pmeems · Oct 31, 2026
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -70,3 +70,4 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 mwg_add_runtime_data_target()
 
 add_subdirectory(src/MapWinGIS.Core)
+add_subdirectory(src/MapWinGIS.ActiveX)
diff --git a/build/scripts/Compare-CompileCommands.ps1 b/build/scripts/Compare-CompileCommands.ps1
@@ -83,6 +83,17 @@ $explainedLinkDifferences = [ordered]@{
     '^lib:<vcpkg_installed>/'          = 'Library from an imported target (find_package)'
     '^lib:odbc(cp)?32\.lib$'           = 'MSBuild default library; unused, not in CMake''s default list'
     '^/version:0\.0$'                  = 'CMake default image version; MSBuild leaves it at 0.0 too'
+    '^input:.*\.res$'                  = 'Compiled resource file name (<name>.rc.res in CMake)'
+    '^lib:(<builddir>/)?lib[\\/]mapwingis\.core\.lib$' = 'Core import library from target_link_libraries (MSBuild: project reference)'
+}
+
+# Compile differences that are deliberate (docs/CMAKE-MIGRATION.md).
+$explainedCompileDifferences = [ordered]@{
+    '^/I<intdir>$'                                = 'MIDL output moved from the intermediate directory to <build>/.../midl (D3)'
+    '^/I<builddir>/.*/midl$'                      = 'MIDL output directory (D3)'
+    '^/I<vcpkg_installed>/[^/]+/include$'         = 'vcpkg auto-include; targets without a vcpkg dependency do not get it, the others get it from imported targets'
+    '^/I<vcpkg_installed>/[^/]+/include/geos$'    = 'Interface include directory of GEOS::geos_c'
+    '^/DGDAL_DEBUG$'                              = 'Interface definition of the debug GDAL::GDAL'
 }
 
 # MSBuild project names that differ from the CMake target names.
@@ -290,7 +301,7 @@ function Read-MSBuildCommands([string] $logPath, [string] $binDir) {
             $set = ConvertTo-OptionSet $arguments $baseDir $placeholders @('.c', '.cpp', '.cxx', '.cc')
             foreach ($source in $set.Sources) {
                 # Keyed by target: the tests compile some ActiveX sources a second time.
-                $compiles["$target $source"] = [pscustomobject]@{
+                $compiles[(Get-SourceKey $target $source)] = [pscustomobject]@{
                     Target  = $target
                     Source  = $source
                     Options = Merge-VcpkgPlatform $set.Options
@@ -327,6 +338,8 @@ function Read-CMakeCommands([string] $buildDir, [string] $logPath, [string] $bin
     }
 
     foreach ($entry in (Get-Content -Raw -LiteralPath $database | ConvertFrom-Json)) {
+        # Resource compiles are in the database too; the MSBuild side has only cl.exe.
+        if ($entry.file -match '\.rc$') { continue }
         $arguments = if ($entry.arguments) { @($entry.arguments | Select-Object -Skip 1) }
                      else { @(Split-CommandLine $entry.command | Select-Object -Skip 1) }
         $fo = $arguments | Where-Object { $_ -match '^[/-]Fo' } | Select-Object -First 1
@@ -335,7 +348,7 @@ function Read-CMakeCommands([string] $buildDir, [string] $logPath, [string] $bin
         $set = ConvertTo-OptionSet $arguments $entry.directory $placeholders @('.c', '.cpp', '.cxx', '.cc')
         $source = Get-NormalizedPath $entry.file $entry.directory $placeholders
         $target = if ($intDir -match '\\CMakeFiles\\(?<t>[^\\]+)\.dir') { $Matches['t'] } else { '' }
-        $compiles["$target $source"] = [pscustomobject]@{
+        $compiles[(Get-SourceKey $target $source)] = [pscustomobject]@{
             Target  = $target
             Source  = $source
             Options = Merge-VcpkgPlatform $set.Options
@@ -407,6 +420,31 @@ function Compare-OptionSets($reference, $actual) {
     return [pscustomobject]@{ Lost = $lost; Added = $added }
 }
 
