/* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % % % % % % SSSSS TTTTT EEEEE GGGG AAA N N OOO % % SS T E G A A NN N O O % % SSS T EEE G GG AAAAA N N N O O % % SS T E G G A A N NN O O % % SSSSS T EEEEE GGG A A N N OOO % % % % % % Write A Steganographic Image. % % % % Software Design % % John Cristy % % July 1992 % % % % % % Copyright 1999-2007 ImageMagick Studio LLC, a non-profit organization % % dedicated to making software imaging solutions freely available. % % % % You may not use this file except in compliance with the License. You may % % obtain a copy of the License at % % % % http://www.imagemagick.org/script/license.php % % % % 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 declarations. */ #include "magick/studio.h" #include "magick/blob.h" #include "magick/blob-private.h" #include "magick/constitute.h" #include "magick/exception.h" #include "magick/exception-private.h" #include "magick/image.h" #include "magick/image-private.h" #include "magick/list.h" #include "magick/magick.h" #include "magick/memory_.h" #include "magick/monitor.h" #include "magick/quantum-private.h" #include "magick/static.h" #include "magick/string_.h" #include "magick/module.h" /* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % % % % % % R e a d S T E G A N O I m a g e % % % % % % % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % ReadSTEGANOImage() reads a steganographic image hidden within another % image type. It allocates the memory necessary for the new Image structure % and returns a pointer to the new image. % % The format of the ReadSTEGANOImage method is: % % Image *ReadSTEGANOImage(const ImageInfo *image_info, % ExceptionInfo *exception) % % A description of each parameter follows: % % o image_info: The image info. % % o exception: return any errors or warnings in this structure. % */ static Image *ReadSTEGANOImage(const ImageInfo *image_info, ExceptionInfo *exception) { #define GetBit(alpha,i) (((unsigned long) (alpha) >> (unsigned long) \ (i)) & 0x01) #define SetBit(alpha,i,set) (alpha)=(Quantum) ((set) != 0 ? (unsigned long) \ (alpha) | (1UL << (unsigned long) (i)) : (unsigned long) (alpha) & \ ~(1UL << (unsigned long) (i))) Image *image, *watermark; ImageInfo *read_info; long c, i, j, k, y; MagickBooleanType status; PixelPacket pixel; register IndexPacket *indexes; register long x; register PixelPacket *q; /* Initialize Image structure. */ assert(image_info != (const ImageInfo *) NULL); assert(image_info->signature == MagickSignature); if (image_info->debug != MagickFalse) (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s", image_info->filename); assert(exception != (ExceptionInfo *) NULL); assert(exception->signature == MagickSignature); image=AllocateImage(image_info); if ((image->columns == 0) || (image->rows == 0)) ThrowReaderException(OptionError,"MustSpecifyImageSize"); read_info=CloneImageInfo(image_info); SetImageInfoBlob(read_info,(void *) NULL,0); *read_info->magick='\0'; watermark=ReadImage(read_info,exception); read_info=DestroyImageInfo(read_info); if (watermark == (Image *) NULL) return((Image *) NULL); watermark->depth=QuantumDepth; if (AllocateImageColormap(image,MaxColormapSize) == MagickFalse) ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed"); if (image_info->ping != MagickFalse) { CloseBlob(image); return(GetFirstImageInList(image)); } /* Get hidden watermark from low-order bits of image. */ c=0; i=0; j=0; k=image->offset; for (i=QuantumDepth-1; (i >= 0) && (j < QuantumDepth); i--) { for (y=0; (y < (long) image->rows) && (j < QuantumDepth); y++) { for (x=0; (x < (long) image->columns) && (j < QuantumDepth); x++) { pixel=AcquireOnePixel(watermark,k % (long) watermark->columns, k/(long) watermark->columns,exception); q=GetImagePixels(image,x,y,1,1); if (q == (PixelPacket *) NULL) break; indexes=GetIndexes(image); switch (c) { case 0: { SetBit(*indexes,i,GetBit(pixel.red,j)); break; } case 1: { SetBit(*indexes,i,GetBit(pixel.green,j)); break; } case 2: { SetBit(*indexes,i,GetBit(pixel.blue,j)); break; } } if (SyncImagePixels(image) == MagickFalse) break; c++; if (c == 3) c=0; k++; if (k == (long) (watermark->columns*watermark->columns)) k=0; if (k == image->offset) j++; } } if ((image->progress_monitor != (MagickProgressMonitor) NULL) && (QuantumTick(i,QuantumDepth) != MagickFalse)) { status=image->progress_monitor(LoadImagesTag,i,QuantumDepth, image->client_data); if (status == MagickFalse) break; } } watermark=DestroyImage(watermark); (void) SyncImage(image); return(GetFirstImageInList(image)); } /* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % % % % % % R e g i s t e r S T E G A N O I m a g e % % % % % % % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % RegisterSTEGANOImage() adds attributes for the STEGANO image format to % the list of supported formats. The attributes include the image format % tag, a method to read and/or write the format, whether the format % supports the saving of more than one frame to the same file or blob, % whether the format supports native in-memory I/O, and a brief % description of the format. % % The format of the RegisterSTEGANOImage method is: % % unsigned long RegisterSTEGANOImage(void) % */ ModuleExport unsigned long RegisterSTEGANOImage(void) { MagickInfo *entry; entry=SetMagickInfo("STEGANO"); entry->decoder=(DecodeImageHandler *) ReadSTEGANOImage; entry->description=ConstantString("Steganographic image"); entry->module=ConstantString("STEGANO"); (void) RegisterMagickInfo(entry); return(MagickImageCoderSignature); } /* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % % % % % % U n r e g i s t e r S T E G A N O I m a g e % % % % % % % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % UnregisterSTEGANOImage() removes format registrations made by the % STEGANO module from the list of supported formats. % % The format of the UnregisterSTEGANOImage method is: % % UnregisterSTEGANOImage(void) % */ ModuleExport void UnregisterSTEGANOImage(void) { (void) UnregisterMagickInfo("STEGANO"); }