Fix Python bindings for IsLineOfSightVisible

alg/gdal_alg.h

@@ -359,8 +359,8 @@ GDALDatasetH CPL_DLL GDALViewshedGenerate(
 
 bool CPL_DLL GDALIsLineOfSightVisible(
     const GDALRasterBandH, const int xA, const int yA, const double zA,
-    const int xB, const int yB, const double zB, int *xTerrainIntersection,
-    int *yTerrainIntersection, CSLConstList papszOptions);
+    const int xB, const int yB, const double zB, int *pnxTerrainIntersection,
+    int *pnyTerrainIntersection, CSLConstList papszOptions);
 
 /************************************************************************/
 /*      Rasterizer API - geometries burned into GDAL raster.            */

alg/los.cpp

@@ -162,27 +162,31 @@ static bool IsAboveTerrain(const GDALRasterBandH hBand, const int x,
  * For example, datasets referenced against geographic coordinate at high latitudes may have issues.
  *
  * @param hBand The band to read the DEM data from. This must NOT be null.
- * 
+ *
  * @param xA The X location (raster column) of the first point to check on the raster.
  *
  * @param yA The Y location (raster row) of the first point to check on the raster.
- * 
+ *
  * @param zA The Z location (height) of the first point to check.
- * 
+ *
  * @param xB The X location (raster column) of the second point to check on the raster.
  *
  * @param yB The Y location (raster row) of the second point to check on the raster.
- * 
+ *
  * @param zB The Z location (height) of the second point to check.
- * 
- * @param xTerrainIntersection The X location where the LOS line intersects with terrain,
- *        or nullptr if it does not intersect terrain. Currently ignored.
- * 
- * @param yTerrainIntersection The Y location where the LOS line intersects with terrain,
- *        or nullptr if it does not intersect terrain. Currently ignored.
- * 
+ *
+ * @param[out] pnxTerrainIntersection The X location where the LOS line
+ *             intersects with terrain, or nullptr if it does not intersect
+ *             terrain. Not implemented currently (*pnxTerrainIntersection
+ *             is set to -1)
+ *
+ * @param[out] pnyTerrainIntersection The Y location where the LOS line
+ *             intersects with terrain, or nullptr if it does not intersect
+ *             terrain. Not implemented currently (*pnyTerrainIntersection
+ *             is set to -1)
+ *
  * @param papszOptions Options for the line of sight algorithm (currently ignored).
- * 
+ *
  * @return True if the two points are within Line of Sight.
  *
  * @since GDAL 3.9
@@ -191,12 +195,18 @@ static bool IsAboveTerrain(const GDALRasterBandH hBand, const int x,
 bool GDALIsLineOfSightVisible(const GDALRasterBandH hBand, const int xA,
                               const int yA, const double zA, const int xB,
                               const int yB, const double zB,
-                              CPL_UNUSED int *xTerrainIntersection,
-                              CPL_UNUSED int *yTerrainIntersection,
+                              int *pnxTerrainIntersection,
+                              int *pnyTerrainIntersection,
                               CPL_UNUSED CSLConstList papszOptions)
 {
     VALIDATE_POINTER1(hBand, "GDALIsLineOfSightVisible", false);
 
+    if (pnxTerrainIntersection)
+        *pnxTerrainIntersection = -1;
+
+    if (pnyTerrainIntersection)
+        *pnyTerrainIntersection = -1;
+
     // Perform a preliminary check of the start and end points.
     if (!IsAboveTerrain(hBand, xA, yA, zA))
     {

autotest/alg/los.py

@@ -37,10 +37,14 @@ def test_los_basic():
 
     mem_ds = gdal.GetDriverByName("MEM").Create("", 2, 1)
 
-    assert gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, 1, 1, 0, 1)
-    assert gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, 1, 0, 0, 1)
-    assert not gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, -1, 1, 0, 1)
-    assert not gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, 1, 1, 0, -1)
+    success, x, y = gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, 1, 1, 0, 1)
+    assert success
+    assert x == -1
+    assert y == -1
+
+    assert gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, 1, 0, 0, 1)[0]
+    assert not gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, -1, 1, 0, 1)[0]
+    assert not gdal.IsLineOfSightVisible(mem_ds.GetRasterBand(1), 0, 0, 1, 1, 0, -1)[0]
 
     with pytest.raises(Exception, match="Received a NULL pointer"):
         assert gdal.IsLineOfSightVisible(None, 0, 0, 0, 0, 0, 0)

swig/include/Operations.i

@@ -639,6 +639,21 @@ GDALDatasetShadow *ViewshedGenerate( GDALRasterBandShadow *srcBand,
 /*                         IsLineOfSightVisible()                       */
 /************************************************************************/
 
