feat(pkg): opencv 0.0.4 — module-level dnn/unifont features (import opencv.dnn)

opencv-m v0.0.4 exposes compat.opencv's optional features through the module
package via mcpp#243 dep/feat forwarding. Bump 0.0.3 -> 0.0.4 (v0.0.4 tarball
GLOBAL + CN mirror, sha256 a2e95e8b…; byte-identical, mirror-cn verified).

Adds two end-to-end workspace members exercising the consumer path
(opencv = { features = ["dnn"|"unifont"] } -> import opencv.dnn / the "uni"
FontFace): tests/examples/opencv-module-{dnn,unifont}. They reuse the
compat.opencv+dnn / +unifont store artifacts already built by the compat-level
opencv-dnn / opencv-unifont members, so no extra heavy build. opencv-module
repinned to 0.0.4.

Member test TUs are import-only (`import std; import opencv.cv[/.dnn];`) — no
textual headers, matching the ffmpeg-module member convention (import std works
alongside the opencv module packages on gcc16).

Validated on mcpp 0.0.99: opencv-m PR#5 green; index CI compat builds green
(dnn feature ok, unifont ink=1301, FFmpeg roundtrip).

Author: Sunrisepeak

mcpp.toml

@@ -29,6 +29,8 @@ members = [
     "tests/examples/opencv-unifont",
     "tests/examples/opencv-dnn",
     "tests/examples/opencv-module",
+    "tests/examples/opencv-module-dnn",
+    "tests/examples/opencv-module-unifont",
     "tests/examples/spdlog",
     "tests/examples/spdlog-compiled",
     "tests/examples/tinyhttps",

pkgs/o/opencv.lua

@@ -2,12 +2,14 @@
 -- mcpp.toml. mcpp's default lookup finds <verdir>/*/mcpp.toml inside
 -- the GitHub source tarball wrap.
 --
--- The package is the thin C++23 module layer (import opencv.cv; and 7
+-- The package is the thin C++23 module layer (import opencv.cv; and the
 -- per-module interfaces) over OpenCV 5's unchanged C++ API; the OpenCV
 -- sources themselves arrive through its compat.opencv dependency (full
 -- source build with SIMD dispatch + build.mcpp consumer-side synthesis,
--- plus the compat.ffmpeg videoio backend — see pkgs/c/compat.opencv.lua;
--- the transitional compat.opencv5 alias is retired as of this bump).
+-- plus the compat.ffmpeg videoio backend — see pkgs/c/compat.opencv.lua).
+-- Optional features (0.0.4+, mcpp#243 forwarding): `dnn` adds the
+-- import opencv.dnn; interface and forwards compat.opencv/dnn; `unifont`
+-- forwards compat.opencv/unifont — `opencv = { features = ["dnn"] }`.
 -- Linux-only for now: compat.opencv carries a linux-x86_64 config snapshot.
 --
 package = {
@@ -21,12 +23,12 @@ package = {
 
     xpm = {
         linux = {
-            ["0.0.3"] = {
+            ["0.0.4"] = {
                 url    = {
-                    GLOBAL = "https://github.com/Sunrisepeak/opencv-m/archive/refs/tags/v0.0.3.tar.gz",
-                    CN     = "https://gitcode.com/mcpp-res/opencv/releases/download/v0.0.3/opencv-m-0.0.3.tar.gz",
+                    GLOBAL = "https://github.com/Sunrisepeak/opencv-m/archive/refs/tags/v0.0.4.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/opencv/releases/download/v0.0.4/opencv-m-0.0.4.tar.gz",
                 },
-                sha256 = "92ffae8bc4253538143319fba59d4933831a92bb03394126baae2f0a3d4b0e2b",
+                sha256 = "a2e95e8b22ae66712e3f78809426e058330073c2679a21c2b2d500faa0b4964f",
             },
         },
     },

