Fix center modifier in interactive rectangle selector - in _onmove of existing shape

Author: ericpre

lib/matplotlib/tests/test_widgets.py

@@ -118,6 +118,158 @@ def onselect(epress, erelease):
         assert artist.get_alpha() == 0.3
 
 
+def test_rectangle_resize():
+    ax = get_ax()
+
+    def onselect(epress, erelease):
+        pass
+
+    tool = widgets.RectangleSelector(ax, onselect, interactive=True)
+    # Create rectangle
+    do_event(tool, 'press', xdata=0, ydata=10, button=1)
+    do_event(tool, 'onmove', xdata=100, ydata=120, button=1)
+    do_event(tool, 'release', xdata=100, ydata=120, button=1)
+    assert tool.extents == (0.0, 100.0, 10.0, 120.0)
+
+    # resize NE handle
+    extents = tool.extents
+    xdata, ydata = extents[1], extents[3]
+    xdata_new, ydata_new = xdata + 10, ydata + 5
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    assert tool.extents == (0.0, xdata_new, 10.0, ydata_new)
+
+    # resize E handle
+    extents = tool.extents
+    xdata, ydata = extents[1], extents[2] + (extents[3] - extents[2]) / 2
+    xdata_new, ydata_new = xdata + 10, ydata
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    assert tool.extents == (0.0, xdata_new, 10.0, 125.0)
+
+    # resize W handle
+    extents = tool.extents
+    xdata, ydata = extents[0], extents[2] + (extents[3] - extents[2]) / 2
+    xdata_new, ydata_new = xdata + 15, ydata
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    assert tool.extents == (xdata_new, 120.0, 10.0, 125.0)
+
+    # resize SW handle
+    extents = tool.extents
+    xdata, ydata = extents[0], extents[2]
+    xdata_new, ydata_new = xdata + 20, ydata + 25
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    assert tool.extents == (xdata_new, 120.0, ydata_new, 125.0)
+
+
+@pytest.mark.parametrize('use_default_state', [True, False])
+def test_rectangle_resize_center(use_default_state):
+    ax = get_ax()
+
+    def onselect(epress, erelease):
+        pass
+
+    tool = widgets.RectangleSelector(ax, onselect, interactive=True)
+    # Create rectangle
+    do_event(tool, 'press', xdata=70, ydata=65, button=1)
+    do_event(tool, 'onmove', xdata=125, ydata=130, button=1)
+    do_event(tool, 'release', xdata=125, ydata=130, button=1)
+    assert tool.extents == (70.0, 125.0, 65.0, 130.0)
+
+    if use_default_state:
+        tool._default_state.add('center')
+
+    # resize NE handle
+    extents = tool.extents
+    xdata, ydata = extents[1], extents[3]
+    xdiff, ydiff = 10, 5
+    xdata_new, ydata_new = xdata + xdiff, ydata + ydiff
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_press', key='control')
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_release', key='control')
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    assert tool.extents == (70.0 - xdiff, xdata_new, 65.0 - ydiff, ydata_new)
+
+    # resize E handle
+    extents = tool.extents
+    xdata, ydata = extents[1], extents[2] + (extents[3] - extents[2]) / 2
+    xdiff = 10
+    xdata_new, ydata_new = xdata + xdiff, ydata
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_press', key='control')
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_release', key='control')
+    assert tool.extents == (60.0 - xdiff, xdata_new, 60.0, 135.0)
+
+    # resize E handle negative diff
+    extents = tool.extents
+    xdata, ydata = extents[1], extents[2] + (extents[3] - extents[2]) / 2
+    xdiff = -20
+    xdata_new, ydata_new = xdata + xdiff, ydata
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_press', key='control')
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_release', key='control')
+    assert tool.extents == (50.0 - xdiff, xdata_new, 60.0, 135.0)
+
+    # resize W handle
+    extents = tool.extents
+    xdata, ydata = extents[0], extents[2] + (extents[3] - extents[2]) / 2
+    xdiff = 15
+    xdata_new, ydata_new = xdata + xdiff, ydata
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_press', key='control')
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_release', key='control')
+    assert tool.extents == (xdata_new, 125.0 - xdiff, 60.0, 135.0)
+
+    # resize W handle
+    extents = tool.extents
+    xdata, ydata = extents[0], extents[2] + (extents[3] - extents[2]) / 2
+    xdiff = -25
+    xdata_new, ydata_new = xdata + xdiff, ydata
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_press', key='control')
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_release', key='control')
+    assert tool.extents == (xdata_new, 110.0 - xdiff, 60.0, 135.0)
+
+    # resize SW handle
+    extents = tool.extents
+    xdata, ydata = extents[0], extents[2]
+    xdiff, ydiff = 20, 25
+    xdata_new, ydata_new = xdata + xdiff, ydata + ydiff
+    do_event(tool, 'press', xdata=xdata, ydata=ydata, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_press', key='control')
+    do_event(tool, 'onmove', xdata=xdata_new, ydata=ydata_new, button=1)
+    do_event(tool, 'release', xdata=xdata_new, ydata=ydata_new, button=1)
+    if not use_default_state:
+        do_event(tool, 'on_key_release', key='control')
+    assert tool.extents == (xdata_new, 135.0 - xdiff, ydata_new, 135.0 - ydiff)
+
+
 def test_ellipse():
     """For ellipse, test out the key modifiers"""
     ax = get_ax()