+# Moves the differences that match a pattern into 'Explained', with the reason.
+function Split-ExplainedDifferences($diff, $patterns) {
+    $explained = [ordered]@{}
+    $lost = @(); $added = @()
+    foreach ($pair in @(@{ Items = $diff.Lost; Kind = 'lost' }, @{ Items = $diff.Added; Kind = 'added' })) {
+        foreach ($option in $pair.Items) {
+            $reason = $null
+            foreach ($pattern in $patterns.Keys) {
+                if ($option -match $pattern) { $reason = $patterns[$pattern]; break }
+            }
+            if ($reason) { $explained["$($pair.Kind) $option"] = $reason }
+            elseif ($pair.Kind -eq 'lost') { $lost += $option }
+            else { $added += $option }
+        }
+    }
+    return [pscustomobject]@{ Lost = $lost; Added = $added; Explained = $explained }
+}
+
+# MIDL output lives in different directories in the two builds (D3); key the
+# generated sources by file name.
+function Get-SourceKey([string] $target, [string] $source) {
+    if ($source -match '^<(intdir|builddir)>/(?:.*/)?(?<file>[^/]+_i\.c)$') { $source = "<generated>/$($Matches['file'])" }
+    return "$target $source"
+}
+
 # --- MSBuild baseline ------------------------------------------------------
 
 if (-not $MSBuildBinDirectory) {
@@ -462,8 +500,9 @@ if ($CMakeBuildDir) {
         }
         $diff = Compare-OptionSets $reference.Options $actual.Options
         if ($diff.Lost.Count -or $diff.Added.Count) {
-            $compileDiff[$key] = $diff
-            $lostTotal += $diff.Lost.Count
+            $split = Split-ExplainedDifferences $diff $explainedCompileDifferences
+            $compileDiff[$key] = $split
+            $lostTotal += $split.Lost.Count
         }
     }
     foreach ($key in ($cmakeCommands.Compiles.Keys | Where-Object { -not $msbuildCommands.Compiles.ContainsKey($_) })) {
@@ -482,22 +521,10 @@ if ($CMakeBuildDir) {
             continue
         }
         $diff = Compare-OptionSets $msbuildCommands.Links[$binary] $cmakeCommands.Links[$binary]
-        $explained = [ordered]@{}
-        $lost = @(); $added = @()
-        foreach ($pair in @(@{ Items = $diff.Lost; Kind = 'lost' }, @{ Items = $diff.Added; Kind = 'added' })) {
-            foreach ($option in $pair.Items) {
-                $reason = $null
-                foreach ($pattern in $explainedLinkDifferences.Keys) {
-                    if ($option -match $pattern) { $reason = $explainedLinkDifferences[$pattern]; break }
-                }
-                if ($reason) { $explained["$($pair.Kind) $option"] = $reason }
-                elseif ($pair.Kind -eq 'lost') { $lost += $option }
-                else { $added += $option }
-            }
-        }
         if ($diff.Lost.Count -or $diff.Added.Count) {
-            $linkDiff[$binary] = [pscustomobject]@{ Lost = $lost; Added = $added; Explained = $explained }
-            $lostTotal += $lost.Count
+            $split = Split-ExplainedDifferences $diff $explainedLinkDifferences
+            $linkDiff[$binary] = $split
+            $lostTotal += $split.Lost.Count
         }
     }
 

diff --git a/cmake/MwgCompilerOptions.cmake b/cmake/MwgCompilerOptions.cmake
@@ -41,6 +41,8 @@ function(mwg_apply_common_options target)
         "$<${c_cxx}:/utf-8;/Zc:__cplusplus;/Zc:preprocessor;/Zc:throwingNew;/bigobj>"
         # ConformanceMode, SDLCheck, ExceptionHandling and MSBuild defaults
         "$<${c_cxx}:/permissive-;/sdl;/EHsc;/GS;/Gd;/Gm-;/fp:precise;/Zc:wchar_t;/Zc:forScope;/Zc:inline>"
+        # CMake passes /TP for C++ but not /TC for C (the MIDL _i.c).
+        "$<$<COMPILE_LANGUAGE:C>:/TC>"
         "$<${debug}:/Od;/JMC>"
         "$<${release}:/O2;/Oi;/Gy;/guard:cf>"
     )

