Port Topocolor algorithm to new API

Author: nyalldawson

python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py

@@ -133,6 +133,7 @@
 from .SumLines import SumLines
 from .SymmetricalDifference import SymmetricalDifference
 from .TextToFloat import TextToFloat
+from .TopoColors import TopoColor
 from .Translate import Translate
 from .TruncateTable import TruncateTable
 from .Union import Union
@@ -169,7 +170,6 @@
 # from .RasterCalculator import RasterCalculator
 # from .ExecuteSQL import ExecuteSQL
 # from .FindProjection import FindProjection
-# from .TopoColors import TopoColor
 # from .EliminateSelection import EliminateSelection
 
 pluginPath = os.path.normpath(os.path.join(
@@ -206,7 +206,7 @@ def getAlgs(self):
         #         IdwInterpolation(), TinInterpolation(),
         #         RasterCalculator(),
         #          ExecuteSQL(), FindProjection(),
-        #         TopoColor(), EliminateSelection()
+        #        EliminateSelection()
         #         ]
         algs = [AddTableField(),
                 Aspect(),
@@ -301,6 +301,7 @@ def getAlgs(self):
                 SumLines(),
                 SymmetricalDifference(),
                 TextToFloat(),
+                TopoColor(),
                 Translate(),
                 TruncateTable(),
                 Union(),

python/plugins/processing/algs/qgis/TopoColors.py

@@ -31,33 +31,31 @@
 
 from collections import defaultdict
 
-from qgis.core import (QgsApplication,
-                       QgsField,
+from qgis.core import (QgsField,
                        QgsFeatureSink,
                        QgsGeometry,
                        QgsSpatialIndex,
                        QgsPointXY,
                        NULL,
-                       QgsProcessingUtils)
+                       QgsProcessing,
+                       QgsProcessingParameterFeatureSource,
+                       QgsProcessingParameterNumber,
+                       QgsProcessingParameterEnum,
+                       QgsProcessingParameterFeatureSink)
 
 from qgis.PyQt.QtCore import (QVariant)
 
 from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
-from processing.core.parameters import (ParameterVector,
-                                        ParameterSelection,
-                                        ParameterNumber)
-from processing.core.outputs import OutputVector
-from processing.tools import dataobjects
 
 pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
 
 
 class TopoColor(QgisAlgorithm):
-    INPUT_LAYER = 'INPUT_LAYER'
+    INPUT = 'INPUT'
     MIN_COLORS = 'MIN_COLORS'
     MIN_DISTANCE = 'MIN_DISTANCE'
     BALANCE = 'BALANCE'
-    OUTPUT_LAYER = 'OUTPUT_LAYER'
+    OUTPUT = 'OUTPUT'
 
     def tags(self):
         return self.tr('topocolor,colors,graph,adjacent,assign').split(',')
@@ -69,21 +67,23 @@ def __init__(self):
         super().__init__()
 
     def initAlgorithm(self, config=None):
-        self.addParameter(ParameterVector(self.INPUT_LAYER,
-                                          self.tr('Input layer'), [dataobjects.TYPE_VECTOR_POLYGON]))
-        self.addParameter(ParameterNumber(self.MIN_COLORS,
-                                          self.tr('Minimum number of colors'), 1, 1000, 4))
-        self.addParameter(ParameterNumber(self.MIN_DISTANCE,
-                                          self.tr('Minimum distance between features'), 0.0, 999999999.0, 0.0))
+
+        self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT,
+                                                              self.tr('Input layer'), [QgsProcessing.TypeVectorPolygon]))
+        self.addParameter(QgsProcessingParameterNumber(self.MIN_COLORS,
+                                                       self.tr('Minimum number of colors'), minValue=1, maxValue=1000, defaultValue=4))
+        self.addParameter(QgsProcessingParameterNumber(self.MIN_DISTANCE,
+                                                       self.tr('Minimum distance between features'), type=QgsProcessingParameterNumber.Double,
+                                                       minValue=0.0, maxValue=999999999.0, defaultValue=0.0))
         balance_by = [self.tr('By feature count'),
                       self.tr('By assigned area'),
                       self.tr('By distance between colors')]
-        self.addParameter(ParameterSelection(
+        self.addParameter(QgsProcessingParameterEnum(
             self.BALANCE,
             self.tr('Balance color assignment'),
-            balance_by, default=0))
+            options=balance_by, defaultValue=0))
 
-        self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Colored'), datatype=[dataobjects.TYPE_VECTOR_POLYGON]))
+        self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Colored'), QgsProcessing.TypeVectorPolygon))
 
     def name(self):
         return 'topologicalcoloring'
@@ -92,18 +92,18 @@ def displayName(self):
         return self.tr('Topological coloring')
 
     def processAlgorithm(self, parameters, context, feedback):
-        layer = QgsProcessingUtils.mapLayerFromString(self.getParameterValue(self.INPUT_LAYER), context)
-        min_colors = self.getParameterValue(self.MIN_COLORS)
-        balance_by = self.getParameterValue(self.BALANCE)
-        min_distance = self.getParameterValue(self.MIN_DISTANCE)
+        source = self.parameterAsSource(parameters, self.INPUT, context)
+        min_colors = self.parameterAsInt(parameters, self.MIN_COLORS, context)
+        balance_by = self.parameterAsEnum(parameters, self.BALANCE, context)
+        min_distance = self.parameterAsDouble(parameters, self.MIN_DISTANCE, context)
 
-        fields = layer.fields()
+        fields = source.fields()
         fields.append(QgsField('color_id', QVariant.Int))
 
