matplotlib · jklymak · Feb 5, 2018 · Jan 10, 2018 · Feb 4, 2018 · Feb 4, 2018
diff --git a/doc/api/api_changes.rst b/doc/api/api_changes.rst
@@ -10,6 +10,16 @@ out what caused the breakage and how to fix it by updating your code.
 For new features that were added to Matplotlib, please see
 :ref:`whats-new`.
 
+API Changes in 2.2.0
+====================
+
+.. toctree::
+   :glob:
+   :maxdepth: 1
+
+   next_api_changes/*
+
+
 API Changes in 2.1.2
 ====================
 

diff --git a/doc/api/backend_qt4cairo_api.rst b/doc/api/backend_qt4cairo_api.rst
@@ -0,0 +1,8 @@
+
+:mod:`matplotlib.backends.backend_qt4cairo`
+===========================================
+
+.. automodule:: matplotlib.backends.backend_qt4cairo
+   :members:
+   :undoc-members:
+   :show-inheritance:
diff --git a/doc/api/backend_qt5cairo_api.rst b/doc/api/backend_qt5cairo_api.rst
@@ -0,0 +1,8 @@
+
+:mod:`matplotlib.backends.backend_qt5cairo`
+===========================================
+
+.. automodule:: matplotlib.backends.backend_qt5cairo
+   :members:
+   :undoc-members:
+   :show-inheritance:
diff --git a/doc/api/index_backend_api.rst b/doc/api/index_backend_api.rst
@@ -19,7 +19,9 @@ backends
    backend_pgf_api.rst
    backend_ps_api.rst
    backend_qt4agg_api.rst
+   backend_qt4cairo_api.rst
    backend_qt5agg_api.rst
+   backend_qt5cairo_api.rst
    backend_svg_api.rst
    backend_tkagg_api.rst
    backend_webagg_api.rst

diff --git a/doc/api/api_changes/01-11-2017-DS.rst → doc/api/next_api_changes/01-11-2017-DS.rst b/doc/api/api_changes/01-11-2017-DS.rst → doc/api/next_api_changes/01-11-2017-DS.rst
diff --git a/doc/api/api_changes/171225-AL-tickbools.rst → .../next_api_changes/171225-AL-tickbools.rst b/doc/api/api_changes/171225-AL-tickbools.rst → .../next_api_changes/171225-AL-tickbools.rst
diff --git a/...api/api_changes/2017-09-22-AL-contour.rst → ...ext_api_changes/2017-09-22-AL-contour.rst b/...api/api_changes/2017-09-22-AL-contour.rst → ...ext_api_changes/2017-09-22-AL-contour.rst
diff --git a/...-22-AL-removal-of-deprecated-features.rst → ...-22-AL-removal-of-deprecated-features.rst b/...-22-AL-removal-of-deprecated-features.rst → ...-22-AL-removal-of-deprecated-features.rst
diff --git a/doc/api/api_changes/2017-11-07-JMK.rst → doc/api/next_api_changes/2017-11-07-JMK.rst b/doc/api/api_changes/2017-11-07-JMK.rst → doc/api/next_api_changes/2017-11-07-JMK.rst
diff --git a/doc/api/api_changes/2017-11-19_svg_size.rst → .../next_api_changes/2017-11-19_svg_size.rst b/doc/api/api_changes/2017-11-19_svg_size.rst → .../next_api_changes/2017-11-19_svg_size.rst
diff --git a/doc/api/api_changes/2017-11-23-AL.rst → doc/api/next_api_changes/2017-11-23-AL.rst b/doc/api/api_changes/2017-11-23-AL.rst → doc/api/next_api_changes/2017-11-23-AL.rst
diff --git a/doc/api/api_changes/2017-11-24-AL.rst → doc/api/next_api_changes/2017-11-24-AL.rst b/doc/api/api_changes/2017-11-24-AL.rst → doc/api/next_api_changes/2017-11-24-AL.rst
diff --git a/doc/api/api_changes/2017-11-31-AL.rst → doc/api/next_api_changes/2017-11-31-AL.rst b/doc/api/api_changes/2017-11-31-AL.rst → doc/api/next_api_changes/2017-11-31-AL.rst
