Implement Pepper IME API.

ppapi/examples/ime/ime.cc

+// Copyright (c) 2011 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 <string>
+#include <utility>
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "ppapi/c/dev/ppb_console_dev.h"
+#include "ppapi/c/dev/ppb_cursor_control_dev.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/dev/font_dev.h"
+#include "ppapi/cpp/dev/ime_input_event_dev.h"
+#include "ppapi/cpp/dev/text_input_dev.h"
+#include "ppapi/cpp/graphics_2d.h"
+#include "ppapi/cpp/image_data.h"
+#include "ppapi/cpp/input_event.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/rect.h"
+#include "ppapi/cpp/size.h"
+#include "ui/base/keycodes/keyboard_codes.h"
+
+namespace {
+
+const uint32_t kTextfieldBgColor = 0xffffffff;
+const uint32_t kTextfieldTextColor = 0xff000000;
+const uint32_t kTextfieldCaretColor = 0xff000000;
+const uint32_t kTextfieldPreeditTextColor = 0xffff0000;
+const uint32_t kTextfieldUnderlineColorMain = 0xffff0000;
+const uint32_t kTextfieldUnderlineColorSub = 0xffddaaaa;
+
+void FillRect(pp::ImageData* image,
+              int left, int top, int width, int height,
+              uint32_t color) {
+  for (int y = std::max(0, top);
+       y < std::min(image->size().height() - 1, top + height);
+       ++y) {
+    for (int x = std::max(0, left);
+         x < std::min(image->size().width() - 1, left + width);
+         ++x)
+      *image->GetAddr32(pp::Point(x, y)) = color;
+  }
+}
+
+void FillRect(pp::ImageData* image, const pp::Rect& rect, uint32_t color) {
+  FillRect(image, rect.x(), rect.y(), rect.width(), rect.height(), color);
+}
+
+size_t Utf8Prev(const std::string& str, size_t i) {

[yzshen1, 2011/10/05 17:19:50]

What about something like
size_t GetPrevCharOffsetUtf8(const std::string& str, size_t current_pos)?
(And please also consider the name of Utf8Next and Utf8NextN.)

[kinaba, 2011/10/06 07:05:01]

Done. For Utf8NextN, I also replaced it with a function to compute the n-th
offset from the beginning.

+  if (i > 0) {
+    do
+      --i;
+    while ((str[i] & 0xc0) == 0x80 && i > 0);
+  }
+  return i;
+}
+
+size_t Utf8Next(const std::string& str, size_t i) {
+  if (i < str.size()) {
+    do
+      ++i;
+    while ((str[i] & 0xc0) == 0x80 && i < str.size());
+  }
+  return i;
+}
+
+size_t Utf8NextN(const std::string& str, size_t i, size_t n) {
+  for (size_t step = 0; step < n; ++step)
+    i = Utf8Next(str, i);
+  return i;
+}
+
+}  // namespace
+
+class TextFieldStatusHandler {
+ public:
+  virtual ~TextFieldStatusHandler() {}
+  virtual void FocusIn(const pp::Rect& caret, const pp::Rect& bounding_box) {}
+  virtual void FocusOut() {}
+};
+
+class TextFieldStatusNotifyingHanlder : public TextFieldStatusHandler {
+ public:
+  explicit TextFieldStatusNotifyingHanlder(pp::Instance* instance)
+      : instance_(instance),
+        textinput_control_(instance) {}
+
+ protected:
+  virtual void FocusIn(const pp::Rect& caret, const pp::Rect& bounding_box) {
+    textinput_control_.SetTextInputType(PP_TEXTINPUT_TYPE_TEXT);
+    textinput_control_.UpdateCaretPosition(caret, bounding_box);
+  }
+  virtual void FocusOut() {
+    textinput_control_.CancelCompositionText();
+    textinput_control_.SetTextInputType(PP_TEXTINPUT_TYPE_NONE);
+  }
+
+ private:
+  pp::Instance* instance_;
+  pp::TextInput_Dev textinput_control_;
+};
+
+// Hand-made text field for demonstrating text input API.
