Linux: write images to clipboard.

Writing a bitmap to the clipboard is a rather slow operation, as it involves piping it over IPC and then converting it to a PNG.

Review URL: http://codereview.chromium.org/42592

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@12482 0039d316-1c4b-4281-b951-d872f2087c98

base/clipboard.cc

@@ -38,7 +38,7 @@ void Clipboard::DispatchObject(ObjectType type, const ObjectMapParams& params) {
       WriteWebSmartPaste();
       break;
 
-#if defined(OS_WIN) || defined(OS_LINUX)  // This is just a stub on Linux
+#if defined(OS_WIN) || defined(OS_LINUX)
     case CBF_BITMAP:
       WriteBitmap(&(params[0].front()), &(params[1].front()));
       break;

base/clipboard_linux.cc

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 #include "base/clipboard.h"
-#include "base/string_util.h"
 
 #include <gtk/gtk.h>
 #include <map>
@@ -11,11 +10,15 @@
 #include <string>
 #include <utility>
 
+#include "base/gfx/png_encoder.h"
+#include "base/string_util.h"
+
 namespace {
 
-static const char* kMimeHtml = "text/html";
-static const char* kMimeText = "text/plain";
-static const char* kMimeWebkitSmartPaste = "chrome-internal/webkit-paste";
+const char* kMimePng = "image/png";
+const char* kMimeHtml = "text/html";
+const char* kMimeText = "text/plain";
+const char* kMimeWebkitSmartPaste = "chromium-internal/webkit-paste";
 
 std::string GdkAtomToString(const GdkAtom& atom) {
   gchar* name = gdk_atom_name(atom);
@@ -158,8 +161,24 @@ void Clipboard::WriteWebSmartPaste() {
   InsertMapping(kMimeWebkitSmartPaste, NULL, 0);
 }
 
+// We have to convert the image to a PNG because gtk_clipboard_request_image()
+// only works with PNGs. Warning: this is an internal implementation detail of
+// gtk_clipboard_request_image() and might change in the future.
 void Clipboard::WriteBitmap(const char* pixel_data, const char* size_data) {
-  NOTIMPLEMENTED();
+  const gfx::Size* size = reinterpret_cast<const gfx::Size*>(size_data);
+
+  std::vector<unsigned char> png_data;
+  if (!PNGEncoder::Encode(
+      reinterpret_cast<const unsigned char*>(pixel_data),
+      PNGEncoder::FORMAT_BGRA, size->width(), size->height(),
+      size->width() * 4, false, &png_data)) {
+    DLOG(ERROR) << "Failed to encode bitmap for clipboard.";
+    return;
+  }
+  char* data = new char[png_data.size()];
+  memcpy(data, png_data.data(), png_data.size());
+
+  InsertMapping(kMimePng, data, png_data.size());
 }
 
 void Clipboard::WriteBookmark(const char* title_data, size_t title_len,

base/scoped_clipboard_writer.cc

@@ -120,7 +120,6 @@ void ScopedClipboardWriter::WriteWebSmartPaste() {
   objects_[Clipboard::CBF_WEBKIT] = Clipboard::ObjectMapParams();
 }
 
-#if defined(OS_WIN)
 void ScopedClipboardWriter::WriteBitmapFromPixels(const void* pixels,
                                                   const gfx::Size& size) {
   Clipboard::ObjectMapParam pixels_parameter, size_parameter;
@@ -139,4 +138,3 @@ void ScopedClipboardWriter::WriteBitmapFromPixels(const void* pixels,
   parameters.push_back(size_parameter);
   objects_[Clipboard::CBF_BITMAP] = parameters;
 }
-#endif  // defined(OS_WIN)

base/scoped_clipboard_writer.h

@@ -51,13 +51,9 @@ class ScopedClipboardWriter {
   // Used by WebKit to determine whether WebKit wrote the clipboard last
   void WriteWebSmartPaste();
 
-#if defined(OS_WIN)
   // Adds a bitmap to the clipboard
-  // This is the slowest way to copy a bitmap to the clipboard as we must first
-  // memcpy the pixels into GDI and the blit the bitmap to the clipboard.
   // Pixel format is assumed to be 32-bit BI_RGB.
   void WriteBitmapFromPixels(const void* pixels, const gfx::Size& size);
-#endif  // defined(OS_WIN)
 
  protected:
   // We accumulate the data passed to the various targets in the |objects_|

chrome/browser/renderer_host/resource_message_filter.cc

@@ -499,13 +499,13 @@ void ResourceMessageFilter::OnClipboardWriteObjects(
   // a task to perform the write on the UI thread.
   Clipboard::ObjectMap* long_living_objects = new Clipboard::ObjectMap(objects);
 
-  // We pass the renderer handle to assist the clipboard with using shared
-  // memory objects. renderer handle is a handle to the process that would
-  // own any shared memory that might be in the object list.
 #if defined(OS_WIN)
+  // We pass the renderer handle to assist the clipboard with using shared
+  // memory objects. handle() is a handle to the process that would
+  // own any shared memory that might be in the object list. We only do this
+  // on Windows and it only applies to bitmaps. (On Linux, bitmaps
+  // are copied pixel by pixel rather than using shared memory.)
   Clipboard::DuplicateRemoteHandles(handle(), long_living_objects);
-#else
-  NOTIMPLEMENTED();  // TODO(port) implement this.
 #endif
 
   render_widget_helper_->ui_loop()->PostTask(FROM_HERE,

tools/gtk_clipboard_dump/gtk_clipboard_dump.cc

@@ -30,6 +30,12 @@ int main(int argc, char* argv[]) {
     }
 
     printf(" / length: %d / bits %d]: ", data->length, data->format);
+
+    if (strstr(gdk_atom_name(targets[i]), "image")) {
+      printf("(image omitted)\n\n");
+      continue;
+    }
+
     for (int j = 0; j < data->length; j++) {
       // Output data one byte at a time. Currently wide strings look
       // pretty weird.

webkit/glue/webclipboard_impl.cc

@@ -119,7 +119,7 @@ void WebClipboardImpl::writeImage(
     const WebImage& image, const WebURL& url, const WebString& title) {
   ScopedClipboardWriterGlue scw(ClipboardGetClipboard());
 
-#if defined(OS_WIN)
+#if defined(OS_WIN) || defined(OS_LINUX)
   if (!image.isNull())
     scw.WriteBitmapFromPixels(image.pixels(), image.size());
 #endif