feat: add screenshot OCR extraction

app.go

@@ -23,6 +23,7 @@ import (
 	"github.com/mmmy/snapgo/internal/infrastructure/display"
 	"github.com/mmmy/snapgo/internal/infrastructure/hotkey"
 	llmpkg "github.com/mmmy/snapgo/internal/infrastructure/llm"
+	ocrpkg "github.com/mmmy/snapgo/internal/infrastructure/ocr"
 	"github.com/mmmy/snapgo/internal/infrastructure/oss"
 	"github.com/mmmy/snapgo/internal/infrastructure/screencapture"
 	sshpkg "github.com/mmmy/snapgo/internal/infrastructure/ssh"
@@ -499,6 +500,48 @@ func (a *App) finishSummary(svc *application.CaptureSummaryService, summary stri
 	return nil
 }
 
+func (a *App) runOCRPipeline(pngBytes []byte) error {
+	a.mu.RLock()
+	cfg := a.cfg
+	a.mu.RUnlock()
+
+	if !cfg.IsOCRConfigured() {
+		err := fmt.Errorf("请先在文字提取配置页填写 OCR Provider 的 AccessKey ID 和 AccessKey Secret")
+		a.emitOperationStatus("ocr", "需要配置 OCR", err.Error(), "error")
+		wruntime.EventsEmit(a.ctx, "upload:failure", err.Error())
+		return err
+	}
+
+	providerID, ocrCfg, _ := cfg.ActiveOCRProvider()
+	recognizer, err := ocrpkg.NewClient(providerID, ocrCfg)
+	if err != nil {
+		a.emitOperationStatus("ocr", "OCR 配置错误", err.Error(), "error")
+		wruntime.EventsEmit(a.ctx, "upload:failure", err.Error())
+		return err
+	}
+
+	svc := &application.CaptureOCRService{
+		Recognizer: recognizer,
+		Clipboard:  a.clip,
+	}
+
+	a.emitOperationStatus("ocr", "识别中", "正在提取截图文字", "running")
+	text, err := svc.Recognize(a.ctx, pngBytes)
+	if err != nil {
+		a.emitOperationStatus("ocr", "识别失败", err.Error(), "error")
+		wruntime.EventsEmit(a.ctx, "upload:failure", err.Error())
+		return err
+	}
+	if err := svc.CopyText(a.ctx, text); err != nil {
+		a.emitOperationStatus("ocr", "复制失败", err.Error(), "error")
+		wruntime.EventsEmit(a.ctx, "upload:failure", err.Error())
+		return err
+	}
+	a.emitOperationStatus("ocr", "提取完成", "文字已复制到剪贴板", "success")
+	wruntime.EventsEmit(a.ctx, "upload:success", "ocr text copied to clipboard")
+	return nil
+}
+
 func (a *App) consumePendingCapture() (*pendingCapture, error) {
 	a.pendingMu.Lock()
 	pc := a.pending
@@ -876,6 +919,35 @@ func (a *App) SummarizeRegion(result CaptureResult) error {
 	return a.runSummaryPipeline(cropped)
 }
 
+// ExtractTextRegion sends the selected screenshot to the configured OCR
+// provider and copies the extracted text to the clipboard.
+func (a *App) ExtractTextRegion(result CaptureResult) error {
+	pc, err := a.consumePendingCapture()
+	if err != nil {
+		slog.Warn("ExtractTextRegion: no pending capture", "err", err)
+		return err
+	}
+	defer func() {
+		a.capturing.Store(false)
+		a.dismissOverlay()
+	}()
+
+	a.dismissOverlay()
+	flushFrame()
+
+	slog.Info("ExtractTextRegion: capturing region",
+		"x", result.Rect.X, "y", result.Rect.Y,
+		"w", result.Rect.W, "h", result.Rect.H,
+		"annotations", len(result.Annotations))
+	cropped, err := a.captureSelectedPNG(result, pc)
+	if err != nil {
+		slog.Error("ExtractTextRegion: capture failed", "err", err)
+		wruntime.EventsEmit(a.ctx, "upload:failure", err.Error())
+		return err
+	}
+	return a.runOCRPipeline(cropped)
+}
+
 // SaveNativeRegionToRemote is the macOS-native overlay equivalent of
 // SaveRegionToRemote. The AppKit panel is already closed by the time this
 // runs (see saveRemoteSelection in native_overlay_darwin.go), so we only
@@ -933,6 +1005,33 @@ func (a *App) SummarizeNativeRegion(result CaptureResult) error {
 	return a.runSummaryPipeline(cropped)
 }
 
+// ExtractTextNativeRegion is the macOS-native overlay equivalent of
+// ExtractTextRegion. The AppKit panel is already closed before this runs.
+func (a *App) ExtractTextNativeRegion(result CaptureResult) error {
+	pc, err := a.consumePendingCapture()
+	if err != nil {
+		slog.Warn("ExtractTextNativeRegion: no pending capture", "err", err)
+		return err
+	}
+	defer func() {
+		a.capturing.Store(false)
+		hideDockIcon()
+	}()
+
+	flushFrame()
+	slog.Info("ExtractTextNativeRegion: capturing region",
+		"x", result.Rect.X, "y", result.Rect.Y,
+		"w", result.Rect.W, "h", result.Rect.H,
+		"annotations", len(result.Annotations))
+	cropped, err := a.captureSelectedPNG(result, pc)
+	if err != nil {
+		slog.Error("ExtractTextNativeRegion: capture failed", "err", err)
+		wruntime.EventsEmit(a.ctx, "upload:failure", err.Error())
+		return err
+	}
+	return a.runOCRPipeline(cropped)
+}
+
 func parseNativeAnnotations(raw string) []application.Annotation {
 	if raw == "" {
 		return nil

frontend/src/App.vue

@@ -23,6 +23,7 @@ import {
   SaveRegionImage,
   SaveRegionToRemote,
   SummarizeRegion,
+  ExtractTextRegion,
   CancelRegion,
   GetConfig,
 } from '../wailsjs/go/main/App'
@@ -58,7 +59,7 @@ async function loadThemePreference() {
 // `SettingsTab` is hoisted to the App shell so the sidebar (which lives
 // here) and the inner SettingsView (which renders the matching card) can
 // share a single source of truth without an event bus.
-type SettingsTab = 'general' | 's3' | 'ssh' | 'llm'
+type SettingsTab = 'general' | 's3' | 'ssh' | 'llm' | 'ocr'
 const activeTab = ref<SettingsTab>('general')
 
 // Sidebar entries are declarative so adding a destination type later is
@@ -68,6 +69,7 @@ const sidebarItems: Array<{ id: SettingsTab; label: string }> = [
   { id: 's3', label: '对象存储' },
   { id: 'ssh', label: '远程主机' },
   { id: 'llm', label: '智能识图' },
+  { id: 'ocr', label: '文字提取' },
 ]
 
 interface OverlayPayload {
@@ -233,6 +235,28 @@ async function onOverlaySummarize(rect: {
   }
 }
 
+async function onOverlayOCR(rect: {
+  rect: {
+    x: number
+    y: number
+    w: number
+    h: number
+  }
+  annotations: Array<{
+    tool: string
+    color: string
+    points: Array<{ x: number; y: number }>
+  }>
+}) {
+  mode.value = 'settings'
+  overlayPayload.value = null
+  try {
+    await ExtractTextRegion(rect as any)
+  } catch {
+    /* Surfaced via upload:failure */
+  }
+}
+
 async function onOverlayCancel() {
   mode.value = 'settings'
   overlayPayload.value = null
@@ -264,6 +288,8 @@ onMounted(() => {
       'success',
       url === 'summary copied to clipboard'
         ? 'Summary copied to clipboard'
+        : url === 'ocr text copied to clipboard'
+          ? 'OCR text copied to clipboard'
         : `Copied: ${url}`
     )
   })
@@ -303,6 +329,7 @@ onUnmounted(() => {
     @save="onOverlaySave"
     @save-remote="onOverlaySaveRemote"
     @summarize="onOverlaySummarize"
+    @ocr="onOverlayOCR"
     @cancel="onOverlayCancel"
   />
 

frontend/src/views/CaptureOverlay.vue

@@ -56,6 +56,10 @@ const emit = defineEmits<{
     e: 'summarize',
     payload: { rect: Rect; annotations: Annotation[] }
   ): void
+  (
+    e: 'ocr',
+    payload: { rect: Rect; annotations: Annotation[] }
+  ): void
   (e: 'cancel'): void
 }>()
 
@@ -119,7 +123,7 @@ const sizeLabel = computed(() => {
 })
 
 const MARK_TOOLBAR_W = 222
-const ACTION_TOOLBAR_W = 216
+const ACTION_TOOLBAR_W = 252
 const TOOLBAR_GROUP_GAP = 8
 
 const rightToolbarPos = computed(() => {
@@ -379,7 +383,11 @@ function onSummarize() {
   emitAction('summarize')
 }
 
