ocpn_pixel.cpp

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/**************************************************************************
 *   Copyright (C) 2010 by David S. Register                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, see <https://www.gnu.org/licenses/>. *
 **************************************************************************/
 
//      Original comment header for xshm test code
//      imported from xshm.c
/* xshm.c */
 
/*
 * Example of how to use the X Shared Memory extension: MIT_SHM.
 * This code was lifted from my Mesa library.  It hasn't been tested
 * in this form but should be close enough for you to get it working.
 * Beware that this extension isn't available on all systems.  Your
 * application code should use #ifdef's around this code so it can be
 * omitted on systems that don't have it, then fallback to using a regular
 * XImage.
 *
 * Brian Paul  Sep, 20, 1995  brianp@ssec.wisc.edu
 */
 
// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
 
#include <stdio.h>
 
#ifdef ocpnUSE_ocpnBitmap
#ifdef __WXX11__
#include <sys/ipc.h>
#include <sys/shm.h>
#include <X11/extensions/XShm.h>
#endif
#endif
 
// For compilers that support precompilation, includes "wx.h".
#include <wx/wxprec.h>
#ifndef WX_PRECOMP
#include <wx/wx.h>
#endif
 
#include <wx/app.h>
#include <wx/bitmap.h>
#include <wx/dcmemory.h>
#include <wx/gdicmn.h>
#include <wx/icon.h>
#include <wx/image.h>
#include <wx/list.h>
#include <wx/log.h>
#include <wx/math.h>
#include <wx/palette.h>
#include <wx/utils.h>
 
#ifdef __WXMSW__
#include <wx/msw/private.h>
#include <wx/msw/dib.h>
#endif
 
#include "dychart.h"
#include "ocpn_pixel.h"
 
// missing from mingw32 header
#ifndef CLR_INVALID
#define CLR_INVALID ((COLORREF) - 1)
#endif  // no CLR_INVALID
 
#ifdef __WXX11__
 
#ifdef ocpUSE_MITSHM
/*
 * MIT-SHM Test Error handling.
 */
static int MITErrorFlag = 0;
static int HandleXError(Display *dpy, XErrorEvent *event) {
  MITErrorFlag = 1;
  return 0;
}
#endif  // ocpUSE_MITSHM
 
//---------------------------------------------------------------------------------------------------------
//              Private Memory Management
//---------------------------------------------------------------------------------------------------------
 
static void *x_malloc(size_t t) {
  void *pr = malloc(t);
 
  //      malloc fails
  if (NULL == pr) {
    wxLogMessage("x_malloc...malloc fails with request of %d bytes.", t);
 
    // Cat the /proc/meminfo file
 
    char *p;
    char buf[2000];
    int len;
 
    int fd = open("/proc/meminfo", O_RDONLY);
 
    if (fd == -1) exit(1);
 
    len = read(fd, buf, sizeof(buf) - 1);
    if (len <= 0) {
      close(fd);
      exit(1);
    }
    close(fd);
    buf[len] = 0;
 
    p = buf;
    while (*p) {
      //                        printf("%c", *p++);
    }
 
    exit(0);
    return NULL;  // for MSVC
  }
 
  else {
    if (t > malloc_max) {
      malloc_max = t;
      //                      wxLogMessage(_T("New malloc_max: %d",
      //                      malloc_max));
    }
 
    return pr;  // good return
  }
}
 
//----------------------------------------------------------------------
//      ocpnXImage Implementation
//----------------------------------------------------------------------
 
ocpnXImage::ocpnXImage(int width, int height) {
  m_width = width;
  m_height = height;
  buse_mit = false;
  m_img = NULL;
 
  xdisplay = (Display *)wxGlobalDisplay();
  xscreen = DefaultScreen(xdisplay);
  xvisual = DefaultVisual(xdisplay, xscreen);
  int bpp = wxTheApp->GetVisualInfo(xdisplay)->m_visualDepth;
 
#ifdef ocpUSE_MITSHM
 
  //      Check to see if the basic extension is supported
  int ignore;
  bool bMIT_SHM =
      XQueryExtension(xdisplay, "MIT-SHM", &ignore, &ignore, &ignore);
 
  if (bMIT_SHM) {
    m_img = XShmCreateImage(xdisplay, xvisual, bpp, ZPixmap, NULL, &shminfo,
                            width, height);
    if (m_img == NULL) {
      wxLogError("XShmCreateImage failed!");
      goto after_check;
    }
 
    //    Identify and allocate the shared memory buffer
    shminfo.shmid = shmget(IPC_PRIVATE, m_img->bytes_per_line * m_img->height,
                           IPC_CREAT | 0777);
    if (shminfo.shmid < 0) {
      XDestroyImage(m_img);
      m_img = NULL;
      wxLogMessage(
          "alloc_back_buffer: Shared memory error (shmget), disabling.");
      goto after_check;
    }
 
    shminfo.shmaddr = m_img->data = (char *)shmat(shminfo.shmid, 0, 0);
 
    if (shminfo.shmaddr == (char *)-1) {
      XDestroyImage(m_img);
      m_img = NULL;
      wxLogMessage("shmat failed");
      goto after_check;
    }
 
    //    Make some further checks
    shminfo.readOnly = False;
    MITErrorFlag = 0;
 
