Изменение цвета края zoom-rect в matplotlib

Question

Я написал приложение для спектрального анализа, используя python + matplotlib + pyqt. Участки должны иметь черный фон с белыми осями и символами в приложении. Я сохранил панель навигации по умолчанию для matplotlib. Одна из проблем, связанных с настройкой инвертированного цвета, заключается в том, что край прямоугольника масштабирования невидим, потому что он черный. Есть простой способ изменить edgecolor прямоугольника масштабирования на яркий цвет, например белый.

Спасибо вам заранее.

Answer 1

в файле

backend_qt4agg.py

# draw the zoom rectangle to the QPainter 
#changed code below... 
# change the color of zooming rectangle from black to red 
if self.drawRect: 
    p.setPen(QtGui.QPen(QtCore.Qt.red, 1, QtCore.Qt.DotLine)) 
    p.drawRect(self.rect[0], self.rect[1], self.rect[2], self.rect[3]) 
p.end() 

просто добавить/изменить часть прямоугольника для рисования в коде выше.

Answer 2

Это может быть сделано с помощью подклассов и переопределения (не распространяющего) paintevent: (код является копией вставленной из оригинального paintevent, изменяя цвет переменного)

from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg 
import PyQt4.QtCore as QCore 
import PyQt4.QtGui as QGui 
class FigureCanvas(FigureCanvasQTAgg): 
    """ 
    Subclassing to change the paint event hosted in matplotlib.backends.backend_qt5agg. 
    Removed all comments for sake of brevity. 
    Paintcolor can be set by settings canvas.rectanglecolor to a QColor. 
    """ 
    def paintEvent(self, e): 
     paintcolor = QCore.Qt.black if not hasattr(self, "rectanglecolor") else self.rectanglecolor 
     if not hasattr(self, 'renderer'): 
      return 
     if self.blitbox is None: 
      if QCore.QSysInfo.ByteOrder == QCore.QSysInfo.LittleEndian: 
       stringBuffer = self.renderer._renderer.tostring_bgra() 
      else: 
       stringBuffer = self.renderer._renderer.tostring_argb() 
      refcnt = sys.getrefcount(stringBuffer) 
      qImage = QGui.QImage(stringBuffer, self.renderer.width, 
            self.renderer.height, 
            QGui.QImage.Format_ARGB32) 
      rect = qImage.rect() 
      p = QGui.QPainter(self) 
      p.eraseRect(rect) 
      p.drawPixmap(QCore.QPoint(0, 0), QGui.QPixmap.fromImage(qImage)) 
      if self._drawRect is not None: 
       p.setPen(QGui.QPen(paintcolor, 1, QCore.Qt.DotLine)) 
       x, y, w, h = self._drawRect 
       p.drawRect(x, y, w, h) 
      p.end() 
      del qImage 
      if refcnt != sys.getrefcount(stringBuffer): 
       _decref(stringBuffer) 
     else: 
      bbox = self.blitbox 
      l, b, r, t = bbox.extents 
      w = int(r) - int(l) 
      h = int(t) - int(b) 
      t = int(b) + h 
      reg = self.copy_from_bbox(bbox) 
      stringBuffer = reg.to_string_argb() 
      qImage = QGui.QImage(stringBuffer, w, h, 
            QGui.QImage.Format_ARGB32) 
      if QT_API == 'PySide' and six.PY3: 
       ctypes.c_long.from_address(id(stringBuffer)).value = 1 
      pixmap = QGui.QPixmap.fromImage(qImage) 
      p = QGui.QPainter(self) 
      p.drawPixmap(QCore.QPoint(l, self.renderer.height-t), pixmap) 
      if self._drawRect is not None: 
       p.setPen(QGui.QPen(paintcolor, 1, QCore.Qt.DotLine)) 
       x, y, w, h = self._drawRect 
       p.drawRect(x, y, w, h) 
      p.end() 
      self.blitbox = None 

В зависимости от вашего приложения, вы можете уметь сокращать немного больше (например, убивать определенную часть PySide). Над работами, и вы можете просто использовать FigureCanvas, как обычно.

