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