class PageViewer(QGraphicsView):
mouseRelaseEvent = pyqtSignal()
wheelZoomEvent = pyqtSignal()
@property
def drawing(self):
return self._drawing
@property
def tool_mode(self):
return self._toolMode
@property
def empty(self):
return self._page is None
@property
def page_layer(self):
return self._pageLayer
@property
def drawing_layer(self):
return self._drawingLayer
@property
def page(self):
return self._page
@property
def pen_size(self):
return self._pen.width()
@property
def eraser_size(self):
return self._eraserSize
def __init__(self, parent):
super(PageViewer, self).__init__(parent)
self._page = None
# todo: add all these constants to preferences dialog
self._zoom = 0
self._zoomMaxDistance = 10
self._zoomInFactor = 1.25
self._zoomOutFactor = 0.8
self._panDivisor = 2
self._toolMode = ToolMode.NOTHING
self._previousToolModeDrag = ToolMode.NOTHING
self._drawing = False
self._dragStart = None
self._drawPoint = None
self._lastPenPos = None
self._scene = QGraphicsScene(self)
self._pageLayer = None
self._drawingLayer = None
self._predrawPixmap = None
self._eraserSize = 100
self._eraserEllipse = self.getEraserEllipse()
pen_brush = QBrush(QColor('red'), Qt.SolidPattern)
self._pen = QPen(pen_brush, 5, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin)
self._increaseSizeAction = QAction('Increase tool size', self)
self._increaseSizeAction.setEnabled(False)
self._increaseSizeAction.triggered.connect(
self.onIncreaseSizeActionTriggered)
self._decreaseSizeAction = QAction('Decrease tool size', self)
self._decreaseSizeAction.setEnabled(False)
self._decreaseSizeAction.triggered.connect(
self.onDecreaseSizeActionTriggered)
self.setTransformationAnchor(QGraphicsView.AnchorUnderMouse)
self.setResizeAnchor(QGraphicsView.AnchorUnderMouse)
self.setMouseTracking(True)
def reset(self):
self.setInteractive(False)
self.setToolMode(ToolMode.NOTHING)
self.setScene(QGraphicsScene(self))
self._page = None
self._zoom = 0
def getEraserEllipse(self):
brush = QBrush(QColor(0, 0, 0, alpha=64), Qt.SolidPattern)
pen = QPen(brush, 2, Qt.DashDotLine, Qt.RoundCap, Qt.RoundJoin)
pen.setCosmetic(True)
ellipse = QGraphicsEllipseItem(0, 0, self._eraserSize,
self._eraserSize)
ellipse.setPen(pen)
return ellipse
def fitPage(self):
if not self.empty:
rect = QRectF(self._pageLayer.pixmap().rect())
if not rect.isNull():
self.setSceneRect(rect)
unity = self.transform().mapRect(QRectF(0, 0, 1, 1))
self.scale(1 / unity.width(), 1 / unity.height())
viewrect = self.viewport().rect()
scenerect = self.transform().mapRect(rect)
factor = min(viewrect.width() / scenerect.width(),
viewrect.height() / scenerect.height())
self.scale(factor, factor)
self._zoom = 0
def setPage(self, page):
self._page = page
if not self._page.page_image.isNull():
self._scene.clear()
self._pageLayer = QGraphicsPixmapItem(self._page.page_image)
self._scene.addItem(self._pageLayer)
self._drawingLayer = QGraphicsPixmapItem(self._page.drawing_image)
self._scene.addItem(self._drawingLayer)
self.fitPage()
self._eraserEllipse = self.getEraserEllipse()
self.setScene(self._scene)
self.setToolMode(self._toolMode)
self.setInteractive(True)
def canZoomIn(self):
return self._zoom < self._zoomMaxDistance
def canZoomOut(self):
return self._zoom > 0
def zoomIn(self):
if self.canZoomIn():
self._zoom += 1
self._applyZoom(self._zoomInFactor)
return True
return False
def zoomOut(self):
if self.canZoomOut():
self._zoom -= 1
self._applyZoom(self._zoomOutFactor)
return True
return False
def _applyZoom(self, factor):
if self._zoom > 0:
self.scale(factor, factor)
else:
self._zoom = 0
self.fitPage()
def wheelEvent(self, event):
if not self.empty:
if event.angleDelta().y() > 0:
factor = self._zoomInFactor
if not self.zoomIn():
return
else:
factor = self._zoomOutFactor
self.zoomOut()
self._applyZoom(factor)
self.wheelZoomEvent.emit()
def _penDraw(self, pos):
self._drawing = True
self._lastPenPos = self._drawPoint
self._drawPoint = pos
self.update()
def _eraseDraw(self, pos):
self._drawing = True
self._drawPoint = pos
self.update()
def mousePressEvent(self, event):
if not self.empty:
button = event.button()
scenePos = self.mapToScene(event.pos())
if button == Qt.MiddleButton:
self._previousToolModeDrag = self._toolMode
self.setToolMode(ToolMode.DRAGGING)
self._dragStart = scenePos
elif button == Qt.LeftButton:
