scrollview.cpp

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// File:        scrollview.cpp
// Description: ScrollView
// Author:      Joern Wanke
//
// (C) Copyright 2007, Google Inc.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//
 
// Include automatically generated configuration file if running autoconf.
#ifdef HAVE_CONFIG_H
#  include "config_auto.h"
#endif
 
#include "scrollview.h"
 
#include "svutil.h" // for SVNetwork
 
#include <allheaders.h>
 
#include <algorithm>
#include <climits>
#include <cstdarg>
#include <cstring>
#include <map>
#include <memory> // for std::unique_ptr
#include <mutex> // for std::mutex
#include <string>
#include <thread> // for std::thread
#include <utility>
#include <vector>
 
namespace tesseract {
 
const int kSvPort = 8461;
const int kMaxMsgSize = 4096;
const int kMaxIntPairSize = 45; // Holds %d,%d, for up to 64 bit.
 
struct SVPolyLineBuffer {
  bool empty; // Independent indicator to allow SendMsg to call SendPolygon.
  std::vector<int> xcoords;
  std::vector<int> ycoords;
};
 
// A map between the window IDs and their corresponding pointers.
static std::map<int, ScrollView *> svmap;
static std::mutex *svmap_mu;
// A map of all semaphores waiting for a specific event on a specific window.
static std::map<std::pair<ScrollView *, SVEventType>,
                std::pair<SVSemaphore *, std::unique_ptr<SVEvent>>> waiting_for_events;
static std::mutex *waiting_for_events_mu;
 
std::unique_ptr<SVEvent> SVEvent::copy() const {
  auto any = std::unique_ptr<SVEvent>(new SVEvent);
  any->command_id = command_id;
  any->counter = counter;
  any->parameter = new char[strlen(parameter) + 1];
  strcpy(any->parameter, parameter);
  any->type = type;
  any->x = x;
  any->y = y;
  any->x_size = x_size;
  any->y_size = y_size;
  any->window = window;
  return any;
}
 
// Destructor.
// It is defined here, so the compiler can create a single vtable
// instead of weak vtables in every compilation unit.
SVEventHandler::~SVEventHandler() = default;
 
#ifndef GRAPHICS_DISABLED
void ScrollView::MessageReceiver() {
  int counter_event_id = 0; // ongoing counter
  char *message = nullptr;
  // Wait until a new message appears in the input stream_.
  do {
    message = ScrollView::GetStream()->Receive();
  } while (message == nullptr);
 
  // This is the main loop which iterates until the server is dead (strlen =
  // -1). It basically parses for 3 different messagetypes and then distributes
  // the events accordingly.
  while (true) {
    // The new event we create.
    std::unique_ptr<SVEvent> cur(new SVEvent);
    // The ID of the corresponding window.
    int window_id;
 
    int ev_type;
 
    int n;
    // Fill the new SVEvent properly.
    sscanf(message, "%d,%d,%d,%d,%d,%d,%d,%n", &window_id, &ev_type, &cur->x, &cur->y, &cur->x_size,
           &cur->y_size, &cur->command_id, &n);
    char *p = (message + n);
 
    svmap_mu->lock();
    cur->window = svmap[window_id];
 
    if (cur->window != nullptr) {
      auto length = strlen(p);
      cur->parameter = new char[length + 1];
      strcpy(cur->parameter, p);
      if (length > 0) { // remove the last \n
        cur->parameter[length - 1] = '\0';
      }
      cur->type = static_cast<SVEventType>(ev_type);
      // Correct selection coordinates so x,y is the min pt and size is +ve.
      if (cur->x_size > 0) {
        cur->x -= cur->x_size;
      } else {
        cur->x_size = -cur->x_size;
      }
      if (cur->y_size > 0) {
        cur->y -= cur->y_size;
      } else {
        cur->y_size = -cur->y_size;
      }
      // Returned y will be the bottom-left if y is reversed.
      if (cur->window->y_axis_is_reversed_) {
        cur->y = cur->window->TranslateYCoordinate(cur->y + cur->y_size);
      }
      cur->counter = counter_event_id;
      // Increase by 2 since we will also create an SVET_ANY event from cur,
      // which will have a counter_id of cur + 1 (and thus gets processed
      // after cur).
      counter_event_id += 2;
 
