bands can be renamed through table, very basic

rename_bands_algorithm.py

@@ -34,8 +34,11 @@ from qgis.PyQt.QtCore import QCoreApplication
 from qgis.core import (QgsProcessing,
                        QgsProcessingAlgorithm,
                        QgsProcessingParameterRasterLayer,
+                       QgsProcessingParameterMatrix,
+                       QgsProcessingParameterBand,
                        QgsProcessingParameterRasterDestination)
 import processing
+from osgeo import gdal
 
 
 class RenameBandsAlgorithm(QgsProcessingAlgorithm):
@@ -48,8 +51,9 @@ class RenameBandsAlgorithm(QgsProcessingAlgorithm):
     # used when calling the algorithm from another algorithm, or when
     # calling from the QGIS console.
 
-    OUTPUT = 'OUTPUT'
     INPUT = 'INPUT'
+    TABLE = 'TABLE'
+    OUTPUT = 'OUTPUT'
 
     def initAlgorithm(self, config):
         """
@@ -66,6 +70,18 @@ class RenameBandsAlgorithm(QgsProcessingAlgorithm):
             )
         )
         
+        # table to reaorder and rename bands
+        self.addParameter(
+            QgsProcessingParameterMatrix(
+                self.TABLE, 
+                self.tr('Nom et ordre des bandes'), 
+                numberRows=0, 
+                hasFixedNumberRows = False, 
+                headers=['futur nom', 'ordre'], 
+                defaultValue=[None,None]
+            )
+        )
+
         # TODO
         # output raster layer
         self.addParameter(
@@ -82,8 +98,28 @@ class RenameBandsAlgorithm(QgsProcessingAlgorithm):
 
         # Retrieve inputs and outputs
         input_raster = self.parameterAsRasterLayer(parameters, self.INPUT, context)
+        band_table = self.parameterAsMatrix(parameters, self.TABLE, context)
         output_path_raster = self.parameterAsOutputLayer(parameters, self.OUTPUT, context)
         
+        # get input raster path
+        raster_path = input_raster.source()
+        # read raster with gdal
+        raster_gdal = gdal.Open(raster_path)
+        # get number of bands
+        nbands = raster_gdal.RasterCount
+        # TODO : check if band number = row number in band_table
+            
+        # transform band_table in a nested list, with 1 element per band, and name and order of each band
+        # [['band 1', 1], ['band 2', 2], ['band 3', 3]]
+        nb_col = 2
+        band_table = [band_table[n:n+nb_col] for n in range(0, len(band_table), nb_col)]
+        
+        # iterate over each band to set its description
+        for band_number in range(nbands):
+            band = raster_gdal.GetRasterBand(band_number + 1)
+            band.SetDescription(band_table[band_number][0])
+        
+        # running gdal:translate processing algorithm
         param_translate = {'INPUT': input_raster,
                            'TARGET_CRS':None,
                            'NODATA':None,
@@ -95,7 +131,7 @@ class RenameBandsAlgorithm(QgsProcessingAlgorithm):
         processing.run("gdal:translate", param_translate)
 
         # Return the results of the algorithm as a dictionary
-        return {self.OUTPUT: output_path_raster}
+        return {self.OUTPUT: output_path_raster, 'matrix': band_table}
 
     def name(self):
         """