ImageManipulation.cpp

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/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  ImageManipulation.cpp
 
  Dominic Mazzoni
  James Crook
 
  wxWidgets license (Dominic to confirm).
 
********************************************************************//*********************************************************************/
 
 
#include "ImageManipulation.h"
 
#include <wx/colour.h>
#include <wx/image.h>
 
#include "AllThemeResources.h"
#include "Theme.h"
 
std::unique_ptr<wxImage> ChangeImageColour(wxImage * srcImage, wxColour & dstColour)
{
   unsigned char *src = srcImage->GetData();
   wxColour c;
   c.Set(src[0], src[1], src[2]);
   return ChangeImageColour(srcImage, c, dstColour);
}
 
std::unique_ptr<wxImage> ChangeImageColour(wxImage * srcImage,
                           wxColour & srcColour,
                           wxColour & dstColour)
{
   // This function takes a source image, which it assumes to
   // be grayscale, and smoothly changes the overall color
   // to the specified color, and returns the result as a
   // NEW image.  This works well for grayscale 3D images.
   // Audacity uses this routines to make the buttons
   // (skip-start, play, stop, record, skip-end) adapt to
   // the color scheme of the user.
 
   unsigned char *src = srcImage->GetData();
   int width = srcImage->GetWidth();
   int height = srcImage->GetHeight();
 
   auto dstImage = std::make_unique<wxImage>(width, height);
   unsigned char *dst = dstImage->GetData();
 
 
   //Get the source color
   int srcVal[3], srcOpp[3];
   srcVal[0] = srcColour.Red();
   srcVal[1] = srcColour.Green();
   srcVal[2] = srcColour.Blue();
 
   int dstVal[3], dstOpp[3];
   dstVal[0] = dstColour.Red();
   dstVal[1] = dstColour.Green();
   dstVal[2] = dstColour.Blue();
 
   int i;
   for (i = 0; i < 3; i++) {
      srcOpp[i] = 256 - srcVal[i];  // avoid zero!
      dstOpp[i] = 255 - dstVal[i];
   }
 
   int c = 0;
   for (i = 0; i < width * height * 3; i++) {
      int s = (int) *src;
 
      if (s >= srcVal[c])
         *dst++ = dstVal[c] + dstOpp[c] * (s - srcVal[c]) / srcOpp[c];
 
      else
         *dst++ = dstVal[c] * s / srcVal[c];
      src++;
      c = (c + 1) % 3;
   }
 
   if (srcImage->HasAlpha()) {
      // Preserve transparencies
      dstImage->InitAlpha();
      memcpy(dstImage->GetAlpha(), srcImage->GetAlpha(), width * height);
   }
 
   return dstImage;
}
 
std::unique_ptr<wxImage> OverlayImage(wxImage * background, wxImage * foreground,
                      wxImage * mask, int xoff, int yoff)
{
   unsigned char *bg = background->GetData();
   unsigned char *fg = foreground->GetData();
   unsigned char *mk = mask->GetData();
 
   int bgWidth = background->GetWidth();
   int bgHeight = background->GetHeight();
   int fgWidth = foreground->GetWidth();
   int fgHeight = foreground->GetHeight();
   int mkWidth = mask->GetWidth();
   int mkHeight = mask->GetHeight();
 
 
   //Now, determine the dimensions of the images to be masked together
   //on top of the background.  This should be equal to the area of the
   //smaller of the foreground and the mask, as long as it is
   //within the area of the background, given the offset.
 
   //Make sure the foreground size is no bigger than the mask
   int wCutoff = (fgWidth < mkWidth) ? fgWidth : mkWidth;
   int hCutoff = (fgHeight < mkHeight) ? fgHeight : mkHeight;
 
 
   // If the masked foreground + offset is bigger than the background, masking
   // should only occur within these bounds of the foreground image
   wCutoff = (bgWidth - xoff > wCutoff) ? wCutoff : bgWidth - xoff;
   hCutoff = (bgHeight - yoff > hCutoff) ? hCutoff : bgHeight - yoff;
 
 
   //Make a NEW image the size of the background
   auto dstImage = std::make_unique<wxImage>(bgWidth, bgHeight);
   unsigned char *dst = dstImage->GetData();
   memcpy(dst, bg, bgWidth * bgHeight * 3);
 