diff --git a/doc/api/api_changes/2017-12-01-AL.rst → doc/api/next_api_changes/2017-12-01-AL.rst b/doc/api/api_changes/2017-12-01-AL.rst → doc/api/next_api_changes/2017-12-01-AL.rst
diff --git a/doc/api/api_changes/2017-12-02-AL.rst → doc/api/next_api_changes/2017-12-02-AL.rst b/doc/api/api_changes/2017-12-02-AL.rst → doc/api/next_api_changes/2017-12-02-AL.rst
diff --git a/...api/api_changes/2017-12-06-imports-AL.rst → ...ext_api_changes/2017-12-06-imports-AL.rst b/...api/api_changes/2017-12-06-imports-AL.rst → ...ext_api_changes/2017-12-06-imports-AL.rst
diff --git a/doc/api/api_changes/2017-12-10-TH.rst → doc/api/next_api_changes/2017-12-10-TH.rst b/doc/api/api_changes/2017-12-10-TH.rst → doc/api/next_api_changes/2017-12-10-TH.rst
diff --git a/doc/api/api_changes/2017-12-14-JMK.rst → doc/api/next_api_changes/2017-12-14-JMK.rst b/doc/api/api_changes/2017-12-14-JMK.rst → doc/api/next_api_changes/2017-12-14-JMK.rst
diff --git a/doc/api/api_changes/2017-12-15-AL.rst → doc/api/next_api_changes/2017-12-15-AL.rst b/doc/api/api_changes/2017-12-15-AL.rst → doc/api/next_api_changes/2017-12-15-AL.rst
diff --git a/doc/api/api_changes/2017-12-17-AL.rst → doc/api/next_api_changes/2017-12-17-AL.rst b/doc/api/api_changes/2017-12-17-AL.rst → doc/api/next_api_changes/2017-12-17-AL.rst
@@ -2,6 +2,7 @@ Removal of deprecated rcParams
 ``````````````````````````````
 
 The following deprecated rcParams have been removed:
+
 - ``axes.color_cycle`` (see ``axes.prop_cycle``),
 - ``legend.isaxes``,
 - ``svg.embed_char_paths`` (see ``svg.fonttype``),

diff --git a/doc/api/api_changes/2017-12-26-AL.rst → doc/api/next_api_changes/2017-12-26-AL.rst b/doc/api/api_changes/2017-12-26-AL.rst → doc/api/next_api_changes/2017-12-26-AL.rst
diff --git a/doc/api/api_changes/2018-01-29-AL.rst → doc/api/next_api_changes/2018-01-29-AL.rst b/doc/api/api_changes/2018-01-29-AL.rst → doc/api/next_api_changes/2018-01-29-AL.rst
diff --git a/doc/api/next_api_changes/2018-02-03-AL.rst b/doc/api/next_api_changes/2018-02-03-AL.rst
@@ -0,0 +1,73 @@
+Changes to Qt backend class MRO
+```````````````````````````````
+
+To support both Agg and cairo rendering for Qt backends all of the
+non-Agg specific code previously in
+:class:`.backend_qt5agg.FigureCanvasQTAggBase` has been moved to
+:class:`.backend_qt5.FigureCanvasQT` so it can be shared with the cairo
+implementation.  The :meth:`.FigureCanvasQTAggBase.paintEvent`,
+:meth:`.FigureCanvasQTAggBase.blit`, and
+:meth:`.FigureCanvasQTAggBase.print_figure` methods have moved to
+:meth:`.FigureCanvasQTAgg.paintEvent`, :meth:`.FigureCanvasQTAgg.blit`, and
+:meth:`.FigureCanvasQTAgg.print_figure`.  The first two methods assume that
+the instance is also a :class:`QWidget` so to use
+:class:`FigureCanvasQTAggBase` it was required to multiple inherit
+from a :class:`QWidget` sub-class.
+
+Having moved all of its methods either up or down the class hierarchy
+:class:`FigureCanvasQTAggBase` has been deprecated.  To do this with
+out warning and to preserve as much API as possible,
+:class:`.backend_qt5.FigureCanvasQTAggBase` now inherits from
+:class:`.backend_qt5.FigureCanvasQTAgg`.
