fix: select supported CPU compute devices for modern Vision OCR

.github/workflows/release.yml

@@ -31,6 +31,7 @@ jobs:
         uses: dtolnay/rust-toolchain@4be7066ada62dd38de10e7b70166bc74ed198c30 # stable
 
       - name: Cache current macOS OCR dependencies
+        id: ocr-cache
         uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
         with:
           path: |
@@ -51,6 +52,24 @@ jobs:
         run: |
           cargo test --manifest-path src-tauri/Cargo.toml ocr:: -- --nocapture
 
+      - name: Diagnose native Vision if OCR fails
+        if: failure()
+        run: |
+          fixture_dir="$RUNNER_TEMP/ttree-ocr-diagnostics"
+          mkdir -p "$fixture_dir"
+          swift src-tauri/src/ocr/tests/generate-fixtures.swift "$fixture_dir"
+          swift src-tauri/src/ocr/tests/diagnose-vision.swift "$fixture_dir/english.png"
+
+      - name: Save compiled OCR dependencies
+        if: always() && steps.ocr-cache.outputs.cache-hit != 'true'
+        uses: actions/cache/save@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            src-tauri/target
+          key: macos-27-ocr-${{ hashFiles('src-tauri/Cargo.lock') }}
+
   verify:
     needs: ocr-current-macos
     runs-on: macos-14

src-tauri/Cargo.lock

@@ -4472,6 +4472,7 @@ dependencies = [
  "objc2-app-kit",
  "objc2-core-foundation",
  "objc2-core-graphics",
+ "objc2-core-ml",
  "objc2-foundation",
  "objc2-image-io",
  "objc2-vision",

src-tauri/Cargo.toml

@@ -38,6 +38,7 @@ core-foundation = "0.10"
 security-framework = "3"
 objc2 = "0.6"
 objc2-core-foundation = "0.3"
+objc2-core-ml = { version = "0.3", features = ["MLCPUComputeDevice", "MLComputeDeviceProtocol"] }
 objc2-image-io = { version = "0.3", features = ["CGImageSource"] }
 objc2-app-kit = { version = "0.3", features = [
     "NSPasteboard",
@@ -62,6 +63,7 @@ objc2-foundation = { version = "0.3", features = [
 ] }
 objc2-vision = { version = "0.3", features = [
     "objc2-core-graphics",
+    "objc2-core-ml",
     "VNRequest",
     "VNRecognizeTextRequest",
     "VNObservation",

src-tauri/src/ocr/tests/diagnose-vision.swift

@@ -0,0 +1,62 @@
+// CI-only comparison against Apple's minimal Vision request; synthetic text only.
+import Foundation
+import ImageIO
+import Vision
+import CoreML
+
+let file = URL(fileURLWithPath: CommandLine.arguments[1])
+let data = try Data(contentsOf: file)
+let source = CGImageSourceCreateWithData(data as CFData, nil)!
+let image = CGImageSourceCreateImageAtIndex(source, 0, nil)!
+print("Vision default revision: \(VNRecognizeTextRequest.defaultRevision)")
+print("Vision supported revisions: \(VNRecognizeTextRequest.supportedRevisions)")
+
+func assignCPU(_ request: VNRecognizeTextRequest) throws {
+    if #available(macOS 14.0, *) {
+        let stages = try request.supportedComputeStageDevices()
+        for (stage, devices) in stages {
+            print("compute stage \(stage): \(devices)")
+            if let cpu = devices.first(where: { $0 is MLCPUComputeDevice }) {
+                request.setComputeDevice(cpu, for: stage)
+            }
+        }
+    }
+}
+
+let profiles: [(String, (VNRecognizeTextRequest) throws -> Void)] = [
+    ("apple-default", { _ in }),
+    ("default-explicit-cpu", { try assignCPU($0) }),
+    ("rev3-english-cpu", { request in
+        request.revision = 3
+        request.recognitionLanguages = ["en-US"]
+        try assignCPU(request)
+    }),
+    ("rev3-chinese-english-cpu", { request in
+        request.revision = 3
+        request.recognitionLanguages = ["zh-Hans", "zh-Hant", "en-US"]
+        try assignCPU(request)
+    }),
+    ("rev2-chinese-english-cpu", { request in
+        request.revision = 2
+        request.recognitionLanguages = ["zh-Hans", "zh-Hant", "en-US"]
+        try assignCPU(request)
+    }),
+    ("fast-english-cpu", { request in
+        request.recognitionLevel = .fast
+        request.recognitionLanguages = ["en-US"]
+        try assignCPU(request)
+    }),
+]
+for (name, configure) in profiles {
+    do {
+        let request = VNRecognizeTextRequest()
+        try configure(request)
+        let handler = VNImageRequestHandler(cgImage: image, options: [:])
+        try handler.perform([request])
+        let text = request.results?.compactMap { $0.topCandidates(1).first?.string }.joined(separator: "\n") ?? ""
+        print("\(name): OK \(text)")
+    } catch {
+        let error = error as NSError
+        print("\(name): ERROR domain=\(error.domain) code=\(error.code) details=\(error.userInfo)")
+    }
+}