diff --git a/cmake/MwgMidl.cmake b/cmake/MwgMidl.cmake
@@ -0,0 +1,111 @@
+# SPDX-License-Identifier: MPL-2.0
+#
+# mwg_add_midl_target(<target> IDL <file.idl> [OUTPUT_DIR <dir>] [DEPENDS <file>...])
+#
+# Runs midl.exe through one explicit custom command for every generator (only
+# the Visual Studio generators understand .idl sources), see
+# docs/CMAKE-MIGRATION.md (D3). Creates:
+#
+#   <target>            custom target that owns the MIDL invocation
+#   <target>.Generated  INTERFACE library: the MIDL output include directory,
+#                       for the OCX and the tests
+#
+# and sets, in the caller's scope:
+#   <target>_HEADER  <name>_i.h
+#   <target>_IID     <name>_i.c (C, compile with the consumer)
+#   <target>_TLB     <name>.tlb
+#   <target>_DIR     output directory
+#
+# The options match the MSBuild Midl task: /W1 /char signed /env x64|win32
+# /target "NT60". This IDL declares no non-automation interfaces, so MIDL
+# writes no proxy or dlldata file; they are redirected into the output
+# directory anyway and are not declared as outputs.
+
+function(_mwg_find_midl out_var)
+    # The MSBuild Midl task uses the SDK's x86 midl.exe; any host build works.
+    set(hints "")
+    if(CMAKE_RC_COMPILER)
+        get_filename_component(rc_dir "${CMAKE_RC_COMPILER}" DIRECTORY)
+        get_filename_component(sdk_bin "${rc_dir}" DIRECTORY)
+        list(APPEND hints "${rc_dir}" "${sdk_bin}/x64" "${sdk_bin}/x86")
+    endif()
+    find_program(MWG_MIDL_EXECUTABLE midl HINTS ${hints} DOC "MIDL compiler from the Windows SDK")
+    if(NOT MWG_MIDL_EXECUTABLE)
+        message(FATAL_ERROR
+            "midl.exe was not found. It ships with the Windows SDK ${MWG_WINDOWS_SDK}; "
+            "configure from a Visual Studio toolchain (CLion) or a VS 2026 Developer PowerShell.")
+    endif()
+    set(${out_var} "${MWG_MIDL_EXECUTABLE}" PARENT_SCOPE)
+endfunction()
+
+function(mwg_add_midl_target target)
+    cmake_parse_arguments(PARSE_ARGV 1 arg "" "IDL;OUTPUT_DIR" "DEPENDS")
+    if(NOT arg_IDL)
+        message(FATAL_ERROR "mwg_add_midl_target: IDL is required")
+    endif()
+    if(NOT arg_OUTPUT_DIR)
+        set(arg_OUTPUT_DIR "${CMAKE_CURRENT_BINARY_DIR}/midl")
+    endif()
+
+    _mwg_find_midl(midl)
+
+    # MIDL preprocesses the IDL with cl.exe, which it finds on PATH only. The
+    # Ninja generator inherits the vcvars PATH; the Visual Studio generators
+    # run custom commands in an MSBuild environment that has it. A plain shell
+    # with a cl.exe from CMAKE_C_COMPILER is not enough.
+    if(NOT CMAKE_GENERATOR MATCHES "^Visual Studio")
+        find_program(_mwg_cl_on_path cl NO_CACHE NO_DEFAULT_PATH PATHS ENV PATH)
+        if(NOT _mwg_cl_on_path)
+            message(FATAL_ERROR
+                "cl.exe is not on PATH, but midl.exe needs it to preprocess ${arg_IDL}.\n"
+                "Use a Visual Studio toolchain in CLion, or configure and build from a "
+                "VS 2026 Developer PowerShell (vcvarsall.bat).")
+        endif()
+    endif()
+
+    cmake_path(ABSOLUTE_PATH arg_IDL BASE_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}" OUTPUT_VARIABLE idl)
+    # LAST_ONLY: MapWinGIS.ActiveX.idl -> MapWinGIS.ActiveX
+    cmake_path(GET idl STEM LAST_ONLY name)
+    cmake_path(GET idl PARENT_PATH idl_dir)
+
+    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+        set(env x64)
+    else()
+        set(env win32)
+    endif()
+
+    set(header "${arg_OUTPUT_DIR}/${name}_i.h")
+    set(iid "${arg_OUTPUT_DIR}/${name}_i.c")
+    set(tlb "${arg_OUTPUT_DIR}/${name}.tlb")
+
+    add_custom_command(
+        OUTPUT "${header}" "${iid}" "${tlb}"
+        COMMAND "${CMAKE_COMMAND}" -E make_directory "${arg_OUTPUT_DIR}"
+        COMMAND "${midl}" /W1 /nologo /char signed /env ${env} /target NT60
+            /I "${idl_dir}"
+            /out "${arg_OUTPUT_DIR}"
+            /h "${name}_i.h"
+            /iid "${name}_i.c"
+            /proxy "${name}_p.c"
+            /dlldata dlldata.c
+            /tlb "${name}.tlb"
+            "${idl}"
+        MAIN_DEPENDENCY "${idl}"
+        DEPENDS ${arg_DEPENDS}
+        WORKING_DIRECTORY "${idl_dir}"
+        COMMENT "MIDL ${name}.idl"
+        VERBATIM
+    )
+
+    add_custom_target(${target} DEPENDS "${header}" "${iid}" "${tlb}" SOURCES "${idl}")
+    set_target_properties(${target} PROPERTIES FOLDER "src")
+
+    add_library(${target}.Generated INTERFACE)
+    target_include_directories(${target}.Generated INTERFACE "${arg_OUTPUT_DIR}")
+    add_dependencies(${target}.Generated ${target})
+
+    set(${target}_HEADER "${header}" PARENT_SCOPE)
+    set(${target}_IID "${iid}" PARENT_SCOPE)
+    set(${target}_TLB "${tlb}" PARENT_SCOPE)
+    set(${target}_DIR "${arg_OUTPUT_DIR}" PARENT_SCOPE)
+endfunction()
diff --git a/docs/BUILDING.md b/docs/BUILDING.md
@@ -198,8 +198,11 @@ MSBuild settings and the decisions the CMake build follows are in
 