+
+The MRO for :class:`FigureCanvasQTAgg` and
+:class:`FigureCanvasQTAggBase` used to be ::
+
+
+   [matplotlib.backends.backend_qt5agg.FigureCanvasQTAgg,
+    matplotlib.backends.backend_qt5agg.FigureCanvasQTAggBase,
+    matplotlib.backends.backend_agg.FigureCanvasAgg,
+    matplotlib.backends.backend_qt5.FigureCanvasQT,
+    PyQt5.QtWidgets.QWidget,
+    PyQt5.QtCore.QObject,
+    sip.wrapper,
+    PyQt5.QtGui.QPaintDevice,
+    sip.simplewrapper,
+    matplotlib.backend_bases.FigureCanvasBase,
+    object]
+
+and ::
+
+
+   [matplotlib.backends.backend_qt5agg.FigureCanvasQTAggBase,
+    matplotlib.backends.backend_agg.FigureCanvasAgg,
+    matplotlib.backend_bases.FigureCanvasBase,
+    object]
+
+
+respectively.  They are now ::
+
+   [matplotlib.backends.backend_qt5agg.FigureCanvasQTAgg,
+    matplotlib.backends.backend_agg.FigureCanvasAgg,
+    matplotlib.backends.backend_qt5.FigureCanvasQT,
+    PyQt5.QtWidgets.QWidget,
+    PyQt5.QtCore.QObject,
+    sip.wrapper,
+    PyQt5.QtGui.QPaintDevice,
+    sip.simplewrapper,
+    matplotlib.backend_bases.FigureCanvasBase,
+    object]
+
+and ::
+
+   [matplotlib.backends.backend_qt5agg.FigureCanvasQTAggBase,
+    matplotlib.backends.backend_qt5agg.FigureCanvasQTAgg,
+    matplotlib.backends.backend_agg.FigureCanvasAgg,
+    matplotlib.backends.backend_qt5.FigureCanvasQT,
+    PyQt5.QtWidgets.QWidget,
+    PyQt5.QtCore.QObject,
+    sip.wrapper,
+    PyQt5.QtGui.QPaintDevice,
+    sip.simplewrapper,
+    matplotlib.backend_bases.FigureCanvasBase,
+    object]
diff --git a/doc/api/api_changes/README.rst → doc/api/next_api_changes/README.rst b/doc/api/api_changes/README.rst → doc/api/next_api_changes/README.rst
@@ -1,3 +1,7 @@
+Adding API change notes
+```````````````````````
+
+
 For changes which require an entry in `api_changes.rst` please create
 a file in this folder with the name :file:`YYYY-MM-DD-[initials].rst`
 (ex :file:`2014-07-31-TAC.rst`) with contents following the form: ::

diff --git a/doc/api/api_changes/removed-attributes.rst → ...i/next_api_changes/removed-attributes.rst b/doc/api/api_changes/removed-attributes.rst → ...i/next_api_changes/removed-attributes.rst
diff --git a/doc/users/next_whats_new/more-cairo.rst b/doc/users/next_whats_new/more-cairo.rst
@@ -0,0 +1,5 @@
+Cairo rendering for Qt canvases
+-------------------------------
+
+The new ``Qt4Cairo`` and ``Qt5Cairo`` backends allow Qt canvases to use Cairo
+rendering instead of Agg.
diff --git a/lib/matplotlib/backends/backend_agg.py b/lib/matplotlib/backends/backend_agg.py
@@ -429,6 +429,9 @@ def draw(self):
             # if toolbar:
             #     toolbar.set_cursor(cursors.WAIT)
             self.figure.draw(self.renderer)
+            # A GUI class may be need to update a window using this draw, so
+            # don't forget to call the superclass.
+            super(FigureCanvasAgg, self).draw()
         finally:
             # if toolbar:
             #     toolbar.set_cursor(toolbar._lastCursor)

diff --git a/lib/matplotlib/backends/backend_qt4cairo.py b/lib/matplotlib/backends/backend_qt4cairo.py
@@ -0,0 +1,6 @@
+from .backend_qt5cairo import _BackendQT5Cairo
+
+
+@_BackendQT5Cairo.export
+class _BackendQT4Cairo(_BackendQT5Cairo):
+    pass
diff --git a/lib/matplotlib/backends/backend_qt5.py b/lib/matplotlib/backends/backend_qt5.py
@@ -8,6 +8,7 @@
 import signal
 import sys
 from six import unichr
+import traceback
 
 import matplotlib
 
@@ -226,19 +227,16 @@ class FigureCanvasQT(QtWidgets.QWidget, FigureCanvasBase):
                # QtCore.Qt.XButton2: None,
                }
 
-    def _update_figure_dpi(self):
-        dpi = self._dpi_ratio * self.figure._original_dpi
-        self.figure._set_dpi(dpi, forward=False)
-
     @_allow_super_init
     def __init__(self, figure):
         _create_qApp()
         super(FigureCanvasQT, self).__init__(figure=figure)
 
-        figure._original_dpi = figure.dpi
         self.figure = figure
+        # We don't want to scale up the figure DPI more than once.
+        # Note, we don't handle a signal for changing DPI yet.