-function emitAction(action: 'confirm' | 'copy' | 'save' | 'save-remote' | 'summarize') {
+function onOCR() {
+  emitAction('ocr')
+}
+
+function emitAction(action: 'confirm' | 'copy' | 'save' | 'save-remote' | 'summarize' | 'ocr') {
   if (!rect.value) return
   commitTextDraft()
   const payload = {
@@ -391,6 +399,7 @@ function emitAction(action: 'confirm' | 'copy' | 'save' | 'save-remote' | 'summa
   if (action === 'save') emit('save', payload)
   if (action === 'save-remote') emit('save-remote', payload)
   if (action === 'summarize') emit('summarize', payload)
+  if (action === 'ocr') emit('ocr', payload)
 }
 
 function onCancel() {
@@ -716,6 +725,21 @@ onUnmounted(() => {
         @click="onSaveRemote"
         v-html="saveRemoteIcon"
       />
+      <button
+        class="action-btn"
+        data-tip="提取文字"
+        aria-label="提取文字"
+        @click="onOCR"
+      >
+        <svg viewBox="0 0 24 24" aria-hidden="true">
+          <path d="M5 8V5h3" />
+          <path d="M16 5h3v3" />
+          <path d="M19 16v3h-3" />
+          <path d="M8 19H5v-3" />
+          <path d="M9 15l3-7 3 7" />
+          <path d="M10 13h4" />
+        </svg>
+      </button>
       <button
         class="action-btn"
         data-tip="复制总结"
@@ -838,7 +862,7 @@ onUnmounted(() => {
   width: 222px;
 }
 .action-toolbar {
-  width: 216px;
+  width: 252px;
 }
 
 .icon-btn,

frontend/src/views/SettingsView.vue

@@ -9,6 +9,7 @@
  *   • "s3"      — S3-compatible object-storage credentials.
  *   • "ssh"     — SSH/SCP destination for the "save remote" button.
  *   • "llm"     — multimodal screenshot summary provider settings.
+ *   • "ocr"     — cloud OCR provider settings for text extraction.
  *
  * State flow: load() pulls config from Go on mount, save() pushes back.
  */
@@ -23,7 +24,7 @@ import {
 
 // Tab discriminator shared with the App shell. Kept as a string union so
 // the parent can pass the value without importing a type from this view.
-type TabId = 'general' | 's3' | 'ssh' | 'llm'
+type TabId = 'general' | 's3' | 'ssh' | 'llm' | 'ocr'
 type ThemeMode = 'auto' | 'light' | 'dark'
 
 const props = defineProps<{
@@ -74,12 +75,30 @@ interface LLMConfig {
   providers: Record<string, LLMProviderConfig>
 }
 
+interface OCRProviderConfig {
+  label: string
+  endpoint: string
+  accessKeyId: string
+  accessKeySecret: string
+  region: string
+  service: string
+  action: string
+  version: string
+  timeoutSecs: number
+}
+
+interface OCRConfig {
+  activeProvider: string
+  providers: Record<string, OCRProviderConfig>
+}
+
 interface AppConfig {
   hotkey: string
   theme: ThemeMode
   s3: S3Config
   ssh: SSHConfig
   llm: LLMConfig
+  ocr: OCRConfig
 }
 
 const llmProviderOptions = [
@@ -88,6 +107,11 @@ const llmProviderOptions = [
   { id: 'openai', label: 'ChatGPT / OpenAI-compatible' },
 ]
 
+const ocrProviderOptions = [
+  { id: 'aliyun', label: '阿里云文字识别' },
+  { id: 'volcengine', label: '火山引擎文字识别' },
+]
+
 const themeOptions: Array<{ id: ThemeMode; label: string }> = [
   { id: 'light', label: '浅色' },
   { id: 'dark', label: '深色' },
@@ -165,6 +189,33 @@ function defaultConfig(): AppConfig {
         },
       },
     },
+    ocr: {
+      activeProvider: 'aliyun',
+      providers: {
+        aliyun: {
+          label: '阿里云文字识别',
+          endpoint: 'https://ocr-api.cn-hangzhou.aliyuncs.com',
+          accessKeyId: '',
+          accessKeySecret: '',
+          region: '',
+          service: '',
+          action: 'RecognizeGeneral',
+          version: '2021-07-07',
+          timeoutSecs: 30,
+        },
+        volcengine: {
+          label: '火山引擎文字识别',
+          endpoint: 'https://visual.volcengineapi.com',
+          accessKeyId: '',
+          accessKeySecret: '',
+          region: 'cn-north-1',
+          service: 'cv',
+          action: 'OCRNormal',
+          version: '2020-08-26',
+          timeoutSecs: 30,
+        },
+      },
+    },
   }
 }
 
@@ -198,6 +249,15 @@ const activeLLMProvider = computed(() => {
   return config.value.llm.providers[id]
 })
 
+const activeOCRProvider = computed(() => {
+  const id = config.value.ocr.activeProvider || 'aliyun'
+  if (!config.value.ocr.providers[id]) {
+    config.value.ocr.activeProvider = 'aliyun'
+    return config.value.ocr.providers.aliyun
+  }
+  return config.value.ocr.providers[id]
+})
+
 function normalizeTheme(theme: unknown): ThemeMode {
   return theme === 'light' || theme === 'dark' || theme === 'auto'
     ? theme
@@ -225,6 +285,11 @@ async function load() {
       ...defaultConfig().llm.providers,
       ...((cfg as any).llm?.providers ?? {}),
     }
+    merged.ocr = { ...merged.ocr, ...(cfg as any).ocr }
+    merged.ocr.providers = {
+      ...defaultConfig().ocr.providers,
+      ...((cfg as any).ocr?.providers ?? {}),
+    }
     merged.theme = normalizeTheme((cfg as any).theme)
     config.value = merged
     emit('theme-change', config.value.theme)
@@ -586,6 +651,103 @@ onMounted(load)
       </div>
     </section>
 
+    <!-- OCR tab — cloud OCR provider settings for screenshot text extraction. -->
+    <section v-if="props.tab === 'ocr'" class="card">
+      <h2>文字提取</h2>
+      <div class="grid">
+        <label class="field full">
+          <span>Provider</span>
+          <select v-model="config.ocr.activeProvider">
+            <option
+              v-for="provider in ocrProviderOptions"
+              :key="provider.id"
+              :value="provider.id"
+            >
+              {{ provider.label }}
+            </option>
+          </select>
+        </label>
+        <label class="field full">
+          <span>Endpoint *</span>
+          <input
+            v-model="activeOCRProvider.endpoint"
+            placeholder="https://ocr-api.cn-hangzhou.aliyuncs.com"
+            spellcheck="false"
+          />
+        </label>
+        <label class="field">
+          <span>AccessKey ID *</span>
+          <input v-model="activeOCRProvider.accessKeyId" spellcheck="false" />
+        </label>
+        <label class="field">
+          <span>AccessKey Secret *</span>
+          <input v-model="activeOCRProvider.accessKeySecret" type="password" />
+        </label>
+        <label
+          v-if="config.ocr.activeProvider === 'volcengine'"
+          class="field"
+        >
+          <span>Region *</span>
+          <input
+            v-model="activeOCRProvider.region"
+            placeholder="cn-north-1"
+            spellcheck="false"
+          />
+        </label>
+        <label
+          v-if="config.ocr.activeProvider === 'volcengine'"
+          class="field"
+        >
+          <span>Service *</span>
+          <input
+            v-model="activeOCRProvider.service"
+            placeholder="cv"
+            spellcheck="false"
+          />
+        </label>
+        <label class="field">
+          <span>Action *</span>
+          <input
+            v-model="activeOCRProvider.action"
+            placeholder="RecognizeGeneral / OCRNormal"
+            spellcheck="false"
+          />
+        </label>
+        <label class="field">
+          <span>Version *</span>
+          <input
+            v-model="activeOCRProvider.version"
+            placeholder="2021-07-07 / 2020-08-26"
+            spellcheck="false"
+          />
+        </label>
+        <label class="field">
+          <span>Timeout (sec)</span>
+          <input
+            v-model.number="activeOCRProvider.timeoutSecs"
+            type="number"
+            min="5"
+            max="120"
+            placeholder="30"
+          />
+        </label>
+      </div>
+      <p v-if="config.ocr.activeProvider === 'aliyun'" class="hint">
+        阿里云默认使用 OCR API 的 <code>RecognizeGeneral</code>，请求体为截图
+        PNG 原始数据，并使用 ACS3-HMAC-SHA256 签名。
+      </p>
+      <p v-else class="hint">
+        火山引擎默认使用视觉智能的 <code>OCRNormal</code>，截图以
+        <code>image_base64</code> 发送，并使用 Region/Service 参与签名。
+      </p>
+
+      <div class="actions">
+        <button class="btn primary" :disabled="saving" @click="save">
+          {{ saving ? 'Saving…' : 'Save' }}
+        </button>
+      </div>
+    </section>
+
     <transition name="fade">
       <div
         v-if="message"

frontend/wailsjs/go/main/App.d.ts

@@ -17,6 +17,10 @@ export function CopyNativeRegionImage(arg1:main.CaptureResult):Promise<void>;
 
 export function CopyRegionImage(arg1:main.CaptureResult):Promise<void>;
 
