PyQT5開發之鼠標響應繪制

mouseMoveEventmousePressEventmouseReleaseEventmouseDoubleClickEvent

其中如果想要捕獲鼠標移動(MouseMove)事件必須設置

setMouseTracking(True)

才可以實現支持。一個簡單鼠標繪制通常包括三個鼠標事件的處理，分別是：

mousePressEvent鼠標按下 為開始繪制mouseMoveEvent 鼠標移動 繪制中mouseReleaseEvent 鼠標釋放 結束繪制

def mousePressEvent(self, event):def mouseMoveEvent(self, event):def mouseReleaseEvent(self, event):

  1class?ImageCanvas(QtWidgets.QWidget):
  2????def?__init__(self):
  3????????super().__init__()
  4????????self.pts?=?[]
  5????????self.temp_pts?=?[]
  6????????self.start_x?=?-1
  7????????self.start_y?=?-1
  8????????self.pressed?=?False
  9????????self.line_width?=?5
 10
 11????????#?monitor?key?and?mouse??event...
 12????????self.setMouseTracking(True)
 13
 14????????#?添加菜單
 15????????self.save_5_action?=?QtWidgets.QAction("線寬2",?self)
 16????????self.save_10_action?=?QtWidgets.QAction("線寬4",?self)
 17????????self.save_15_action?=?QtWidgets.QAction("線寬8",?self)
 18????????self.clear_action?=?QtWidgets.QAction("清除",?self)
 19
 20????????self.save_5_action.triggered.connect(self.on_save_5)
 21????????self.save_10_action.triggered.connect(self.on_save_10)
 22????????self.save_15_action.triggered.connect(self.on_save_15)
 23????????self.clear_action.triggered.connect(self.clear_canvas)
 24
 25????????self.addAction(self.save_5_action)
 26????????self.addAction(self.save_10_action)
 27????????self.addAction(self.save_15_action)
 28????????self.addAction(self.clear_action)
 29
 30????????#?0?-?圓形,?1?-?矩形,?2?-?直線,?3?-?free-style
 31????????self.draw_type?=?0
 32????????self.circle?=?[0,?0,?0]
 33????????self.box?=?[0,?0,?0,?0]
 34????????self.line?=?[0,?0,?0,?0]
 35????????#?trick?settings?here!!!
 36????????self.setContextMenuPolicy(2)
 37
 38????def?clear_canvas(self):
 39????????self.pts.clear()
 40????????self.temp_pts.clear()
 41????????self.circle?=?[0,?0,?0]
 42????????self.box?=?[0,?0,?0,?0]
 43????????self.line?=?[0,?0,?0,?0]
 44????????self.repaint()
 45
 46????def?on_save_5(self,?s):
 47????????print(s)
 48????????self.line_width?=?2
 49
 50????def?on_save_10(self,?s):
 51????????print(s)
 52????????self.line_width?=?4
 53
 54????def?on_save_15(self,?s):
 55????????print(s)
 56????????self.line_width?=?8
 57
 58????def?query_draw_type(self):
 59????????if?rbtn1.isChecked():
 60????????????self.draw_type?=?0
 61????????if?rbtn2.isChecked():
 62????????????self.draw_type?=?1
 63????????if?rbtn3.isChecked():
 64????????????self.draw_type?=?2
 65????????if?rbtn4.isChecked():
 66????????????self.draw_type?=?3
 67
 68????def?mousePressEvent(self,?event):
 69????????self.query_draw_type()
 70????????self.pressed?=?True
 71????????self.start_x?=?event.x()
 72????????self.start_y?=?event.y()
 73????????if?self.draw_type?==?0:
 74????????????self.circle?=?[self.start_x,?self.start_y,?0]
 75????????if?self.draw_type?==?1:
 76????????????self.box?=?[self.start_x,?self.start_y,?0,?0]
 77????????if?self.draw_type?==?2:
 78????????????self.line?=?[self.start_x,?self.start_y,?0,?0]
 79????????if?self.draw_type?==?3:
 80????????????self.temp_pts.clear()
 81????????????self.temp_pts.append((self.start_x,?self.start_y))
 82
 83????def?mouseMoveEvent(self,?event):
 84????????if?self.pressed?and?self.start_x?>?0?and?self.start_y?>?0:
 85????????????x?=?event.x()
 86????????????y?=?event.y()
