From ccaebae3cb9424a9b21d0c58237d7e95c9e16b1b Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Sat, 14 Dec 2019 10:15:05 +1000
Subject: Add proj_coordoperation_create_inverse to C API (#1795)

---
 src/iso19111/c_api.cpp | 28 ++++++++++++++++++++++++++++
 src/proj.h             |  3 +++
 2 files changed, 31 insertions(+)

(limited to 'src')

diff --git a/src/iso19111/c_api.cpp b/src/iso19111/c_api.cpp
index 9db9e5b3..5e2ac522 100644
--- a/src/iso19111/c_api.cpp
+++ b/src/iso19111/c_api.cpp
@@ -7769,6 +7769,34 @@ PJ *proj_normalize_for_visualization(PJ_CONTEXT *ctx, const PJ *obj) {
 
 // ---------------------------------------------------------------------------
 
+/** \brief Returns a PJ* coordinate operation object which represents the
+ * inverse operation of the specified coordinate operation.
+ *
+ * @param ctx PROJ context, or NULL for default context
+ * @param obj Object of type CoordinateOperation (must not be NULL)
+ * @return a new PJ* object to free with proj_destroy() in case of success, or
+ * nullptr in case of error
+ * @since 6.3
+ */
+PJ *proj_coordoperation_create_inverse(PJ_CONTEXT *ctx, const PJ *obj) {
+
+    SANITIZE_CTX(ctx);
+    auto co = dynamic_cast<const CoordinateOperation *>(obj->iso_obj.get());
+    if (!co) {
+        proj_log_error(ctx, __FUNCTION__,
+                       "Object is not a CoordinateOperation");
+        return nullptr;
+    }
+    try {
+        return pj_obj_create(ctx, co->inverse());
+    } catch (const std::exception &e) {
+        proj_log_debug(ctx, __FUNCTION__, e.what());
+        return nullptr;
+    }
+}
+
+// ---------------------------------------------------------------------------
+
 /** \brief Returns the number of steps of a concatenated operation.
  *
  * The input object must be a concatenated operation.
diff --git a/src/proj.h b/src/proj.h
index fc309542..b8b90277 100644
--- a/src/proj.h
+++ b/src/proj.h
@@ -1091,6 +1091,9 @@ int PROJ_DLL proj_coordoperation_get_towgs84_values(PJ_CONTEXT *ctx,
                                                     int value_count,
                                                     int emit_error_if_incompatible);
 
+PJ PROJ_DLL *proj_coordoperation_create_inverse(PJ_CONTEXT *ctx, const PJ *obj);
+
+
 int PROJ_DLL proj_concatoperation_get_step_count(PJ_CONTEXT *ctx,
                                                  const PJ *concatoperation);
 
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