      // In case of an SVET_EXIT event, quit the whole application.
      if (ev_type == SVET_EXIT) {
        SendRawMessage("svmain:exit()");
        break;
      }
 
      // Place two copies of it in the table for the window.
      cur->window->SetEvent(cur.get());
 
      // Check if any of the threads currently waiting want it.
      std::pair<ScrollView *, SVEventType> awaiting_list(cur->window, cur->type);
      std::pair<ScrollView *, SVEventType> awaiting_list_any(cur->window, SVET_ANY);
      std::pair<ScrollView *, SVEventType> awaiting_list_any_window((ScrollView *)nullptr,
                                                                    SVET_ANY);
      waiting_for_events_mu->lock();
      if (waiting_for_events.count(awaiting_list) > 0) {
        waiting_for_events[awaiting_list].second = std::move(cur);
        waiting_for_events[awaiting_list].first->Signal();
      } else if (waiting_for_events.count(awaiting_list_any) > 0) {
        waiting_for_events[awaiting_list_any].second = std::move(cur);
        waiting_for_events[awaiting_list_any].first->Signal();
      } else if (waiting_for_events.count(awaiting_list_any_window) > 0) {
        waiting_for_events[awaiting_list_any_window].second = std::move(cur);
        waiting_for_events[awaiting_list_any_window].first->Signal();
      }
      waiting_for_events_mu->unlock();
      // Signal the corresponding semaphore twice (for both copies).
      ScrollView *sv = svmap[window_id];
      if (sv != nullptr) {
        sv->Signal();
        sv->Signal();
      }
    }
    svmap_mu->unlock();
 
    // Wait until a new message appears in the input stream_.
    do {
      message = ScrollView::GetStream()->Receive();
    } while (message == nullptr);
  }
}
 
// Table to implement the color index values in the old system.
static const uint8_t table_colors[ScrollView::GREEN_YELLOW + 1][4] = {
    {0, 0, 0, 0},         // NONE (transparent)
    {0, 0, 0, 255},       // BLACK.
    {255, 255, 255, 255}, // WHITE.
    {255, 0, 0, 255},     // RED.
    {255, 255, 0, 255},   // YELLOW.
    {0, 255, 0, 255},     // GREEN.
    {0, 255, 255, 255},   // CYAN.
    {0, 0, 255, 255},     // BLUE.
    {255, 0, 255, 255},   // MAGENTA.
    {0, 128, 255, 255},   // AQUAMARINE.
    {0, 0, 64, 255},      // DARK_SLATE_BLUE.
    {128, 128, 255, 255}, // LIGHT_BLUE.
    {64, 64, 255, 255},   // MEDIUM_BLUE.
    {0, 0, 32, 255},      // MIDNIGHT_BLUE.
    {0, 0, 128, 255},     // NAVY_BLUE.
    {192, 192, 255, 255}, // SKY_BLUE.
    {64, 64, 128, 255},   // SLATE_BLUE.
    {32, 32, 64, 255},    // STEEL_BLUE.
    {255, 128, 128, 255}, // CORAL.
    {128, 64, 0, 255},    // BROWN.
    {128, 128, 0, 255},   // SANDY_BROWN.
    {192, 192, 0, 255},   // GOLD.
    {192, 192, 128, 255}, // GOLDENROD.
    {0, 64, 0, 255},      // DARK_GREEN.
    {32, 64, 0, 255},     // DARK_OLIVE_GREEN.
    {64, 128, 0, 255},    // FOREST_GREEN.
    {128, 255, 0, 255},   // LIME_GREEN.
    {192, 255, 192, 255}, // PALE_GREEN.
    {192, 255, 0, 255},   // YELLOW_GREEN.
    {192, 192, 192, 255}, // LIGHT_GREY.
    {64, 64, 128, 255},   // DARK_SLATE_GREY.
    {64, 64, 64, 255},    // DIM_GREY.
    {128, 128, 128, 255}, // GREY.
    {64, 192, 0, 255},    // KHAKI.
    {255, 0, 192, 255},   // MAROON.
    {255, 128, 0, 255},   // ORANGE.
    {255, 128, 64, 255},  // ORCHID.
    {255, 192, 192, 255}, // PINK.
    {128, 0, 128, 255},   // PLUM.
    {255, 0, 64, 255},    // INDIAN_RED.
    {255, 64, 0, 255},    // ORANGE_RED.
    {255, 0, 192, 255},   // VIOLET_RED.
    {255, 192, 128, 255}, // SALMON.
    {128, 128, 0, 255},   // TAN.
    {0, 255, 255, 255},   // TURQUOISE.
    {0, 128, 128, 255},   // DARK_TURQUOISE.
    {192, 0, 255, 255},   // VIOLET.
    {128, 128, 0, 255},   // WHEAT.
    {128, 255, 0, 255}    // GREEN_YELLOW
};
 