 ### Building with CMake
 
-The CMake build currently covers `MapWinGIS.Core.dll`; the ActiveX control,
-tests and samples follow. It needs CMake 3.28 or later and Ninja; both ship
+The CMake build currently covers `MapWinGIS.Core.dll` and `MapWinGIS.ocx`; the
+tests and samples follow. The OCX needs the **C++ ATL for latest v145 build
+tools** component for each architecture you build, and `midl.exe` needs `cl.exe`
+on `PATH`, so configure and build from a Visual Studio toolchain (CLion) or a
+Developer PowerShell. CMake 3.28 or later and Ninja are required; both ship
 with Visual Studio 2026 and CLion. Run the bootstrap script first, then
 configure from a VS 2026 Developer PowerShell (or any shell after
 `vcvarsall.bat x64`):
@@ -218,7 +221,11 @@ cmake --build --preset x64-debug
 
 - Output goes to `<build directory>\bin` (`bin\<Config>` for the Visual Studio
   presets) and import libraries to `lib`, never to the MSBuild `bin\` folder, so
-  both builds can be used side by side.
+  both builds can be used side by side. MIDL output (`MapWinGIS.ActiveX_i.h`,
+  `_i.c`, `.tlb`) goes to `<build directory>\src\MapWinGIS.ActiveX\midl`.
+- To register the CMake-built control for the current user:
+  `regsvr32 /n /i:user out\b\x64d\bin\MapWinGIS.ocx` (use
+  `%WINDIR%\SysWOW64\regsvr32.exe` for Win32; add `/u` to unregister).
 - The vcpkg root is found in the same order as above. CMake uses its own install
   tree, `vcpkg_installed\cmake-<Platform>`, shared by Debug and Release; the
   binary cache makes it cheap.