+export function ExtractTextNativeRegion(arg1:main.CaptureResult):Promise<void>;
+
+export function ExtractTextRegion(arg1:main.CaptureResult):Promise<void>;
+
 export function GetConfig():Promise<domain.AppConfig>;
 
 export function QuitApp():Promise<void>;

frontend/wailsjs/go/main/App.js

@@ -30,6 +30,14 @@ export function CopyRegionImage(arg1) {
   return window['go']['main']['App']['CopyRegionImage'](arg1);
 }
 
+export function ExtractTextNativeRegion(arg1) {
+  return window['go']['main']['App']['ExtractTextNativeRegion'](arg1);
+}
+
+export function ExtractTextRegion(arg1) {
+  return window['go']['main']['App']['ExtractTextRegion'](arg1);
+}
+
 export function GetConfig() {
   return window['go']['main']['App']['GetConfig']();
 }

frontend/wailsjs/go/models.ts

@@ -55,6 +55,66 @@ export namespace application {
 
 export namespace domain {
 
+	export class OCRProviderConfig {
+	    label: string;
+	    endpoint: string;
+	    accessKeyId: string;
+	    accessKeySecret: string;
+	    region: string;
+	    service: string;
+	    action: string;
+	    version: string;
+	    timeoutSecs: number;
+
+	    static createFrom(source: any = {}) {
+	        return new OCRProviderConfig(source);
+	    }
+
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.label = source["label"];
+	        this.endpoint = source["endpoint"];
+	        this.accessKeyId = source["accessKeyId"];
+	        this.accessKeySecret = source["accessKeySecret"];
+	        this.region = source["region"];
+	        this.service = source["service"];
+	        this.action = source["action"];
+	        this.version = source["version"];
+	        this.timeoutSecs = source["timeoutSecs"];
+	    }
+	}
+	export class OCRConfig {
+	    activeProvider: string;
+	    providers: Record<string, OCRProviderConfig>;
+
+	    static createFrom(source: any = {}) {
+	        return new OCRConfig(source);
+	    }
+
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.activeProvider = source["activeProvider"];
+	        this.providers = this.convertValues(source["providers"], OCRProviderConfig, true);
+	    }
+
+		convertValues(a: any, classs: any, asMap: boolean = false): any {
+		    if (!a) {
+		        return a;
+		    }
+		    if (a.slice && a.map) {
+		        return (a as any[]).map(elem => this.convertValues(elem, classs));
+		    } else if ("object" === typeof a) {
+		        if (asMap) {
+		            for (const key of Object.keys(a)) {
+		                a[key] = new classs(a[key]);
+		            }
+		            return a;
+		        }
+		        return new classs(a);
+		    }
+		    return a;
+		}
+	}
 	export class LLMProviderConfig {
 	    label: string;
 	    baseUrl: string;
@@ -175,6 +235,7 @@ export namespace domain {
 	    s3: S3Config;
 	    ssh: SSHConfig;
 	    llm: LLMConfig;
+	    ocr: OCRConfig;
 
 	    static createFrom(source: any = {}) {
 	        return new AppConfig(source);
@@ -187,6 +248,7 @@ export namespace domain {
 	        this.s3 = this.convertValues(source["s3"], S3Config);
 	        this.ssh = this.convertValues(source["ssh"], SSHConfig);
 	        this.llm = this.convertValues(source["llm"], LLMConfig);
+	        this.ocr = this.convertValues(source["ocr"], OCRConfig);
 	    }
 
 		convertValues(a: any, classs: any, asMap: boolean = false): any {
@@ -211,6 +273,8 @@ export namespace domain {
 
 
 
+
+
 }
 
 export namespace main {

internal/application/capture_ocr.go

@@ -0,0 +1,57 @@
+package application
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/mmmy/snapgo/internal/infrastructure/clipboard"
+)
+
+// OCRRecognizer describes a provider capable of extracting text from a PNG
+// screenshot.
+type OCRRecognizer interface {
+	RecognizeText(ctx context.Context, pngBytes []byte) (string, error)
+}
+
+// CaptureOCRService wires screenshot bytes -> OCR provider -> clipboard. It
+// leaves progress reporting to the caller so native and web overlays can share
+// the same status HUD.
+type CaptureOCRService struct {
+	Recognizer OCRRecognizer
+	Clipboard  clipboard.Writer
+}
+
+// Recognize asks the configured OCR provider to extract text from the PNG.
+func (s *CaptureOCRService) Recognize(ctx context.Context, pngBytes []byte) (string, error) {
+	if s.Recognizer == nil {
+		return "", fmt.Errorf("ocr is not configured")
+	}
+	if len(pngBytes) == 0 {
+		return "", fmt.Errorf("empty screenshot")
+	}
+	text, err := s.Recognizer.RecognizeText(ctx, pngBytes)
+	if err != nil {
+		return "", err
+	}
+	text = strings.TrimSpace(text)
+	if text == "" {
+		return "", fmt.Errorf("ocr result is empty")
+	}
+	return text, nil
+}
+
+// CopyText writes the extracted text to the clipboard.
+func (s *CaptureOCRService) CopyText(_ context.Context, text string) error {
+	text = strings.TrimSpace(text)
+	if text == "" {
+		return fmt.Errorf("empty ocr text")
+	}
+	if s.Clipboard == nil {
+		return fmt.Errorf("clipboard is not configured")
+	}
+	if err := s.Clipboard.WriteText(text); err != nil {
+		return fmt.Errorf("clipboard write failed: %w", err)
+	}
+	return nil
+}

internal/application/capture_ocr_test.go

@@ -0,0 +1,50 @@
+package application
+
+import (
+	"context"
+	"testing"
+)
+
+type fakeOCRRecognizer struct {
+	image []byte
+	text  string
+}
+
+func (f *fakeOCRRecognizer) RecognizeText(_ context.Context, pngBytes []byte) (string, error) {
+	f.image = append([]byte(nil), pngBytes...)
+	if f.text == "" {
+		return "extracted text", nil
+	}
+	return f.text, nil
+}
+
+func TestCaptureOCRServiceRecognizesAndCopies(t *testing.T) {
+	ctx := context.Background()
+	recognizer := &fakeOCRRecognizer{}
+	clip := &fakeClipboard{}
+	svc := &CaptureOCRService{Recognizer: recognizer, Clipboard: clip}
+
+	text, err := svc.Recognize(ctx, []byte("png"))
+	if err != nil {
+		t.Fatalf("recognize: %v", err)
+	}
+	if string(recognizer.image) != "png" {
+		t.Fatalf("expected screenshot bytes forwarded, got %q", string(recognizer.image))
+	}
+	if text != "extracted text" {
+		t.Fatalf("expected extracted text, got %q", text)
+	}
+	if err := svc.CopyText(ctx, text); err != nil {
+		t.Fatalf("copy text: %v", err)
+	}
+	if clip.text != "extracted text" {
+		t.Fatalf("expected ocr text copied, got %q", clip.text)
+	}
+}
+
+func TestCaptureOCRServiceRejectsEmptyResult(t *testing.T) {
+	svc := &CaptureOCRService{Recognizer: &fakeOCRRecognizer{text: " \n "}}
+	if _, err := svc.Recognize(context.Background(), []byte("png")); err == nil {
+		t.Fatalf("expected empty OCR result to fail")
+	}
+}

internal/domain/config.go

@@ -107,6 +107,29 @@ type LLMConfig struct {
 	Providers      map[string]LLMProviderConfig `json:"providers"`
 }
 
+// OCRProviderConfig stores one cloud OCR endpoint that accepts a screenshot
+// image and returns extracted text. Aliyun and Volcengine both authenticate
+// with an AccessKey pair, but their signing schemes use slightly different
+// endpoint metadata; keeping Region/Service/Action/Version configurable lets
+// the presets track official API changes without a schema rewrite.
+type OCRProviderConfig struct {
+	Label           string `json:"label"`
+	Endpoint        string `json:"endpoint"`
+	AccessKeyID     string `json:"accessKeyId"`
+	AccessKeySecret string `json:"accessKeySecret"`
+	Region          string `json:"region"`
+	Service         string `json:"service"`
+	Action          string `json:"action"`
+	Version         string `json:"version"`
+	TimeoutSecs     int    `json:"timeoutSecs"`
+}
+
+// OCRConfig controls screenshot text extraction.
+type OCRConfig struct {
+	ActiveProvider string                       `json:"activeProvider"`
+	Providers      map[string]OCRProviderConfig `json:"providers"`
+}
+
 // SSH authentication method identifiers stored in SSHConfig.AuthMethod.
 const (
 	// SSHAuthBuiltin is the legacy combined method (password → agent → key
@@ -129,6 +152,12 @@ const (
 	LLMProviderOpenAI = "openai"
 )
 