if self._toolMode == ToolMode.NOTHING:
self.setToolMode(ToolMode.DRAGGING)
else:
sceneRect = self._drawingLayer.mapRectToScene(
QRectF(self._page.drawing_image.rect()))
if sceneRect.contains(scenePos.x(), scenePos.y()):
self._predrawPixmap = copyPixmap(
self._page.drawing_image)
if self._toolMode == ToolMode.PEN:
self._penDraw(scenePos)
if self._toolMode == ToolMode.ERASER:
self._eraseDraw(scenePos)
super(PageViewer, self).mousePressEvent(event)
def mouseMoveEvent(self, event):
scenePos = self.mapToScene(event.pos())
if self._toolMode == ToolMode.ERASER:
r = self._eraserEllipse.rect()
x = scenePos.x() - (r.width() / 2)
y = scenePos.y() - (r.height() / 2)
self._eraserEllipse.setPos(x, y)
if not self.empty:
if self._toolMode == ToolMode.DRAGGING and self._dragStart is not None:
delta = self.mapToScene(event.pos())
self.translate(delta.x() - self._dragStart.x(),
delta.y() - self._dragStart.y())
else:
if self._drawing:
if self._toolMode == ToolMode.PEN:
self._penDraw(scenePos)
super(PageViewer, self).mouseMoveEvent(event)
def mouseReleaseEvent(self, event):
if not self.empty:
button = event.button()
scenePos = self.mapToScene(event.pos())
if button == Qt.MiddleButton:
self.setToolMode(self._previousToolModeDrag)
elif button == Qt.LeftButton:
if self._toolMode == ToolMode.DRAGGING:
self.setToolMode(ToolMode.NOTHING)
elif self._toolMode == ToolMode.PEN:
self._penDraw(scenePos)
self._page.pushCommand(
DrawCommand(self, self._predrawPixmap))
self._lastPenPos = None
elif self._toolMode == ToolMode.ERASER:
self._eraseDraw(scenePos)
self._page.pushCommand(
DrawCommand(self, self._predrawPixmap))
self._drawPoint = None
self._drawing = False
self.mouseRelaseEvent.emit()
def paintEvent(self, event):
if self._drawing:
painter = QPainter(self._page.drawing_image)
painter.setRenderHint(QPainter.HighQualityAntialiasing, True)
if self._toolMode == ToolMode.ERASER:
painter.setPen(Qt.NoPen)
painter.setBrush(painter.background())
r = int(self._eraserSize / 2)
painter.drawEllipse(self._drawPoint, r, r)
if self._toolMode == ToolMode.PEN:
painter.setPen(self._pen)
if self._lastPenPos is None:
painter.drawPoint(self._drawPoint)
else:
painter.drawLine(self._lastPenPos, self._drawPoint)
painter.end()
self.updateDrawingLayer()
super(PageViewer, self).paintEvent(event)
def setToolMode(self, mode: ToolMode):
self._toolMode = mode
self._increaseSizeAction.setEnabled(False)
self._decreaseSizeAction.setEnabled(False)
for item in self._scene.items():
if isinstance(item, QGraphicsEllipseItem):
self._scene.removeItem(item)
if self._toolMode == ToolMode.DRAGGING:
self.setCursor(Qt.ClosedHandCursor)
else:
if self._toolMode == ToolMode.ERASER:
self._scene.addItem(self._eraserEllipse)
self._increaseSizeAction.setText('Increase Eraser width')
self._decreaseSizeAction.setText('Decrease Eraser width')
self._increaseSizeAction.setEnabled(True)
self._decreaseSizeAction.setEnabled(True)
elif self._toolMode == ToolMode.PEN:
self.setDragMode(QGraphicsView.NoDrag)
self.setCursor(Qt.CrossCursor)
self._increaseSizeAction.setText('Increase Pen width')
self._decreaseSizeAction.setText('Decrease Pen width')
self._increaseSizeAction.setEnabled(True)
self._decreaseSizeAction.setEnabled(True)
else:
self.setDragMode(QGraphicsView.NoDrag)
self.setCursor(Qt.ArrowCursor)
def setEraserSize(self, v):
if 500 >= v >= 10:
self._eraserEllipse.setRect(0, 0, v, v)
self._eraserSize = v
def setPenSize(self, v):
if 30 >= v > 0:
self._pen.setWidth(v)
def onIncreaseSizeActionTriggered(self):
if self._toolMode == ToolMode.ERASER:
v = self._eraserSize + 1
self.setEraserSize(v)
elif self._toolMode == ToolMode.PEN:
v = self._pen.width() + 1
self.setPenSize(v)
def onDecreaseSizeActionTriggered(self):
if self._toolMode == ToolMode.ERASER:
v = self._eraserSize - 1
self.setEraserSize(v)
elif self._toolMode == ToolMode.PEN:
v = self._pen.width() - 1
self.setPenSize(v)
def getActiveToolSizeText(self):
if self._toolMode == ToolMode.ERASER:
return '{:03d}px'.format(self._eraserSize)
elif self._toolMode == ToolMode.PEN:
return '{:02d}px'.format(self._pen.width())
else:
return ''
def getIncreaseSizeAction(self):
return self._increaseSizeAction
def getDecreaseSizeAction(self):
return self._decreaseSizeAction
def updateDrawingLayer(self):
self._drawingLayer.setPixmap(self._page.drawing_image)