diff --git a/docs/CMAKE-MIGRATION.md b/docs/CMAKE-MIGRATION.md
@@ -328,3 +328,31 @@ Measured for Debug and Release, x64 and Win32 (Ninja presets):
   by default for that platform.
 - `dumpbin`: identical dependents, exports (260), subsystem and DLL
   characteristics.
+
+### MapWinGIS.ActiveX (Phase 2)
+
+Measured for Debug and Release, x64 and Win32 (Ninja presets):
+
+- Compile and link options: none lost; 0 warnings. Explained differences:
+  - The MIDL include directory is `<build>/src/MapWinGIS.ActiveX/midl`
+    instead of the intermediate directory (D3); the generated `_i.c` is
+    compared by file name.
+  - No vcpkg include directory: the OCX has no direct vcpkg dependency.
+  - The compiled resource is named `MapWinGIS.ActiveX.rc.res`, and the Core
+    import library comes from `target_link_libraries` instead of the project
+    reference.
+- CMake needs two explicit settings to match MSBuild: `DEFINE_SYMBOL ""` (no
+  `MapWinGIS_ActiveX_EXPORTS`; the `.def` file exports the entry points) and
+  `/TC` for C sources (CMake passes `/TP` for C++ only).
+- `dumpbin`: identical dependents, the five COM exports, subsystem and DLL
+  characteristics.
+- The generated type library is byte-identical to the MSBuild one, and
+  `MapWinGIS.ActiveX_i.h` is identical below its generated header comment.
+- MIDL runs through one custom command for all generators
+  (`cmake/MwgMidl.cmake`) with the MSBuild options. This IDL produces no
+  proxy or `dlldata.c`; MIDL is told to write them into the output directory
+  anyway, so nothing can land in the source tree.
+- Per-user registration (`regsvr32 /n /i:user`), `New-Object -ComObject
+  MapWinGIS6.Control` and unregistration work for the x64 and Win32 OCX.
+- Three clean `-j32` Ninja builds in a row succeeded (no MIDL/RC race), and the
+  Visual Studio generator builds x64 Debug/Release and x86 Debug.
diff --git a/src/MapWinGIS.ActiveX/CMakeLists.txt b/src/MapWinGIS.ActiveX/CMakeLists.txt
@@ -0,0 +1,99 @@
+# SPDX-License-Identifier: MPL-2.0
+#
+# MapWinGIS.ocx: thin ActiveX/COM wrapper over MapWinGIS.Core (static ATL,
+# apartment threaded).
+
+include(MwgMidl)
+
+mwg_add_midl_target(MapWinGIS.ActiveX.Interface IDL MapWinGIS.ActiveX.idl)
+
+# Compiled into the OCX and, with MWG_ENABLE_RENDERER_TEST_HOOKS, into the
+# tests (docs/CMAKE-MIGRATION.md, D4).
+set(MWG_ACTIVEX_SHARED_SOURCES
+    ComConversion.cpp
+    GdalOperationDispatcher.cpp
+    GdiVectorLayerRenderer.cpp
+    OpenGlVectorLayerRenderer.cpp
+    VectorLayerRenderer.cpp
+    ViewTransform.cpp
+)
+list(TRANSFORM MWG_ACTIVEX_SHARED_SOURCES PREPEND "${CMAKE_CURRENT_SOURCE_DIR}/"
+    OUTPUT_VARIABLE MWG_ACTIVEX_SHARED_SOURCES)
+set(MWG_ACTIVEX_SHARED_SOURCES "${MWG_ACTIVEX_SHARED_SOURCES}" PARENT_SCOPE)
+
+set(MWG_ACTIVEX_HEADERS
+    ActiveXModule.h
