126 lines
4.8 KiB
Python
126 lines
4.8 KiB
Python
from ..Qt import QtGui, QtCore
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from .UIGraphicsItem import *
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from .. import functions as fn
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__all__ = ['GradientLegend']
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class GradientLegend(UIGraphicsItem):
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"""
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Draws a color gradient rectangle along with text labels denoting the value at specific
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points along the gradient.
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"""
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def __init__(self, size, offset):
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self.size = size
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self.offset = offset
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UIGraphicsItem.__init__(self)
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self.setAcceptedMouseButtons(QtCore.Qt.MouseButton.NoButton)
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self.brush = QtGui.QBrush(QtGui.QColor(255,255,255,100)) # background color
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self.pen = QtGui.QPen(QtGui.QColor(0,0,0))
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self.textPen = QtGui.QPen(QtGui.QColor(0,0,0))
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self.labels = {'max': 1, 'min': 0}
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self.gradient = QtGui.QLinearGradient()
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self.gradient.setColorAt(0, QtGui.QColor(0,0,0))
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self.gradient.setColorAt(1, QtGui.QColor(255,0,0))
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self.setZValue(100) # draw on top of ordinary plots
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def setGradient(self, g):
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self.gradient = g
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self.update()
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def setColorMap(self, colormap):
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"""
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Set displayed gradient from a :class:`~pyqtgraph.ColorMap` object.
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"""
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self.gradient = colormap.getGradient()
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def setIntColorScale(self, minVal, maxVal, *args, **kargs):
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colors = [fn.intColor(i, maxVal-minVal, *args, **kargs) for i in range(minVal, maxVal)]
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g = QtGui.QLinearGradient()
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for i in range(len(colors)):
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x = float(i)/len(colors)
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g.setColorAt(x, colors[i])
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self.setGradient(g)
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if 'labels' not in kargs:
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self.setLabels({str(minVal/10.): 0, str(maxVal): 1})
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else:
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self.setLabels({kargs['labels'][0]:0, kargs['labels'][1]:1})
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def setLabels(self, l):
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"""Defines labels to appear next to the color scale. Accepts a dict of {text: value} pairs"""
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self.labels = l
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self.update()
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def paint(self, p, opt, widget):
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UIGraphicsItem.paint(self, p, opt, widget)
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view = self.getViewBox()
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if view is None:
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return
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p.save() # save painter state before we change transformation
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trans = view.sceneTransform()
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p.setTransform( trans ) # draw in ViewBox pixel coordinates
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rect = view.rect()
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## determine max width of all labels
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labelWidth = 0
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labelHeight = 0
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for k in self.labels:
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b = p.boundingRect(QtCore.QRectF(0, 0, 0, 0), QtCore.Qt.AlignmentFlag.AlignLeft | QtCore.Qt.AlignmentFlag.AlignVCenter, str(k))
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labelWidth = max(labelWidth, b.width())
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labelHeight = max(labelHeight, b.height())
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textPadding = 2 # in px
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xR = rect.right()
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xL = rect.left()
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yT = rect.top()
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yB = rect.bottom()
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# coordinates describe edges of text and bar, additional margins will be added for background
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if self.offset[0] < 0:
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x3 = xR + self.offset[0] # right edge from right edge of view, offset is negative!
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x2 = x3 - labelWidth - 2*textPadding # right side of color bar
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x1 = x2 - self.size[0] # left side of color bar
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else:
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x1 = xL + self.offset[0] # left edge from left edge of view
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x2 = x1 + self.size[0]
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x3 = x2 + labelWidth + 2*textPadding # leave room for 2x textpadding between bar and text
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if self.offset[1] < 0:
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y2 = yB + self.offset[1] # bottom edge from bottom of view, offset is negative!
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y1 = y2 - self.size[1]
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else:
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y1 = yT + self.offset[1] # top edge from top of view
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y2 = y1 + self.size[1]
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self.b = [x1,x2,x3,y1,y2,labelWidth]
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## Draw background
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p.setPen(self.pen)
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p.setBrush(self.brush) # background color
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rect = QtCore.QRectF(
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QtCore.QPointF(x1 - textPadding, y1-labelHeight/2 - textPadding), # extra left/top padding
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QtCore.QPointF(x3 + textPadding, y2+labelHeight/2 + textPadding) # extra bottom/right padding
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)
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p.drawRect(rect)
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## Draw color bar
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self.gradient.setStart(0, y2)
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self.gradient.setFinalStop(0, y1)
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p.setBrush(self.gradient)
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rect = QtCore.QRectF(
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QtCore.QPointF(x1, y1),
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QtCore.QPointF(x2, y2)
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)
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p.drawRect(rect)
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## draw labels
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p.setPen(self.textPen)
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tx = x2 + 2 * textPadding # margin between bar and text
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lh = labelHeight
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lw = labelWidth
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for k in self.labels:
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y = y2 - self.labels[k] * (y2-y1)
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p.drawText(QtCore.QRectF(tx, y - lh/2, lw, lh), QtCore.Qt.AlignmentFlag.AlignLeft | QtCore.Qt.AlignmentFlag.AlignVCenter, str(k))
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p.restore() # restore QPainter transform to original state
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