    XSetErrorHandler(HandleXError);
    // This may trigger the X protocol error we're ready to catch:
    XShmAttach(xdisplay, &shminfo);
    XSync(xdisplay, False);
 
    if (MITErrorFlag) {
      // we are on a remote display, this error is normal, don't print it
      XFlush(xdisplay);
      MITErrorFlag = 0;
      XDestroyImage(m_img);
      m_img = NULL;
      shmdt(shminfo.shmaddr);
      shmctl(shminfo.shmid, IPC_RMID, 0);
      goto after_check;
    }
 
    shmctl(shminfo.shmid, IPC_RMID, 0); /* nobody else needs it */
 
    buse_mit = true;  // passed all tests
  }
 
after_check:
  // if bMIT_SHM
#endif
 
  if (NULL == m_img) {
    m_img = XCreateImage(xdisplay, xvisual, bpp, ZPixmap, 0, 0, width, height,
                         32, 0);
    m_img->data = (char *)x_malloc(m_img->bytes_per_line * m_img->height);
 
    if (m_img->data == NULL) {
      XDestroyImage(m_img);
      m_img = NULL;
      wxLogError("ocpn_Bitmap:Cannot malloc for data image.");
    }
  }
}
 
ocpnXImage::~ocpnXImage() {
#ifdef ocpUSE_MITSHM
  if (buse_mit) {
    XShmDetach(xdisplay, &shminfo);
    XDestroyImage(m_img);
    shmdt(shminfo.shmaddr);
  } else {
    XDestroyImage(m_img);
  }
#else
  XDestroyImage(m_img);
#endif
}
 
bool ocpnXImage::PutImage(Pixmap pixmap, GC gc) {
#ifdef ocpUSE_MITSHM
  if (buse_mit)
    XShmPutImage(xdisplay, pixmap, gc, m_img, 0, 0, 0, 0, m_width, m_height,
                 False);
  else
    XPutImage(xdisplay, pixmap, gc, m_img, 0, 0, 0, 0, m_width, m_height);
 
#else
  XPutImage(xdisplay, pixmap, gc, m_img, 0, 0, 0, 0, m_width, m_height);
#endif
 
  return true;
}
 
#endif  //  __WXX11__
 
/*  Class : PixelCache
    Why a specific class for what is, in effect, a simple unsigned char[] ?
    Answer: Allow performance optimization for specific platforms,
            such as MSW dibSections, and X11 Pixmaps
*/
 
// ============================================================================
// PixelCache Implementation
// ============================================================================
PixelCache::PixelCache(int width, int height, int depth) {
  m_width = width;
  m_height = height;
  m_depth = depth;
  m_pbm = NULL;
  m_rgbo = RGB;  // default value;
  pData = NULL;
 
  bytes_per_pixel = BPP / 8;
  line_pitch_bytes = bytes_per_pixel * width;
 
#ifdef ocpnUSE_ocpnBitmap
  m_rgbo = BGR;
#endif
 
#ifdef __PIX_CACHE_PIXBUF__
  m_rgbo = RGB;
#endif
 
#ifdef __PIX_CACHE_DIBSECTION__
  m_pDS = new wxDIB(width, -height, BPP);
  pData = m_pDS->GetData();
  //        For DIBsections, each scan line is DWORD aligned, padded on the
  //        right
  line_pitch_bytes = (((m_width * 24) + 31) & ~31) >> 3;
 
#endif
 
#ifdef __PIX_CACHE_WXIMAGE__
  m_pimage = new wxImage(m_width, m_height, (bool)FALSE);
  pData = m_pimage->GetData();
#endif
 
#ifdef __PIX_CACHE_X11IMAGE__
  m_pocpnXI = new ocpnXImage(width, height);
  pData = (unsigned char *)m_pocpnXI->m_img->data;
#endif  //__PIX_CACHE_X11IMAGE__
 
#ifdef __PIX_CACHE_PIXBUF__
  //      m_pbm = new ocpnBitmap((unsigned char *)NULL, m_width, m_height,
  //      m_depth);
 
 
 
  pData = (unsigned char *)malloc(m_width * m_height * 4);
#endif
}
 
PixelCache::~PixelCache() {
#ifdef __PIX_CACHE_WXIMAGE__
  delete m_pimage;
  delete m_pbm;
#endif
 
#ifdef __PIX_CACHE_DIBSECTION__
  delete m_pDS;
#endif
 
#ifdef __PIX_CACHE_X11IMAGE__
  delete m_pbm;
  delete m_pocpnXI;
#endif
 
#ifdef __PIX_CACHE_PIXBUF__
  free(pData);
  delete m_pbm;
#endif
}
 
size_t PixelCache::GetLength() {
#ifdef __PIX_CACHE_WXIMAGE__
  return m_width * m_height * 3;
#else
  return 0;
#endif
}
 
void PixelCache::Update() {
#ifdef __PIX_CACHE_WXIMAGE__
  delete m_pbm;  // kill the old one
  m_pbm = NULL;
#endif
}
 
void PixelCache::SelectIntoDC(wxMemoryDC &dc) {
#ifdef __PIX_CACHE_DIBSECTION__
  ocpnMemDC *pmdc = dynamic_cast<ocpnMemDC *>(&dc);
  pmdc->SelectObject(*m_pDS);
 
#endif  //__PIX_CACHE_DIBSECTION__
 
#ifdef __PIX_CACHE_WXIMAGE__
  //    delete m_pbm;                       // kill the old one
 
  //    Convert image to bitmap
#ifdef ocpnUSE_ocpnBitmap
  if (!m_pbm) m_pbm = new ocpnBitmap(*m_pimage, m_depth);
#else
  if (!m_pbm) m_pbm = new wxBitmap(*m_pimage, -1);
#endif
 
  if (m_pbm) dc.SelectObject(*m_pbm);
#endif  // __PIX_CACHE_WXIMAGE__
 
#ifdef __PIX_CACHE_X11IMAGE__
  if (!m_pbm) m_pbm = new ocpnBitmap(m_pocpnXI, m_width, m_height, m_depth);
  dc.SelectObject(*m_pbm);
#endif  //__PIX_CACHE_X11IMAGE__
 
#ifdef __PIX_CACHE_PIXBUF__
  if (!m_pbm) m_pbm = new ocpnBitmap(pData, m_width, m_height, m_depth);
  if (m_pbm) {
    dc.SelectObject(*m_pbm);
  }
#endif  //__PIX_CACHE_PIXBUF__
}
 
unsigned char *PixelCache::GetpData() const { return pData; }
 
#ifdef ocpnUSE_ocpnBitmap
//-----------------------------------------------------------------------------
/*
    Class: ocpnBitmap
 
    Derived from wxBitmap
 
    Why?....
    wxWidgets does a very correct, but sometimes slow job of bitmap creation
    and copying. ocpnBitmap is an optimization of wxBitmap for specific
    platforms and color formats.
 
    ocpn_Bitmap is optimized specifically for Windows and X11 Linux/Unix
   systems, taking advantage of some known underlying data structures and
   formats.
 
