[processing] add optional EXTRA parameter to gdalwarp algorithm (fix #20721)

alexbruy · nyalldawson · commit bb2c3663b003 · 2019-01-22T09:39:57.000+11:00
This allows users to pass additional command-line arguments which are
not exposed in the algorithm definition. The most frequent use case is
enabling transparency and adding nodata values.
diff --git a/python/plugins/processing/algs/gdal/warp.py b/python/plugins/processing/algs/gdal/warp.py
@@ -38,6 +38,7 @@
                        QgsProcessingParameterEnum,
                        QgsProcessingParameterBoolean,
                        QgsProcessingParameterExtent,
+                       QgsProcessingParameterString,
                        QgsProcessingParameterRasterDestination,
                        QgsProcessingUtils)
 from processing.algs.gdal.GdalAlgorithm import GdalAlgorithm
@@ -59,6 +60,7 @@ class warp(GdalAlgorithm):
     TARGET_EXTENT = 'TARGET_EXTENT'
     TARGET_EXTENT_CRS = 'TARGET_EXTENT_CRS'
     MULTITHREADING = 'MULTITHREADING'
+    EXTRA = 'EXTRA'
     OUTPUT = 'OUTPUT'
 
     TYPES = ['Use input layer data type', 'Byte', 'Int16', 'UInt16', 'UInt32', 'Int32', 'Float32', 'Float64', 'CInt16', 'CInt32', 'CFloat32', 'CFloat64']
@@ -139,6 +141,13 @@ def initAlgorithm(self, config=None):
         multithreading_param.setFlags(multithreading_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
         self.addParameter(multithreading_param)
 
+        extra_param = QgsProcessingParameterBoolean(self.EXTRA,
+                                                    self.tr('Additional command-line parameters'),
+                                                    defaultValue=None,
+                                                    optional=True)
+        extra_param.setFlags(extra_param.flags() | QgsProcessingParameterDefinition.FlagAdvanced)
+        self.addParameter(extra_param)
+
         self.addParameter(QgsProcessingParameterRasterDestination(self.OUTPUT,
                                                                   self.tr('Reprojected')))
 
@@ -228,6 +237,10 @@ def getConsoleCommands(self, parameters, context, feedback, executing=True):
         if options:
             arguments.extend(GdalUtils.parseCreationOptions(options))
 
+        if self.EXTRA in parameters and parameters[self.EXTRA] not in (None, ''):
+            extra = self.parameterAsString(parameters, self.EXTRA, context)
+            arguments.append(extra)
+
         arguments.append(inLayer.source())
         arguments.append(out)
 
diff --git a/python/plugins/processing/tests/GdalAlgorithmsTest.py b/python/plugins/processing/tests/GdalAlgorithmsTest.py
@@ -2213,6 +2213,43 @@ def testWarp(self):
                  source + ' ' +
                  outdir + '/check.jpg'])
 
+            # with additional command-line parameter
+            self.assertEqual(
+                alg.getConsoleCommands({'INPUT': source,
+                                        'EXTRA': '-dstalpha',
+                                        'OUTPUT': outdir + '/check.jpg'}, context, feedback),
+                ['gdalwarp',
+                 '-t_srs EPSG:4326 -r near -of JPEG -dstalpha ' +
+                 source + ' ' +
+                 outdir + '/check.jpg'])
+
+            self.assertEqual(
+                alg.getConsoleCommands({'INPUT': source,
+                                        'EXTRA': '-dstalpha -srcnodata -9999',
+                                        'OUTPUT': outdir + '/check.jpg'}, context, feedback),
+                ['gdalwarp',
+                 '-t_srs EPSG:4326 -r near -of JPEG -dstalpha -srcnodata -9999 ' +
+                 source + ' ' +
+                 outdir + '/check.jpg'])
+
+            self.assertEqual(
+                alg.getConsoleCommands({'INPUT': source,
+                                        'EXTRA': '-dstalpha -srcnodata "-9999 -8888"',
+                                        'OUTPUT': outdir + '/check.jpg'}, context, feedback),
+                ['gdalwarp',
+                 '-t_srs EPSG:4326 -r near -of JPEG -dstalpha -srcnodata "-9999 -8888" ' +
+                 source + ' ' +
+                 outdir + '/check.jpg'])
+
+            self.assertEqual(
+                alg.getConsoleCommands({'INPUT': source,
+                                        'EXTRA': '',
+                                        'OUTPUT': outdir + '/check.jpg'}, context, feedback),
+                ['gdalwarp',
+                 '-t_srs EPSG:4326 -r near -of JPEG ' +
+                 source + ' ' +
+                 outdir + '/check.jpg'])
+
     def testRearrangeBands(self):
         context = QgsProcessingContext()
         feedback = QgsProcessingFeedback()
