build(linux): switch to vcpkg static linking for libpict.so

Linux/arm64 CI now uses vcpkg with x64-linux-static / arm64-linux-static
triplets instead of apt + pkg-config. This statically links libavif,
libwebp, libjpeg-turbo, and libpng into libpict.so, eliminating runtime
dependencies on system shared libraries.

- Add cmake/triplets/x64-linux-static.cmake
- Add cmake/triplets/arm64-linux-static.cmake
- CMakeLists.txt: extend WIN32 guard to VCPKG_TARGET_TRIPLET so Linux
  uses find_package (vcpkg) path when triplet is set
- build.yml: replace apt deps + plain cmake with vcpkg install + Ninja

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tsukasa-art

.github/workflows/build.yml

@@ -13,16 +13,32 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Install dependencies
+      - name: Install build tools
         run: |
           sudo apt-get update -qq
-          sudo apt-get install -y cmake pkg-config \
-            libavif-dev libwebp-dev libjpeg-dev libpng-dev
+          sudo apt-get install -y cmake ninja-build pkg-config curl zip unzip tar
+      - name: Cache vcpkg
+        uses: actions/cache@v4
+        with:
+          path: ${{ github.workspace }}/vcpkg_installed
+          key: vcpkg-x64-linux-static-${{ hashFiles('vcpkg.json') }}-v1
+      - name: Install vcpkg dependencies
+        run: |
+          vcpkg install --triplet x64-linux-static \
+            --overlay-triplets=cmake/triplets \
+            --x-install-root=${{ github.workspace }}/vcpkg_installed
       - uses: oven-sh/setup-bun@v2
         with:
           bun-version: latest
       - name: Build
-        run: cmake -S . -B build -DCMAKE_BUILD_TYPE=Release && cmake --build build --parallel
+        run: |
+          cmake -S . -B build -G Ninja \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_TOOLCHAIN_FILE="$VCPKG_INSTALLATION_ROOT/scripts/buildsystems/vcpkg.cmake" \
+            -DVCPKG_TARGET_TRIPLET=x64-linux-static \
+            -DVCPKG_OVERLAY_TRIPLETS=cmake/triplets \
+            -DVCPKG_INSTALLED_DIR=${{ github.workspace }}/vcpkg_installed
+          cmake --build build --parallel
       - name: Test — Lanczos-3 precision
         run: bun run test/lanczos_precision.ts
       - name: Test — ops precision
@@ -37,16 +53,32 @@ jobs:
     runs-on: ubuntu-24.04-arm
     steps:
       - uses: actions/checkout@v4
-      - name: Install dependencies
+      - name: Install build tools
         run: |
           sudo apt-get update -qq
-          sudo apt-get install -y cmake pkg-config \
-            libavif-dev libwebp-dev libjpeg-dev libpng-dev
+          sudo apt-get install -y cmake ninja-build pkg-config curl zip unzip tar
+      - name: Cache vcpkg
+        uses: actions/cache@v4
+        with:
+          path: ${{ github.workspace }}/vcpkg_installed
+          key: vcpkg-arm64-linux-static-${{ hashFiles('vcpkg.json') }}-v1
+      - name: Install vcpkg dependencies
+        run: |
+          vcpkg install --triplet arm64-linux-static \
+            --overlay-triplets=cmake/triplets \
+            --x-install-root=${{ github.workspace }}/vcpkg_installed
       - uses: oven-sh/setup-bun@v2
         with:
           bun-version: latest
       - name: Build
-        run: cmake -S . -B build -DCMAKE_BUILD_TYPE=Release && cmake --build build --parallel
+        run: |
+          cmake -S . -B build -G Ninja \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_TOOLCHAIN_FILE="$VCPKG_INSTALLATION_ROOT/scripts/buildsystems/vcpkg.cmake" \
+            -DVCPKG_TARGET_TRIPLET=arm64-linux-static \
+            -DVCPKG_OVERLAY_TRIPLETS=cmake/triplets \
+            -DVCPKG_INSTALLED_DIR=${{ github.workspace }}/vcpkg_installed
+          cmake --build build --parallel
       - name: Test — Lanczos-3 precision
         run: bun run test/lanczos_precision.ts
       - name: Test — ops precision

CMakeLists.txt

@@ -60,14 +60,16 @@ set_target_properties(pict PROPERTIES
 target_include_directories(pict PRIVATE ${CMAKE_SOURCE_DIR}/include)
 
 # ── Platform-specific dependencies ────────────────────────────────────────
-if(WIN32)
-  # vcpkg provides these via CMAKE_TOOLCHAIN_FILE
+# vcpkg path: Windows always, Linux/macOS when VCPKG_TARGET_TRIPLET is set
+if(WIN32 OR DEFINED VCPKG_TARGET_TRIPLET)
   find_package(libavif CONFIG REQUIRED)
   find_package(WebP    CONFIG REQUIRED)
   find_package(JPEG           REQUIRED)
   find_package(PNG            REQUIRED)
 
-  target_compile_definitions(pict PRIVATE PICT_DISABLE_HEIC)
+  if(WIN32)
+    target_compile_definitions(pict PRIVATE PICT_DISABLE_HEIC)
+  endif()
   target_link_libraries(pict PRIVATE
     avif
     WebP::webp WebP::webpdemux WebP::libwebpmux

cmake/triplets/arm64-linux-static.cmake

@@ -0,0 +1,4 @@
+set(VCPKG_TARGET_ARCHITECTURE arm64)
+set(VCPKG_CRT_LINKAGE dynamic)
+set(VCPKG_LIBRARY_LINKAGE static)
+set(VCPKG_CMAKE_SYSTEM_NAME Linux)

cmake/triplets/x64-linux-static.cmake

@@ -0,0 +1,4 @@
+set(VCPKG_TARGET_ARCHITECTURE x64)
+set(VCPKG_CRT_LINKAGE dynamic)
+set(VCPKG_LIBRARY_LINKAGE static)
+set(VCPKG_CMAKE_SYSTEM_NAME Linux)