouseTracking(False)
self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.setDragMode(QGraphicsView.NoDrag)
def mousePressEvent(self, event):
sc_pos = self.mapToScene(event.pos())
if self.panSelect:
self.setDragMode(QGraphicsView.ScrollHandDrag)
if self.zoomSelect:
self.setDragMode(QGraphicsView.RubberBandDrag)
self.afterLeftClick.emit(sc_pos.x(), sc_pos.y())
QGraphicsView.mousePressEvent(self, event)
def mouseDoubleClickEvent(self, event):
sc_pos = self.mapToScene(event.pos())
if self.zoomSelect or self.panSelect:
self.zoom_data = []
self.fitInView(self.sceneRect(), Qt.KeepAspectRatio)
self.afterDoubleClick.emit(sc_pos.x(), sc_pos.y())
QGraphicsView.mouseDoubleClickEvent(self, event)
def mouseReleaseEvent(self, event):
QGraphicsView.mouseReleaseEvent(self, event)
sc_pos = self.mapToScene(event.pos())
if self.zoomSelect:
view_bb = self.sceneRect()
if self.zoom_data:
view_bb = self.zoom_data
selection_bb = self.scene.selectionArea().boundingRect(
).intersected(view_bb)
self.scene.setSelectionArea(QPainterPath())
if selection_bb.isValid() and (selection_bb != view_bb):
self.zoom_data = selection_bb
self.fitInView(self.zoom_data, Qt.KeepAspectRatio)
self.setDragMode(QGraphicsView.NoDrag)
self.afterLeftClickReleased.emit(sc_pos.x(), sc_pos.y())
def resizeEvent(self, event):
self.fitInView(self.scene.sceneRect(), Qt.KeepAspectRatio)
class ImageViewerQt(QGraphicsView):
""" PyQt image viewer widget for a QPixmap in a QGraphicsView scene with mouse zooming and panning.
Displays a QImage or QPixmap (QImage is internally converted to a QPixmap).
To display any other image format, you must first convert it to a QImage or QPixmap.
Some useful image format conversion utilities:
qimage2ndarray: NumPy ndarray <==> QImage (https://github.com/hmeine/qimage2ndarray)
ImageQt: PIL Image <==> QImage (https://github.com/python-pillow/Pillow/blob/master/PIL/ImageQt.py)
Mouse interaction:
Left mouse button drag: Pan image.
Right mouse button drag: Zoom box.
Right mouse button doubleclick: Zoom to show entire image.
"""
# Mouse button signals emit image scene (x, y) coordinates.
# !!! For image (row, column) matrix indexing, row = y and column = x.
leftMouseButtonPressed = pyqtSignal(float, float)
rightMouseButtonPressed = pyqtSignal(float, float)
leftMouseButtonReleased = pyqtSignal(float, float)
rightMouseButtonReleased = pyqtSignal(float, float)
leftMouseButtonDoubleClicked = pyqtSignal(float, float)
rightMouseButtonDoubleClicked = pyqtSignal(float, float)
def __init__(self):
QGraphicsView.__init__(self)
# Image is displayed as a QPixmap in a QGraphicsScene attached to this QGraphicsView.
self.scene = QGraphicsScene()
self.setScene(self.scene)
# Store a local handle to the scene's current image pixmap.
self._pixmapHandle = None
# Image aspect ratio mode.
# !!! ONLY applies to full image. Aspect ratio is always ignored when zooming.
# Qt.IgnoreAspectRatio: Scale image to fit viewport.
# Qt.KeepAspectRatio: Scale image to fit inside viewport, preserving aspect ratio.
# Qt.KeepAspectRatioByExpanding: Scale image to fill the viewport, preserving aspect ratio.
self.aspectRatioMode = Qt.KeepAspectRatio
# Scroll bar behaviour.
# Qt.ScrollBarAlwaysOff: Never shows a scroll bar.
# Qt.ScrollBarAlwaysOn: Always shows a scroll bar.
# Qt.ScrollBarAsNeeded: Shows a scroll bar only when zoomed.
self.setHorizontalScrollBarPolicy(Qt.ScrollBarAsNeeded)
self.setVerticalScrollBarPolicy(Qt.ScrollBarAsNeeded)
# Stack of QRectF zoom boxes in scene coordinates.
self.zoomStack = []
# Flags for enabling/disabling mouse interaction.
self.canZoom = True
self.canPan = True
def hasImage(self):
""" Returns whether or not the scene contains an image pixmap.
"""
return self._pixmapHandle is not None
def clearImage(self):
""" Removes the current image pixmap from the scene if it exists.
