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.NoButton)
self.brush = QtGui.QBrush(QtGui.QColor(200,0,0))
self.pen = 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))
def setGradient(self, g):
self.gradient = g
self.update()
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)
rect = self.boundingRect() ## Boundaries of visible area in scene coords.
unit = self.pixelSize() ## Size of one view pixel in scene coords.
if unit[0] is None:
return
## 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.AlignLeft | QtCore.Qt.AlignVCenter, str(k))
labelWidth = max(labelWidth, b.width())
labelHeight = max(labelHeight, b.height())
labelWidth *= unit[0]
labelHeight *= unit[1]
textPadding = 2 # in px
if self.offset[0] < 0:
x3 = rect.right() + unit[0] * self.offset[0]
x2 = x3 - labelWidth - unit[0]*textPadding*2
x1 = x2 - unit[0] * self.size[0]
else:
x1 = rect.left() + unit[0] * self.offset[0]
x2 = x1 + unit[0] * self.size[0]
x3 = x2 + labelWidth + unit[0]*textPadding*2
if self.offset[1] < 0:
y2 = rect.top() - unit[1] * self.offset[1]
y1 = y2 + unit[1] * self.size[1]
else:
y1 = rect.bottom() - unit[1] * self.offset[1]
y2 = y1 - unit[1] * self.size[1]
self.b = [x1,x2,x3,y1,y2,labelWidth]
## Draw background
p.setPen(self.pen)
p.setBrush(QtGui.QBrush(QtGui.QColor(255,255,255,100)))
rect = QtCore.QRectF(
QtCore.QPointF(x1 - unit[0]*textPadding, y1 + labelHeight/2 + unit[1]*textPadding),
QtCore.QPointF(x3, y2 - labelHeight/2 - unit[1]*textPadding)
)
p.drawRect(rect)
## Have to scale painter so that text and gradients are correct size. Bleh.
p.scale(unit[0], unit[1])
## Draw color bar
self.gradient.setStart(0, y1/unit[1])
self.gradient.setFinalStop(0, y2/unit[1])
p.setBrush(self.gradient)
rect = QtCore.QRectF(
QtCore.QPointF(x1/unit[0], y1/unit[1]),
QtCore.QPointF(x2/unit[0], y2/unit[1])
)
p.drawRect(rect)
## draw labels
p.setPen(QtGui.QPen(QtGui.QColor(0,0,0)))
tx = x2 + unit[0]*textPadding
lh = labelHeight/unit[1]
for k in self.labels:
y = y1 + self.labels[k] * (y2-y1)
p.drawText(QtCore.QRectF(tx/unit[0], y/unit[1] - lh/2.0, 1000, lh), QtCore.Qt.AlignLeft | QtCore.Qt.AlignVCenter, str(k))