Answer 3

Добавляя к ответу Gloweye, вы должны в PyQt5.

import six 

import ctypes 
import sys 

from PyQt5 import QtCore, QtGui 

from PyQt5.QtWidgets import QSizePolicy, QWidget, QVBoxLayout 
from matplotlib.figure import Figure 
from matplotlib.backends.backend_qt5agg import (
    FigureCanvasQTAgg as FigureCanvas, 
    NavigationToolbar2QT as NavigationToolbar) 

QT_API = 'PyQt5' 
DEBUG = False 

_decref = ctypes.pythonapi.Py_DecRef 
_decref.argtypes = [ctypes.py_object] 
_decref.restype = None 

class MplCanvas(FigureCanvas): 
    def __init__(self): 
     FigureCanvas.__init__(self,self.fig) 
     FigureCanvas.setSizePolicy(self, QSizePolicy.Expanding, 
            QSizePolicy.Expanding) 
     FigureCanvas.updateGeometry(self) 


    #Change de color of rectangle zoom toolbar rewriting painEvent 
    #the original code is in the backend_qt5agg.py file inside 
    #matplotlib/backends directory 
    def paintEvent(self, e): 
     """ 
     Copy the image from the Agg canvas to the qt.drawable. 
     In Qt, all drawing should be done inside of here when a widget is 
     shown onscreen. 
     """ 
     # if the canvas does not have a renderer, then give up and wait for 
     # FigureCanvasAgg.draw(self) to be called 
     if not hasattr(self, 'renderer'): 
      return 

     if DEBUG: 
      print('FigureCanvasQtAgg.paintEvent: ', self, 
        self.get_width_height()) 

     if len(self.blitbox) == 0: 
      # matplotlib is in rgba byte order. QImage wants to put the bytes 
      # into argb format and is in a 4 byte unsigned int. Little endian 
      # system is LSB first and expects the bytes in reverse order 
      # (bgra). 
      if QtCore.QSysInfo.ByteOrder == QtCore.QSysInfo.LittleEndian: 
       stringBuffer = self.renderer._renderer.tostring_bgra() 
      else: 
       stringBuffer = self.renderer._renderer.tostring_argb() 

      refcnt = sys.getrefcount(stringBuffer) 

      # convert the Agg rendered image -> qImage 
      qImage = QtGui.QImage(stringBuffer, self.renderer.width, 
            self.renderer.height, 
            QtGui.QImage.Format_ARGB32) 
      if hasattr(qImage, 'setDevicePixelRatio'): 
       # Not available on Qt4 or some older Qt5. 
       qImage.setDevicePixelRatio(self._dpi_ratio) 
      # get the rectangle for the image 
      rect = qImage.rect() 
      p = QtGui.QPainter(self) 
      # reset the image area of the canvas to be the back-ground color 
      p.eraseRect(rect) 
      # draw the rendered image on to the canvas 
      p.drawPixmap(QtCore.QPoint(0, 0), QtGui.QPixmap.fromImage(qImage)) 

      # draw the zoom rectangle to the QPainter 
      ######################################################## 
      #  HERE CHANGE THE COLOR, IN THIS EXAMPLE  # 
      #   THE COLOR IS WHITE       # 
      ######################################################## 
      if self._drawRect is not None: 
       pen = QtGui.QPen(QtCore.Qt.white, 1/self._dpi_ratio, 
           QtCore.Qt.DotLine) 
       p.setPen(pen) 
       x, y, w, h = self._drawRect 
       p.drawRect(x, y, w, h) 
      p.end() 

      # This works around a bug in PySide 1.1.2 on Python 3.x, 
      # where the reference count of stringBuffer is incremented 
      # but never decremented by QImage. 
      # TODO: revert PR #1323 once the issue is fixed in PySide. 
      del qImage 
      if refcnt != sys.getrefcount(stringBuffer): 
       _decref(stringBuffer) 
     else: 
      p = QtGui.QPainter(self) 

      while len(self.blitbox): 
       bbox = self.blitbox.pop() 
       l, b, r, t = bbox.extents 
       w = int(r) - int(l) 
       h = int(t) - int(b) 
       t = int(b) + h 
       reg = self.copy_from_bbox(bbox) 
       stringBuffer = reg.to_string_argb() 
       qImage = QtGui.QImage(stringBuffer, w, h, 
             QtGui.QImage.Format_ARGB32) 
       if hasattr(qImage, 'setDevicePixelRatio'): 
        # Not available on Qt4 or some older Qt5. 
        qImage.setDevicePixelRatio(self._dpi_ratio) 
       # Adjust the stringBuffer reference count to work 
       # around a memory leak bug in QImage() under PySide on 
       # Python 3.x 
       if QT_API == 'PySide' and six.PY3: 
        ctypes.c_long.from_address(id(stringBuffer)).value = 1 

       origin = QtCore.QPoint(l, self.renderer.height - t) 
       pixmap = QtGui.QPixmap.fromImage(qImage) 
       p.drawPixmap(origin/self._dpi_ratio, pixmap) 

      # draw the zoom rectangle to the QPainter 
      if self._drawRect is not None: 
       pen = QtGui.QPen(QtCore.Qt.black, 1/self._dpi_ratio, 
           QtCore.Qt.DotLine) 
       p.setPen(pen) 
       x, y, w, h = self._drawRect 
       p.drawRect(x, y, w, h) 

      p.end()