/*******************************************************************************
 * Scrollview implementation.
 *******************************************************************************/
 
SVNetwork *ScrollView::stream_ = nullptr;
int ScrollView::nr_created_windows_ = 0;
int ScrollView::image_index_ = 0;
 
ScrollView::ScrollView(const char *name, int x_pos, int y_pos, int x_size, int y_size,
                       int x_canvas_size, int y_canvas_size, bool y_axis_reversed,
                       const char *server_name) {
  Initialize(name, x_pos, y_pos, x_size, y_size, x_canvas_size, y_canvas_size, y_axis_reversed,
             server_name);
}
 
ScrollView::ScrollView(const char *name, int x_pos, int y_pos, int x_size, int y_size,
                       int x_canvas_size, int y_canvas_size, bool y_axis_reversed) {
  Initialize(name, x_pos, y_pos, x_size, y_size, x_canvas_size, y_canvas_size, y_axis_reversed,
             "localhost");
}
 
ScrollView::ScrollView(const char *name, int x_pos, int y_pos, int x_size, int y_size,
                       int x_canvas_size, int y_canvas_size) {
  Initialize(name, x_pos, y_pos, x_size, y_size, x_canvas_size, y_canvas_size, false, "localhost");
}
 
void ScrollView::Initialize(const char *name, int x_pos, int y_pos, int x_size, int y_size,
                            int x_canvas_size, int y_canvas_size, bool y_axis_reversed,
                            const char *server_name) {
  // If this is the first ScrollView Window which gets created, there is no
  // network connection yet and we have to set it up in a different thread.
  if (stream_ == nullptr) {
    nr_created_windows_ = 0;
    stream_ = new SVNetwork(server_name, kSvPort);
    waiting_for_events_mu = new std::mutex();
    svmap_mu = new std::mutex();
    SendRawMessage("svmain = luajava.bindClass('com.google.scrollview.ScrollView')\n");
    std::thread t(&ScrollView::MessageReceiver);
    t.detach();
  }
 
  // Set up the variables on the clientside.
  nr_created_windows_++;
  event_handler_ = nullptr;
  event_handler_ended_ = false;
  y_axis_is_reversed_ = y_axis_reversed;
  y_size_ = y_canvas_size;
  window_name_ = name;
  window_id_ = nr_created_windows_;
  // Set up polygon buffering.
  points_ = new SVPolyLineBuffer;
  points_->empty = true;
 
  svmap_mu->lock();
  svmap[window_id_] = this;
  svmap_mu->unlock();
 
  for (auto &i : event_table_) {
    i = nullptr;
  }
 
  semaphore_ = new SVSemaphore();
 
  // Set up an actual Window on the client side.
  char message[kMaxMsgSize];
  snprintf(message, sizeof(message),
           "w%u = luajava.newInstance('com.google.scrollview.ui"
           ".SVWindow','%s',%u,%u,%u,%u,%u,%u,%u)\n",
           window_id_, window_name_, window_id_, x_pos, y_pos, x_size, y_size, x_canvas_size,
           y_canvas_size);
  SendRawMessage(message);
 
  std::thread t(&ScrollView::StartEventHandler, this);
  t.detach();
}
 
void ScrollView::StartEventHandler() {
  for (;;) {
    stream_->Flush();
    semaphore_->Wait();
    int serial = -1;
    int k = -1;
    mutex_.lock();
    // Check every table entry if it is valid and not already processed.
 