+class MyTextField {
+ public:
+  MyTextField(pp::Instance* instance, TextFieldStatusHandler* handler,
+              int x, int y, int width, int height)
+      : instance_(instance),
+        status_handler_(handler),
+        area_(x, y, width, height),
+        font_size_(height - 2),
+        caret_pos_(std::string::npos) {
+    pp::FontDescription_Dev desc;
+    desc.set_family(PP_FONTFAMILY_SANSSERIF);
+    desc.set_size(font_size_);
+    font_ = pp::Font_Dev(instance_, desc);
+  }
+
+  // Paint on the specified ImageData.
+  void PaintOn(pp::ImageData* image, pp::Rect clip) {
+    clip = clip.Intersect(area_);
+    FillRect(image, clip, kTextfieldBgColor);
+
+    if (caret_pos_ != std::string::npos) {
+      int offset = area_.x();
+      // before caret
+      {
+        std::string str = utf8_text_.substr(0, caret_pos_);
+        font_.DrawTextAt(
+            image,
+            pp::TextRun_Dev(str.c_str(), false, false),
+            pp::Point(offset, area_.y() + font_size_),
+            kTextfieldTextColor,
+            clip,
+            false);
+        offset += font_.MeasureSimpleText(str);
+      }
+      // composition
+      {
+        const std::string& str = composition_;
+        font_.DrawTextAt(
+            image,
+            pp::TextRun_Dev(str.c_str(), false, false),
+            pp::Point(offset, area_.y() + font_size_),
+            kTextfieldPreeditTextColor,
+            clip,
+            false);
+        for (size_t i = 0; i < segments_.size(); ++i) {
+          size_t l = segments_[i].first;
+          size_t r = segments_[i].second;
+          if (l != r) {
+            int lx = font_.MeasureSimpleText(str.substr(0, l));
+            int rx = font_.MeasureSimpleText(str.substr(0, r));
+            FillRect(image,
+                     offset + lx + 2, area_.y() + font_size_ + 1,
+                     rx - lx - 4, 2,
+                     i == static_cast<size_t>(target_segment_) ?
+                         kTextfieldUnderlineColorMain :
+                         kTextfieldUnderlineColorSub);
+          }
+        }
+        // caret
+        int caretx = font_.MeasureSimpleText(str.substr(0, selection_.first));
+        FillRect(image,
+                 pp::Rect(offset + caretx, area_.y(), 2, area_.height()),
+                 kTextfieldCaretColor);
+        offset += font_.MeasureSimpleText(str);
+      }
+      // after caret
+      {
+        std::string str = utf8_text_.substr(caret_pos_);
+        font_.DrawTextAt(
+            image,
+            pp::TextRun_Dev(str.c_str(), false, false),
+            pp::Point(offset, area_.y() + font_size_),
+            kTextfieldTextColor,
+            clip,
+            false);
+      }
+    } else {
+      font_.DrawTextAt(
+          image,
+          pp::TextRun_Dev(utf8_text_.c_str(), false, false),
+          pp::Point(area_.x(), area_.y() + font_size_),
+          kTextfieldTextColor,
+          clip,
+          false);
+    }
+  }
+
+  // Update current composition text.
+  void SetComposition(
+      const std::string& text,
+      const std::vector< std::pair<uint32_t, uint32_t> >& segments,
+      int32_t target_segment,
+      const std::pair<uint32_t, uint32_t>& selection) {
+    composition_ = text;
+    segments_ = segments;
+    target_segment_ = target_segment;
+    selection_ = selection;
+    CaretPosChanged();
+  }
+
+  // Is the text field focused?
+  bool Focused() const {
+    return caret_pos_ != std::string::npos;
+  }
+
+  // Does the coordinate (x,y) is contained inside the edit box?
+  bool Contains(int x, int y) const {
+    return area_.Contains(x, y);
+  }
+
+  // Resets the content text.
+  void SetText(const std::string& text) {
+    utf8_text_ = text;
+    if (Focused()) {
+      caret_pos_ = text.size();
+      CaretPosChanged();
+    }
+  }
+
+  // Inserts a text at the current caret position.