+// Built-in OCR provider identifiers.
+const (
+	OCRProviderAliyun     = "aliyun"
+	OCRProviderVolcengine = "volcengine"
+)
+
 // Theme preference identifiers stored in AppConfig.Theme.
 const (
 	ThemeAuto  = "auto"
@@ -172,6 +201,9 @@ type AppConfig struct {
 
 	// LLM holds provider settings for the "copy summary" screenshot action.
 	LLM LLMConfig `json:"llm"`
+
+	// OCR holds provider settings for the "extract text" screenshot action.
+	OCR OCRConfig `json:"ocr"`
 }
 
 // DefaultAppConfig returns sane zero-value defaults used on first launch.
@@ -190,6 +222,7 @@ func DefaultAppConfig() AppConfig {
 			StrictHostKey:      false,
 		},
 		LLM: DefaultLLMConfig(),
+		OCR: DefaultOCRConfig(),
 	}
 	cfg.Normalize()
 	return cfg
@@ -234,6 +267,33 @@ func DefaultLLMConfig() LLMConfig {
 	}
 }
 
+// DefaultOCRConfig returns the built-in OCR provider presets. Users only need
+// to fill AccessKey credentials for the common regions/actions, while advanced
+// accounts can still override endpoint metadata from the settings UI.
+func DefaultOCRConfig() OCRConfig {
+	return OCRConfig{
+		ActiveProvider: OCRProviderAliyun,
+		Providers: map[string]OCRProviderConfig{
+			OCRProviderAliyun: {
+				Label:       "阿里云文字识别",
+				Endpoint:    "https://ocr-api.cn-hangzhou.aliyuncs.com",
+				Action:      "RecognizeGeneral",
+				Version:     "2021-07-07",
+				TimeoutSecs: 30,
+			},
+			OCRProviderVolcengine: {
+				Label:       "火山引擎文字识别",
+				Endpoint:    "https://visual.volcengineapi.com",
+				Region:      "cn-north-1",
+				Service:     "cv",
+				Action:      "OCRNormal",
+				Version:     "2020-08-26",
+				TimeoutSecs: 30,
+			},
+		},
+	}
+}
+
 // Normalize fills defaults into configs written by older app versions while
 // preserving any user-provided provider fields.
 func (c *AppConfig) Normalize() {
@@ -295,6 +355,43 @@ func (c *AppConfig) Normalize() {
 		}
 		c.LLM.Providers[id] = current
 	}
+
+	defaultOCR := DefaultOCRConfig()
+	if c.OCR.ActiveProvider == "" {
+		c.OCR.ActiveProvider = defaultOCR.ActiveProvider
+	}
+	if c.OCR.Providers == nil {
+		c.OCR.Providers = map[string]OCRProviderConfig{}
+	}
+	for id, def := range defaultOCR.Providers {
+		current, ok := c.OCR.Providers[id]
+		if !ok {
+			c.OCR.Providers[id] = def
+			continue
+		}
+		if current.Label == "" {
+			current.Label = def.Label
+		}
+		if current.Endpoint == "" {
+			current.Endpoint = def.Endpoint
+		}
+		if current.Region == "" {
+			current.Region = def.Region
+		}
+		if current.Service == "" {
+			current.Service = def.Service
+		}
+		if current.Action == "" {
+			current.Action = def.Action
+		}
+		if current.Version == "" {
+			current.Version = def.Version
+		}
+		if current.TimeoutSecs == 0 {
+			current.TimeoutSecs = def.TimeoutSecs
+		}
+		c.OCR.Providers[id] = current
+	}
 }
 
 // IsS3Configured reports whether the user has filled the mandatory S3 fields.
@@ -329,3 +426,32 @@ func (c AppConfig) IsLLMConfigured() bool {
 	_, provider, ok := c.ActiveLLMProvider()
 	return ok && provider.BaseURL != "" && provider.APIKey != "" && provider.Model != ""
 }
+
+// ActiveOCRProvider returns the selected OCR provider config plus a boolean
+// indicating whether the selection exists.
+func (c AppConfig) ActiveOCRProvider() (string, OCRProviderConfig, bool) {
+	id := c.OCR.ActiveProvider
+	if id == "" {
+		id = OCRProviderAliyun
+	}
+	provider, ok := c.OCR.Providers[id]
+	return id, provider, ok
+}
+
+// IsOCRConfigured reports whether the selected OCR provider has the fields
+// required to sign and send a request.
+func (c AppConfig) IsOCRConfigured() bool {
+	id, provider, ok := c.ActiveOCRProvider()
+	if !ok ||
+		provider.Endpoint == "" ||
+		provider.AccessKeyID == "" ||
+		provider.AccessKeySecret == "" ||
+		provider.Action == "" ||
+		provider.Version == "" {
+		return false
+	}
+	if id == OCRProviderVolcengine && (provider.Region == "" || provider.Service == "") {
+		return false
+	}
+	return true
+}