+    ComConversion.h
+    GdalDispatchWindow.h
+    GdalEventSource.h
+    GdalOperationDispatcher.h
+    GdiVectorLayerRenderer.h
+    MapWinGISControl.h
+    OpenGlVectorLayerRenderer.h
+    VectorLayerRenderer.h
+    VectorRenderBackend.h
+    ViewTransform.h
+    resource.h
+)
+
+set(MWG_ACTIVEX_SOURCES
+    ActiveXModule.cpp
+    GdalEventSource.cpp
+    MapWinGISControl.cpp
+)
+
+set(MWG_ACTIVEX_RESOURCES
+    MapWinGIS.ActiveX.rc
+    MapWinGIS.ActiveX.def
+    MapWinGISControl.rgs
+)
+
+# SHARED, not MODULE: keeps the import library and the runtime-DLL handling.
+add_library(MapWinGIS.ActiveX SHARED)
+
+target_sources(MapWinGIS.ActiveX PRIVATE
+    ${MWG_ACTIVEX_HEADERS}
+    ${MWG_ACTIVEX_SOURCES}
+    ${MWG_ACTIVEX_SHARED_SOURCES}
+    ${MWG_ACTIVEX_RESOURCES}
+    "${MapWinGIS.ActiveX.Interface_HEADER}"
+    "${MapWinGIS.ActiveX.Interface_IID}"
+)
+source_group("Header Files" FILES ${MWG_ACTIVEX_HEADERS})
+source_group("Source Files" FILES ${MWG_ACTIVEX_SOURCES} ${MWG_ACTIVEX_SHARED_SOURCES})
+source_group("Resource Files" FILES ${MWG_ACTIVEX_RESOURCES})
+source_group("Generated Files" FILES
+    "${MapWinGIS.ActiveX.Interface_HEADER}"
+    "${MapWinGIS.ActiveX.Interface_IID}")
+
+# The .rc embeds the generated type library (1 TYPELIB "MapWinGIS.ActiveX.tlb");
+# rc's dependency scanner does not see it.
+set_source_files_properties(MapWinGIS.ActiveX.rc PROPERTIES
+    OBJECT_DEPENDS "${MapWinGIS.ActiveX.Interface_TLB};${CMAKE_CURRENT_SOURCE_DIR}/MapWinGISControl.rgs")
+
+target_link_libraries(MapWinGIS.ActiveX PRIVATE
+    MapWinGIS::Core
+    MapWinGIS.ActiveX.Interface.Generated
+    # Explicit Windows libraries (audit). ATL is static: atlbase.h links
+    # atls.lib through #pragma comment, and OpenGlVectorLayerRenderer.cpp links
+    # opengl32.lib the same way.
+    ole32 oleaut32 uuid user32 gdi32 advapi32 kernel32
+)
+
+target_compile_definitions(MapWinGIS.ActiveX PRIVATE "$<$<COMPILE_LANGUAGE:C,CXX>:_ATL_APARTMENT_THREADED>")
+
+# MSBuild ResourceCompile: /l 0x0409 and the MIDL output directory on the include path.
+target_compile_options(MapWinGIS.ActiveX PRIVATE "$<$<COMPILE_LANGUAGE:RC>:/l0x0409>")
+
+mwg_apply_common_options(MapWinGIS.ActiveX)
+
+set_target_properties(MapWinGIS.ActiveX PROPERTIES
+    OUTPUT_NAME MapWinGIS
+    SUFFIX ".ocx"
+    # The COM entry points are exported through MapWinGIS.ActiveX.def; no
+    # <target>_EXPORTS macro, as in MSBuild.
+    DEFINE_SYMBOL ""
+    FOLDER "src"
+)
+
+add_dependencies(MapWinGIS.ActiveX MapWinGIS.ActiveX.Interface)
Original file line number	Diff line number	Diff line change
Expand Up		@@ -70,3 +70,4 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
		mwg_add_runtime_data_target()

		add_subdirectory(src/MapWinGIS.Core)
		add_subdirectory(src/MapWinGIS.ActiveX)