    for (int i = 0; i < SVET_COUNT; i++) {
      if (event_table_[i] != nullptr && (serial < 0 || event_table_[i]->counter < serial)) {
        serial = event_table_[i]->counter;
        k = i;
      }
    }
    // If we didn't find anything we had an old alarm and just sleep again.
    if (k != -1) {
      auto new_event = std::move(event_table_[k]);
      mutex_.unlock();
      if (event_handler_ != nullptr) {
        event_handler_->Notify(new_event.get());
      }
      if (new_event->type == SVET_DESTROY) {
        // Signal the destructor that it is safe to terminate.
        event_handler_ended_ = true;
        return;
      }
    } else {
      mutex_.unlock();
    }
    // The thread should run as long as its associated window is alive.
  }
}
#endif // !GRAPHICS_DISABLED
 
ScrollView::~ScrollView() {
#ifndef GRAPHICS_DISABLED
  svmap_mu->lock();
  if (svmap[window_id_] != nullptr) {
    svmap_mu->unlock();
    // So the event handling thread can quit.
    SendMsg("destroy()");
 
    AwaitEvent(SVET_DESTROY);
    svmap_mu->lock();
    svmap[window_id_] = nullptr;
    svmap_mu->unlock();
    // The event handler thread for this window *must* receive the
    // destroy event and set its pointer to this to nullptr before we allow
    // the destructor to exit.
    while (!event_handler_ended_) {
      Update();
    }
  } else {
    svmap_mu->unlock();
  }
  delete semaphore_;
  delete points_;
#endif // !GRAPHICS_DISABLED
}
 
#ifndef GRAPHICS_DISABLED
void ScrollView::SendMsg(const char *format, ...) {
  if (!points_->empty) {
    SendPolygon();
  }
  va_list args;
  char message[kMaxMsgSize - 4];
 
  va_start(args, format); // variable list
  vsnprintf(message, sizeof(message), format, args);
  va_end(args);
 
  char form[kMaxMsgSize];
  snprintf(form, sizeof(form), "w%u:%s\n", window_id_, message);
 
  stream_->Send(form);
}
 
void ScrollView::SendRawMessage(const char *msg) {
  stream_->Send(msg);
}
 
void ScrollView::AddEventHandler(SVEventHandler *listener) {
  event_handler_ = listener;
}
 
void ScrollView::Signal() {
  semaphore_->Signal();
}
 
void ScrollView::SetEvent(const SVEvent *svevent) {
  // Copy event
  auto any = svevent->copy();
  auto specific = svevent->copy();
  any->counter = specific->counter + 1;
 
  // Place both events into the queue.
  std::lock_guard<std::mutex> guard(mutex_);
 
  event_table_[specific->type] = std::move(specific);
  event_table_[SVET_ANY] = std::move(any);
}
 
std::unique_ptr<SVEvent> ScrollView::AwaitEvent(SVEventType type) {
  // Initialize the waiting semaphore.
  auto *sem = new SVSemaphore();
  std::pair<ScrollView *, SVEventType> ea(this, type);
  waiting_for_events_mu->lock();
  waiting_for_events[ea] = {sem, nullptr};
  waiting_for_events_mu->unlock();
  // Wait on it, but first flush.
  stream_->Flush();
  sem->Wait();
  // Process the event we got woken up for (its in waiting_for_events pair).
  waiting_for_events_mu->lock();
  auto ret = std::move(waiting_for_events[ea].second);
  waiting_for_events.erase(ea);
  delete sem;
  waiting_for_events_mu->unlock();
  return ret;
}
 
// Send the current buffered polygon (if any) and clear it.
void ScrollView::SendPolygon() {
  if (!points_->empty) {
    points_->empty = true; // Allows us to use SendMsg.
    int length = points_->xcoords.size();
    // length == 1 corresponds to 2 SetCursors in a row and only the
    // last setCursor has any effect.
    if (length == 2) {
      // An isolated line!
      SendMsg("drawLine(%d,%d,%d,%d)", points_->xcoords[0], points_->ycoords[0],
              points_->xcoords[1], points_->ycoords[1]);
    } else if (length > 2) {
      // A polyline.
      SendMsg("createPolyline(%d)", length);
      char coordpair[kMaxIntPairSize];
      std::string decimal_coords;
      for (int i = 0; i < length; ++i) {
        snprintf(coordpair, kMaxIntPairSize, "%d,%d,", points_->xcoords[i], points_->ycoords[i]);
        decimal_coords += coordpair;
      }
      decimal_coords += '\n';
      SendRawMessage(decimal_coords.c_str());
      SendMsg("drawPolyline()");
    }
    points_->xcoords.clear();
    points_->ycoords.clear();
  }
}
 
