Round values in ExtentFromLayer processing algorithm

qgis · May 11, 2019 · 052db03 · 052db03
1 parent d174840
commit 052db03
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Showing 2 changed files with 20 additions and 2 deletions.
diff --git a/python/plugins/processing/algs/help/qgis.yaml b/python/plugins/processing/algs/help/qgis.yaml
@@ -334,7 +334,7 @@ qgis:polygoncentroids: >
   NOTE: This algorithm is deprecated and the generic "centroids" algorithm (which works for line and multi geometry layers) should be used instead.
 
 qgis:polygonfromlayerextent: >
-  This algorithm takes a map layer and generates a new vector layer with the minimum bounding box (rectangle with N-S orientation) that covers the input layer.
+  This algorithm takes a map layer and generates a new vector layer with the minimum bounding box (rectangle polygon with N-S orientation) that covers the input layer. The extent can be enlarged to a rounded value.
 
 qgis:polygonize:  >
   This algorithm takes a lines layer and creates a polygon layer, with polygons generated from the lines in the input layer.

diff --git a/python/plugins/processing/algs/qgis/ExtentFromLayer.py b/python/plugins/processing/algs/qgis/ExtentFromLayer.py
@@ -26,6 +26,7 @@
 __revision__ = '$Format:%H$'
 
 import os
+from math import floor, ceil
 
 from qgis.PyQt.QtGui import QIcon
 from qgis.PyQt.QtCore import QVariant
@@ -39,6 +40,7 @@
                        QgsProcessing,
                        QgsProcessingException,
                        QgsProcessingParameterMapLayer,
+                       QgsProcessingParameterNumber,
                        QgsProcessingParameterFeatureSink,
                        QgsFields)
 
@@ -51,6 +53,7 @@ class ExtentFromLayer(QgisAlgorithm):
 
     INPUT = 'INPUT'
     BY_FEATURE = 'BY_FEATURE'
+    ROUND_TO = 'ROUND_TO'
 
     OUTPUT = 'OUTPUT'
 
@@ -61,7 +64,7 @@ def svgIconPath(self):
         return QgsApplication.iconPath("/algorithms/mAlgorithmExtractLayerExtent.svg")
 
     def tags(self):
-        return self.tr('polygon,from,vector,raster,extent,envelope,bounds,bounding,boundary,layer').split(',')
+        return self.tr('polygon,from,vector,raster,extent,envelope,bounds,bounding,boundary,layer,round,rounded').split(',')
 
     def group(self):
         return self.tr('Layer tools')
@@ -74,6 +77,10 @@ def __init__(self):
 
     def initAlgorithm(self, config=None):
         self.addParameter(QgsProcessingParameterMapLayer(self.INPUT, self.tr('Input layer')))
+        self.addParameter(QgsProcessingParameterNumber(self.ROUND_TO,
+                                                       self.tr('Round values to'), minValue=0,
+                                                       defaultValue=0,
+                                                       type=QgsProcessingParameterNumber.Double))
         self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Extent'), type=QgsProcessing.TypeVectorPolygon))
 
     def name(self):
@@ -85,6 +92,9 @@ def displayName(self):
     def processAlgorithm(self, parameters, context, feedback):
         layer = self.parameterAsLayer(parameters, self.INPUT, context)
 
+        round_to = self.parameterAsDouble(parameters, self.ROUND_TO, context)
+
+
         fields = QgsFields()
         fields.append(QgsField('MINX', QVariant.Double))
         fields.append(QgsField('MINY', QVariant.Double))
@@ -109,7 +119,15 @@ def processAlgorithm(self, parameters, context, feedback):
             pass
 
         rect = layer.extent()
+
+        if round_to > 0:
+            rect.setXMinimum(floor(rect.xMinimum() / round_to) * round_to)
+            rect.setYMinimum(floor(rect.yMinimum() / round_to) * round_to)
+            rect.setXMaximum(ceil(rect.xMaximum() / round_to) * round_to)
+            rect.setYMaximum(ceil(rect.yMaximum() / round_to) * round_to)
+
         geometry = QgsGeometry.fromRect(rect)
+
         minx = rect.xMinimum()
         miny = rect.yMinimum()
         maxx = rect.xMaximum()