 
   // Go through the foreground image bit by bit and mask it on to the
   // background, at an offset of xoff,yoff.
   // BUT...Don't go beyond the size of the background image,
   // the foreground image, or the mask
   int x, y;
   for (y = 0; y < hCutoff; y++) {
 
      unsigned char *bkp = bg + 3 * ((y + yoff) * bgWidth + xoff);
      unsigned char *dstp = dst + 3 * ((y + yoff) * bgWidth + xoff);
 
      for (x = 0; x < wCutoff; x++) {
 
         int value = mk[3 * (y * mkWidth + x)];
         int opp = 255 - value;
 
         for (int c = 0; c < 3; c++)
            dstp[x * 3 + c] =
               ((bkp[x * 3 + c] * opp) +
                (fg[3 * (y * fgWidth + x) + c] * value)) / 255;
      }
   }
   return dstImage;
}
 
std::unique_ptr<wxImage> OverlayImage(teBmps eBack, teBmps eForeground,
                      int xoff, int yoff)
{
   wxImage imgBack(theTheme.Image( eBack       ));
   wxImage imgFore(theTheme.Image( eForeground ));
 
 
   // TMP: dmazzoni - just so the code runs even though not all of
   // our images have transparency...
   if (!imgFore.HasAlpha())
      return std::make_unique<wxImage>(imgBack);
 
 
   wxASSERT( imgFore.HasAlpha() );
 
   unsigned char *bg = imgBack.GetData();
   unsigned char *fg = imgFore.GetData();
   unsigned char *mk = imgFore.GetAlpha();
 
   int bgWidth = imgBack.GetWidth();
   int bgHeight = imgBack.GetHeight();
   int fgWidth = imgFore.GetWidth();
   int fgHeight = imgFore.GetHeight();
 
 
   //Now, determine the dimensions of the images to be masked together
   //on top of the background.  This should be equal to the area of the
   //smaller of the foreground and the mask, as long as it is
   //within the area of the background, given the offset.
 
   //Make sure the foreground size is no bigger than the mask
   int wCutoff = fgWidth;
   int hCutoff = fgHeight;
 
 
   // If the masked foreground + offset is bigger than the background, masking
   // should only occur within these bounds of the foreground image
   wCutoff = (bgWidth - xoff > wCutoff) ? wCutoff : bgWidth - xoff;
   hCutoff = (bgHeight - yoff > hCutoff) ? hCutoff : bgHeight - yoff;
 
   //Make a NEW image the size of the background
   auto dstImage = std::make_unique<wxImage>(bgWidth, bgHeight);
   unsigned char *dst = dstImage->GetData();
   memcpy(dst, bg, bgWidth * bgHeight * 3);
 
   // If background image has tranparency, then we want to blend with the 
   // current background colour.
   if( imgBack.HasAlpha() ){
      unsigned char *pAlpha = imgBack.GetAlpha();
      wxColour c = theTheme.Colour( clrMedium  );
      unsigned char onePixImage[3];
      // GetData() guarantees RGB order [wxWidgets does the ocnversion]
      onePixImage[ 0 ] = c.Red();
      onePixImage[ 1 ] = c.Green();
      onePixImage[ 2 ] = c.Blue();
      for( int i=0;i< bgWidth*bgHeight;i++){
         unsigned char * pPix = &dst[ 3*i];
         float alpha = 1.0 - (pAlpha[i]/255.0);
         pPix[0] = pPix[0] + alpha *( (int)onePixImage[0]-(int)pPix[0]);
         pPix[1] = pPix[1] + alpha *( (int)onePixImage[1]-(int)pPix[1]);
         pPix[2] = pPix[2] + alpha *( (int)onePixImage[2]-(int)pPix[2]);
      }
   }
 
   // Go through the foreground image bit by bit and mask it on to the
   // background, at an offset of xoff,yoff.
   // BUT...Don't go beyond the size of the background image,
   // the foreground image, or the mask
   int x, y;
   for (y = 0; y < hCutoff; y++) {
 
      unsigned char *bkp = bg + 3 * ((y + yoff) * bgWidth + xoff);
      unsigned char *dstp = dst + 3 * ((y + yoff) * bgWidth + xoff);
 
      for (x = 0; x < wCutoff; x++) {
 
         int value = mk[(y * fgWidth + x)];// Don't multiply by 3...
         int opp = 255 - value;
 
         for (int c = 0; c < 3; c++)
            dstp[x * 3 + c] =
               ((bkp[x * 3 + c] * opp) +
                (fg[3 * (y * fgWidth + x) + c] * value)) / 255;
      }
   }
   return dstImage;
}
 