internal/infrastructure/ocr/client.go

@@ -0,0 +1,568 @@
+// Package ocr contains cloud OCR adapters.
+package ocr
+
+import (
+	"bytes"
+	"context"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/mmmy/snapgo/internal/application"
+	"github.com/mmmy/snapgo/internal/domain"
+)
+
+// Client calls one configured OCR provider.
+type Client struct {
+	providerID string
+	cfg        domain.OCRProviderConfig
+	httpClient *http.Client
+	now        func() time.Time
+	nonce      func() string
+}
+
+var _ application.OCRRecognizer = (*Client)(nil)
+
+// NewClient validates cfg and returns a reusable OCR client.
+func NewClient(providerID string, cfg domain.OCRProviderConfig) (*Client, error) {
+	if strings.TrimSpace(cfg.Endpoint) == "" {
+		return nil, fmt.Errorf("ocr endpoint is required")
+	}
+	if strings.TrimSpace(cfg.AccessKeyID) == "" {
+		return nil, fmt.Errorf("ocr access key id is required")
+	}
+	if strings.TrimSpace(cfg.AccessKeySecret) == "" {
+		return nil, fmt.Errorf("ocr access key secret is required")
+	}
+	if strings.TrimSpace(cfg.Action) == "" {
+		return nil, fmt.Errorf("ocr action is required")
+	}
+	if strings.TrimSpace(cfg.Version) == "" {
+		return nil, fmt.Errorf("ocr version is required")
+	}
+	switch providerID {
+	case domain.OCRProviderAliyun:
+	case domain.OCRProviderVolcengine:
+		if strings.TrimSpace(cfg.Region) == "" {
+			return nil, fmt.Errorf("volcengine ocr region is required")
+		}
+		if strings.TrimSpace(cfg.Service) == "" {
+			return nil, fmt.Errorf("volcengine ocr service is required")
+		}
+	default:
+		return nil, fmt.Errorf("unsupported ocr provider %q", providerID)
+	}
+	timeout := cfg.TimeoutSecs
+	if timeout <= 0 {
+		timeout = 30
+	}
+	return &Client{
+		providerID: providerID,
+		cfg:        cfg,
+		httpClient: &http.Client{Timeout: time.Duration(timeout) * time.Second},
+		now:        time.Now,
+		nonce:      randomNonce,
+	}, nil
+}
+
+// RecognizeText extracts visible text from a PNG screenshot.
+func (c *Client) RecognizeText(ctx context.Context, pngBytes []byte) (string, error) {
+	if len(pngBytes) == 0 {
+		return "", fmt.Errorf("empty screenshot")
+	}
+	switch c.providerID {
+	case domain.OCRProviderAliyun:
+		return c.recognizeAliyun(ctx, pngBytes)
+	case domain.OCRProviderVolcengine:
+		return c.recognizeVolcengine(ctx, pngBytes)
+	default:
+		return "", fmt.Errorf("unsupported ocr provider %q", c.providerID)
+	}
+}
+
+func (c *Client) recognizeAliyun(ctx context.Context, pngBytes []byte) (string, error) {
+	endpoint, err := parseEndpoint(c.cfg.Endpoint)
+	if err != nil {
+		return "", err
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint.String(), bytes.NewReader(pngBytes))
+	if err != nil {
+		return "", fmt.Errorf("build aliyun ocr request: %w", err)
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Content-Type", "application/octet-stream")
+	c.signAliyun(req, pngBytes)
+	return c.doOCRRequest(req, "aliyun ocr")
+}
+
+func (c *Client) recognizeVolcengine(ctx context.Context, pngBytes []byte) (string, error) {
+	endpoint, err := parseEndpoint(c.cfg.Endpoint)
+	if err != nil {
+		return "", err
+	}
+	query := endpoint.Query()
+	query.Set("Action", c.cfg.Action)
+	query.Set("Version", c.cfg.Version)
+	endpoint.RawQuery = query.Encode()
+
+	body := map[string]string{
+		"image_base64": base64.StdEncoding.EncodeToString(pngBytes),
+	}
+	payload, err := json.Marshal(body)
+	if err != nil {
+		return "", fmt.Errorf("marshal volcengine ocr request: %w", err)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint.String(), bytes.NewReader(payload))
+	if err != nil {
+		return "", fmt.Errorf("build volcengine ocr request: %w", err)
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Content-Type", "application/json")
+	c.signVolcengine(req, payload)
+	return c.doOCRRequest(req, "volcengine ocr")
+}
+
+func (c *Client) doOCRRequest(req *http.Request, label string) (string, error) {
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("%s request: %w", label, err)
+	}
+	defer resp.Body.Close()
+	data, _ := io.ReadAll(io.LimitReader(resp.Body, 8<<20))
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return "", fmt.Errorf("%s status %d: %s", label, resp.StatusCode, compactBody(data))
+	}
+	text, err := parseOCRText(data)
+	if err != nil {
+		return "", fmt.Errorf("%s response: %w", label, err)
+	}
+	return text, nil
+}
+
+func (c *Client) signAliyun(req *http.Request, payload []byte) {
+	now := c.now().UTC()
+	payloadHash := sha256Hex(payload)
+	nonce := c.nonce()
+
+	req.Header.Set("x-acs-action", c.cfg.Action)
+	req.Header.Set("x-acs-version", c.cfg.Version)
+	req.Header.Set("x-acs-date", now.Format("2006-01-02T15:04:05Z"))
+	req.Header.Set("x-acs-signature-nonce", nonce)
+	req.Header.Set("x-acs-content-sha256", payloadHash)
+
+	signedHeaders := []string{
+		"content-type",
+		"host",
+		"x-acs-action",
+		"x-acs-content-sha256",
+		"x-acs-date",
+		"x-acs-signature-nonce",
+		"x-acs-version",
+	}
+	canonicalHeaders := canonicalHeaders(req, signedHeaders)
+	canonicalRequest := strings.Join([]string{
+		req.Method,
+		canonicalURI(req.URL),
+		canonicalQuery(req.URL),
+		canonicalHeaders,
+		strings.Join(signedHeaders, ";"),
+		payloadHash,
+	}, "\n")
+	stringToSign := "ACS3-HMAC-SHA256\n" + sha256Hex([]byte(canonicalRequest))
+	signature := hmacSHA256Hex([]byte(c.cfg.AccessKeySecret), []byte(stringToSign))
+	req.Header.Set(
+		"Authorization",
+		fmt.Sprintf("ACS3-HMAC-SHA256 Credential=%s,SignedHeaders=%s,Signature=%s",
+			c.cfg.AccessKeyID,
+			strings.Join(signedHeaders, ";"),
+			signature,
+		),
+	)
+}
+
+func (c *Client) signVolcengine(req *http.Request, payload []byte) {
+	now := c.now().UTC()
+	xDate := now.Format("20060102T150405Z")
+	shortDate := now.Format("20060102")
+	payloadHash := sha256Hex(payload)
+
+	req.Header.Set("X-Date", xDate)
+	req.Header.Set("X-Content-Sha256", payloadHash)
+
+	signedHeaders := []string{
+		"content-type",
+		"host",
+		"x-content-sha256",
+		"x-date",
+	}
+	canonicalHeaders := canonicalHeaders(req, signedHeaders)
+	canonicalRequest := strings.Join([]string{
+		req.Method,
+		canonicalURI(req.URL),
+		canonicalQuery(req.URL),
+		canonicalHeaders,
+		strings.Join(signedHeaders, ";"),
+		payloadHash,
+	}, "\n")
+	scope := strings.Join([]string{shortDate, c.cfg.Region, c.cfg.Service, "request"}, "/")
+	stringToSign := strings.Join([]string{
+		"HMAC-SHA256",
+		xDate,
+		scope,
+		sha256Hex([]byte(canonicalRequest)),
+	}, "\n")
+	signingKey := volcengineSigningKey(c.cfg.AccessKeySecret, shortDate, c.cfg.Region, c.cfg.Service)
+	signature := hmacSHA256Hex(signingKey, []byte(stringToSign))
+	req.Header.Set(
+		"Authorization",
+		fmt.Sprintf("HMAC-SHA256 Credential=%s/%s, SignedHeaders=%s, Signature=%s",
+			c.cfg.AccessKeyID,
+			scope,
+			strings.Join(signedHeaders, ";"),
+			signature,
+		),
+	)
+}
+
+func parseEndpoint(raw string) (*url.URL, error) {
+	endpoint := strings.TrimSpace(raw)
+	if endpoint == "" {
+		return nil, fmt.Errorf("ocr endpoint is required")
+	}
+	if !strings.Contains(endpoint, "://") {
+		endpoint = "https://" + endpoint
+	}
+	parsed, err := url.Parse(endpoint)
+	if err != nil {
+		return nil, fmt.Errorf("parse ocr endpoint: %w", err)
+	}
+	if parsed.Scheme == "" || parsed.Host == "" {
+		return nil, fmt.Errorf("invalid ocr endpoint %q", raw)
+	}
+	if parsed.Path == "" {
+		parsed.Path = "/"
+	}
+	return parsed, nil
+}
+
+func parseOCRText(data []byte) (string, error) {
+	var root any
+	if err := json.Unmarshal(data, &root); err != nil {
+		return "", fmt.Errorf("decode json: %w", err)
+	}
+	if msg := responseError(root); msg != "" {
+		return "", errors.New(msg)
+	}
+	parts := collectOCRParts(root, "")
+	if len(parts) == 0 {
+		return "", fmt.Errorf("no text found")
+	}
+	return strings.Join(dedupeNonEmpty(parts), "\n"), nil
+}
+
+func responseError(v any) string {
+	obj, ok := v.(map[string]any)
+	if !ok {
+		return ""
+	}
+	if meta, ok := obj["ResponseMetadata"].(map[string]any); ok {
+		if errObj, ok := meta["Error"].(map[string]any); ok {
+			if msg := stringValue(errObj["Message"]); msg != "" {
+				return msg
+			}
+			if code := stringValue(errObj["Code"]); code != "" {
+				return code
+			}
+		}
+	}
+	if errObj, ok := obj["Error"].(map[string]any); ok {
+		if msg := stringValue(errObj["Message"]); msg != "" {
+			return msg
+		}
+		if msg := stringValue(errObj["message"]); msg != "" {
+			return msg
+		}
+	}
+	if code, ok := numericCode(obj["code"]); ok && code != 0 && code != 10000 {
+		if msg := stringValue(obj["message"]); msg != "" {
+			return msg
+		}
+		if msg := stringValue(obj["msg"]); msg != "" {
+			return msg
+		}
+		return fmt.Sprintf("provider code %.0f", code)
+	}
+	if code := stringValue(obj["Code"]); code != "" && !isSuccessCode(code) {
+		if msg := stringValue(obj["Message"]); msg != "" {
+			return msg
+		}
+		return code
+	}
+	return ""
+}
+
+func collectOCRParts(v any, parentKey string) []string {
+	switch value := v.(type) {
+	case string:
+		text := strings.TrimSpace(value)
+		if text == "" {
+			return nil
+		}
+		if looksLikeJSON(text) {
+			var nested any
+			if err := json.Unmarshal([]byte(text), &nested); err == nil {
+				return collectOCRParts(nested, parentKey)
+			}
+		}
+		if isTextKey(parentKey) || isContainerTextKey(parentKey) {
+			return []string{text}
+		}
+		return nil
+	case []any:
+		parts := make([]string, 0, len(value))
+		for _, item := range value {
+			parts = append(parts, collectOCRParts(item, parentKey)...)
+		}
+		return parts
+	case map[string]any:
+		parts := make([]string, 0)
+		for _, key := range priorityOCRKeys() {
+			if child, ok := value[key]; ok {
+				parts = append(parts, collectOCRParts(child, key)...)
+			}
+		}
+		keys := make([]string, 0, len(value))
+		for key := range value {
+			keys = append(keys, key)
+		}
+		sort.Strings(keys)
+		for _, key := range keys {
+			if isPriorityOCRKey(key) || isMetadataKey(key) {
+				continue
+			}
+			parts = append(parts, collectOCRParts(value[key], key)...)
+		}
+		return parts
+	default:
+		return nil
+	}
+}
+
+func priorityOCRKeys() []string {
+	return []string{
+		"Data",
+		"data",
+		"Result",
+		"result",
+		"content",
+		"Content",
+		"text",
+		"Text",
+		"DetectedText",
+		"detected_text",
+		"line_text",
+		"LineText",
+		"line_texts",
+		"LineTexts",
+		"word",
+		"Word",
+		"words",
+		"Words",
+		"words_result",
+		"WordsResult",
+		"prism_wordsInfo",
+		"prism_words_info",
+		"ocr_infos",
+		"OCRInfos",
+		"items",
+		"Items",
+		"blocks",
+		"Blocks",
+		"regions",
+		"Regions",
+	}
+}
+
+func isPriorityOCRKey(key string) bool {
+	for _, item := range priorityOCRKeys() {
+		if item == key {
+			return true
+		}
+	}
+	return false
+}
+
+func isTextKey(key string) bool {
+	switch normalizeKey(key) {
+	case "content", "text", "detectedtext", "linetext", "word", "words", "value":
+		return true
+	default:
+		return false
+	}
+}
+
+func isContainerTextKey(key string) bool {
+	switch normalizeKey(key) {
+	case "data", "result", "linetexts", "texts":
+		return true
+	default:
+		return false
+	}
+}
+
+func isMetadataKey(key string) bool {
+	switch normalizeKey(key) {
+	case "requestid", "request", "code", "status", "statuscode", "success",
+		"error", "errors", "message", "msg", "cost", "angle", "probability",
+		"confidence", "height", "width", "left", "top", "right", "bottom",
+		"x", "y", "responsemetadata":
+		return true
+	default:
+		return false
+	}
+}
+
+func normalizeKey(key string) string {
+	key = strings.ToLower(key)
+	key = strings.ReplaceAll(key, "_", "")
+	key = strings.ReplaceAll(key, "-", "")
+	return key
+}
+
+func dedupeNonEmpty(parts []string) []string {
+	seen := map[string]struct{}{}
+	out := make([]string, 0, len(parts))
+	for _, part := range parts {
+		for _, line := range strings.Split(part, "\n") {
+			line = strings.TrimSpace(line)
+			if line == "" {
+				continue
+			}
+			if _, ok := seen[line]; ok {
+				continue
+			}
+			seen[line] = struct{}{}
+			out = append(out, line)
+		}
+	}
+	return out
+}
+
+func looksLikeJSON(text string) bool {
+	return strings.HasPrefix(text, "{") || strings.HasPrefix(text, "[")
+}
+
+func stringValue(v any) string {
+	if s, ok := v.(string); ok {
+		return strings.TrimSpace(s)
+	}
+	return ""
+}
+
+func numericCode(v any) (float64, bool) {
+	switch n := v.(type) {
+	case float64:
+		return n, true
+	case int:
+		return float64(n), true
+	case json.Number:
+		f, err := n.Float64()
+		return f, err == nil
+	default:
+		return 0, false
+	}
+}
+
+func isSuccessCode(code string) bool {
+	switch strings.ToLower(strings.TrimSpace(code)) {
+	case "", "ok", "success", "200", "10000":
+		return true
+	default:
+		return false
+	}
+}
+
+func canonicalURI(u *url.URL) string {
+	if u == nil || u.EscapedPath() == "" {
+		return "/"
+	}
+	return u.EscapedPath()
+}
+
+func canonicalQuery(u *url.URL) string {
+	if u == nil || u.RawQuery == "" {
+		return ""
+	}
+	values, _ := url.ParseQuery(u.RawQuery)
+	return values.Encode()
+}
+
+func canonicalHeaders(req *http.Request, signedHeaders []string) string {
+	lines := make([]string, 0, len(signedHeaders))
+	for _, key := range signedHeaders {
+		var value string
+		if key == "host" {
+			value = req.URL.Host
+		} else {
+			value = req.Header.Get(key)
+		}
+		lines = append(lines, key+":"+normalizeHeaderValue(value)+"\n")
+	}
+	return strings.Join(lines, "")
+}
+
+func normalizeHeaderValue(value string) string {
+	return strings.Join(strings.Fields(strings.TrimSpace(value)), " ")
+}
+
+func volcengineSigningKey(secret, date, region, service string) []byte {
+	kDate := hmacSHA256([]byte(secret), []byte(date))
+	kRegion := hmacSHA256(kDate, []byte(region))
+	kService := hmacSHA256(kRegion, []byte(service))
+	return hmacSHA256(kService, []byte("request"))
+}
+
+func hmacSHA256(key, data []byte) []byte {
+	mac := hmac.New(sha256.New, key)
+	mac.Write(data)
+	return mac.Sum(nil)
+}
+
+func hmacSHA256Hex(key, data []byte) string {
+	return hex.EncodeToString(hmacSHA256(key, data))
+}
+
+func sha256Hex(data []byte) string {
+	sum := sha256.Sum256(data)
+	return hex.EncodeToString(sum[:])
+}
+
+func randomNonce() string {
+	buf := make([]byte, 16)
+	if _, err := rand.Read(buf); err != nil {
+		return fmt.Sprintf("%d", time.Now().UnixNano())
+	}
+	return hex.EncodeToString(buf)
+}
+
+func compactBody(data []byte) string {
+	text := strings.TrimSpace(string(data))
+	if text == "" {
+		return "<empty body>"
+	}
+	if len(text) > 800 {
+		return text[:800] + "..."
+	}
+	return text
+}