+#ifdef SWIGPYTHON
+%feature( "kwargs" ) IsLineOfSightVisible;
+%apply Pointer NONNULL {GDALRasterBandShadow *band};
+%inline %{
+void IsLineOfSightVisible(GDALRasterBandShadow *band,
+                          int xA, int yA, double zA,
+                          int xB, int yB, double zB,
+                          bool *pbVisible, int *pnXIntersection, int *pnYIntersection,
+                          char** options = NULL)
+{
+    *pbVisible = GDALIsLineOfSightVisible(band, xA, yA, zA, xB, yB, zB, pnXIntersection, pnYIntersection, options);
+}
+%}
+%clear GDALRasterBandShadow *band;
+#else
 #ifndef SWIGJAVA
 %feature( "kwargs" ) IsLineOfSightVisible;
 #endif
@@ -647,13 +662,13 @@ GDALDatasetShadow *ViewshedGenerate( GDALRasterBandShadow *srcBand,
 bool IsLineOfSightVisible(GDALRasterBandShadow *band,
                           int xA, int yA, double zA,
                           int xB, int yB, double zB,
-                          int *xTerrainIntersection, int *yTerrainIntersection,
                           char** options = NULL)
 {
-    return GDALIsLineOfSightVisible(band, xA, yA, zA, xB, yB, zB, xTerrainIntersection, yTerrainIntersection, options);
+    return GDALIsLineOfSightVisible(band, xA, yA, zA, xB, yB, zB, NULL, NULL, options);
 }
 %}
 %clear GDALRasterBandShadow *band;
+#endif
 
 /************************************************************************/
 /*                        AutoCreateWarpedVRT()                         */

swig/include/python/docs/gdal_operations_docs.i

@@ -24,17 +24,13 @@ yB : int
     The Y location (raster row) of the second point to check on the raster.
 zB : float
     The Z location (height) of the second point to check.
-xTerrainIntersection : int
-    The X location where the LOS line intersects with terrain, or nullptr if it does not
-    intersect terrain. Currently ignored.
-yTerrainIntersection : int
-    The Y location where the LOS line intersects with terrain, or nullptr if it does not
-    intersect terrain. Currently ignored.
 options : dict/list, optional
     A dict or list of name=value of options for the line of sight algorithm (currently ignored).
 
 Returns
 -------
-bool
-    True if the two points are within Line of Sight.
+(bool, int, int)
+    First value of tuple is True if the two points are within Line of Sight.
+    Second value is the X location where the LOS line intersects with terrain (will be set in the future, currently set to -1).
+    Third value is the Y location where the LOS line intersects with terrain (will be set in the future, currently set to -1).
 ";

swig/include/python/typemaps_python.i

@@ -3449,3 +3449,22 @@ OBJECT_LIST_INPUT(GDALMDArrayHS);
   /* %typemap(freearg) (int nUsages, GDALRATFieldUsage *paeUsages)*/
   CPLFree( $2 );
 }
+
+
+%typemap(in,numinputs=0) (bool *pbVisible, int *pnXIntersection, int *pnYIntersection) ( bool visible = 0, int nxintersection = 0, int nyintersection = 0  )
+{
+  /* %typemap(in) (bool *pbVisible, int *pnXIntersection, int *pnYIntersection) */
+  $1 = &visible;
+  $2 = &nxintersection;
+  $3 = &nyintersection;
+}
+
+%typemap(argout) (bool *pbVisible, int *pnXIntersection, int *pnYIntersection)
+{
+   /* %typemap(argout) (bool *pbVisible, int *pnXIntersection, int *pnYIntersection)  */
+  PyObject *r = PyTuple_New( 3 );
+  PyTuple_SetItem( r, 0, PyBool_FromLong(*$1) );
+  PyTuple_SetItem( r, 1, PyLong_FromLong(*$2) );
+  PyTuple_SetItem( r, 2, PyLong_FromLong(*$3) );
+  $result = t_output_helper($result,r);
+}