"""
if self.hasImage():
self.scene.removeItem(self._pixmapHandle)
self._pixmapHandle = None
def pixmap(self):
""" Returns the scene's current image pixmap as a QPixmap, or else None if no image exists.
:rtype: QPixmap | None
"""
if self.hasImage():
return self._pixmapHandle.pixmap()
return None
def image(self):
""" Returns the scene's current image pixmap as a QImage, or else None if no image exists.
:rtype: QImage | None
"""
if self.hasImage():
return self._pixmapHandle.pixmap().toImage()
return None
def setImage(self, image):
""" Set the scene's current image pixmap to the input QImage or QPixmap.
Raises a RuntimeError if the input image has type other than QImage or QPixmap.
:type image: QImage | QPixmap
"""
if type(image) is QPixmap:
pixmap = image
elif type(image) is QImage:
pixmap = QPixmap.fromImage(image)
else:
raise RuntimeError(
"ImageViewer.setImage: Argument must be a QImage or QPixmap.")
if self.hasImage():
self._pixmapHandle.setPixmap(pixmap)
else:
self._pixmapHandle = self.scene.addPixmap(pixmap)
self.setSceneRect(QRectF(
pixmap.rect())) # Set scene size to image size.
self.updateViewer()
def loadImageFromFile(self, fileName=""):
""" Load an image from file.
Without any arguments, loadImageFromFile() will popup a file dialog to choose the image file.
With a fileName argument, loadImageFromFile(fileName) will attempt to load the specified image file directly.
"""
if len(fileName) == 0:
if QT_VERSION_STR[0] == '4':
fileName = QFileDialog.getOpenFileName(self,
"Open image file.")
elif QT_VERSION_STR[0] == '5':
fileName, dummy = QFileDialog.getOpenFileName(
self, "Open image file.")
if len(fileName) and os.path.isfile(fileName):
image = QImage(fileName)
self.setImage(image)
def updateViewer(self):
""" Show current zoom (if showing entire image, apply current aspect ratio mode).
"""
if not self.hasImage():
return
if len(self.zoomStack) and self.sceneRect().contains(
self.zoomStack[-1]):
self.fitInView(self.zoomStack[-1], Qt.IgnoreAspectRatio
) # Show zoomed rect (ignore aspect ratio).
else:
self.zoomStack = [
] # Clear the zoom stack (in case we got here because of an invalid zoom).
self.fitInView(
self.sceneRect(), self.aspectRatioMode
) # Show entire image (use current aspect ratio mode).
def resizeEvent(self, event):
""" Maintain current zoom on resize.
"""
self.updateViewer()
def mousePressEvent(self, event):
""" Start mouse pan or zoom mode.
"""
scenePos = self.mapToScene(event.pos())
if event.button() == Qt.LeftButton:
if self.canPan:
self.setDragMode(QGraphicsView.ScrollHandDrag)
self.leftMouseButtonPressed.emit(scenePos.x(), scenePos.y())
elif event.button() == Qt.RightButton:
if self.canZoom:
self.setDragMode(QGraphicsView.RubberBandDrag)
self.rightMouseButtonPressed.emit(scenePos.x(), scenePos.y())
QGraphicsView.mousePressEvent(self, event)
def mouseReleaseEvent(self, event):
""" Stop mouse pan or zoom mode (apply zoom if valid).
"""
QGraphicsView.mouseReleaseEvent(self, event)
scenePos = self.mapToScene(event.pos())
if event.button() == Qt.LeftButton:
self.setDragMode(QGraphicsView.NoDrag)
self.leftMouseButtonReleased.emit(scenePos.x(), scenePos.y())
elif event.button() == Qt.RightButton:
if self.canZoom:
viewBBox = self.zoomStack[-1] if len(
self.zoomStack) else self.sceneRect()
selectionBBox = self.scene.selectionArea().boundingRect(
).intersected(viewBBox)
self.scene.setSelectionArea(
QPainterPath()) # Clear current selection area.
if selectionBBox.isValid() and (selectionBBox != viewBBox):
self.zoomStack.append(selectionBBox)
self.updateViewer()
self.setDragMode(QGraphicsView.NoDrag)
self.rightMouseButtonReleased.emit(scenePos.x(), scenePos.y())
def mouseDoubleClickEvent(self, event):
""" Show entire image.
"""
scenePos = self.mapToScene(event.pos())
if event.button() == Qt.LeftButton:
self.leftMouseButtonDoubleClicked.emit(scenePos.x(), scenePos.y())
elif event.button() == Qt.RightButton:
if self.canZoom:
self.zoomStack = [] # Clear zoom stack.
self.updateViewer()
self.rightMouseButtonDoubleClicked.emit(scenePos.x(), scenePos.y())
QGraphicsView.mouseDoubleClickEvent(self, event)