 87????????????dx?=?x?-?self.start_x
 88????????????dy?=?y?-?self.start_y
 89????????????if?self.draw_type?==?0?and?dx?>?0?and?dy?>?0:
 90????????????????r?=?int(np.sqrt(dx*dx?+?dy*dy))
 91????????????????self.circle?=?[self.start_x,?self.start_y,?r]
 92????????????if?self.draw_type?==?1?and?dx?>?0?and?dy?>?0:
 93????????????????self.box?=?[self.start_x,?self.start_y,?dx,?dy]
 94????????????if?self.draw_type?==?2?and?abs(dx)?>?0?and?abs(dy)?>?0:
 95????????????????self.line?=?[self.start_x,?self.start_y,?x,?y]
 96????????????if?self.draw_type?==?3:
 97????????????????self.temp_pts.append((x,?y))
 98????????????self.repaint()
 99
100????def?mouseReleaseEvent(self,?event):
101????????x?=?event.x()
102????????y?=?event.y()
103????????dx?=?x?-?self.start_x
104????????dy?=?y?-?self.start_y
105????????if?self.draw_type?==?0?and?dx?>?0?and?dy?>?0:
106????????????r?=?int(np.sqrt(dx?*?dx?+?dy?*?dy))
107????????????self.circle?=?[self.start_x,?self.start_y,?r]
108????????if?self.draw_type?==?1?and?dx?>?0?and?dy?>?0:
109????????????self.box?=?[self.start_x,?self.start_y,?dx,?dy]
110????????if?self.draw_type?==?2?and?abs(dx)?>?0?and?abs(dy)?>?0:
111????????????self.line?=?[self.start_x,?self.start_y,?x,?y]
112????????if?self.draw_type?==?3:
113????????????self.temp_pts.append((x,?y))
114????????????self.pts.append(np.copy(self.temp_pts))
115????????self.pressed?=?False
116????????self.temp_pts.clear()
117????????self.repaint()
118
119????def?paintEvent(self,?event):
120????????painter?=?QtGui.QPainter(self)
121????????painter.fillRect(self.rect(),?QtCore.Qt.black)
122????????pen?=?QtGui.QPen(QtCore.Qt.green,?5,?QtCore.Qt.DashLine)
123????????painter.setPen(pen)
124????????font?=?QtGui.QFont()
125????????font.setBold(True)
126????????font.setPointSizeF(16)
127????????painter.setFont(font)
128????????painter.drawText(QtCore.QPoint(5,?25),?"OpenCV開發者聯盟")
129
130????????pen?=?QtGui.QPen(QtCore.Qt.green,?self.line_width)
131????????painter.setPen(pen)
132????????painter.drawRect(QtCore.QRect(self.box[0],?self.box[1],?self.box[2],?self.box[3]))
133
134????????pen?=?QtGui.QPen(QtCore.Qt.blue,?self.line_width)
135????????painter.setPen(pen)
136????????cx,?cy,?r?=?self.circle
137????????painter.drawEllipse(QtCore.QRect(cx-r,?cy-r,?2*r,?2*r))
138
139????????pen?=?QtGui.QPen(QtCore.Qt.yellow,?self.line_width)
140????????painter.setPen(pen)
141????????painter.drawLine(self.line[0],?self.line[1],?self.line[2],?self.line[3])
142
143????????#?5表示線寬
144????????pen?=?QtGui.QPen(QtCore.Qt.red,?self.line_width,?QtCore.Qt.DashLine)
145????????painter.setPen(pen)
146????????for?c?in?range(0,?len(self.pts),?1):
147????????????one_contours?=?self.pts[c]
148????????????for?i?in?range(0,?len(one_contours)-1,?1):
149????????????????x1?=?one_contours[i][0]
150????????????????y1?=?one_contours[i][1]
151????????????????x2?=?one_contours[i+1][0]
152????????????????y2?=?one_contours[i+1][1]
153????????????????painter.drawLine(x1,?y1,?x2,?y2)
154
155????????for?i?in?range(0,?len(self.temp_pts)?-?1,?1):
156????????????x1?=?self.temp_pts[i][0]
157????????????y1?=?self.temp_pts[i][1]
158????????????x2?=?self.temp_pts[i?+?1][0]
159????????????y2?=?self.temp_pts[i?+?1][1]
160????????????painter.drawLine(x1,?y1,?x2,?y2)

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