-        writer = self.getOutputFromName(
-            self.OUTPUT_LAYER).getVectorWriter(fields, layer.wkbType(), layer.crs(), context)
+        (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
+                                               fields, source.wkbType(), source.sourceCrs())
 
-        features = {f.id(): f for f in QgsProcessingUtils.getFeatures(layer, context)}
+        features = {f.id(): f for f in source.getFeatures()}
 
         topology, id_graph = self.compute_graph(features, feedback, min_distance=min_distance)
         feature_colors = ColoringAlgorithm.balanced(features,
@@ -118,6 +118,9 @@ def processAlgorithm(self, parameters, context, feedback):
         total = 20.0 / len(features)
         current = 0
         for feature_id, input_feature in features.items():
+            if feedback.isCanceled():
+                break
+
             output_feature = input_feature
             attributes = input_feature.attributes()
             if feature_id in feature_colors:
@@ -126,11 +129,11 @@ def processAlgorithm(self, parameters, context, feedback):
                 attributes.append(NULL)
             output_feature.setAttributes(attributes)
 
-            writer.addFeature(output_feature, QgsFeatureSink.FastInsert)
+            sink.addFeature(output_feature, QgsFeatureSink.FastInsert)
             current += 1
             feedback.setProgress(80 + int(current * total))
 
-        del writer
+        return {self.OUTPUT: dest_id}
 
     @staticmethod
     def compute_graph(features, feedback, create_id_graph=False, min_distance=0):
@@ -148,6 +151,9 @@ def compute_graph(features, feedback, create_id_graph=False, min_distance=0):
 
         i = 0
         for feature_id, f in features_with_geometry.items():
+            if feedback.isCanceled():
+                break
+
             g = f.geometry()
             if min_distance > 0:
                 g = g.buffer(min_distance, 5)
@@ -172,6 +178,9 @@ def compute_graph(features, feedback, create_id_graph=False, min_distance=0):
             feedback.setProgress(int(i * total))
 
         for feature_id, f in features_with_geometry.items():
+            if feedback.isCanceled():
+                break
+
             if feature_id not in s.node_edge:
                 s.add_edge(feature_id, None)
 
@@ -206,6 +215,9 @@ def balanced(features, graph, feedback, balance=0, min_colors=4):
         i = 0
 
         for (feature_id, n) in sorted_by_count:
+            if feedback.isCanceled():
+                break
+
             # first work out which already assigned colors are adjacent to this feature
             adjacent_colors = set()
             for neighbour in graph.node_edge[feature_id]:
@@ -240,6 +252,9 @@ def balanced(features, graph, feedback, balance=0, min_colors=4):
                     # loop through these, and calculate the minimum distance from this feature to the nearest
                     # feature with each assigned color
                     for other_feature_id, c in other_features.items():
+                        if feedback.isCanceled():
+                            break
+
                         other_geometry = features[other_feature_id].geometry()
                         other_centroid = QgsPointXY(other_geometry.centroid().geometry())
 

python/plugins/processing/tests/testdata/expected/topocolor_polys.gml

@@ -41,7 +41,7 @@
       <ogr:right>8.23935</ogr:right>
       <ogr:bottom>-3.11331</ogr:bottom>
       <ogr:id>11</ogr:id>
-      <ogr:color_id>4</ogr:color_id>
+      <ogr:color_id>5</ogr:color_id>
     </ogr:topocolor_polys>
   </gml:featureMember>
   <gml:featureMember>
@@ -52,7 +52,7 @@
       <ogr:right>8.23935</ogr:right>
       <ogr:bottom>-6.11331</ogr:bottom>
       <ogr:id>12</ogr:id>
-      <ogr:color_id>5</ogr:color_id>
+      <ogr:color_id>4</ogr:color_id>
     </ogr:topocolor_polys>
   </gml:featureMember>
   <gml:featureMember>

python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml

@@ -2598,32 +2598,33 @@ tests:
         name: expected/polygon_from_extent.gml
         type: vector
 
-#  - algorithm: qgis:topologicalcoloring
-#    name: Topological coloring
-#    params:
-#      INPUT_LAYER:
-#        name: custom/adjacent_polys.gml
-#        type: vector
-#      MIN_COLORS: 4
-#    results:
-#      OUTPUT_LAYER:
-#        name: expected/topocolor_polys.gml
-#        type: vector
-#
-#  - algorithm: qgis:topologicalcoloring
-#    name: Topological coloring w/ min distance
-#    params:
-#      BALANCE: '0'
-#      INPUT_LAYER:
-#        name: custom/adjacent_polys.gml
-#        type: vector
-#      MIN_COLORS: 4
-#      MIN_DISTANCE: 4.0
-#    results:
-#      OUTPUT_LAYER:
-#        name: expected/topocolor_polys_min_dist.gml
-#        type: vector
-#
+  - algorithm: qgis:topologicalcoloring
+    name: Topological coloring
+    params:
+      BALANCE: 0
+      INPUT:
+        name: custom/adjacent_polys.gml
+        type: vector
+      MIN_COLORS: 4
+    results:
+      OUTPUT:
+        name: expected/topocolor_polys.gml
+        type: vector
+
+  - algorithm: qgis:topologicalcoloring
+    name: Topological coloring w/ min distance
+    params:
+      BALANCE: 0
+      INPUT:
+        name: custom/adjacent_polys.gml
+        type: vector
+      MIN_COLORS: 4
+      MIN_DISTANCE: 4.0
+    results:
+      OUTPUT:
+        name: expected/topocolor_polys_min_dist.gml
+        type: vector
+
   - algorithm: qgis:regularpoints
     name: Regular point with standard extent
     params: