Merge pull request #128 from atom/api-capture-page

Add BrowserWindow.capturePage API.

browser/api/atom_api_window.cc

@@ -14,6 +14,7 @@
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
+#include "vendor/node/src/node_buffer.h"
 
 using content::V8ValueConverter;
 using content::NavigationController;
@@ -82,6 +83,20 @@ void Window::OnRendererCrashed() {
   Emit("crashed");
 }
 
+void Window::OnCapturePageDone(v8::Persistent<v8::Function> callback,
+                               const std::vector<unsigned char>& data) {
+  v8::HandleScope scope;
+
+  // TODO(zcbenz): Use new Buffer API when we updated to node v0.12.x.
+  node::Buffer* buffer = node::Buffer::New(
+      reinterpret_cast<const char*>(data.data()),
+      data.size());
+
+  v8::Handle<v8::Value> arg = buffer->handle_;
+  callback->Call(v8::Context::GetCurrent()->Global(), 1, &arg);
+  callback.Dispose(v8::Isolate::GetCurrent());
+}
+
 // static
 v8::Handle<v8::Value> Window::New(const v8::Arguments &args) {
   v8::HandleScope scope;
@@ -480,6 +495,23 @@ v8::Handle<v8::Value> Window::RestartHangMonitorTimeout(
   return v8::Undefined();
 }
 
+// static
+v8::Handle<v8::Value> Window::CapturePage(const v8::Arguments& args) {
+  UNWRAP_WINDOW_AND_CHECK;
+
+  gfx::Rect rect;
+  v8::Persistent<v8::Function> callback;
+  if (!FromV8Arguments(args, &rect, &callback) &&
+      !FromV8Arguments(args, &callback))
+    return node::ThrowTypeError("Bad argument");
+
+  self->window_->CapturePage(rect, base::Bind(&Window::OnCapturePageDone,
+                                              base::Unretained(self),
+                                              callback));
+
+  return v8::Undefined();
+}
+
 // static
 v8::Handle<v8::Value> Window::GetPageTitle(const v8::Arguments &args) {
   UNWRAP_WINDOW_AND_CHECK;
@@ -721,6 +753,7 @@ void Window::Initialize(v8::Handle<v8::Object> target) {
   NODE_SET_PROTOTYPE_METHOD(t,
                             "restartHangMonitorTimeout",
                             RestartHangMonitorTimeout);
+  NODE_SET_PROTOTYPE_METHOD(t, "capturePage", CapturePage);
 
   NODE_SET_PROTOTYPE_METHOD(t, "getPageTitle", GetPageTitle);
   NODE_SET_PROTOTYPE_METHOD(t, "isLoading", IsLoading);

browser/api/atom_api_window.h

@@ -5,6 +5,8 @@
 #ifndef ATOM_BROWSER_API_ATOM_API_WINDOW_H_
 #define ATOM_BROWSER_API_ATOM_API_WINDOW_H_
 
+#include <vector>
+
 #include "base/memory/scoped_ptr.h"
 #include "browser/api/atom_api_event_emitter.h"
 #include "browser/native_window_observer.h"
@@ -87,6 +89,7 @@ class Window : public EventEmitter,
   static v8::Handle<v8::Value> IsWebViewFocused(const v8::Arguments& args);
   static v8::Handle<v8::Value> RestartHangMonitorTimeout(
       const v8::Arguments &args);
+  static v8::Handle<v8::Value> CapturePage(const v8::Arguments& args);
 
   // APIs for WebContents.
   static v8::Handle<v8::Value> GetPageTitle(const v8::Arguments &args);
@@ -110,6 +113,10 @@ class Window : public EventEmitter,
   static v8::Handle<v8::Value> Reload(const v8::Arguments &args);
   static v8::Handle<v8::Value> ReloadIgnoringCache(const v8::Arguments &args);
 
+  // Called when capturePage is done.
+  void OnCapturePageDone(v8::Persistent<v8::Function> callback,
+                         const std::vector<unsigned char>& data);
+
   scoped_ptr<NativeWindow> window_;
 
   DISALLOW_COPY_AND_ASSIGN(Window);

browser/native_window.cc

@@ -29,6 +29,7 @@
 #include "common/api/api_messages.h"
 #include "common/options_switches.h"
 #include "ipc/ipc_message_macros.h"
+#include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
@@ -198,6 +199,16 @@ bool NativeWindow::SetIcon(const std::string& str_path) {
   return true;
 }
 
+void NativeWindow::CapturePage(const gfx::Rect& rect,
+                               const CapturePageCallback& callback) {
+  GetWebContents()->GetRenderViewHost()->CopyFromBackingStore(
+      rect,
+      gfx::Size(),
+      base::Bind(&NativeWindow::OnCapturePageDone,
+                 base::Unretained(this),
+                 callback));
+}
+
 void NativeWindow::CloseWebContents() {
   bool prevent_default = false;
   FOR_EACH_OBSERVER(NativeWindowObserver,
@@ -374,6 +385,15 @@ void NativeWindow::Observe(int type,
   }
 }
 
+void NativeWindow::OnCapturePageDone(const CapturePageCallback& callback,
+                                     bool succeed,
+                                     const SkBitmap& bitmap) {
+  std::vector<unsigned char> data;
+  if (succeed)
+    gfx::PNGCodec::EncodeBGRASkBitmap(bitmap, true, &data);
+  callback.Run(data);
+}
+
 void NativeWindow::OnRendererMessage(const string16& channel,
                                      const base::ListValue& args) {
   AtomBrowserMainParts::Get()->atom_bindings()->OnRendererMessage(

browser/native_window.h

@@ -49,6 +49,9 @@ class NativeWindow : public brightray::DefaultWebContentsDelegate,
                      public content::WebContentsObserver,
                      public content::NotificationObserver {
  public:
+  typedef base::Callback<void(const std::vector<unsigned char>& buffer)>
+      CapturePageCallback;
+
   virtual ~NativeWindow();
 