// Creates an image with a solid background color
std::unique_ptr<wxImage> CreateBackground(int width, int height, wxColour colour)
{
   auto i = std::make_unique<wxImage>(width, height);
   unsigned char *ip;
   int srcVal[3];
   int x;
 
   srcVal[0] = colour.Red();
   srcVal[1] = colour.Green();
   srcVal[2] = colour.Blue();
 
   ip = i->GetData();
   for(x=0; x<width*height; x++) {
      *ip++ = srcVal[0];
      *ip++ = srcVal[1];
      *ip++ = srcVal[2];
   }
 
   return i;
}
 
std::unique_ptr<wxImage> CreateSysBackground
   (int width, int height, int WXUNUSED(offset), wxColour colour)
{
   return CreateBackground(width, height, colour);
}
 
void PasteSubImage( wxImage * background, wxImage * foreground, int xoff, int yoff )
{
 
   unsigned char *bg = background->GetData();
   unsigned char *fg = foreground->GetData();
   unsigned char *bgAlpha = background->HasAlpha() ? background->GetAlpha() : NULL;
   unsigned char *fgAlpha = foreground->HasAlpha() ? foreground->GetAlpha() : NULL;
   // For testing... Set as if no alpha in foreground....
   // fgAlpha = NULL;
 
   int bgWidth = background->GetWidth();
   int bgHeight = background->GetHeight();
   int fgWidth = foreground->GetWidth();
   int fgHeight = foreground->GetHeight();
 
   int wCutoff = fgWidth;
   int hCutoff = fgHeight;
 
   // If the masked foreground + offset is bigger than the background, masking
   // should only occur within these bounds of the foreground image
   wCutoff = (bgWidth - xoff > wCutoff) ? wCutoff : bgWidth - xoff;
   hCutoff = (bgHeight - yoff > hCutoff) ? hCutoff : bgHeight - yoff;
 
   // Go through the foreground image bit by bit and place it on to the
   // background, at an offset of xoff,yoff.
   // Don't go beyond the size of the background image,
   // or the foreground image.
   int y;
   unsigned char *bkp;
   unsigned char *fgp;
   unsigned char *bgAlphap;
   unsigned char *fgAlphap;
   for (y = 0; y < hCutoff; y++) {
      // RGB bytes
      bkp = bg + 3 * ((y + yoff) * bgWidth + xoff);
      fgp = fg + 3 * ( y * fgWidth);
      memcpy( bkp, fgp, 3 * wCutoff );
 
      // Alpha bytes.
      if( bgAlpha )
      {
         bgAlphap = bgAlpha + ((y+yoff) * bgWidth + xoff );
         if( fgAlpha )
         {
            fgAlphap = fgAlpha + (y * fgWidth );
            memcpy( bgAlphap, fgAlphap, wCutoff );
         }
         else
         {
            memset( bgAlphap, 255, wCutoff );
         }
      }
   }
}
 
wxImage GetSubImageWithAlpha( const wxImage & Src,  const wxRect &rect )
{
   //First part of this code is lifted from wxImage::GetSubImage() source code.
   wxImage image;
 
   wxCHECK_MSG( Src.Ok(), image, wxT("invalid image") );
 
   wxCHECK_MSG( (rect.GetLeft()>=0) && (rect.GetTop()>=0) && (
      rect.GetRight()<=Src.GetWidth()) && (rect.GetBottom()<=Src.GetHeight()),
      image, wxT("invalid subimage size") );
 
   int subwidth=rect.GetWidth();
   const int subheight=rect.GetHeight();
 
   image.Create( subwidth, subheight, false );
 
   unsigned char *subdata = image.GetData(), *data=Src.GetData();
 
   wxCHECK_MSG( subdata, image, wxT("unable to create image") );
 
   // JKC: Quick hack - don't deal with masks - need to understand macro M_IMGDATA first.
//   if (Src.M_IMGDATA->m_hasMask)
//      image.SetMaskColour( Src.M_IMGDATA->m_maskRed, Src.M_IMGDATA->m_maskGreen, Src.M_IMGDATA->m_maskBlue );
 
   int subleft=3*rect.GetLeft();
   int width=3*Src.GetWidth();
   subwidth*=3;
 
   data+=rect.GetTop()*width+subleft;
 
   for (long j = 0; j < subheight; ++j)
   {
      memcpy( subdata, data, subwidth);
      subdata+=subwidth;
      data+=width;
   }
 
   image.InitAlpha();
   if( !Src.HasAlpha() )
      return image;
   // OK, so we've copied the RGB data.
   // Now do the Alpha channel.
   //wxASSERT( Src.HasAlpha() );
 
   subleft/=3;
   width/=3;
   subwidth/=3;
 
   data =Src.GetAlpha();
   subdata =image.GetAlpha();
 
   data+=rect.GetTop()*width+subleft;
 
   for (long j = 0; j < subheight; ++j)
   {
      memcpy( subdata, data, subwidth);
      subdata+=subwidth;
      data+=width;
   }
   return image;
}