+        figure._original_dpi = figure.dpi
         self._update_figure_dpi()
-        self.resize(*self.get_width_height())
         # In cases with mixed resolution displays, we need to be careful if the
         # dpi_ratio changes - in this case we need to resize the canvas
         # accordingly. We could watch for screenChanged events from Qt, but
@@ -248,13 +246,23 @@ def __init__(self, figure):
         # needed.
         self._dpi_ratio_prev = None
 
+        self._draw_pending = False
+        self._is_drawing = False
+        self._draw_rect_callback = lambda painter: None
+
+        self.setAttribute(QtCore.Qt.WA_OpaquePaintEvent)
         self.setMouseTracking(True)
+        self.resize(*self.get_width_height())
         # Key auto-repeat enabled by default
         self._keyautorepeat = True
 
         palette = QtGui.QPalette(QtCore.Qt.white)
         self.setPalette(palette)
 
+    def _update_figure_dpi(self):
+        dpi = self._dpi_ratio * self.figure._original_dpi
+        self.figure._set_dpi(dpi, forward=False)
+
     @property
     def _dpi_ratio(self):
         # Not available on Qt4 or some older Qt5.
@@ -263,6 +271,26 @@ def _dpi_ratio(self):
         except AttributeError:
             return 1
 
+    def _update_dpi(self):
+        # As described in __init__ above, we need to be careful in cases with
+        # mixed resolution displays if dpi_ratio is changing between painting
+        # events.
+        # Return whether we triggered a resizeEvent (and thus a paintEvent)
+        # from within this function.
+        if self._dpi_ratio != self._dpi_ratio_prev:
+            # We need to update the figure DPI.
+            self._update_figure_dpi()
+            self._dpi_ratio_prev = self._dpi_ratio
+            # The easiest way to resize the canvas is to emit a resizeEvent
+            # since we implement all the logic for resizing the canvas for
+            # that event.
+            event = QtGui.QResizeEvent(self.size(), self.size())
+            self.resizeEvent(event)
+            # resizeEvent triggers a paintEvent itself, so we exit this one
+            # (after making sure that the event is immediately handled).
+            return True
+        return False
+
     def get_width_height(self):
         w, h = FigureCanvasBase.get_width_height(self)
         return int(w / self._dpi_ratio), int(h / self._dpi_ratio)
@@ -453,6 +481,60 @@ def stop_event_loop(self, event=None):
         if hasattr(self, "_event_loop"):
             self._event_loop.quit()
 
+    def draw(self):
+        """Render the figure, and queue a request for a Qt draw.
+        """
+        # The renderer draw is done here; delaying causes problems with code
+        # that uses the result of the draw() to update plot elements.
+        if self._is_drawing:
+            return
+        self._is_drawing = True
+        try:
+            super(FigureCanvasQT, self).draw()
+        finally:
+            self._is_drawing = False
+        self.update()
+
+    def draw_idle(self):
+        """Queue redraw of the Agg buffer and request Qt paintEvent.
+        """
+        # The Agg draw needs to be handled by the same thread matplotlib
+        # modifies the scene graph from. Post Agg draw request to the
+        # current event loop in order to ensure thread affinity and to
+        # accumulate multiple draw requests from event handling.
+        # TODO: queued signal connection might be safer than singleShot
+        if not (self._draw_pending or self._is_drawing):
+            self._draw_pending = True
+            QtCore.QTimer.singleShot(0, self._draw_idle)
+
+    def _draw_idle(self):
+        if self.height() < 0 or self.width() < 0:
+            self._draw_pending = False
+        if not self._draw_pending:
+            return
+        try:
+            self.draw()
+        except Exception:
+            # Uncaught exceptions are fatal for PyQt5, so catch them instead.
+            traceback.print_exc()
+        finally:
+            self._draw_pending = False
+
+    def drawRectangle(self, rect):
+        # Draw the zoom rectangle to the QPainter.  _draw_rect_callback needs
+        # to be called at the end of paintEvent.
+        if rect is not None:
+            def _draw_rect_callback(painter):
+                pen = QtGui.QPen(QtCore.Qt.black, 1 / self._dpi_ratio,
+                                 QtCore.Qt.DotLine)
+                painter.setPen(pen)
+                painter.drawRect(*(pt / self._dpi_ratio for pt in rect))
+        else:
+            def _draw_rect_callback(painter):
+                return
+        self._draw_rect_callback = _draw_rect_callback
+        self.update()
+
 
 class MainWindow(QtWidgets.QMainWindow):
     closing = QtCore.Signal()