   // Create window with existing WebContents.
@@ -108,6 +111,11 @@ class NativeWindow : public brightray::DefaultWebContentsDelegate,
   virtual void RestartHangMonitorTimeout();
   virtual bool SetIcon(const std::string& path);
 
+  // Captures the page with |rect|, |callback| would be called when capturing is
+  // done.
+  virtual void CapturePage(const gfx::Rect& rect,
+                           const CapturePageCallback& callback);
+
   // The same with closing a tab in a real browser.
   //
   // Should be called by platform code when user want to close the window.
@@ -184,6 +192,11 @@ class NativeWindow : public brightray::DefaultWebContentsDelegate,
  private:
   void RendererUnresponsiveDelayed();
 
+  // Called when CapturePage has done.
+  void OnCapturePageDone(const CapturePageCallback& callback,
+                         bool succeed,
+                         const SkBitmap& bitmap);
+
   void OnRendererMessage(const string16& channel,
                          const base::ListValue& args);
 

common/v8_conversions.h

@@ -11,6 +11,7 @@
 #include "base/files/file_path.h"
 #include "base/string16.h"
 #include "browser/api/atom_api_window.h"
+#include "ui/gfx/rect.h"
 #include "v8/include/v8.h"
 
 // Convert V8 value to arbitrary supported types.
@@ -38,6 +39,20 @@ struct FromV8Value {
     return base::FilePath::FromUTF8Unsafe(FromV8Value(value_));
   }
 
+  operator gfx::Rect() {
+    v8::Handle<v8::Object> rect = value_->ToObject();
+    v8::Handle<v8::Value> x = rect->Get(v8::String::New("x"));
+    v8::Handle<v8::Value> y = rect->Get(v8::String::New("y"));
+    v8::Handle<v8::Value> width = rect->Get(v8::String::New("width"));
+    v8::Handle<v8::Value> height = rect->Get(v8::String::New("height"));
+    if (!x->IsNumber() || !y->IsNumber() ||
+        !width->IsNumber() || !height->IsNumber())
+      return gfx::Rect();
+    else
+      return gfx::Rect(x->IntegerValue(), y->IntegerValue(),
+                       width->IntegerValue(), height->IntegerValue());
+  }
+
   operator std::vector<std::string>() {
     std::vector<std::string> array;
     v8::Handle<v8::Array> v8_array = v8::Handle<v8::Array>::Cast(value_);
@@ -58,11 +73,9 @@ struct FromV8Value {
   }
 
   operator v8::Persistent<v8::Function>() {
-    return value_->IsFunction() ?
-      v8::Persistent<v8::Function>::New(
-          node::node_isolate,
-          v8::Handle<v8::Function>::Cast(value_)) :
-      v8::Persistent<v8::Function>();
+    return v8::Persistent<v8::Function>::New(
+        node::node_isolate,
+        v8::Handle<v8::Function>::Cast(value_));
   }
 
   v8::Handle<v8::Value> value_;
@@ -137,6 +150,11 @@ bool V8ValueCanBeConvertedTo<base::FilePath>(v8::Handle<v8::Value> value) {
   return V8ValueCanBeConvertedTo<std::string>(value);
 }
 
+template<> inline
+bool V8ValueCanBeConvertedTo<gfx::Rect>(v8::Handle<v8::Value> value) {
+  return value->IsObject();
+}
+
 template<> inline
 bool V8ValueCanBeConvertedTo<std::vector<std::string>>(
     v8::Handle<v8::Value> value) {

docs/api/browser/browser-window.md

@@ -290,6 +290,23 @@ Starts inspecting element at position (`x`, `y`).
 
 ### BrowserWindow.restartHangMonitorTimeout()
 
+### BrowserWindow.capturePage([rect, ]callback)
+
+* `rect` Object - The area of page to be captured
+  * `x`
+  * `y`
+  * `width`
+  * `height`
+* `callback` Function
+
+Captures the snapshot of page within `rect`, upon completion `callback` would be
+called with `callback(image)`, the `image` is a `Buffer` that stores the PNG
+encoded data of the snapshot. Omitting the `rect` would capture the whole
+visible page.
+
+You can write received `image` directly to a `.png` file, or you can base64
+encode it and use data URL to embed the image in HTML.
+
 ### BrowserWindow.getPageTitle()
 
 Returns the title of web page.

spec/api/window.coffee

@@ -75,6 +75,13 @@ describe 'window module', ->
       assert.equal w.isVisible(), false
       w.close()
 
+  describe 'BrowserWindow.capturePage(rect, callback)', ->
+    it 'calls the callback with a Buffer', ->
+      w = new BrowserWindow(show: false)
+      w.capturePage {x: 0, y: 0, width: 100, height: 100}, (image) ->
+        assert.equal image.constructor.name, 'SlowBuffer'
+        w.close()
+
   describe 'beforeunload handler', ->
     it 'returning true would not prevent close', (done) ->
       w = new BrowserWindow(show: false)

vendor/node

@@ -1 +1 @@
-Subproject commit 7f44fac0fd64af7ec172c9606af1f3cec684a9ce
+Subproject commit 24c11bdc794c2b7b79163cb4737046f8de42446d