[processing] fixes for Create Grid algorithm (fix #14303)

Author: alexbruy

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

@@ -81,8 +81,10 @@ def processAlgorithm(self, progress):
         height = bbox.height()
         centerX = bbox.center().x()
         centerY = bbox.center().y()
-        originX = centerX - width / 2.0
-        originY = centerY - height / 2.0
+        #~ originX = centerX - width / 2.0
+        #~ originY = centerY - height / 2.0
+        originX = bbox.xMinimum()
+        originY = bbox.yMaximum()
 
         if hSpacing <= 0 or vSpacing <= 0:
             raise GeoAlgorithmExecutionException(
@@ -130,15 +132,15 @@ def _rectangleGridLine(self, writer, width, height, originX, originY,
                            hSpacing, vSpacing):
         ft = QgsFeature()
 
-        columns = int(math.floor(float(width) / hSpacing))
-        rows = int(math.floor(float(height) / vSpacing))
+        columns = int(math.ceil(float(width) / hSpacing))
+        rows = int(math.ceil(float(height) / vSpacing))
 
         # Longitude lines
         for col in xrange(0, columns + 1):
             polyline = []
             x = originX + (col * hSpacing)
             for row in xrange(0, rows + 1):
-                y = originY + (row * vSpacing)
+                y = originY - (row * vSpacing)
                 polyline.append(QgsPoint(x, y))
 
             ft.setGeometry(QgsGeometry.fromPolyline(polyline))
@@ -148,7 +150,7 @@ def _rectangleGridLine(self, writer, width, height, originX, originY,
         # Latitude lines
         for row in xrange(0, rows + 1):
             polyline = []
-            y = originY + (row * vSpacing)
+            y = originY - (row * vSpacing)
             for col in xrange(0, columns + 1):
                 x = originX + (col * hSpacing)
                 polyline.append(QgsPoint(x, y))
@@ -161,8 +163,8 @@ def _rectangleGridPoly(self, writer, width, height, originX, originY,
                            hSpacing, vSpacing):
         ft = QgsFeature()
 
-        columns = int(math.floor(float(width) / hSpacing))
-        rows = int(math.floor(float(height) / vSpacing))
+        columns = int(math.ceil(float(width) / hSpacing))
+        rows = int(math.ceil(float(height) / vSpacing))
 
         for col in xrange(0, columns):
             # (column + 1) and (row + 1) calculation is used to maintain
@@ -171,8 +173,8 @@ def _rectangleGridPoly(self, writer, width, height, originX, originY,
             x1 = originX + (col * hSpacing)
             x2 = originX + ((col + 1) * hSpacing)
             for row in xrange(0, rows):
-                y1 = originY + (row * vSpacing)
-                y2 = originY + ((row + 1) * vSpacing)
+                y1 = originY - (row * vSpacing)
+                y2 = originY - ((row + 1) * vSpacing)
 
                 polyline = []
                 polyline.append(QgsPoint(x1, y1))
@@ -192,8 +194,8 @@ def _diamondGrid(self, writer, width, height, originX, originY,
         halfHSpacing = hSpacing / 2
         halfVSpacing = vSpacing / 2
 
-        columns = int(math.floor(float(width) / halfHSpacing))
-        rows = int(math.floor(float(height) / vSpacing))
+        columns = int(math.ceil(float(width) / halfHSpacing))
+        rows = int(math.ceil(float(height) / vSpacing))
 
         for col in xrange(0, columns):
             x1 = originX + ((col + 0) * halfHSpacing)
@@ -202,13 +204,13 @@ def _diamondGrid(self, writer, width, height, originX, originY,
 
             for row in xrange(0, rows):
                 if (col % 2) == 0:
-                    y1 = originY + (((row * 2) + 0) * halfVSpacing)
-                    y2 = originY + (((row * 2) + 1) * halfVSpacing)
-                    y3 = originY + (((row * 2) + 2) * halfVSpacing)
+                    y1 = originY - (((row * 2) + 0) * halfVSpacing)
+                    y2 = originY - (((row * 2) + 1) * halfVSpacing)
+                    y3 = originY - (((row * 2) + 2) * halfVSpacing)
                 else:
-                    y1 = originY + (((row * 2) + 1) * halfVSpacing)
-                    y2 = originY + (((row * 2) + 2) * halfVSpacing)
-                    y3 = originY + (((row * 2) + 3) * halfVSpacing)
+                    y1 = originY - (((row * 2) + 1) * halfVSpacing)
+                    y2 = originY - (((row * 2) + 2) * halfVSpacing)
+                    y3 = originY - (((row * 2) + 3) * halfVSpacing)
 
                 polyline = []
                 polyline.append(QgsPoint(x1, y2))
@@ -232,8 +234,8 @@ def _hexagonGrid(self, writer, width, height, originX, originY,
 
         halfVSpacing = vSpacing / 2
 
-        columns = int(math.floor(float(width) / hSpacing))
-        rows = int(math.floor(float(height) / vSpacing))
+        columns = int(math.ceil(float(width) / hSpacing))
+        rows = int(math.ceil(float(height) / vSpacing))
 
         for col in xrange(0, columns):
             # (column + 1) and (row + 1) calculation is used to maintain
@@ -246,13 +248,13 @@ def _hexagonGrid(self, writer, width, height, originX, originY,
 
             for row in xrange(0, rows):
                 if (col % 2) == 0:
-                    y1 = originY + (((row * 2) + 0) * halfVSpacing) # hi
-                    y2 = originY + (((row * 2) + 1) * halfVSpacing) # mid
-                    y3 = originY + (((row * 2) + 2) * halfVSpacing) # lo
+                    y1 = originY - (((row * 2) + 0) * halfVSpacing) # hi
+                    y2 = originY - (((row * 2) + 1) * halfVSpacing) # mid
+                    y3 = originY - (((row * 2) + 2) * halfVSpacing) # lo
                 else:
-                    y1 = originY + (((row * 2) + 1) * halfVSpacing) # hi
-                    y2 = originY + (((row * 2) + 2) * halfVSpacing) # mid
-                    y3 = originY + (((row * 2) + 3) * halfVSpacing) # lo
+                    y1 = originY - (((row * 2) + 1) * halfVSpacing) # hi
+                    y2 = originY - (((row * 2) + 2) * halfVSpacing) # mid
+                    y3 = originY - (((row * 2) + 3) * halfVSpacing) # lo
 
                 polyline = []
                 polyline.append(QgsPoint(x1, y2))