internal/infrastructure/ocr/client_test.go

@@ -0,0 +1,150 @@
+package ocr
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/mmmy/snapgo/internal/domain"
+)
+
+type roundTripFunc func(*http.Request) (*http.Response, error)
+
+func (f roundTripFunc) RoundTrip(req *http.Request) (*http.Response, error) {
+	return f(req)
+}
+
+func TestAliyunRecognizeTextSignsRawPNGRequest(t *testing.T) {
+	var requestBody []byte
+	transport := roundTripFunc(func(r *http.Request) (*http.Response, error) {
+		if r.URL.Host != "ocr-api.cn-hangzhou.aliyuncs.com" {
+			t.Fatalf("unexpected host %s", r.URL.Host)
+		}
+		if got := r.Header.Get("x-acs-action"); got != "RecognizeGeneral" {
+			t.Fatalf("unexpected action %q", got)
+		}
+		if got := r.Header.Get("x-acs-version"); got != "2021-07-07" {
+			t.Fatalf("unexpected version %q", got)
+		}
+		if got := r.Header.Get("x-acs-date"); got != "2026-07-08T01:02:03Z" {
+			t.Fatalf("unexpected date %q", got)
+		}
+		if got := r.Header.Get("Authorization"); !strings.Contains(got, "ACS3-HMAC-SHA256 Credential=ak") {
+			t.Fatalf("unexpected auth header %q", got)
+		}
+		var err error
+		requestBody, err = io.ReadAll(r.Body)
+		if err != nil {
+			t.Fatalf("read body: %v", err)
+		}
+		return &http.Response{
+			StatusCode: http.StatusOK,
+			Header:     http.Header{"Content-Type": []string{"application/json"}},
+			Body: io.NopCloser(bytes.NewBufferString(
+				`{"Data":"{\"content\":\"第一行\\n第二行\"}"}`,
+			)),
+		}, nil
+	})
+
+	client, err := NewClient(domain.OCRProviderAliyun, domain.OCRProviderConfig{
+		Endpoint:        "https://ocr-api.cn-hangzhou.aliyuncs.com",
+		AccessKeyID:     "ak",
+		AccessKeySecret: "sk",
+		Action:          "RecognizeGeneral",
+		Version:         "2021-07-07",
+	})
+	if err != nil {
+		t.Fatalf("new client: %v", err)
+	}
+	client.httpClient.Transport = transport
+	client.now = func() time.Time { return time.Date(2026, 7, 8, 1, 2, 3, 0, time.UTC) }
+	client.nonce = func() string { return "nonce" }
+
+	text, err := client.RecognizeText(context.Background(), []byte("png"))
+	if err != nil {
+		t.Fatalf("recognize text: %v", err)
+	}
+	if string(requestBody) != "png" {
+		t.Fatalf("expected raw png body, got %q", string(requestBody))
+	}
+	if text != "第一行\n第二行" {
+		t.Fatalf("unexpected OCR text %q", text)
+	}
+}
+
+func TestVolcengineRecognizeTextSignsBase64JSONRequest(t *testing.T) {
+	var requestBody map[string]string
+	transport := roundTripFunc(func(r *http.Request) (*http.Response, error) {
+		if got := r.URL.Query().Get("Action"); got != "OCRNormal" {
+			t.Fatalf("unexpected action %q", got)
+		}
+		if got := r.URL.Query().Get("Version"); got != "2020-08-26" {
+			t.Fatalf("unexpected version %q", got)
+		}
+		if got := r.Header.Get("X-Date"); got != "20260708T010203Z" {
+			t.Fatalf("unexpected x-date %q", got)
+		}
+		if got := r.Header.Get("Authorization"); !strings.Contains(got, "HMAC-SHA256 Credential=ak/20260708/cn-north-1/cv/request") {
+			t.Fatalf("unexpected auth header %q", got)
+		}
+		if err := json.NewDecoder(r.Body).Decode(&requestBody); err != nil {
+			t.Fatalf("decode request: %v", err)
+		}
+		return &http.Response{
+			StatusCode: http.StatusOK,
+			Header:     http.Header{"Content-Type": []string{"application/json"}},
+			Body: io.NopCloser(bytes.NewBufferString(
+				`{"ResponseMetadata":{"RequestId":"r"},"Result":{"LineTexts":["你好","世界"]}}`,
+			)),
+		}, nil
+	})
+
+	client, err := NewClient(domain.OCRProviderVolcengine, domain.OCRProviderConfig{
+		Endpoint:        "https://visual.volcengineapi.com",
+		AccessKeyID:     "ak",
+		AccessKeySecret: "sk",
+		Region:          "cn-north-1",
+		Service:         "cv",
+		Action:          "OCRNormal",
+		Version:         "2020-08-26",
+	})
+	if err != nil {
+		t.Fatalf("new client: %v", err)
+	}
+	client.httpClient.Transport = transport
+	client.now = func() time.Time { return time.Date(2026, 7, 8, 1, 2, 3, 0, time.UTC) }
+
+	text, err := client.RecognizeText(context.Background(), []byte("png"))
+	if err != nil {
+		t.Fatalf("recognize text: %v", err)
+	}
+	if requestBody["image_base64"] != base64.StdEncoding.EncodeToString([]byte("png")) {
+		t.Fatalf("expected base64 image body, got %#v", requestBody)
+	}
+	if text != "你好\n世界" {
+		t.Fatalf("unexpected OCR text %q", text)
+	}
+}
+
+func TestParseOCRTextSupportsWordsResult(t *testing.T) {
+	text, err := parseOCRText([]byte(`{"data":{"words_result":[{"words":"foo"},{"words":"bar"}]}}`))
+	if err != nil {
+		t.Fatalf("parse ocr text: %v", err)
+	}
+	if text != "foo\nbar" {
+		t.Fatalf("unexpected OCR text %q", text)
+	}
+}
+
+func TestParseOCRTextReturnsProviderError(t *testing.T) {
+	_, err := parseOCRText([]byte(`{"ResponseMetadata":{"Error":{"Code":"BadRequest","Message":"bad image"}}}`))
+	if err == nil || !strings.Contains(err.Error(), "bad image") {
+		t.Fatalf("expected provider error, got %v", err)
+	}
+}