+  void InsertText(const std::string& text) {
+    if (!Focused())
+      return;
+    utf8_text_.insert(caret_pos_, text);
+    if (Focused()) {
+      caret_pos_ += text.size();
+      CaretPosChanged();
+    }
+  }
+
+  // Handles mouse click event and changes the focus state.
+  bool RefocusByMouseClick(int x, int y) {
+    if (!Contains(x, y)) {
+      // The text field is unfocused.
+      caret_pos_ = std::string::npos;
+      return false;
+    }
+
+    // The text field is focused.
+    size_t n = font_.CharacterOffsetForPixel(
+        pp::TextRun_Dev(utf8_text_.c_str()), x - area_.x());
+    caret_pos_ = Utf8NextN(utf8_text_, 0, n);
+    CaretPosChanged();
+    return true;
+  }
+
+  void KeyLeft() {
+    if (!Focused())
+      return;
+    caret_pos_ = Utf8Prev(utf8_text_, caret_pos_);
+    CaretPosChanged();
+  }
+
+  void KeyRight() {
+    if (!Focused())
+      return;
+    caret_pos_ = Utf8Next(utf8_text_, caret_pos_);
+    CaretPosChanged();
+  }
+
+  void KeyDelete() {
+    if (!Focused())
+      return;
+    size_t i = Utf8Next(utf8_text_, caret_pos_);
+    utf8_text_.erase(caret_pos_, i - caret_pos_);
+    CaretPosChanged();
+  }
+
+  void KeyBackspace() {
+    if (!Focused() || caret_pos_ == 0)
+      return;
+    KeyLeft();
+    KeyDelete();
+  }
+
+ private:
+  // Notify the plugin instance that the caret position has changed.
+  void CaretPosChanged() {
+    if (Focused()) {
+      std::string str = utf8_text_.substr(0, caret_pos_);
+      if (!composition_.empty())
+        str += composition_.substr(0, selection_.first);
+      int px = font_.MeasureSimpleText(str);
+      pp::Rect caret(area_.x() + px, area_.y(), 0, area_.height() + 2);
+      status_handler_->FocusIn(caret, area_);
+    }
+  }
+
+  pp::Instance* instance_;
+  TextFieldStatusHandler* status_handler_;
+
+  pp::Rect area_;
+  int font_size_;
+  pp::Font_Dev font_;
+  std::string utf8_text_;
+  size_t caret_pos_;
+  std::string composition_;
+  std::vector< std::pair<uint32_t, uint32_t> > segments_;
+  std::pair<uint32_t, uint32_t> selection_;
+  int target_segment_;
+};
+
+class MyInstance : public pp::Instance {
+ public:
+  explicit MyInstance(PP_Instance instance)
+      : pp::Instance(instance),
+        status_handler_(new TextFieldStatusHandler) {
+  }
+
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE);
+    RequestFilteringInputEvents(PP_INPUTEVENT_CLASS_KEYBOARD);
+
+    for (uint32_t i = 0; i < argc; ++i) {
+      if (argn[i] == std::string("ime")) {
+        if (argv[i] == std::string("no")) {
+          // Example of NO-IME plugins (e.g., games).
+          //
+          // When a plugin never wants to accept text input, at initialization
+          // explicitly turn off the text input feature by calling:
+          pp::TextInput_Dev(this).SetTextInputType(PP_TEXTINPUT_TYPE_NONE);
+        } else if (argv[i] == std::string("unaware")) {
+          // Demonstrating the behavior of IME-unaware plugins.
+          // Never call any text input related APIs.
+          //
+          // In such a case, the plugin is assumed to always accept text input.
+          // For example, when the plugin is focused in touch devices a virtual
+          // keyboard may pop up, or in environment IME is used, users can type
+          // text via IME on the plugin. The characters are delivered to the
+          // plugin via PP_INPUTEVENT_TYPE_CHAR events.
+        } else if (argv[i] == std::string("caretmove")) {
+          // Demonstrating the behavior of plugins with limited IME support.
+          //
+          // It uses SetTextInputType() and UpdateCaretPosition() API to notify
+          // text input status to the browser, but unable to handle inline
+          // compositions. By using the notified information. the browser can,
+          // say, show virtual keyboards or IMEs only at appropriate timing
+          // that the plugin does need to accept text input.
+          status_handler_.reset(new TextFieldStatusNotifyingHanlder(this));
+        } else if (argv[i] == std::string("full")) {
+          // Demonstrating the behavior of plugins fully supporting IME.
+          //
+          // It notifies updates of caret positions to the browser,
+          // and handles all text input events by itself.
+          status_handler_.reset(new TextFieldStatusNotifyingHanlder(this));
+          RequestInputEvents(PP_INPUTEVENT_CLASS_IME);
+        }
+        break;
+      }
+    }
+
+    textfield_.push_back(MyTextField(this, status_handler_.get(),
+                                     10, 10, 300, 20));
+    textfield_.back().SetText("Hello");
+    textfield_.push_back(MyTextField(this, status_handler_.get(),
+                                     30, 100, 300, 20));
+    textfield_.back().SetText("World");
+    return true;
+  }
+
+ protected:
+  virtual bool HandleInputEvent(const pp::InputEvent& event) {
+    bool ret = false;
+    switch (event.GetType()) {
+      case PP_INPUTEVENT_TYPE_MOUSEDOWN: {
+        const pp::MouseInputEvent mouseEvent(event);
+        ret = OnMouseDown(mouseEvent);
+        break;
+      }
+      case PP_INPUTEVENT_TYPE_MOUSEMOVE: {
+        const pp::MouseInputEvent mouseEvent(event);
+        ret = OnMouseMove(mouseEvent);
+        break;
+      }
+      case PP_INPUTEVENT_TYPE_KEYDOWN: {
+        Log("Keydown");
+        const pp::KeyboardInputEvent keyEvent(event);
+        ret = OnKeyDown(keyEvent);
+        break;
+      }
+      case PP_INPUTEVENT_TYPE_CHAR: {
+        const pp::KeyboardInputEvent keyEvent(event);
+        Log("Char [" + keyEvent.GetCharacterText().AsString() + "]");
+        ret = OnChar(keyEvent);
+        break;
+      }
+      case PP_INPUTEVENT_TYPE_IME_COMPOSITION_START: {
+        const pp::IMEInputEvent_Dev imeEvent(event);
+        Log("CompositionStart [" + imeEvent.GetText().AsString() + "]");
+        ret = true;
+        break;
+      }
+      case PP_INPUTEVENT_TYPE_IME_COMPOSITION_UPDATE: {
+        const pp::IMEInputEvent_Dev imeEvent(event);
+        Log("CompositionUpdate [" + imeEvent.GetText().AsString() + "]");
+        ret = OnCompositionUpdate(imeEvent);
+        break;
+      }
+      case PP_INPUTEVENT_TYPE_IME_COMPOSITION_END: {
+        const pp::IMEInputEvent_Dev imeEvent(event);
+        Log("CompositionEnd [" + imeEvent.GetText().AsString() + "]");
+        ret = OnCompositionEnd(imeEvent);
+        break;
+      }
+      case PP_INPUTEVENT_TYPE_IME_TEXT: {
+        const pp::IMEInputEvent_Dev imeEvent(event);
+        Log("ImeText [" + imeEvent.GetText().AsString() + "]");
+        ret = OnImeText(imeEvent);
+        break;
+      }
+      default:
+        break;
+    }
+    if (ret && event.GetType() != PP_INPUTEVENT_TYPE_MOUSEMOVE)
+      Paint();
+    return ret;
+  }
+
+  virtual void DidChangeView(const pp::Rect& position, const pp::Rect& clip) {
+    if (position.size() == last_size_)
+      return;
+    last_size_ = position.size();
+    Paint();
+  }
+
+ private:
+  bool OnCompositionUpdate(const pp::IMEInputEvent_Dev& ev) {
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      if (it->Focused()) {
+        std::vector< std::pair<uint32_t, uint32_t> > segs;
+        for (uint32_t i = 0; i < ev.GetSegmentNumber(); ++i)
+          segs.push_back(std::make_pair(ev.GetSegmentOffset(i),
+                                        ev.GetSegmentOffset(i + 1)));
+        it->SetComposition(ev.GetText().AsString(),
+                           segs,
+                           ev.GetTargetSegment(),
+                           ev.GetSelection());
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool OnCompositionEnd(const pp::IMEInputEvent_Dev& ev) {
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      if (it->Focused()) {
