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# -*- coding: utf-8 -*-
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# Copyright © 2009-2010 CEA
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# Licensed under the terms of the CECILL License
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# (see guiqwt/__init__.py for details)
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The `colormap` module contains definition of common colormaps and tools
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to manipulate and create them
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from PyQt4.Qwt5 import QwtLinearColorMap, QwtDoubleInterval, toQImage
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from PyQt4.QtGui import QColor, QIcon, QPixmap
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from numpy import array, uint8, linspace, zeros, newaxis
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from guiqwt import _cm # Reuse matplotlib data
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def _interpolate(val, vmin, vmax):
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"""Interpolate a color component between to values as provided
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by matplotlib colormaps
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interp = (val-vmin[0])/(vmax[0]-vmin[0])
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return (1-interp)*vmin[1] + interp*vmax[2]
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def _setup_colormap(cmap, cmdata):
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"""Setup a QwtLinearColorMap according to
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red = array(cmdata["red"])
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green = array(cmdata["green"])
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blue = array(cmdata["blue"])
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qmin.setRgbF(red[ 0, 2], green[ 0, 2], blue[ 0, 2])
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qmax.setRgbF(red[-1, 2], green[-1, 2], blue[-1, 2])
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cmap.setColorInterval( qmin, qmax )
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indices = sorted(set(red[:, 0]) | set(green[:, 0]) | set(blue[:, 0]))
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for i in indices[1:-1]:
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idxr = red[:, 0].searchsorted(i)
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idxg = green[:, 0].searchsorted(i)
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idxb = blue[:, 0].searchsorted(i)
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compr = _interpolate(i, red[idxr-1], red[idxr])
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compg = _interpolate(i, green[idxg-1], green[idxg])
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compb = _interpolate(i, blue[idxb-1], blue[idxb] )
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col.setRgbF(compr, compg, compb)
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cmap.addColorStop(i, col)
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# usefull to obtain a full color map
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FULLRANGE = QwtDoubleInterval(0.0, 1.0)
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Return a QwtColormap based on matplotlib's colormap of the same name
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We avoid rebuilding the cmap by keeping it in cache
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return COLORMAPS[name]
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colormap = QwtLinearColorMap()
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COLORMAPS[name] = colormap
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COLORMAPS[colormap] = name
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data = getattr(_cm, "_"+name+"_data")
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_setup_colormap(colormap, data)
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def get_cmap_name(cmap):
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"""Return colormap's name"""
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return COLORMAPS.get(cmap, None)
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def get_colormap_list():
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"""Builds a list of available colormaps
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by introspection of the _cm module"""
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if name.endswith("_data"):
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obj = getattr(_cm, name)
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if isinstance(obj, dict):
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cmlist.append(name[1:-5])
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def build_icon_from_cmap(cmap, width=32, height=32):
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Builds an icon representing the colormap
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data = zeros((width, height), uint8)
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line = linspace(0, 255, width)
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data[:, :] = line[:, newaxis]
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img.setColorTable(cmap.colorTable(FULLRANGE))
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return QIcon(QPixmap.fromImage(img))
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def build_icon_from_cmap_name(cmap_name):
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if cmap_name in ICON_CACHE:
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return ICON_CACHE[cmap_name]
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icon = build_icon_from_cmap(get_cmap(cmap_name))
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ICON_CACHE[cmap_name] = icon
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guiqwt/colormap.py