native_overlay_callbacks_darwin.go

@@ -86,6 +86,18 @@ func nativeOverlaySummarize(x, y, w, h C.int, annotationsJSON *C.char) {
 	}()
 }
 
+//export nativeOverlayOCR
+func nativeOverlayOCR(x, y, w, h C.int, annotationsJSON *C.char) {
+	app := consumeNativeOverlayApp()
+	if app == nil {
+		return
+	}
+	result := nativeCaptureResult(x, y, w, h, annotationsJSON)
+	go func() {
+		_ = app.ExtractTextNativeRegion(result)
+	}()
+}
+
 //export nativeOverlayCancel
 func nativeOverlayCancel() {
 	app := consumeNativeOverlayApp()

native_overlay_darwin.go

@@ -16,6 +16,7 @@ extern void nativeOverlayCopy(int x, int y, int w, int h, const char *annotation
 extern void nativeOverlaySave(int x, int y, int w, int h, const char *annotationsJSON, const char *dir);
 extern void nativeOverlaySaveRemote(int x, int y, int w, int h, const char *annotationsJSON);
 extern void nativeOverlaySummarize(int x, int y, int w, int h, const char *annotationsJSON);
+extern void nativeOverlayOCR(int x, int y, int w, int h, const char *annotationsJSON);
 extern void nativeOverlayCancel(void);
 
 static NSWindow *nativeOverlayWindow = nil;
@@ -103,6 +104,7 @@ static id nativeOverlayKeyMonitor = nil;
 @property(strong) NSButton *clipboardButton;
 @property(strong) NSButton *saveButton;
 @property(strong) NSButton *saveRemoteButton;
+@property(strong) NSButton *ocrButton;
 @property(strong) NSButton *summaryButton;
 @property(strong) NSButton *uploadButton;
 @property(strong) NSButton *penButton;
@@ -124,6 +126,7 @@ static id nativeOverlayKeyMonitor = nil;
 - (void)copySelection;
 - (void)saveSelection;
 - (void)saveRemoteSelection;
+- (void)ocrSelection;
 - (void)summarizeSelection;
 - (void)cancelSelection;
 - (void)beginTextAnnotationAtPoint:(NSPoint)localPoint;
@@ -146,13 +149,14 @@ static id nativeOverlayKeyMonitor = nil;
         _activeColor = [NSColor colorWithCalibratedRed:239.0/255.0 green:68.0/255.0 blue:68.0/255.0 alpha:1.0];
         _annotations = [NSMutableArray array];
 
-        // Use SnipHoverButton for the 5 action buttons so we get hover-color
+        // Use SnipHoverButton for the action buttons so we get hover-color
         // animation. Annotation buttons stay as plain NSButton because they
         // already have explicit on/off "active" styling.
         _cancelButton = [SnipHoverButton buttonWithTitle:@"" target:self action:@selector(cancelSelection)];
         _clipboardButton = [SnipHoverButton buttonWithTitle:@"" target:self action:@selector(copySelection)];
         _saveButton = [SnipHoverButton buttonWithTitle:@"" target:self action:@selector(saveSelection)];
         _saveRemoteButton = [SnipHoverButton buttonWithTitle:@"" target:self action:@selector(saveRemoteSelection)];
+        _ocrButton = [SnipHoverButton buttonWithTitle:@"" target:self action:@selector(ocrSelection)];
         _summaryButton = [SnipHoverButton buttonWithTitle:@"" target:self action:@selector(summarizeSelection)];
         _uploadButton = [SnipHoverButton buttonWithTitle:@"" target:self action:@selector(confirmSelection)];
         // Tooltip strings shown on hover for each action button.
@@ -161,6 +165,7 @@ static id nativeOverlayKeyMonitor = nil;
         [_clipboardButton setToolTip:@"复制图片"];
         [_saveButton setToolTip:@"保存本地"];
         [_saveRemoteButton setToolTip:@"保存远端"];
+        [_ocrButton setToolTip:@"提取文字"];
         [_summaryButton setToolTip:@"复制总结"];
         [_uploadButton setToolTip:@"上传云端"];
         _penButton = [NSButton buttonWithTitle:@"" target:self action:@selector(selectPen)];
@@ -183,10 +188,10 @@ static id nativeOverlayKeyMonitor = nil;
         // Add the action toolbar background BEFORE the buttons so it sits
         // behind them in the view hierarchy (AppKit z-order = subview order).
         [self addSubview:_actionToolbarBg];
-        for (NSView *view in @[_cancelButton, _clipboardButton, _saveButton, _saveRemoteButton, _summaryButton, _uploadButton, _penButton, _rectButton, _ellipseButton, _textButton, _colorButton, _undoButton, _paletteView, _sizeLabel, _hintLabel]) {
+        for (NSView *view in @[_cancelButton, _clipboardButton, _saveButton, _saveRemoteButton, _ocrButton, _summaryButton, _uploadButton, _penButton, _rectButton, _ellipseButton, _textButton, _colorButton, _undoButton, _paletteView, _sizeLabel, _hintLabel]) {
             [self addSubview:view];
         }
-        for (NSView *view in @[_cancelButton, _clipboardButton, _saveButton, _saveRemoteButton, _summaryButton, _uploadButton, _penButton, _rectButton, _ellipseButton, _textButton, _colorButton, _undoButton, _paletteView, _actionToolbarBg]) {
+        for (NSView *view in @[_cancelButton, _clipboardButton, _saveButton, _saveRemoteButton, _ocrButton, _summaryButton, _uploadButton, _penButton, _rectButton, _ellipseButton, _textButton, _colorButton, _undoButton, _paletteView, _actionToolbarBg]) {
             [view setHidden:YES];
         }
         [_sizeLabel setHidden:YES];
@@ -249,8 +254,8 @@ static id nativeOverlayKeyMonitor = nil;
 }
 
