granicus.if.org Git - imagemagick/blob - coders/gradient.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %            GGGG  RRRR    AAA   DDDD   IIIII  EEEEE  N   N  TTTTT            %
   7 %           G      R   R  A   A  D   D    I    E      NN  N    T              %
   8 %           G  GG  RRRR   AAAAA  D   D    I    EEE    N N N    T              %
   9 %           G   G  R R    A   A  D   D    I    E      N  NN    T              %
  10 %            GGG   R  R   A   A  DDDD   IIIII  EEEEE  N   N    T              %
  11 %                                                                             %
  12 %                                                                             %
  13 %                   Read An Image Filled Using Gradient.                      %
  14 %                                                                             %
  15 %                              Software Design                                %
  16 %                                John Cristy                                  %
  17 %                                 July 1992                                   %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2011 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    http://www.imagemagick.org/script/license.php                            %
  27 %                                                                             %
  28 %  Unless required by applicable law or agreed to in writing, software        %
  29 %  distributed under the License is distributed on an "AS IS" BASIS,          %
  30 %  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
  31 %  See the License for the specific language governing permissions and        %
  32 %  limitations under the License.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  36 %
  37 */
  38 \f
  39 /*
  40   Include declarations.
  41 */
  42 #include "magick/studio.h"
  43 #include "magick/blob.h"
  44 #include "magick/blob-private.h"
  45 #include "magick/color.h"
  46 #include "magick/color-private.h"
  47 #include "magick/draw.h"
  48 #include "magick/exception.h"
  49 #include "magick/exception-private.h"
  50 #include "magick/image.h"
  51 #include "magick/image-private.h"
  52 #include "magick/list.h"
  53 #include "magick/magick.h"
  54 #include "magick/memory_.h"
  55 #include "magick/paint.h"
  56 #include "magick/pixel-private.h"
  57 #include "magick/quantum-private.h"
  58 #include "magick/static.h"
  59 #include "magick/string_.h"
  60 #include "magick/module.h"
  61 #include "magick/studio.h"
  62 \f
  63 /*
  64 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  65 %                                                                             %
  66 %                                                                             %
  67 %                                                                             %
  68 %   R e a d G R A D I E N T I m a g e                                         %
  69 %                                                                             %
  70 %                                                                             %
  71 %                                                                             %
  72 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  73 %
  74 %  ReadGRADIENTImage creates a gradient image and initializes it to
  75 %  the color range as specified by the filename.  It allocates the memory
  76 %  necessary for the new Image structure and returns a pointer to the new
  77 %  image.
  78 %
  79 %  The format of the ReadGRADIENTImage method is:
  80 %
  81 %      Image *ReadGRADIENTImage(const ImageInfo *image_info,
  82 %        ExceptionInfo *exception)
  83 %
  84 %  A description of each parameter follows:
  85 %
  86 %    o image_info: the image info.
  87 %
  88 %    o exception: return any errors or warnings in this structure.
  89 %
  90 */
  91 static Image *ReadGRADIENTImage(const ImageInfo *image_info,
  92   ExceptionInfo *exception)
  93 {
  94   char
  95     colorname[MaxTextExtent];
  96
  97   PixelPacket
  98     start_color,
  99     stop_color;
 100
 101   Image
 102     *image;