    There is (currently) no optimization for for other platforms,
    such as GTK or MAC
 
    The included methods are very different for MSW and X11
          See the Code
 
    */
 
// ----------------------------------------------------------------------------
// macros
// ----------------------------------------------------------------------------
#define M_BMPDATA wx_static_cast(wxBitmapRefData *, m_refData)
 
// class wxBitmapRefData;
 
// ============================================================================
// implementation
// ============================================================================
 
ocpnBitmap::ocpnBitmap() {}
 
// ocpnBitmap::~ocpnBitmap()
//{
//}
 
#ifdef __WXGTK__
#ifdef opcnUSE_GTK_OPTIMIZE
 
// ----------------------------------------------------------------------------
// Create from Data
// ----------------------------------------------------------------------------
 
bool ocpnBitmap::CreateFromData(void *pPix, int width, int height, int depth) {
  /*
  XImage *img = NULL;
 
//    Do some basic setup in the parent wxBitmap class
  Create(width, height, -1);
 
  Display *xdisplay = (Display *)GetDisplay();
 
  ocpnXImage *pXI = new ocpnXImage(width, height);
  img = pXI->m_img;
 
//    Faster render from a 24 or 32 bit pixel buffer
 
  if((pPix != NULL ) && (NULL != img))
  {
      unsigned char* data = (unsigned char *)pPix;
      if(depth == 32)                          // special fast case
      {
          for (int y = 0; y < height; y++)
          {
              char *pd = img->data + (y * img->bytes_per_line);
              unsigned char *ps = data + (y * width * 4);
              memcpy(pd, ps, width*4);
          }
      }
 
      else
      {
          int *pi = (int *)img->data;
          int index = 0;
          for (int y = 0; y < height; y++)
          {
              for (int x = 0; x < width; x++)
              {
                  int ri = *(int *)(&data[index]);
                  index++;
                  index++;
                  index++;
 
                  *pi = ri;
                  pi++;
 
              }
          }
      }
  }
 
      // Blit picture
 
  Pixmap mypixmap = ((Pixmap )GetPixmap());
  GC gc = XCreateGC( xdisplay, mypixmap, 0, NULL );
 
  pXI->PutImage(mypixmap, gc);
 
  delete pXI;
 
  XFreeGC( xdisplay, gc );
  */
 
  Create(width, height, 32);
 
  //    GdkPixbuf* pixbuf = wx_static_cast(wxBitmapRefData*,
  //    m_refData))->m_pixbuf;
  //   GdkPixbuf* pixbuf = M_BMPDATA->m_pixbuf;
 
  // Copy the data:
  if (NULL != pPix) {
    GdkPixbuf *pixbuf = GetPixbuf();
 
    if (!pixbuf) return false;
 
    unsigned char *in = (unsigned char *)pPix;
    unsigned char *out = gdk_pixbuf_get_pixels(pixbuf);
 
    int rowpad = gdk_pixbuf_get_rowstride(pixbuf) - 4 * width;
 
    for (int y = 0; y < height; y++, out += rowpad) {
 
      for (int x = 0; x < width; x++, out += 4, in += 4) {
        out[0] = in[0];
        out[1] = in[1];
        out[2] = in[2];
        out[3] = in[3];
      }
    }
  }
  return true;
}
 
/*
bool wxBitmap::CreateFromImageAsPixbuf(const wxImage& image)
{
    wxASSERT(image.HasAlpha());
 
    int width = image.GetWidth();
    int height = image.GetHeight();
 
    Create(width, height, 32);
    GdkPixbuf* pixbuf = M_BMPDATA->m_pixbuf;
    if (!pixbuf)
        return false;
 
    // Copy the data:
    const unsigned char* in = image.GetData();
    unsigned char *out = gdk_pixbuf_get_pixels(pixbuf);
    unsigned char *alpha = image.GetAlpha();
 
    int rowpad = gdk_pixbuf_get_rowstride(pixbuf) - 4 * width;
 
    for (int y = 0; y < height; y++, out += rowpad)
    {
        for (int x = 0; x < width; x++, alpha++, out += 4, in += 3)
        {
            out[0] = in[0];
            out[1] = in[1];
            out[2] = in[2];
            out[3] = *alpha;
        }
    }
 
    return true;
}
*/
#endif  // opcnUSE_GTK_OPTIMIZE
#endif
 
#ifdef __WXX11__
//    This is the X11 Version
 
// ----------------------------------------------------------------------------
// Create from ocpnXImage
// ----------------------------------------------------------------------------
 
bool ocpnBitmap::CreateFromocpnXImage(ocpnXImage *poXI, int width, int height,
                                      int depth) {
  //    Do some basic setup in the parent  wxBitmap class
  Create(width, height, -1);
 
  Display *xdisplay = (Display *)GetDisplay();
 
  XImage *data_image = poXI->m_img;
  bool bShared = poXI->buse_mit;
 
  // Blit picture
 
  Pixmap mypixmap = ((Pixmap)GetPixmap());
 
  GC gc = XCreateGC(xdisplay, mypixmap, 0, NULL);
 
  if (bShared)
    XShmPutImage(xdisplay, mypixmap, gc, data_image, 0, 0, 0, 0, width, height,
                 False);
  else
    XPutImage(xdisplay, mypixmap, gc, data_image, 0, 0, 0, 0, width, height);
 
  XFreeGC(xdisplay, gc);
 
  return true;
}
 
// ----------------------------------------------------------------------------
// Create from Data
// ----------------------------------------------------------------------------
 
bool ocpnBitmap::CreateFromData(void *pPix, int width, int height, int depth) {
  XImage *img = NULL;
 
  //    Do some basic setup in the parent wxBitmap class
  Create(width, height, -1);
 
  Display *xdisplay = (Display *)GetDisplay();
 
  ocpnXImage *pXI = new ocpnXImage(width, height);
  img = pXI->m_img;
 
  //    Faster render from a 24 or 32 bit pixel buffer
 
  if ((pPix != NULL) && (NULL != img)) {
    unsigned char *data = (unsigned char *)pPix;
    if (depth == 32)  // special fast case
    {
      for (int y = 0; y < height; y++) {
        char *pd = img->data + (y * img->bytes_per_line);
        unsigned char *ps = data + (y * width * 4);
        memcpy(pd, ps, width * 4);
      }
    }
 
    else {
      int *pi = (int *)img->data;
      int index = 0;
      for (int y = 0; y < height; y++) {
        for (int x = 0; x < width; x++) {
          int ri = *(int *)(&data[index]);
          index++;
          index++;
          index++;
 
          *pi = ri;
          pi++;
        }
      }
    }
  }
 
  // Blit picture
 
  Pixmap mypixmap = ((Pixmap)GetPixmap());
  GC gc = XCreateGC(xdisplay, mypixmap, 0, NULL);
 
  pXI->PutImage(mypixmap, gc);
 
  delete pXI;
 
  XFreeGC(xdisplay, gc);
 
  return TRUE;
}
 
#endif  //__WXX11__
 
#ifdef __WXMSW__
 
// ----------------------------------------------------------------------------
// Create from Data
// ----------------------------------------------------------------------------
bool ocpnBitmap::CreateFromData(void *pPix, int width, int height, int depth) {
  m_refData = CreateData();  // found in wxBitmap
                             //    int width = image.GetWidth();
                             //    int height0 = image.GetHeight();
 
  int height0 = height;
  int sizeLimit = 1280 * 1024 * 3;
 
  int bmpHeight = height0;
  //    int height = bmpHeight;
 
  // calc the number of bytes per scanline and padding
  int bytePerLine = width * 3;
  int sizeDWORD = sizeof(DWORD);
  int lineBoundary = bytePerLine % sizeDWORD;
  int padding = 0;
  if (lineBoundary > 0) {
    padding = sizeDWORD - lineBoundary;
    bytePerLine += padding;
  }
 
  // set bitmap parameters
  SetWidth(width);
  SetHeight(bmpHeight);
  if (depth == -1) depth = wxDisplayDepth();
  SetDepth(depth);
 
  // create a DIB header
  int headersize = sizeof(BITMAPINFOHEADER);
  BITMAPINFO *lpDIBh = (BITMAPINFO *)malloc(headersize);
  wxCHECK_MSG(lpDIBh, FALSE, "could not allocate memory for DIB header");
  // Fill in the DIB header
  lpDIBh->bmiHeader.biSize = headersize;
  lpDIBh->bmiHeader.biWidth = (DWORD)width;
  lpDIBh->bmiHeader.biHeight = (DWORD)(-height);
  lpDIBh->bmiHeader.biSizeImage = bytePerLine * height;
  //   the general formula for biSizeImage:
  //      ( ( ( ((DWORD)width*24) +31 ) & ~31 ) >> 3 ) * height;
  lpDIBh->bmiHeader.biPlanes = 1;
  lpDIBh->bmiHeader.biBitCount = 24;
  lpDIBh->bmiHeader.biCompression = BI_RGB;
  lpDIBh->bmiHeader.biClrUsed = 0;
  // These seem not really needed for our purpose here.
  lpDIBh->bmiHeader.biClrImportant = 0;
  lpDIBh->bmiHeader.biXPelsPerMeter = 0;
  lpDIBh->bmiHeader.biYPelsPerMeter = 0;
  // memory for DIB data
  unsigned char *lpBits;
  lpBits = (unsigned char *)malloc(lpDIBh->bmiHeader.biSizeImage);
  if (!lpBits) {
    wxFAIL_MSG("could not allocate memory for DIB");
    free(lpDIBh);
    return FALSE;
  }
 
  // create and set the device-dependent bitmap
  HDC hdc = ::GetDC(NULL);
  HDC memdc = ::CreateCompatibleDC(hdc);
  HBITMAP hbitmap;
  //    hbitmap = ::CreateCompatibleBitmap( hdc, width, bmpHeight );
 
  //    if(hbitmap == NULL)
  //          int cop =0;
 
  //    ::SelectObject( memdc, hbitmap);
 
  // copy image data into DIB data
  unsigned char *data = (unsigned char *)pPix;
  int i, j;
  unsigned char *ptdata = data;
  unsigned char *ptbits;
 
  ptbits = lpBits;
 
  if (pPix) {
    for (j = 0; j < height; j++) {
      memcpy(ptbits, ptdata, width * 3);
      ptbits += width * 3;
      ptdata += width * 3;
 
      for (i = 0; i < padding; i++) *(ptbits++) = 0;
    }
  }
 
  else {
    for (j = 0; j < height; j++) {
      memset(ptbits, 0, width * 3);
      ptbits += width * 3;
 
      for (i = 0; i < padding; i++) *(ptbits++) = 0;
    }
  }
 
  hbitmap = CreateDIBitmap(hdc, &(lpDIBh->bmiHeader), CBM_INIT, lpBits, lpDIBh,
                           DIB_RGB_COLORS);
  // The above line is equivalent to the following two lines.
  //    hbitmap = ::CreateCompatibleBitmap( hdc, width, height );
  //    ::SetDIBits( hdc, hbitmap, 0, height, lpBits, lpDIBh, DIB_RGB_COLORS);
  // or the following lines
  //    hbitmap = ::CreateCompatibleBitmap( hdc, width, height );
  //    HDC memdc = ::CreateCompatibleDC( hdc );
  //    ::SelectObject( memdc, hbitmap);
  //    ::SetDIBitsToDevice( memdc, 0, 0, width, height,
  //              0, 0, 0, height, (void *)lpBits, lpDIBh, DIB_RGB_COLORS);
  //    ::SelectObject( memdc, 0 );
  //    ::DeleteDC( memdc );
  SetHBITMAP((WXHBITMAP)hbitmap);
 
  // free allocated resources
  ::DeleteDC(memdc);
  ::ReleaseDC(NULL, hdc);
  free(lpDIBh);
  free(lpBits);
 
  return TRUE;
}
 
// ----------------------------------------------------------------------------
// wxImage from conversion
// ----------------------------------------------------------------------------
 
bool ocpnBitmap::CreateFromImage(const wxImage &image, int depth) {
  //    wxCHECK_MSG( image.Ok(), FALSE, "invalid image" )
 
  m_refData = CreateData();  // found in wxBitmap
 
  // sizeLimit is the MS upper limit for the DIB size
  int sizeLimit = 1280 * 1024 * 3;
 
  // width and height of the device-dependent bitmap
  int width = image.GetWidth();
  int bmpHeight = image.GetHeight();
 
  // calc the number of bytes per scanline and padding
  int bytePerLine = width * 3;
  int sizeDWORD = sizeof(DWORD);
  int lineBoundary = bytePerLine % sizeDWORD;
  int padding = 0;
  if (lineBoundary > 0) {
    padding = sizeDWORD - lineBoundary;
    bytePerLine += padding;
  }
  // calc the number of DIBs and heights of DIBs
  int numDIB = 1;
  int hRemain = 0;
  int height = sizeLimit / bytePerLine;
  if (height >= bmpHeight)
    height = bmpHeight;
  else {
    numDIB = bmpHeight / height;
    hRemain = bmpHeight % height;
    if (hRemain > 0) numDIB++;
  }
 
  // set bitmap parameters
  wxCHECK_MSG(image.Ok(), FALSE, "invalid image");
  SetWidth(width);
  SetHeight(bmpHeight);
  if (depth == -1) depth = wxDisplayDepth();
  SetDepth(depth);
 
#if wxUSE_PALETTE
  // Copy the palette from the source image
  SetPalette(image.GetPalette());
#endif  // wxUSE_PALETTE
 
  // create a DIB header
  int headersize = sizeof(BITMAPINFOHEADER);
  BITMAPINFO *lpDIBh = (BITMAPINFO *)malloc(headersize);
  wxCHECK_MSG(lpDIBh, FALSE, "could not allocate memory for DIB header");
  // Fill in the DIB header
  lpDIBh->bmiHeader.biSize = headersize;
  lpDIBh->bmiHeader.biWidth = (DWORD)width;
  lpDIBh->bmiHeader.biHeight = (DWORD)(-height);
  lpDIBh->bmiHeader.biSizeImage = bytePerLine * height;
  //   the general formula for biSizeImage:
  //      ( ( ( ((DWORD)width*24) +31 ) & ~31 ) >> 3 ) * height;
  lpDIBh->bmiHeader.biPlanes = 1;
  lpDIBh->bmiHeader.biBitCount = 24;
  lpDIBh->bmiHeader.biCompression = BI_RGB;
  lpDIBh->bmiHeader.biClrUsed = 0;
  // These seem not really needed for our purpose here.
  lpDIBh->bmiHeader.biClrImportant = 0;
  lpDIBh->bmiHeader.biXPelsPerMeter = 0;
  lpDIBh->bmiHeader.biYPelsPerMeter = 0;
  // memory for DIB data
  unsigned char *lpBits;
  lpBits = (unsigned char *)malloc(lpDIBh->bmiHeader.biSizeImage);
  if (!lpBits) {
    wxFAIL_MSG("could not allocate memory for DIB");
    free(lpDIBh);
    return FALSE;
  }
 
  // create and set the device-dependent bitmap
  HDC hdc = ::GetDC(NULL);
  HDC memdc = ::CreateCompatibleDC(hdc);
  HBITMAP hbitmap;
  //    hbitmap = ::CreateCompatibleBitmap( hdc, width, bmpHeight );
 
  //    if(hbitmap == NULL)
  //          int cop =0;
 
  //    ::SelectObject( memdc, hbitmap);
 
#if wxUSE_PALETTE
  HPALETTE hOldPalette = 0;
  if (image.GetPalette().Ok()) {
    hOldPalette = ::SelectPalette(
        memdc, (HPALETTE)image.GetPalette().GetHPALETTE(), FALSE);
    ::RealizePalette(memdc);
  }
#endif  // wxUSE_PALETTE
 
  // copy image data into DIB data and then into DDB (in a loop)
  unsigned char *data = image.GetData();
  int i, j, n;
  int origin = 0;
  unsigned char *ptdata = data;
  unsigned char *ptbits;
 
  for (n = 0; n < numDIB; n++) {
    if (numDIB > 1 && n == numDIB - 1 && hRemain > 0) {
      // redefine height and size of the (possibly) last smaller DIB
      // memory is not reallocated
      height = hRemain;
      lpDIBh->bmiHeader.biHeight = (DWORD)(-height);
      lpDIBh->bmiHeader.biSizeImage = bytePerLine * height;
    }
    ptbits = lpBits;
 
    for (j = 0; j < height; j++) {
      memcpy(ptbits, ptdata, width * 3);
      ptbits += width * 3;
      ptdata += width * 3;
 
      /*
                        for( i=0; i<width; i++ )
                  {
                      *(ptbits++) = *(ptdata+2);
                      *(ptbits++) = *(ptdata+1);
                      *(ptbits++) = *(ptdata  );
                      ptdata += 3;
                  }
      */
      for (i = 0; i < padding; i++) *(ptbits++) = 0;
    }
    //        ::StretchDIBits( memdc, 0, origin, width, height,
    //            0, 0, width, height, lpBits, lpDIBh, DIB_RGB_COLORS, SRCCOPY);
    origin += height;
    // if numDIB = 1,  lines below can also be used
    hbitmap = CreateDIBitmap(hdc, &(lpDIBh->bmiHeader), CBM_INIT, lpBits,
                             lpDIBh, DIB_RGB_COLORS);
    //      if(hbitmap == NULL)
    //            int cop =0;
 
    // The above line is equivalent to the following two lines.
    //    hbitmap = ::CreateCompatibleBitmap( hdc, width, height );
    //    ::SetDIBits( hdc, hbitmap, 0, height, lpBits, lpDIBh, DIB_RGB_COLORS);
    // or the following lines
    //    hbitmap = ::CreateCompatibleBitmap( hdc, width, height );
    //    HDC memdc = ::CreateCompatibleDC( hdc );
    //    ::SelectObject( memdc, hbitmap);
    //    ::SetDIBitsToDevice( memdc, 0, 0, width, height,
    //              0, 0, 0, height, (void *)lpBits, lpDIBh, DIB_RGB_COLORS);
    //    ::SelectObject( memdc, 0 );
    //    ::DeleteDC( memdc );
  }
  SetHBITMAP((WXHBITMAP)hbitmap);
 
  //      if(!this->Ok())
  //         int cop = this->Ok();
 
#if wxUSE_PALETTE
  if (hOldPalette) SelectPalette(memdc, hOldPalette, FALSE);
#endif  // wxUSE_PALETTE
 
  // similarly, created an mono-bitmap for the possible mask
  if (image.HasMask()) {
    hbitmap = ::CreateBitmap((WORD)width, (WORD)bmpHeight, 1, 1, NULL);
    HGDIOBJ hbmpOld = ::SelectObject(memdc, hbitmap);
    if (numDIB == 1)
      height = bmpHeight;
    else
      height = sizeLimit / bytePerLine;
    lpDIBh->bmiHeader.biHeight = (DWORD)(-height);
    lpDIBh->bmiHeader.biSizeImage = bytePerLine * height;
    origin = 0;
    unsigned char r = image.GetMaskRed();
    unsigned char g = image.GetMaskGreen();
    unsigned char b = image.GetMaskBlue();
    unsigned char zero = 0, one = 255;
    ptdata = data;
    for (n = 0; n < numDIB; n++) {
      if (numDIB > 1 && n == numDIB - 1 && hRemain > 0) {
        // redefine height and size of the (possibly) last smaller DIB
        // memory is not reallocated
        height = hRemain;
        lpDIBh->bmiHeader.biHeight = (DWORD)(-height);
        lpDIBh->bmiHeader.biSizeImage = bytePerLine * height;
      }
      ptbits = lpBits;
      for (int j = 0; j < height; j++) {
        for (i = 0; i < width; i++) {
          // was causing a code gen bug in cw : if( ( cr !=r) || (cg!=g) ||
          // (cb!=b) )
          unsigned char cr = (*(ptdata++));
          unsigned char cg = (*(ptdata++));
          unsigned char cb = (*(ptdata++));
 
          if ((cr != r) || (cg != g) || (cb != b)) {
            *(ptbits++) = one;
            *(ptbits++) = one;
            *(ptbits++) = one;
          } else {
            *(ptbits++) = zero;
            *(ptbits++) = zero;
            *(ptbits++) = zero;
          }
        }
        for (i = 0; i < padding; i++) *(ptbits++) = zero;
      }
      ::StretchDIBits(memdc, 0, origin, width, height, 0, 0, width, height,
                      lpBits, lpDIBh, DIB_RGB_COLORS, SRCCOPY);
      origin += height;
    }
    // create a wxMask object
    wxMask *mask = new wxMask();
    mask->SetMaskBitmap((WXHBITMAP)hbitmap);
    SetMask(mask);
    // It will be deleted when the wxBitmap object is deleted (as of 01/1999)
    /* The following can also be used but is slow to run
    wxColour colour( GetMaskRed(), GetMaskGreen(), GetMaskBlue());
    wxMask *mask = new wxMask( *this, colour );
    SetMask( mask );
    */
 
    ::SelectObject(memdc, hbmpOld);
  }
 
  // free allocated resources
  ::DeleteDC(memdc);
  ::ReleaseDC(NULL, hdc);
  free(lpDIBh);
  free(lpBits);
 
#if WXWIN_COMPATIBILITY_2
  // check the wxBitmap object
  GetBitmapData()->SetOk();
#endif  // WXWIN_COMPATIBILITY_2
 
  return TRUE;
}
 
#endif  // __WXMSW__
 
#endif  // ocpnUSE_ocpnBitmap
 
// ============================================================================
// ocpnMemDC implementation
// ============================================================================
 
ocpnMemDC::ocpnMemDC() {}
 
#ifdef ocpnUSE_DIBSECTION
void ocpnMemDC::SelectObject(wxDIB &dib) {
  // select old bitmap out of the device context
  if (m_oldBitmap) {
    ::SelectObject(GetHdc(), (HBITMAP)m_oldBitmap);
    if (m_selectedBitmap.Ok()) {
#ifdef __WXDEBUG__
      //           m_selectedBitmap.SetSelectedInto(NULL);
#endif
      m_selectedBitmap = wxNullBitmap;
    }
  }
 
  // check for whether the bitmap is already selected into a device context
  //    wxASSERT_MSG( !bitmap.GetSelectedInto() ||
  //                  (bitmap.GetSelectedInto() == this),
  //                  _T("Bitmap is selected in another wxMemoryDC, delete the
  //                  first wxMemoryDC or use SelectObject(NULL)") );
 
  /*
      m_selectedBitmap = bitmap;
      WXHBITMAP hBmp = m_selectedBitmap.GetHBITMAP();
      if ( !hBmp )
      return;                             // already selected
  */
  m_pselectedDIB = &dib;
  HBITMAP hDIB = m_pselectedDIB->GetHandle();
  if (!hDIB) return;  // already selected
 
#ifdef __WXDEBUG__
//    m_selectedBitmap.SetSelectedInto(this);
#endif
 
  //    hBmp = (WXHBITMAP)::SelectObject(GetHdc(), (HBITMAP)hBmp);
 
  hDIB = (HBITMAP)::SelectObject(GetHdc(), hDIB);
 
  if (!hDIB) {
    wxLogLastError("SelectObject(ocpnMemDC, DIB)");
 
    wxFAIL_MSG("Couldn't select a DIB into ocpnMemDC");
  }
 
  else if (!m_oldBitmap) {
    m_oldBitmap = hDIB;
  }
}
 
#endif  // ocpnUSE_DIBSECTION
 
/*
 * Rotation code by Carlos Moreno
 * Adapted to static and modified for improved performance by dsr
 */
 
static const double wxROTATE_EPSILON = 1e-10;
 
// Auxiliary function to rotate a point (x,y) with respect to point p0
// make it inline and use a straight return to facilitate optimization
// also, the function receives the sine and cosine of the angle to avoid
// repeating the time-consuming calls to these functions -- sin/cos can
// be computed and stored in the calling function.
 
static inline wxRealPoint wxRotatePoint(const wxRealPoint &p, double cos_angle,
                                        double sin_angle,
                                        const wxRealPoint &p0) {
  return wxRealPoint(
      p0.x + (p.x - p0.x) * cos_angle - (p.y - p0.y) * sin_angle,
      p0.y + (p.y - p0.y) * cos_angle + (p.x - p0.x) * sin_angle);
}
 
static inline wxRealPoint wxRotatePoint(double x, double y, double cos_angle,
                                        double sin_angle,
                                        const wxRealPoint &p0) {
  return wxRotatePoint(wxRealPoint(x, y), cos_angle, sin_angle, p0);
}
 
wxImage Image_Rotate(wxImage &base_image, double angle,
                     const wxPoint &centre_of_rotation, bool interpolating,
                     wxPoint *offset_after_rotation) {
  int i;
  angle =
      -angle;  // screen coordinates are a mirror image of "real" coordinates
 
  bool has_alpha = base_image.HasAlpha();
 
  const int w = base_image.GetWidth(), h = base_image.GetHeight();
 
  // Create pointer-based array to accelerate access to wxImage's data
  unsigned char **data = new unsigned char *[h];
  data[0] = base_image.GetData();
  for (i = 1; i < h; i++) data[i] = data[i - 1] + (3 * w);
 
  // Same for alpha channel
  unsigned char **alpha = NULL;
  if (has_alpha) {
    alpha = new unsigned char *[h];
    alpha[0] = base_image.GetAlpha();
    for (i = 1; i < h; i++) alpha[i] = alpha[i - 1] + w;
  }
 
  // precompute coefficients for rotation formula
  // (sine and cosine of the angle)
  const double cos_angle = cos(angle);
  const double sin_angle = sin(angle);
 
  // Create new Image to store the result
  // First, find rectangle that covers the rotated image;  to do that,
  // rotate the four corners
 
  const wxRealPoint p0(centre_of_rotation.x, centre_of_rotation.y);
 
  wxRealPoint p1 = wxRotatePoint(0, 0, cos_angle, sin_angle, p0);
  wxRealPoint p2 = wxRotatePoint(0, h, cos_angle, sin_angle, p0);
  wxRealPoint p3 = wxRotatePoint(w, 0, cos_angle, sin_angle, p0);
  wxRealPoint p4 = wxRotatePoint(w, h, cos_angle, sin_angle, p0);
 
  int x1a = (int)floor(wxMin(wxMin(p1.x, p2.x), wxMin(p3.x, p4.x)));
  int y1a = (int)floor(wxMin(wxMin(p1.y, p2.y), wxMin(p3.y, p4.y)));
  int x2a = (int)ceil(wxMax(wxMax(p1.x, p2.x), wxMax(p3.x, p4.x)));
  int y2a = (int)ceil(wxMax(wxMax(p1.y, p2.y), wxMax(p3.y, p4.y)));
 
  // Create rotated image
  wxImage rotated(x2a - x1a + 1, y2a - y1a + 1, false);
  // With alpha channel
  if (has_alpha) rotated.SetAlpha();
 
  if (offset_after_rotation != NULL) {
    *offset_after_rotation = wxPoint(x1a, y1a);
  }
 
  // GRG: The rotated (destination) image is always accessed
  //      sequentially, so there is no need for a pointer-based
  //      array here (and in fact it would be slower).
  //
  unsigned char *dst = rotated.GetData();
 
  unsigned char *alpha_dst = NULL;
  if (has_alpha) alpha_dst = rotated.GetAlpha();
 
  // GRG: if the original image has a mask, use its RGB values
  //      as the blank pixel, else, fall back to default (black).
  //
  unsigned char blank_r = 0;
  unsigned char blank_g = 0;
  unsigned char blank_b = 0;
 
  if (base_image.HasMask()) {
    blank_r = base_image.GetMaskRed();
    blank_g = base_image.GetMaskGreen();
    blank_b = base_image.GetMaskBlue();
    rotated.SetMaskColour(blank_r, blank_g, blank_b);
  }
 
  // Now, for each point of the rotated image, find where it came from, by
  // performing an inverse rotation (a rotation of -angle) and getting the
  // pixel at those coordinates
 
  const int rH = rotated.GetHeight();
  const int rW = rotated.GetWidth();
 
  // GRG: I've taken the (interpolating) test out of the loops, so that
  //      it is done only once, instead of repeating it for each pixel.
 
  if (interpolating) {
    for (int y = 0; y < rH; y++) {
      for (int x = 0; x < rW; x++) {
        wxRealPoint src =
            wxRotatePoint(x + x1a, y + y1a, cos_angle, -sin_angle, p0);
 
        if (-0.25 < src.x && src.x < w - 0.75 && -0.25 < src.y &&
            src.y < h - 0.75) {
          // interpolate using the 4 enclosing grid-points.  Those
          // points can be obtained using floor and ceiling of the
          // exact coordinates of the point
          int x1, y1, x2, y2;
 
          if (0 < src.x && src.x < w - 1) {
            x1 = wxRound(floor(src.x));
            x2 = wxRound(ceil(src.x));
          } else  // else means that x is near one of the borders (0 or width-1)
          {
            x1 = x2 = wxRound(src.x);
          }
 
          if (0 < src.y && src.y < h - 1) {
            y1 = wxRound(floor(src.y));
            y2 = wxRound(ceil(src.y));
          } else {
            y1 = y2 = wxRound(src.y);
          }
 
          // get four points and the distances (square of the distance,
          // for efficiency reasons) for the interpolation formula
 