/*******************************************************************************
 * LUA "API" functions.
 *******************************************************************************/
 
// Sets the position from which to draw to (x,y).
void ScrollView::SetCursor(int x, int y) {
  SendPolygon();
  DrawTo(x, y);
}
 
// Draws from the current position to (x,y) and sets the new position to it.
void ScrollView::DrawTo(int x, int y) {
  points_->xcoords.push_back(x);
  points_->ycoords.push_back(TranslateYCoordinate(y));
  points_->empty = false;
}
 
// Draw a line using the current pen color.
void ScrollView::Line(int x1, int y1, int x2, int y2) {
  if (!points_->xcoords.empty() && x1 == points_->xcoords.back() &&
      TranslateYCoordinate(y1) == points_->ycoords.back()) {
    // We are already at x1, y1, so just draw to x2, y2.
    DrawTo(x2, y2);
  } else if (!points_->xcoords.empty() && x2 == points_->xcoords.back() &&
             TranslateYCoordinate(y2) == points_->ycoords.back()) {
    // We are already at x2, y2, so just draw to x1, y1.
    DrawTo(x1, y1);
  } else {
    // This is a new line.
    SetCursor(x1, y1);
    DrawTo(x2, y2);
  }
}
 
// Set the visibility of the window.
void ScrollView::SetVisible(bool visible) {
  if (visible) {
    SendMsg("setVisible(true)");
  } else {
    SendMsg("setVisible(false)");
  }
}
 
// Set the alwaysOnTop flag.
void ScrollView::AlwaysOnTop(bool b) {
  if (b) {
    SendMsg("setAlwaysOnTop(true)");
  } else {
    SendMsg("setAlwaysOnTop(false)");
  }
}
 
// Adds a message entry to the message box.
void ScrollView::AddMessage(const char *message) {
  char form[kMaxMsgSize];
  snprintf(form, sizeof(form), "w%u:%s", window_id_, message);
 
  char *esc = AddEscapeChars(form);
  SendMsg("addMessage(\"%s\")", esc);
  delete[] esc;
}
 
void ScrollView::AddMessageF(const char *format, ...) {
  va_list args;
  char message[kMaxMsgSize - 4];
 
  va_start(args, format); // variable list
  vsnprintf(message, sizeof(message), format, args);
  va_end(args);
 
  AddMessage(message);
}
 
// Set a messagebox.
void ScrollView::AddMessageBox() {
  SendMsg("addMessageBox()");
}
 
// Exit the client completely (and notify the server of it).
void ScrollView::Exit() {
  SendRawMessage("svmain:exit()");
  exit(0);
}
 
// Clear the canvas.
void ScrollView::Clear() {
  SendMsg("clear()");
}
 
// Set the stroke width.
void ScrollView::Stroke(float width) {
  SendMsg("setStrokeWidth(%f)", width);
}
 
// Draw a rectangle using the current pen color.
// The rectangle is filled with the current brush color.
void ScrollView::Rectangle(int x1, int y1, int x2, int y2) {
  if (x1 == x2 && y1 == y2) {
    return; // Scrollviewer locks up.
  }
  SendMsg("drawRectangle(%d,%d,%d,%d)", x1, TranslateYCoordinate(y1), x2, TranslateYCoordinate(y2));
}
 
// Draw an ellipse using the current pen color.
// The ellipse is filled with the current brush color.
void ScrollView::Ellipse(int x1, int y1, int width, int height) {
  SendMsg("drawEllipse(%d,%d,%u,%u)", x1, TranslateYCoordinate(y1), width, height);
}
 
// Set the pen color to the given RGB values.
void ScrollView::Pen(int red, int green, int blue) {
  SendMsg("pen(%d,%d,%d)", red, green, blue);
}
 