+        it->SetComposition("", std::vector< std::pair<uint32_t, uint32_t> >(),
+                           0, std::make_pair(0, 0));
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool OnMouseDown(const pp::MouseInputEvent& ev) {
+    bool anyone_focused = false;
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      if (it->RefocusByMouseClick(ev.GetPosition().x(),
+                                  ev.GetPosition().y())) {
+        anyone_focused = true;
+      }
+    }
+    if (!anyone_focused)
+      status_handler_->FocusOut();
+    return true;
+  }
+
+  bool OnMouseMove(const pp::MouseInputEvent& ev) {
+    const PPB_CursorControl_Dev* cursor_control =
+        reinterpret_cast<const PPB_CursorControl_Dev*>(
+            pp::Module::Get()->GetBrowserInterface(
+                PPB_CURSOR_CONTROL_DEV_INTERFACE));
+    if (!cursor_control)
+      return false;
+
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      if (it->Contains(ev.GetPosition().x(),
+                       ev.GetPosition().y())) {
+        cursor_control->SetCursor(pp_instance(), PP_CURSORTYPE_IBEAM,
+                                  0, NULL);
+        return true;
+      }
+    }
+    cursor_control->SetCursor(pp_instance(), PP_CURSORTYPE_POINTER,
+                              0, NULL);
+    return true;
+  }
+
+  bool OnKeyDown(const pp::KeyboardInputEvent& ev) {
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      if (it->Focused()) {
+        switch (ev.GetKeyCode()) {
+          case ui::VKEY_LEFT:
+            it->KeyLeft();
+            break;
+          case ui::VKEY_RIGHT:
+            it->KeyRight();
+            break;
+          case ui::VKEY_DELETE:
+            it->KeyDelete();
+            break;
+          case ui::VKEY_BACK:
+            it->KeyBackspace();
+            break;
+        }
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool OnChar(const pp::KeyboardInputEvent& ev) {
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      if (it->Focused()) {
+        std::string str = ev.GetCharacterText().AsString();
+        if (str != "\r" && str != "\n")
+          it->InsertText(str);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool OnImeText(const pp::IMEInputEvent_Dev ev) {
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      if (it->Focused()) {
+        it->InsertText(ev.GetText().AsString());
+        return true;
+      }
+    }
+    return false;
+  }
+
+  void Paint() {
+    pp::Rect clip(0, 0, last_size_.width(), last_size_.height());
+    PaintClip(clip);
+  }
+
+  void PaintClip(const pp::Rect& clip) {
+    pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL, last_size_, true);
+    pp::Graphics2D device(this, last_size_, false);
+    BindGraphics(device);
+
+    for (std::vector<MyTextField>::iterator it = textfield_.begin();
+         it != textfield_.end();
+         ++it) {
+      it->PaintOn(&image, clip);
+    }
+
+    device.PaintImageData(image, pp::Point(0, 0));
+    device.Flush(pp::CompletionCallback(&OnFlush, this));
+  }
+
+  static void OnFlush(void* user_data, int32_t result) {}
+
+  // Prints a debug message.
+  void Log(const pp::Var& value) {
+    const PPB_Console_Dev* console = reinterpret_cast<const PPB_Console_Dev*>(
+        pp::Module::Get()->GetBrowserInterface(PPB_CONSOLE_DEV_INTERFACE));
+    if (!console)
+      return;
+    console->Log(pp_instance(), PP_LOGLEVEL_LOG, value.pp_var());
+  }
+
+  // IME Control interface.
+  scoped_ptr<TextFieldStatusHandler> status_handler_;
+
+  // Remembers the size of this instance.
+  pp::Size last_size_;
+
+  // Holds instances of text fields.
+  std::vector<MyTextField> textfield_;
+};
+
+class MyModule : public pp::Module {
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new MyInstance(instance);
+  }
+};
+
+namespace pp {
+
+Module* CreateModule() {
+  return new MyModule();
+}
+
+}  // namespace pp