Changes between Version 1 and Version 2 of GSoC/CAPI_PrecisionModel

Timestamp:

Mar 16, 2014, 11:19:28 AM (10 years ago)

Author:

sgillies

Comment:

--

GSoC/CAPI_PrecisionModel

@@ -7 +7 @@
  * Write test cases.
 
+= Requirements for Shapely =
+
+Shapely (https://github.com/Toblerity/Shapely) is one of the major Python users of GEOS. I want to let programmers select and use a precision model like this:
+
+{{{
+from shapely.geometry import Point
+from shapely.precision import fixed_model
+
+# make a fixed-precision model.
+fixed = fixed_model(scale=1.0, offset=(0.0, 0.0))
+
+# make a point snapped to a fixed-precision grid.
+p = Point(0, 0, model=fixed)
+
+# make a float-precision point.
+q = Point(0, 0)
+}}}
+
+The above is a bit of a reversal from what I've previously written about my precision model requirements. A Python API like the one above is going to be very reliable and doesn't leave any geometry objects twisting in the wind when their precision model goes away: they have references to the model which keep it "alive". So, my main requirement for the precision model in the C API is now:
+
+== No global state ==
+
+There shouldn't be a precision model in the global context. Or if there is, it shouldn't preclude precision models outside the global context.
+