Merge pull request opencv#18083 from IanMaquignaz:fix_gen_pattern_centering

* Fixed centering issue with make_cicle_pattern and make_acircle_pattern()

* Fixed issue where asymmetric circles were not at 45 degree angles. Also fixed support for inch measurement by converting parsing to usage of floating points for page size

* Fixed copy-paste error from experimental workspace

Author: IanMaquignaz

doc/pattern_tools/gen_pattern.py

@@ -36,18 +36,27 @@ def __init__(self, cols, rows, output, units, square_size, radius_rate, page_wid
     def make_circles_pattern(self):
         spacing = self.square_size
         r = spacing / self.radius_rate
-        for x in range(1, self.cols + 1):
-            for y in range(1, self.rows + 1):
-                dot = SVG("circle", cx=x * spacing, cy=y * spacing, r=r, fill="black", stroke="none")
+        pattern_width = ((self.cols - 1.0) * spacing) + (2.0 * r)
+        pattern_height = ((self.rows - 1.0) * spacing) + (2.0 * r)
+        x_spacing = (self.width - pattern_width) / 2.0
+        y_spacing = (self.height - pattern_height) / 2.0
+        for x in range(0, self.cols):
+            for y in range(0, self.rows):
+                dot = SVG("circle", cx=(x * spacing) + x_spacing + r,
+                          cy=(y * spacing) + y_spacing + r, r=r, fill="black", stroke="none")
                 self.g.append(dot)
 
     def make_acircles_pattern(self):
         spacing = self.square_size
         r = spacing / self.radius_rate
-        for i in range(0, self.rows):
-            for j in range(0, self.cols):
-                dot = SVG("circle", cx=((j * 2 + i % 2) * spacing) + spacing, cy=self.height - (i * spacing + spacing),
-                          r=r, fill="black", stroke="none")
+        pattern_width = ((self.cols-1.0) * 2 * spacing) + spacing + (2.0 * r)
+        pattern_height = ((self.rows-1.0) * spacing) + (2.0 * r)
+        x_spacing = (self.width - pattern_width) / 2.0
+        y_spacing = (self.height - pattern_height) / 2.0
+        for x in range(0, self.cols):
+            for y in range(0, self.rows):
+                dot = SVG("circle", cx=(2 * x * spacing) + (y % 2)*spacing + x_spacing + r,
+                          cy=(y * spacing) + y_spacing + r, r=r, fill="black", stroke="none")
                 self.g.append(dot)
 
     def make_checkerboard_pattern(self):
@@ -84,9 +93,9 @@ def main():
     parser.add_argument("-R", "--radius_rate", help="circles_radius = square_size/radius_rate", default="5.0",
                         action="store", dest="radius_rate", type=float)
     parser.add_argument("-w", "--page_width", help="page width in units", default="216", action="store",
-                        dest="page_width", type=int)
+                        dest="page_width", type=float)
     parser.add_argument("-h", "--page_height", help="page height in units", default="279", action="store",
-                        dest="page_width", type=int)
+                        dest="page_width", type=float)
     parser.add_argument("-a", "--page_size", help="page size, supersedes -h -w arguments", default="A4", action="store",
                         dest="page_size", choices=["A0", "A1", "A2", "A3", "A4", "A5"])
     args = parser.parse_args()