          // GRG: Do not calculate the points until they are
          //      really needed -- this way we can calculate
          //      just one, instead of four, if d1, d2, d3
          //      or d4 are < wxROTATE_EPSILON
 
          const double d1 =
              (src.x - x1) * (src.x - x1) + (src.y - y1) * (src.y - y1);
          const double d2 =
              (src.x - x2) * (src.x - x2) + (src.y - y1) * (src.y - y1);
          const double d3 =
              (src.x - x2) * (src.x - x2) + (src.y - y2) * (src.y - y2);
          const double d4 =
              (src.x - x1) * (src.x - x1) + (src.y - y2) * (src.y - y2);
 
          // Now interpolate as a weighted average of the four surrounding
          // points, where the weights are the distances to each of those points
 
          // If the point is exactly at one point of the grid of the source
          // image, then don't interpolate -- just assign the pixel
 
          // d1,d2,d3,d4 are positive -- no need for abs()
          if (d1 < wxROTATE_EPSILON) {
            unsigned char *p = data[y1] + (3 * x1);
            *(dst++) = *(p++);
            *(dst++) = *(p++);
            *(dst++) = *p;
 
            if (has_alpha) *(alpha_dst++) = *(alpha[y1] + x1);
          } else if (d2 < wxROTATE_EPSILON) {
            unsigned char *p = data[y1] + (3 * x2);
            *(dst++) = *(p++);
            *(dst++) = *(p++);
            *(dst++) = *p;
 
            if (has_alpha) *(alpha_dst++) = *(alpha[y1] + x2);
          } else if (d3 < wxROTATE_EPSILON) {
            unsigned char *p = data[y2] + (3 * x2);
            *(dst++) = *(p++);
            *(dst++) = *(p++);
            *(dst++) = *p;
 
            if (has_alpha) *(alpha_dst++) = *(alpha[y2] + x2);
          } else if (d4 < wxROTATE_EPSILON) {
            unsigned char *p = data[y2] + (3 * x1);
            *(dst++) = *(p++);
            *(dst++) = *(p++);
            *(dst++) = *p;
 
            if (has_alpha) *(alpha_dst++) = *(alpha[y2] + x1);
          } else {
            // weights for the weighted average are proportional to the inverse
            // of the distance
            unsigned char *v1 = data[y1] + (3 * x1);
            unsigned char *v2 = data[y1] + (3 * x2);
            unsigned char *v3 = data[y2] + (3 * x2);
            unsigned char *v4 = data[y2] + (3 * x1);
 
            const double w1 = 1 / d1, w2 = 1 / d2, w3 = 1 / d3, w4 = 1 / d4;
 
            // GRG: Unrolled.
 
            *(dst++) = (unsigned char)((w1 * *(v1++) + w2 * *(v2++) +
                                        w3 * *(v3++) + w4 * *(v4++)) /
                                       (w1 + w2 + w3 + w4));
            *(dst++) = (unsigned char)((w1 * *(v1++) + w2 * *(v2++) +
                                        w3 * *(v3++) + w4 * *(v4++)) /
                                       (w1 + w2 + w3 + w4));
            *(dst++) =
                (unsigned char)((w1 * *v1 + w2 * *v2 + w3 * *v3 + w4 * *v4) /
                                (w1 + w2 + w3 + w4));
 
            if (has_alpha) {
              v1 = alpha[y1] + (x1);
              v2 = alpha[y1] + (x2);
              v3 = alpha[y2] + (x2);
              v4 = alpha[y2] + (x1);
 
              *(alpha_dst++) =
                  (unsigned char)((w1 * *v1 + w2 * *v2 + w3 * *v3 + w4 * *v4) /
                                  (w1 + w2 + w3 + w4));
            }
          }
        } else {
          *(dst++) = blank_r;
          *(dst++) = blank_g;
          *(dst++) = blank_b;
 
          if (has_alpha) *(alpha_dst++) = 0;
        }
      }
    }
  } else  // not interpolating
  {
    double x0 = p0.x;
    double y0 = p0.y;
    double x1b = x1a - p0.x;
    double y1b = y1a - p0.y;
    double msa = -sin_angle;
 
    for (int y = 0; y < rH; y++) {
      for (int x = 0; x < rW; x++) {
        //                                               wxRealPoint src =
        //                                               wxRotatePoint (x + x1a,
        //                                               y + y1a, cos_angle,
        //                                               -sin_angle, p0);
 
        //                                               double sx = p0.x + (x +
        //                                               x1a - p0.x) * cos_angle
        //                                               - (y + y1a - p0.y) *
        //                                               -sin_angle; double sy=
        //                                               p0.y + (y + y1a - p0.y)
        //                                               * cos_angle + (x + x1a
        //                                               - p0.x) * -sin_angle;
 
        double sx = x0 + (x + x1b) * cos_angle - (y + y1b) * msa;
        double sy = y0 + (y + y1b) * cos_angle + (x + x1b) * msa;
 
        const int xs = (int)sx;
        const int ys = (int)sy;
 
        //                                               return wxRealPoint(p0.x
        //                                               + (p.x - p0.x) *
        //                                               cos_angle - (p.y -
        //                                               p0.y) * sin_angle,
        //                                                           p0.y + (p.y
        //                                                           - p0.y) *
        //                                                           cos_angle +
        //                                                           (p.x -
        //                                                           p0.x) *
        //                                                           sin_angle);
 
        //                                               const int xs =
        //                                               /*wxRound*/ (src.x); //
        //                                               wxRound rounds to the
        //                                               const int ys =
        //                                               /*wxRound*/ (src.y); //
        //                                               closest integer
 
        if (0 <= xs && xs < w && 0 <= ys && ys < h) {
          unsigned char *p = data[ys] + (3 * xs);
          *(dst++) = *(p++);
          *(dst++) = *(p++);
          *(dst++) = *p;
 
          if (has_alpha) *(alpha_dst++) = *(alpha[ys] + (xs));
        } else {
          *(dst++) = blank_r;
          *(dst++) = blank_g;
          *(dst++) = blank_b;
 
          if (has_alpha) *(alpha_dst++) = 255;
        }
      }
    }
  }
 
  delete[] data;
 
  if (has_alpha) delete[] alpha;
 
  return rotated;
}