Add a switch to invert web contents (non-accel only).

content/renderer/render_widget.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_widget.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "content/common/swapped_out_messages.h"
 #include "content/common/view_messages.h"
 #include "content/public/common/content_switches.h"
 #include "content/renderer/gpu/compositor_thread.h"
 #include "content/renderer/render_process.h"
 #include "content/renderer/render_thread_impl.h"
 #include "content/renderer/renderer_webkitplatformsupport_impl.h"
 #include "ipc/ipc_sync_message.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/skia/include/core/SkShader.h"
+#include "third_party/skia/include/effects/SkTableColorFilter.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCursorInfo.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebPoint.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupMenu.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupMenuInfo.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebRange.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebRect.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebScreenInfo.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebSize.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebString.h"
 #include "ui/gfx/point.h"
@@ skipping 54 matching lines @@
       is_swapped_out_(false),
       input_method_is_active_(false),
       text_input_type_(ui::TEXT_INPUT_TYPE_NONE),
       can_compose_inline_(true),
       popup_type_(popup_type),
       pending_window_rect_count_(0),
       suppress_next_char_events_(false),
       is_accelerated_compositing_active_(false),
       animation_update_pending_(false),
       animation_task_posted_(false),
-      invalidation_task_posted_(false) {
+      invalidation_task_posted_(false),
+      invert_(false) {
   RenderProcess::current()->AddRefProcess();
   DCHECK(RenderThread::Get());
   has_disable_gpu_vsync_switch_ = CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableGpuVsync);
 }
 
 RenderWidget::~RenderWidget() {
   DCHECK(!webwidget_) << "Leaking our WebWidget!";
   STLDeleteElements(&updates_pending_swap_);
   if (current_paint_buf_) {
@@ skipping 98 matching lines @@
     IPC_MESSAGE_HANDLER(ViewMsg_HandleInputEvent, OnHandleInputEvent)
     IPC_MESSAGE_HANDLER(ViewMsg_MouseCaptureLost, OnMouseCaptureLost)
     IPC_MESSAGE_HANDLER(ViewMsg_SetFocus, OnSetFocus)
     IPC_MESSAGE_HANDLER(ViewMsg_SetInputMethodActive, OnSetInputMethodActive)
     IPC_MESSAGE_HANDLER(ViewMsg_ImeSetComposition, OnImeSetComposition)
     IPC_MESSAGE_HANDLER(ViewMsg_ImeConfirmComposition, OnImeConfirmComposition)
     IPC_MESSAGE_HANDLER(ViewMsg_PaintAtSize, OnMsgPaintAtSize)
     IPC_MESSAGE_HANDLER(ViewMsg_Repaint, OnMsgRepaint)
     IPC_MESSAGE_HANDLER(ViewMsg_SetTextDirection, OnSetTextDirection)
     IPC_MESSAGE_HANDLER(ViewMsg_Move_ACK, OnRequestMoveAck)
+    IPC_MESSAGE_HANDLER(ViewMsg_InvertWebContent, OnInvertWebContent)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 bool RenderWidget::Send(IPC::Message* message) {
   // Don't send any messages after the browser has told us to close, and filter
   // most outgoing messages while swapped out.
   if ((is_swapped_out_ &&
        !content::SwappedOutMessages::CanSendWhileSwappedOut(message)) ||
@@ skipping 350 matching lines @@
                              const gfx::Point& canvas_origin,
                              skia::PlatformCanvas* canvas) {
   TRACE_EVENT2("renderer", "PaintRect",
                "width", rect.width(), "height", rect.height());
   canvas->save();
 
   // Bring the canvas into the coordinate system of the paint rect.
   canvas->translate(static_cast<SkScalar>(-canvas_origin.x()),
                     static_cast<SkScalar>(-canvas_origin.y()));
 
