/* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % % % % % % 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 1999-2011 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 "MagickCore/studio.h" #include "MagickCore/blob.h" #include "MagickCore/blob-private.h" #include "MagickCore/cache.h" #include "MagickCore/colormap.h" #include "MagickCore/constitute.h" #include "MagickCore/exception.h" #include "MagickCore/exception-private.h" #include "MagickCore/image.h" #include "MagickCore/image-private.h" #include "MagickCore/list.h" #include "MagickCore/magick.h" #include "MagickCore/memory_.h" #include "MagickCore/monitor.h" #include "MagickCore/monitor-private.h" #include "MagickCore/pixel-accessor.h" #include "MagickCore/quantum-private.h" #include "MagickCore/static.h" #include "MagickCore/string_.h" #include "MagickCore/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 inline size_t MagickMin(const size_t x, const size_t y) { if (x < y) return(x); return(y); } static Image *ReadSTEGANOImage(const ImageInfo *image_info, ExceptionInfo *exception) { #define GetBit(alpha,i) MagickMin((((size_t) (alpha) >> (size_t) \ (i)) & 0x01),16) #define SetBit(i,set) SetPixelIndex(image,((set) != 0 ? \ (size_t) GetPixelIndex(image,q) | (one << (size_t) (i)) : \ (size_t) GetPixelIndex(image,q) & ~(one << (size_t) (i))),q) Image *image, *watermark; ImageInfo *read_info; int c; MagickBooleanType status; PixelPacket pixel; register Quantum *q; register ssize_t x; size_t depth, one; ssize_t i, j, k, y; /* 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); one=1; image=AcquireImage(image_info,exception); 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=MAGICKCORE_QUANTUM_DEPTH; if (AcquireImageColormap(image,MaxColormapSize,exception) == MagickFalse) ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed"); if (image_info->ping != MagickFalse) { (void) CloseBlob(image); return(GetFirstImageInList(image)); } /* Get hidden watermark from low-order bits of image. */ c=0; i=0; j=0; i=(ssize_t) (watermark->depth-1); depth=watermark->depth; for (k=image->offset; (i >= 0) && (j < (ssize_t) depth); i--) { for (y=0; (y < (ssize_t) image->rows) && (j < (ssize_t) depth); y++) { x=0; for ( ; (x < (ssize_t) image->columns) && (j < (ssize_t) depth); x++) { if ((k/(ssize_t) watermark->columns) >= (ssize_t) watermark->rows) break; (void) GetOneVirtualPixel(watermark,k % (ssize_t) watermark->columns, k/(ssize_t) watermark->columns,&pixel,exception); q=GetAuthenticPixels(image,x,y,1,1,exception); if (q == (Quantum *) NULL) break; switch (c) { case 0: { SetBit(i,GetBit(pixel.red,j)); break; } case 1: { SetBit(i,GetBit(pixel.green,j)); break; } case 2: { SetBit(i,GetBit(pixel.blue,j)); break; } } if (SyncAuthenticPixels(image,exception) == MagickFalse) break; c++; if (c == 3) c=0; k++; if (k == (ssize_t) (watermark->columns*watermark->columns)) k=0; if (k == image->offset) j++; } } status=SetImageProgress(image,LoadImagesTag,(MagickOffsetType) i,depth); 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: % % size_t RegisterSTEGANOImage(void) % */ ModuleExport size_t RegisterSTEGANOImage(void) { MagickInfo *entry; entry=SetMagickInfo("STEGANO"); entry->decoder=(DecodeImageHandler *) ReadSTEGANOImage; entry->format_type=ImplicitFormatType; 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"); }