// Set the pen color to the given RGB values.
void ScrollView::Pen(int red, int green, int blue, int alpha) {
  SendMsg("pen(%d,%d,%d,%d)", red, green, blue, alpha);
}
 
// Set the brush color to the given RGB values.
void ScrollView::Brush(int red, int green, int blue) {
  SendMsg("brush(%d,%d,%d)", red, green, blue);
}
 
// Set the brush color to the given RGB values.
void ScrollView::Brush(int red, int green, int blue, int alpha) {
  SendMsg("brush(%d,%d,%d,%d)", red, green, blue, alpha);
}
 
// Set the attributes for future Text(..) calls.
void ScrollView::TextAttributes(const char *font, int pixel_size, bool bold, bool italic,
                                bool underlined) {
  const char *b;
  const char *i;
  const char *u;
 
  if (bold) {
    b = "true";
  } else {
    b = "false";
  }
  if (italic) {
    i = "true";
  } else {
    i = "false";
  }
  if (underlined) {
    u = "true";
  } else {
    u = "false";
  }
  SendMsg("textAttributes('%s',%u,%s,%s,%s)", font, pixel_size, b, i, u);
}
 
// Draw text at the given coordinates.
void ScrollView::Text(int x, int y, const char *mystring) {
  SendMsg("drawText(%d,%d,'%s')", x, TranslateYCoordinate(y), mystring);
}
 
// Open and draw an image given a name at (x,y).
void ScrollView::Draw(const char *image, int x_pos, int y_pos) {
  SendMsg("openImage('%s')", image);
  SendMsg("drawImage('%s',%d,%d)", image, x_pos, TranslateYCoordinate(y_pos));
}
 
// Add new checkboxmenuentry to menubar.
void ScrollView::MenuItem(const char *parent, const char *name, int cmdEvent, bool flag) {
  if (parent == nullptr) {
    parent = "";
  }
  if (flag) {
    SendMsg("addMenuBarItem('%s','%s',%d,true)", parent, name, cmdEvent);
  } else {
    SendMsg("addMenuBarItem('%s','%s',%d,false)", parent, name, cmdEvent);
  }
}
 
// Add new menuentry to menubar.
void ScrollView::MenuItem(const char *parent, const char *name, int cmdEvent) {
  if (parent == nullptr) {
    parent = "";
  }
  SendMsg("addMenuBarItem('%s','%s',%d)", parent, name, cmdEvent);
}
 
// Add new submenu to menubar.
void ScrollView::MenuItem(const char *parent, const char *name) {
  if (parent == nullptr) {
    parent = "";
  }
  SendMsg("addMenuBarItem('%s','%s')", parent, name);
}
 
// Add new submenu to popupmenu.
void ScrollView::PopupItem(const char *parent, const char *name) {
  if (parent == nullptr) {
    parent = "";
  }
  SendMsg("addPopupMenuItem('%s','%s')", parent, name);
}
 
// Add new submenuentry to popupmenu.
void ScrollView::PopupItem(const char *parent, const char *name, int cmdEvent, const char *value,
                           const char *desc) {
  if (parent == nullptr) {
    parent = "";
  }
  char *esc = AddEscapeChars(value);
  char *esc2 = AddEscapeChars(desc);
  SendMsg("addPopupMenuItem('%s','%s',%d,'%s','%s')", parent, name, cmdEvent, esc, esc2);
  delete[] esc;
  delete[] esc2;
}
 
// Send an update message for a single window.
void ScrollView::UpdateWindow() {
  SendMsg("update()");
}
 
// Note: this is an update to all windows
void ScrollView::Update() {
  std::lock_guard<std::mutex> guard(*svmap_mu);
  for (auto &iter : svmap) {
    if (iter.second != nullptr) {
      iter.second->UpdateWindow();
    }
  }
}
 
// Set the pen color, using an enum value (e.g. ScrollView::ORANGE)
void ScrollView::Pen(Color color) {
  Pen(table_colors[color][0], table_colors[color][1], table_colors[color][2],
      table_colors[color][3]);
}
 
// Set the brush color, using an enum value (e.g. ScrollView::ORANGE)
void ScrollView::Brush(Color color) {
  Brush(table_colors[color][0], table_colors[color][1], table_colors[color][2],
        table_colors[color][3]);
}
 