lib/matplotlib/widgets.py

@@ -1829,6 +1829,7 @@ def __init__(self, ax, onselect, useblit=False, button=None,
         self._eventrelease = None
         self._prev_event = None
         self._state = set()
+        self._default_state = set()
 
     eventpress = _api.deprecate_privatize_attribute("3.5")
     eventrelease = _api.deprecate_privatize_attribute("3.5")
@@ -2965,20 +2966,48 @@ def _release(self, event):
     def _onmove(self, event):
         """Motion notify event handler."""
 
-
+        state = self._state | self._default_state
         # resize an existing shape
         if self._active_handle and self._active_handle != 'C':
             x0, x1, y0, y1 = self._extents_on_press
-            # Switch variables so that only x1 and/or y1 are updated on move.
-            if self._active_handle in ['W', 'SW', 'NW']:
-                x0, x1 = x1, event.xdata
-            if self._active_handle in ['S', 'SW', 'SE']:
-                y0, y1 = y1, event.ydata
+            if len(state) == 0:
+	            # Switch variables so that only x1 and/or y1 are updated on move.
+	            if self._active_handle in ['W', 'SW', 'NW']:
+	                x0, x1 = x1, event.xdata
+	            if self._active_handle in ['S', 'SW', 'SE']:
+	                y0, y1 = y1, event.ydata
+
+	            if self._active_handle in ['E', 'W'] + self._corner_order:
+	                x1 = event.xdata
+	            if self._active_handle in ['N', 'S'] + self._corner_order:
+	                y1 = event.ydata
+
+            else:
+                dx = event.xdata - self._eventpress.xdata
+                dy = event.ydata - self._eventpress.ydata
+
+                sizepress = [x1 - x0, y1 - y0]
+                centerpress = [x0 + sizepress[0] / 2, y0 + sizepress[1] / 2]
+                center = centerpress
+
+                # from center
+                if 'center' in state:
+                    if 'W' in self._active_handle:
+                        dx = -dx
+                    if 'S' in self._active_handle:
+                        dy = -dy
+                    dw = sizepress[0] / 2 + dx
+                    dh = sizepress[1] / 2 + dy
+
+                    # cancel changes in perpendicular direction
+                    if self._active_handle in ['E', 'W']:
+                        dh = sizepress[1] / 2
+                    if self._active_handle in ['N', 'S']:
+                        dw = sizepress[0] / 2
+
+                x0, x1, y0, y1 = (center[0] - dw, center[0] + dw,
+                                  center[1] - dh, center[1] + dh)
 
-            if self._active_handle in ['E', 'W'] + self._corner_order:
-                x1 = event.xdata
-            if self._active_handle in ['N', 'S'] + self._corner_order:
-                y1 = event.ydata
 
         # move existing shape
         elif (self._active_handle == 'C' or
@@ -3004,7 +3033,7 @@ def _onmove(self, event):
             dy = (event.ydata - center[1]) / 2.
 
             # square shape
-            if 'square' in self._state:
+            if 'square' in state:
                 dx_pix = abs(event.x - center_pix[0])
                 dy_pix = abs(event.y - center_pix[1])
                 if not dx_pix:
@@ -3016,7 +3045,7 @@ def _onmove(self, event):
                     dy *= maxd / (abs(dy_pix) + 1e-6)
 
             # from center
-            if 'center' in self._state:
+            if 'center' in state:
                 dx *= 2
                 dy *= 2