[processing] update raster layer histogram

alexbruy · alexbruy · commit 2abc3f7233de · 2017-02-15T20:07:24.000+02:00
diff --git a/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py b/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py
@@ -277,15 +277,14 @@ def __init__(self):
             #~ ])
         if hasPlotly:
             from .VectorLayerHistogram import VectorLayerHistogram
-            #~ from .RasterLayerHistogram import RasterLayerHistogram
+            from .RasterLayerHistogram import RasterLayerHistogram
             from .VectorLayerScatterplot import VectorLayerScatterplot
             #~ from .MeanAndStdDevPlot import MeanAndStdDevPlot
             from .BarPlot import BarPlot
             #~ from .PolarPlot import PolarPlot
 
-            self.alglist.extend([
-                VectorLayerHistogram(), VectorLayerScatterplot(),
-                BarPlot()])
+            self.alglist.extend([VectorLayerHistogram(), RasterLayerHistogram(),
+                VectorLayerScatterplot(), BarPlot()])
 
         self.externalAlgs = []  # to store algs added by 3rd party plugins as scripts
 
diff --git a/python/plugins/processing/algs/qgis/RasterLayerHistogram.py b/python/plugins/processing/algs/qgis/RasterLayerHistogram.py
@@ -27,27 +27,21 @@
 
 __revision__ = '$Format:%H$'
 
-import matplotlib.pyplot as plt
-import matplotlib.pylab as lab
-
-from qgis.PyQt.QtCore import QVariant
-from qgis.core import QgsField
+import plotly as plt
+import plotly.graph_objs as go
 
 from processing.core.GeoAlgorithm import GeoAlgorithm
 from processing.core.parameters import ParameterNumber
 from processing.core.parameters import ParameterRaster
-from processing.core.outputs import OutputTable
 from processing.core.outputs import OutputHTML
-from processing.tools import dataobjects
-from processing.tools import raster
+from processing.tools import dataobjects, raster
 
 
 class RasterLayerHistogram(GeoAlgorithm):
 
     INPUT = 'INPUT'
-    PLOT = 'PLOT'
-    TABLE = 'TABLE'
     BINS = 'BINS'
+    PLOT = 'PLOT'
 
     def defineCharacteristics(self):
         self.name, self.i18n_name = self.trAlgorithm('Raster layer histogram')
@@ -59,33 +53,22 @@ def defineCharacteristics(self):
                                           self.tr('Number of bins'), 2, None, 10))
 
         self.addOutput(OutputHTML(self.PLOT, self.tr('Histogram')))
-        self.addOutput(OutputTable(self.TABLE, self.tr('Table')))
 
     def processAlgorithm(self, feedback):
         layer = dataobjects.getObjectFromUri(
             self.getParameterValue(self.INPUT))
         nbins = self.getParameterValue(self.BINS)
 
-        outputplot = self.getOutputValue(self.PLOT)
-        outputtable = self.getOutputFromName(self.TABLE)
+        output = self.getOutputValue(self.PLOT)
 
+        # ALERT: this is potentially blocking if the layer is too big
         values = raster.scanraster(layer, feedback)
 
-        # ALERT: this is potentially blocking if the layer is too big
-        plt.close()
         valueslist = []
         for v in values:
             if v is not None:
                 valueslist.append(v)
-        (n, bins, values) = plt.hist(valueslist, nbins)
-
-        fields = [QgsField('CENTER_VALUE', QVariant.Double),
-                  QgsField('NUM_ELEM', QVariant.Double)]
-        writer = outputtable.getTableWriter(fields)
-        for i in range(len(values)):
-            writer.addRecord([str(bins[i]) + '-' + str(bins[i + 1]), n[i]])
-
-        plotFilename = outputplot + '.png'
-        lab.savefig(plotFilename)
-        with open(outputplot, 'w') as f:
-            f.write('<html><img src="' + plotFilename + '"/></html>')
+
+        data = [go.Histogram(x=valueslist,
+                             nbinsx=nbins)]
+        plt.offline.plot(data, filename=output)