src-tauri/src/ocr/vision.rs

@@ -6,9 +6,10 @@
 #![cfg(target_os = "macos")]
 
 use objc2::rc::{autoreleasepool, Retained};
-use objc2::AnyThread;
+use objc2::{AnyThread, ClassType};
 use objc2_core_graphics::CGImage;
-use objc2_foundation::{NSArray, NSString};
+use objc2_core_ml::MLCPUComputeDevice;
+use objc2_foundation::{NSArray, NSObjectProtocol, NSString};
 use objc2_vision::{VNImageRequestHandler, VNRecognizeTextRequest, VNRequestTextRecognitionLevel};
 
 /// 对指定图片文件路径执行 OCR，返回识别文本（按行拼接）。
@@ -85,11 +86,6 @@ fn configure_request(request: &VNRecognizeTextRequest, compatibility: bool) -> R
     unsafe {
         request.setRevision(revision);
         request.setPreferBackgroundProcessing(true);
-        if compatibility {
-            // macOS 11 也必须支持回退，因此保留兼容的 CPU-only API。
-            #[allow(deprecated)]
-            request.setUsesCPUOnly(true);
-        }
     }
     if objc2::available!(macos = 13.0) {
         request.setAutomaticallyDetectsLanguage(!compatibility);
@@ -116,6 +112,41 @@ fn configure_request(request: &VNRecognizeTextRequest, compatibility: bool) -> R
     if !languages.is_empty() {
         request.setRecognitionLanguages(&NSArray::from_retained_slice(&languages));
     }
+    // 新系统后台 OCR 不能依赖 ANE 自动选择。旧 usesCPUOnly 属性在新
+    // Vision 上不足以保证 CPU 执行，必须按模型支持的计算阶段显式选择。
+    if compatibility || objc2::available!(macos = 27.0) {
+        configure_cpu(request)?;
+    }
+    Ok(())
+}
+
+fn configure_cpu(request: &VNRecognizeTextRequest) -> Result<(), String> {
+    // SAFETY: 新计算设备 API 和 MLCPUComputeDevice 从 macOS 14 才可用。
+    unsafe {
+        if objc2::available!(macos = 14.0) {
+            let stages = request
+                .supportedComputeStageDevicesAndReturnError()
+                .map_err(|error| format!("读取 OCR 计算设备失败: {error}"))?;
+            let mut assigned = false;
+            for stage in stages.allKeys().iter() {
+                if let Some(devices) = stages.objectForKey(stage) {
+                    if let Some(cpu) = devices
+                        .iter()
+                        .find(|device| device.isKindOfClass(MLCPUComputeDevice::class()))
+                    {
+                        request.setComputeDevice_forComputeStage(Some(cpu), stage);
+                        assigned = true;
+                    }
+                }
+            }
+            if !assigned {
+                return Err("此 OCR 模型没有可用的 CPU 计算设备".to_string());
+            }
+        } else {
+            #[allow(deprecated)]
+            request.setUsesCPUOnly(true);
+        }
+    }
     Ok(())
 }