Add DrawBoxTool

PreCourlis/widgets/graph_tools.py

+from qgis.PyQt import QtCore
+
+from matplotlib.pyplot import Rectangle
+
+
+class DrawBoxTool(QtCore.QObject):
+
+    released = QtCore.pyqtSignal(float, float, float, float)  # xmin, ymin, xmax, ymax
+
+    def __init__(self, canvas, graph):
+        super().__init__(canvas)
+        self.canvas = canvas
+        self.graph = graph
+        self.x0 = None
+        self.y0 = None
+        self.background = None
+
+    def activate(self):
+        self.cidpress = self.canvas.mpl_connect("button_press_event", self.on_press)
+        self.cidrelease = self.canvas.mpl_connect(
+            "button_release_event", self.on_release
+        )
+        self.cidmotion = self.canvas.mpl_connect("motion_notify_event", self.on_motion)
+
+    def deactivate(self):
+        self.canvas.mpl_disconnect(self.cidpress)
+        self.canvas.mpl_disconnect(self.cidrelease)
+        self.canvas.mpl_disconnect(self.cidmotion)
+
+    def on_press(self, event):
+        if event.button == 1:
+            self.x0, self.y0 = event.xdata, event.ydata
+            self.rect = Rectangle((event.xdata, event.ydata), 0, 0, fill=False)
+            self.graph.add_patch(self.rect)
+
+            # draw everything but the selected rectangle and store the pixel buffer
+            self.rect.set_animated(True)
+            self.canvas.draw()
+            self.background = self.canvas.copy_from_bbox(self.graph.bbox)
+            self.graph.draw_artist(self.rect)
+            self.canvas.blit(self.graph.bbox)
+
+    def on_motion(self, event):
+        if event.button == 1:
+            x1, y1 = event.xdata, event.ydata
+            xmin, ymin, width, height = (
+                min(self.x0, x1),
+                min(self.y0, y1),
+                abs(self.x0 - x1),
+                abs(self.y0 - y1),
+            )
+            self.rect.set_bounds(xmin, ymin, width, height)
+
+            self.canvas.restore_region(self.background)
+            self.graph.draw_artist(self.rect)
+            self.canvas.blit(self.graph.bbox)
+
+    def on_release(self, event):
+        if event.button == 1:
+            self.rect.remove()
+            self.rect = None
+            self.background = None
+            self.canvas.draw()
+
+            x1, y1 = event.xdata, event.ydata
+            xmin, ymin, xmax, ymax = (
+                min(self.x0, x1),
+                min(self.y0, y1),
+                max(self.x0, x1),
+                max(self.y0, y1),
+            )
+            self.released.emit(xmin, ymin, xmax, ymax)

PreCourlis/widgets/graph_widget.py

@@ -5,6 +5,7 @@ from qgis.core import (
 from qgis.PyQt import QtCore, QtWidgets
 
 from PreCourlis.core.precourlis_file import PreCourlisFileLine
+from PreCourlis.widgets.graph_tools import DrawBoxTool
 
 import matplotlib.pyplot as plt
 from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
@@ -21,6 +22,9 @@ class GraphWidget(FigureCanvas):
 
         self.graph = plt.subplot(111)
 
+        self.zoom_tool = DrawBoxTool(self, self.graph)
+        self.zoom_tool.activate()
+
         self.file = None
         self.feature = None
         self.previous_section = None