 103
 104   /*
 105     Initialize Image structure.
 106   */
 107   assert(image_info != (const ImageInfo *) NULL);
 108   assert(image_info->signature == MagickSignature);
 109   if (image_info->debug != MagickFalse)
 110     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
 111       image_info->filename);
 112   assert(exception != (ExceptionInfo *) NULL);
 113   assert(exception->signature == MagickSignature);
 114   image=AcquireImage(image_info);
 115   if ((image->columns == 0) || (image->rows == 0))
 116     ThrowReaderException(OptionError,"MustSpecifyImageSize");
 117   (void) SetImageOpacity(image,(Quantum) TransparentOpacity);
 118   (void) CopyMagickString(image->filename,image_info->filename,MaxTextExtent);
 119   (void) CopyMagickString(colorname,image_info->filename,MaxTextExtent);
 120   (void) sscanf(image_info->filename,"%[^-]",colorname);
 121   if (QueryColorDatabase(colorname,&start_color,exception) == MagickFalse)
 122     {
 123       image=DestroyImage(image);
 124       return((Image *) NULL);
 125     }
 126   (void) CopyMagickString(colorname,"white",MaxTextExtent);
 127   if (PixelIntensityToQuantum(&start_color) > (Quantum) (QuantumRange/2))
 128     (void) CopyMagickString(colorname,"black",MaxTextExtent);
 129   (void) sscanf(image_info->filename,"%*[^-]-%s",colorname);
 130   if (QueryColorDatabase(colorname,&stop_color,exception) == MagickFalse)
 131     {
 132       image=DestroyImage(image);
 133       return((Image *) NULL);
 134     }
 135   (void) GradientImage(image,LocaleCompare(image_info->magick,"GRADIENT") == 0 ?
 136     LinearGradient : RadialGradient,PadSpread,&start_color,&stop_color);
 137   return(GetFirstImageInList(image));
 138 }
 139 \f
 140 /*
 141 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 142 %                                                                             %
 143 %                                                                             %
 144 %                                                                             %
 145 %   R e g i s t e r G R A D I E N T I m a g e                                 %
 146 %                                                                             %
 147 %                                                                             %
 148 %                                                                             %
 149 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 150 %
 151 %  RegisterGRADIENTImage() adds attributes for the GRADIENT image format
 152 %  to the list of supported formats.  The attributes include the image format
 153 %  tag, a method to read and/or write the format, whether the format
 154 %  supports the saving of more than one frame to the same file or blob,
 155 %  whether the format supports native in-memory I/O, and a brief
 156 %  description of the format.
 157 %
 158 %  The format of the RegisterGRADIENTImage method is:
 159 %
 160 %      size_t RegisterGRADIENTImage(void)
 161 %
 162 */
 163 ModuleExport size_t RegisterGRADIENTImage(void)
 164 {
 165   MagickInfo
 166     *entry;
 167
 168   entry=SetMagickInfo("GRADIENT");
 169   entry->decoder=(DecodeImageHandler *) ReadGRADIENTImage;
 170   entry->adjoin=MagickFalse;
 171   entry->raw=MagickTrue;
 172   entry->format_type=ImplicitFormatType;
 173   entry->description=ConstantString("Gradual linear passing from one shade to "
 174     "another");
 175   entry->module=ConstantString("GRADIENT");
 176   (void) RegisterMagickInfo(entry);
 177   entry=SetMagickInfo("RADIAL-GRADIENT");
 178   entry->decoder=(DecodeImageHandler *) ReadGRADIENTImage;
 179   entry->adjoin=MagickFalse;
 180   entry->raw=MagickTrue;
 181   entry->format_type=ImplicitFormatType;
 182   entry->description=ConstantString("Gradual radial passing from one shade to "
 183     "another");
 184   entry->module=ConstantString("GRADIENT");
 185   (void) RegisterMagickInfo(entry);
 186   return(MagickImageCoderSignature);
 187 }
 188 \f
 189 /*
 190 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 191 %                                                                             %
 192 %                                                                             %
 193 %                                                                             %
 194 %   U n r e g i s t e r G R A D I E N T I m a g e                             %
 195 %                                                                             %
 196 %                                                                             %
 197 %                                                                             %
 198 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 199 %
 200 %  UnregisterGRADIENTImage() removes format registrations made by the
 201 %  GRADIENT module from the list of supported formats.
 202 %
 203 %  The format of the UnregisterGRADIENTImage method is:
 204 %
 205 %      UnregisterGRADIENTImage(void)
 206 %
 207 */
 208 ModuleExport void UnregisterGRADIENTImage(void)
 209 {
 210   (void) UnregisterMagickInfo("RADIAL-GRADIENT");
 211   (void) UnregisterMagickInfo("GRADIENT");
 212 }