tests/examples/opencv-module-dnn/mcpp.toml

@@ -0,0 +1,15 @@
+# Public `opencv` module package `dnn` FEATURE test: `opencv = { features =
+# ["dnn"] }` forwards compat.opencv/dnn (mcpp#243) AND compiles opencv-m's
+# opencv.dnn interface, so `import opencv.dnn;` is available. Reuses the
+# compat.opencv+dnn store artifact built by the opencv-dnn member (same feature
+# set — no extra heavy build). Linux-only (compat.opencv linux snapshot);
+# off-Linux the test compiles to a no-op main().
+[package]
+name    = "opencv-module-dnn-tests"
+version = "0.1.0"
+
+[indices]
+default = { path = "../../.." }
+
+[target.'cfg(linux)'.dependencies]
+opencv = { version = "0.0.4", features = ["dnn"] }

tests/examples/opencv-module-dnn/tests/opencv_dnn_iface.cpp

@@ -0,0 +1,27 @@
+// The opencv.dnn MODULE interface (not textual headers) must expose the dnn
+// surface when opencv is pulled with features=["dnn"] — proves the module-level
+// dep/feat forward compiled src/dnn.cppm and built compat.opencv with dnn.
+// Linux-only (see mcpp.toml). Not named dnn.cpp (would collide with the dep's
+// modules/dnn/src/dnn.cpp — #240 family). Import-only (import std + the opencv
+// modules): no textual headers, matching the ffmpeg-module member convention.
+#ifdef __linux__
+import std;
+import opencv.cv;
+import opencv.dnn;
+
+int main() {
+    cv::Mat img(32, 32, cv::CV_8UC3, cv::Scalar(10, 20, 30));
+    cv::Mat blob = cv::dnn::blobFromImage(img, 1.0 / 255.0, cv::Size(16, 16),
+                                          cv::Scalar(), true, false);
+    if (blob.dims != 4 || blob.size[0] != 1 || blob.size[1] != 3
+        || blob.size[2] != 16 || blob.size[3] != 16) return 1;
+    float v = blob.ptr<float>(0)[0];
+    if (v < 0.117f || v > 0.118f) return 2;   // 30/255, channels swapped
+    cv::dnn::Net net;
+    if (!net.empty()) return 3;
+    std::println("opencv.dnn module ok: blobFromImage 1x3x16x16 first={}", v);
+    return 0;
+}
+#else
+int main() { return 0; }
+#endif

tests/examples/opencv-module-unifont/mcpp.toml

@@ -0,0 +1,14 @@
+# Public `opencv` module package `unifont` FEATURE test: `opencv = { features =
+# ["unifont"] }` forwards compat.opencv/unifont (mcpp#243 — pure forward, no new
+# module surface), so FontFace("uni") renders CJK through `import opencv.cv;`.
+# Reuses the compat.opencv+unifont store artifact from the opencv-unifont member.
+# Linux-only; no-op main elsewhere.
+[package]
+name    = "opencv-module-unifont-tests"
+version = "0.1.0"
+
+[indices]
+default = { path = "../../.." }
+
+[target.'cfg(linux)'.dependencies]
+opencv = { version = "0.0.4", features = ["unifont"] }

tests/examples/opencv-module-unifont/tests/opencv_unifont_iface.cpp

@@ -0,0 +1,20 @@
+// The "uni" FontFace only exists when opencv's unifont feature forwarded
+// compat.opencv/unifont — CJK rendering through the module layer must ink.
+// Linux-only (see mcpp.toml). Import-only (import std + opencv.cv): no textual
+// headers, matching the ffmpeg-module member convention.
+#ifdef __linux__
+import std;
+import opencv.cv;
+
+int main() {
+    cv::FontFace uni("uni");
+    cv::Mat img(64, 256, cv::CV_8UC1, cv::Scalar(0));
+    cv::putText(img, "中文字体", cv::Point(8, 44), cv::Scalar(255), uni, 28);
+    int ink = cv::countNonZero(img);
+    if (ink < 100) { std::println("opencv.unifont: CJK ink {} too low", ink); return 1; }
+    std::println("opencv.unifont module ok: CJK putText ink={}", ink);
+    return 0;
+}
+#else
+int main() { return 0; }
+#endif

tests/examples/opencv-module/mcpp.toml

@@ -17,4 +17,4 @@ version = "0.1.0"
 default = { path = "../../.." }
 
 [target.'cfg(linux)'.dependencies]
-opencv = "0.0.3"
+opencv = "0.0.4"