 - (void)styleControls {
-    // Cancel / Copy / Save / Save-remote / Upload — square icon buttons
+    // Cancel / Copy / Save / Save-remote / OCR / Summary / Upload — square icon buttons
-    // rendered from the user-supplied SVG assets. All five default to white
+    // rendered from the user-supplied SVG assets. All actions default to white
     // and animate to a per-action accent color on hover (cancel = red,
     // others = blue). The base "white default" replaces the previous blue
     // upload tint so the toolbar reads as a uniform icon row.
@@ -260,6 +265,7 @@ static id nativeOverlayKeyMonitor = nil;
     // save-remote.svg — provided by the user; its content is the same arrow
     // icon as the previous upload, so we reuse it verbatim here.
     NSImage *saveRemoteIcon = [self iconFromSVG:@"<svg viewBox='0 0 1024 1024' xmlns='http://www.w3.org/2000/svg'><path d='M481.749333 353.792c16.682667-16.64 43.690667-16.64 60.373334 0l120.917333 120.832 3.541333 4.010667a42.666667 42.666667 0 0 1-63.872 56.32L554.666667 486.954667V896a42.666667 42.666667 0 0 1-85.333334 0v-409.173333l-48.170666 48.128a42.666667 42.666667 0 0 1-60.330667 0l-3.541333-4.010667a42.666667 42.666667 0 0 1 3.541333-56.32zM512 85.333333c122.538667 0 227.84 73.813333 273.92 179.370667A213.333333 213.333333 0 0 1 725.333333 682.666667a42.666667 42.666667 0 0 1-4.992-85.034667L725.333333 597.333333a128 128 0 0 0 36.394667-250.794666l-38.144-11.264-15.914667-36.437334a213.376 213.376 0 0 0-407.296 58.026667l-7.381333 58.368-57.173333 13.824A85.418667 85.418667 0 0 0 256 597.333333h42.666667a42.666667 42.666667 0 0 1 0 85.333334H256a170.666667 170.666667 0 0 1-40.277333-336.554667A298.709333 298.709333 0 0 1 512 85.333333z' fill='white'/></svg>"];
+    NSImage *ocrIcon = [self iconFromSVG:@"<svg viewBox='0 0 1024 1024' xmlns='http://www.w3.org/2000/svg'><path d='M192 160h192v64H256v128h-64V160zM640 160h192v192h-64V224H640v-64zM256 672v128h128v64H192V672h64zM832 672v192H640v-64h128V672h64zM469.333333 288h85.333334l170.666666 448h-78.933333l-39.253333-106.666667H416.853333L377.6 736H298.666667l170.666666-448zM439.466667 565.333333h144.896L512 368.981333 439.466667 565.333333z' fill='white'/></svg>"];
     NSImage *summaryIcon = [self iconFromSVG:@"<svg viewBox='0 0 1024 1024' xmlns='http://www.w3.org/2000/svg'><path d='M256 128h448l192 192v576H256V128z m64 64v640h512V352H672V192H320z m416 45.248V288h50.752L736 237.248zM384 448h384v64H384v-64z m0 128h384v64H384v-64z m0 128h256v64H384v-64zM192 256v704h512v64H128V256h64z' fill='white'/></svg>"];
     // upload.svg — newly replaced "send/cloud" icon supplied by the user.
     NSImage *uploadIcon = [self iconFromSVG:@"<svg viewBox='0 0 1024 1024' xmlns='http://www.w3.org/2000/svg'><path d='M550.528 544.128L640 539.776V678.4l178.005333-178.005333L640 322.389333v129.024l-72.618667 10.922667c-155.52 23.424-251.733333 73.557333-312.874666 164.437333 84.906667-50.602667 178.261333-76.928 296.021333-82.645333zM554.666667 629.376c-27.392 1.322667-53.034667 3.968-77.141334 7.808l-8.192 1.365333c-136.704 23.637333-224.810667 87.168-310.954666 176.128-26.154667 27.008-51.882667 59.648-51.882667 59.648-14.848 18.176-24.021333 14.037333-20.352-9.173333 0 0 4.394667-31.402667 11.690667-65.792C144.938667 577.066667 250.581333 423.68 554.666667 377.941333V209.066667a38.4 38.4 0 0 1 65.536-27.136l291.328 291.285333a38.4 38.4 0 0 1 0 54.314667l-291.328 291.285333A38.4 38.4 0 0 1 554.666667 791.637333v-162.261333z' fill='white'/></svg>"];
@@ -268,10 +274,11 @@ static id nativeOverlayKeyMonitor = nil;
     [self styleIconButton:_clipboardButton image:copyIcon];
     [self styleIconButton:_saveButton image:saveIcon];
     [self styleIconButton:_saveRemoteButton image:saveRemoteIcon];
+    [self styleIconButton:_ocrButton image:ocrIcon];
     [self styleIconButton:_summaryButton image:summaryIcon];
     [self styleIconButton:_uploadButton image:uploadIcon];
 
-    // Configure hover colors for the 5 action buttons. White is the shared
+    // Configure hover colors for the action buttons. White is the shared
     // base; cancel turns red on hover and the rest turn blue, providing a
     // glance-able cue for destructive vs. constructive actions.
     NSColor *baseWhite = [NSColor whiteColor];
@@ -281,12 +288,14 @@ static id nativeOverlayKeyMonitor = nil;
     SnipHoverButton *clipboardHB  = (SnipHoverButton *)_clipboardButton;
     SnipHoverButton *saveHB       = (SnipHoverButton *)_saveButton;
     SnipHoverButton *saveRemoteHB = (SnipHoverButton *)_saveRemoteButton;
+    SnipHoverButton *ocrHB        = (SnipHoverButton *)_ocrButton;
     SnipHoverButton *summaryHB    = (SnipHoverButton *)_summaryButton;
     SnipHoverButton *uploadHB     = (SnipHoverButton *)_uploadButton;
     cancelHB.baseColor = baseWhite;     cancelHB.hoverColor = hoverRed;
     clipboardHB.baseColor = baseWhite;  clipboardHB.hoverColor = hoverBlue;
     saveHB.baseColor = baseWhite;       saveHB.hoverColor = hoverBlue;
     saveRemoteHB.baseColor = baseWhite; saveRemoteHB.hoverColor = hoverBlue;
+    ocrHB.baseColor = baseWhite;        ocrHB.hoverColor = hoverBlue;
     summaryHB.baseColor = baseWhite;    summaryHB.hoverColor = hoverBlue;
     uploadHB.baseColor = baseWhite;     uploadHB.hoverColor = hoverBlue;
 
@@ -646,6 +655,7 @@ static id nativeOverlayKeyMonitor = nil;
     [_clipboardButton setHidden:!visible];
     [_saveButton setHidden:!visible];
     [_saveRemoteButton setHidden:!visible];
+    [_ocrButton setHidden:!visible];
     [_summaryButton setHidden:!visible];
     [_uploadButton setHidden:!visible];
     [_actionToolbarBg setHidden:!visible];
@@ -665,12 +675,12 @@ static id nativeOverlayKeyMonitor = nil;
     [_sizeLabel setStringValue:[NSString stringWithFormat:@"%.0f × %.0f", _selection.size.width, _selection.size.height]];
     [_sizeLabel setFrame:NSMakeRect(_selection.origin.x, MAX(0, _selection.origin.y - 26), 110, 22)];
 
-    // Action toolbar layout — 6 icon buttons, each 28x28, separated by 8px,
+    // Action toolbar layout — 7 icon buttons, each 28x28, separated by 8px,
-    // with 4px outer padding. Total = 6*28 + 5*8 + 2*4 = 216px wide.
+    // with 4px outer padding. Total = 7*28 + 6*8 + 2*4 = 252px wide.
     CGFloat actionBtnSize = 28;
     CGFloat actionGap = 8;
     CGFloat actionPad = 4;
-    NSInteger actionCount = 6;
+    NSInteger actionCount = 7;
     CGFloat toolbarW = actionPad * 2 + actionBtnSize * actionCount + actionGap * (actionCount - 1);
     CGFloat toolbarH = 40;
     CGFloat x = _selection.origin.x + _selection.size.width - toolbarW;
@@ -688,8 +698,9 @@ static id nativeOverlayKeyMonitor = nil;
     [_clipboardButton  setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 1, btnY, actionBtnSize, actionBtnSize)];
     [_saveButton       setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 2, btnY, actionBtnSize, actionBtnSize)];
     [_saveRemoteButton setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 3, btnY, actionBtnSize, actionBtnSize)];
-    [_summaryButton    setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 4, btnY, actionBtnSize, actionBtnSize)];
+    [_ocrButton        setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 4, btnY, actionBtnSize, actionBtnSize)];
-    [_uploadButton     setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 5, btnY, actionBtnSize, actionBtnSize)];
+    [_summaryButton    setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 5, btnY, actionBtnSize, actionBtnSize)];
+    [_uploadButton     setFrame:NSMakeRect(baseX + (actionBtnSize + actionGap) * 6, btnY, actionBtnSize, actionBtnSize)];
 
     // Mark toolbar sits to the LEFT of the action toolbar (same row) with an
     // 8px gap between the two groups, so they never overlap on tiny selections.
@@ -930,6 +941,18 @@ static id nativeOverlayKeyMonitor = nil;
     nativeOverlaySaveRemote((int)llround(r.origin.x), (int)llround(r.origin.y), (int)llround(r.size.width), (int)llround(r.size.height), [json UTF8String]);
 }
 
+// `ocrSelection` sends the screenshot to the configured OCR provider and
+// copies the extracted text.
+- (void)ocrSelection {
+    if (!_hasSelection) {
+        return;
+    }
+    NSRect r = [self globalRectForSelection:_selection];
+    [self closeOverlayWindow];
+    NSString *json = [self annotationsJSON];
+    nativeOverlayOCR((int)llround(r.origin.x), (int)llround(r.origin.y), (int)llround(r.size.width), (int)llround(r.size.height), [json UTF8String]);
+}
+
 // `summarizeSelection` uploads the screenshot to S3, sends it to the
 // configured multimodal model, and copies the generated summary.
 - (void)summarizeSelection {