+  if (invert_) {
+    // Draw everything to a temporary bitmap and then apply an
+    // inverting color map to the result. This is balanced by an extra
+    // call to canvas->restore(), below.
+    DCHECK(invert_paint_.get());
+    SkRect bounds;
+    bounds.set(rect.x(), rect.y(), rect.right(), rect.bottom());
+    canvas->saveLayer(&bounds, invert_paint_.get());
+  }
+
   // If there is a custom background, tile it.
   if (!background_.empty()) {
     SkPaint paint;
     SkShader* shader = SkShader::CreateBitmapShader(background_,
                                                     SkShader::kRepeat_TileMode,
                                                     SkShader::kRepeat_TileMode);
     paint.setShader(shader)->unref();
 
     // Use kSrc_Mode to handle background_ transparency properly.
     paint.setXfermodeMode(SkXfermode::kSrc_Mode);
@@ skipping 40 matching lines @@
     optimized_instance->Paint(webkit_glue::ToWebCanvas(canvas),
                               optimized_copy_location, rect);
   } else {
     // Normal painting case.
     webwidget_->paint(webkit_glue::ToWebCanvas(canvas), rect);
 
     // Flush to underlying bitmap.  TODO(darin): is this needed?
     skia::GetTopDevice(*canvas)->accessBitmap(false);
   }
 
+  if (invert_)
+    canvas->restore();
+
   PaintDebugBorder(rect, canvas);
   canvas->restore();
 }
 
 void RenderWidget::PaintDebugBorder(const gfx::Rect& rect,
                                     skia::PlatformCanvas* canvas) {
   static bool kPaintBorder =
       CommandLine::ForCurrentProcess()->HasSwitch(switches::kShowPaintRects);
   if (!kPaintBorder)
     return;
@@ skipping 722 matching lines @@
     didInvalidateRect(repaint_rect);
   }
 }
 
 void RenderWidget::OnSetTextDirection(WebTextDirection direction) {
   if (!webwidget_)
     return;
   webwidget_->setTextDirection(direction);
 }
 
+void RenderWidget::OnInvertWebContent(bool invert) {
+  if (invert_ == invert)
+    return;
+
+  invert_ = invert;
+
+  if (invert_ && !invert_paint_.get()) {
+    // Gamma-aware color inversion: each source pixel value x is normally
+    // displayed on a computer monitor with a gamma correction x^gamma,
+    // where gamma is typically in the range 1.8...2.2. By approximating
+    // gamma as exactly 2, the formula to invert one value is sqrt(1 - x^2).
+    uint8_t table[256];
+    for (unsigned int i = 0; i < 256; i++) {
+      double value = i / 255.0;
+      value = sqrt(1 - (value * value));
+      table[i] = static_cast<uint8_t>(255 * value);
+    }
+
+    // Create a Skia Paint with this inverting color map.
+    invert_paint_.reset(new SkPaint());
+    invert_paint_->setStyle(SkPaint::kFill_Style);
+    invert_paint_->setColor(SK_ColorBLACK);
+    SkColorFilter* filter = SkTableColorFilter::CreateARGB(
+        NULL, table, table, table);
+    invert_paint_->setColorFilter(filter);
+    filter->unref();
+  }
+
+  OnMsgRepaint(size_);
+}
+
 webkit::ppapi::PluginInstance* RenderWidget::GetBitmapForOptimizedPluginPaint(
     const gfx::Rect& paint_bounds,
     TransportDIB** dib,
     gfx::Rect* location,
     gfx::Rect* clip) {
   // Bare RenderWidgets don't support optimized plugin painting.
   return NULL;
 }
 
 gfx::Point RenderWidget::GetScrollOffset() {
@@ skipping 203 matching lines @@
   }
 }
 
 bool RenderWidget::WillHandleMouseEvent(const WebKit::WebMouseEvent& event) {
   return false;
 }
 
 bool RenderWidget::WebWidgetHandlesCompositorScheduling() const {
   return false;
 }