// Shows a modal Input Dialog which can return any kind of String
char *ScrollView::ShowInputDialog(const char *msg) {
  SendMsg("showInputDialog(\"%s\")", msg);
  // wait till an input event (all others are thrown away)
  auto ev = AwaitEvent(SVET_INPUT);
  char *p = new char[strlen(ev->parameter) + 1];
  strcpy(p, ev->parameter);
  return p;
}
 
// Shows a modal Yes/No Dialog which will return 'y' or 'n'
int ScrollView::ShowYesNoDialog(const char *msg) {
  SendMsg("showYesNoDialog(\"%s\")", msg);
  // Wait till an input event (all others are thrown away)
  auto ev = AwaitEvent(SVET_INPUT);
  int a = ev->parameter[0];
  return a;
}
 
// Zoom the window to the rectangle given upper left corner and
// lower right corner.
void ScrollView::ZoomToRectangle(int x1, int y1, int x2, int y2) {
  y1 = TranslateYCoordinate(y1);
  y2 = TranslateYCoordinate(y2);
  SendMsg("zoomRectangle(%d,%d,%d,%d)", std::min(x1, x2), std::min(y1, y2), std::max(x1, x2),
          std::max(y1, y2));
}
 
// Send an image of type Pix.
void ScrollView::Draw(Image image, int x_pos, int y_pos) {
  l_uint8 *data;
  size_t size;
  pixWriteMem(&data, &size, image, IFF_PNG);
  int base64_len = (size + 2) / 3 * 4;
  y_pos = TranslateYCoordinate(y_pos);
  SendMsg("readImage(%d,%d,%d)", x_pos, y_pos, base64_len);
  // Base64 encode the data.
  const char kBase64Table[64] = {
      'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
      'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
      'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
      'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
  };
  char *base64 = new char[base64_len + 1];
  memset(base64, '=', base64_len);
  base64[base64_len] = '\0';
  int remainder = 0;
  int bits_left = 0;
  int code_len = 0;
  for (size_t i = 0; i < size; ++i) {
    int code = (data[i] >> (bits_left + 2)) | remainder;
    base64[code_len++] = kBase64Table[code & 63];
    bits_left += 2;
    remainder = data[i] << (6 - bits_left);
    if (bits_left == 6) {
      base64[code_len++] = kBase64Table[remainder & 63];
      bits_left = 0;
      remainder = 0;
    }
  }
  if (bits_left > 0) {
    base64[code_len++] = kBase64Table[remainder & 63];
  }
  SendRawMessage(base64);
  delete[] base64;
  lept_free(data);
}
 
// Escapes the ' character with a \, so it can be processed by LUA.
// Note: The caller will have to make sure it deletes the newly allocated item.
char *ScrollView::AddEscapeChars(const char *input) {
  const char *nextptr = strchr(input, '\'');
  const char *lastptr = input;
  char *message = new char[kMaxMsgSize];
  int pos = 0;
  while (nextptr != nullptr) {
    strncpy(message + pos, lastptr, nextptr - lastptr);
    pos += nextptr - lastptr;
    message[pos] = '\\';
    pos += 1;
    lastptr = nextptr;
    nextptr = strchr(nextptr + 1, '\'');
  }
  strcpy(message + pos, lastptr);
  return message;
}
 
// Inverse the Y axis if the coordinates are actually inversed.
int ScrollView::TranslateYCoordinate(int y) {
  if (!y_axis_is_reversed_) {
    return y;
  } else {
    return y_size_ - y;
  }
}
 
char ScrollView::Wait() {
  // Wait till an input or click event (all others are thrown away)
  char ret = '\0';
  SVEventType ev_type = SVET_ANY;
  do {
    std::unique_ptr<SVEvent> ev(AwaitEvent(SVET_ANY));
    ev_type = ev->type;
    if (ev_type == SVET_INPUT) {
      ret = ev->parameter[0];
    }
  } while (ev_type != SVET_INPUT && ev_type != SVET_CLICK);
  return ret;
}
 
#endif // !GRAPHICS_DISABLED
 
} // namespace tesseract