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The expression consists of one or more channels, either mnemonic or numeric (e.g. red, 1), separated by actions as follows:</p> 60 61 <dd> 62 </dd> 63 64 <dd> <=> exchange two channels (e.g. red<=>blue) => copy one channel to another channel (e.g. red=>green) = assign a constant value to a channel (e.g. red=50) , write new image channels in the specified order (e.g. red, green) | add a new output image for the next set of channel operations ; move to the next input image for the source of channel data </dd> 65 66 <dd> For example, to create 3 grayscale images from the red, green, and blue channels of an image, use: </dd> 67 68 <pre class="text"> 69 -channel-fx "red; green; blue" 70 </pre> 71 72 <p>A channel without an operation symbol implies separate (i.e, semicolon). </dd> 73 74 <dd> The format of the ChannelFxImage method is: </dd> 75 76 <pre class="text"> 77 Image *ChannelFxImage(const Image *image,const char *expression, 78 ExceptionInfo *exception) 79 </pre> 80 81 <p>A description of each parameter follows: </dd> 82 83 <dd> 84 </dd> 85 86 <dd> </dd> 87 <dl class="dl-horizontal"> 88 <dt>image</dt> 89 <dd>the image. </dd> 90 91 <dd> </dd> 92 <dt>expression</dt> 93 <dd>A channel expression. </dd> 94 95 <dd> </dd> 96 <dt>exception</dt> 97 <dd>return any errors or warnings in this structure. </dd> 98 99 <dd> </dd> 100 </dl> 101 <h2><a href="http://nextgen.imagemagick.org/api/MagickCore/channel_8c.html" id="CombineImages">CombineImages</a></h2> 102 103 <p>CombineImages() combines one or more images into a single image. The grayscale value of the pixels of each image in the sequence is assigned in order to the specified channels of the combined image. The typical ordering would be image 1 => Red, 2 => Green, 3 => Blue, etc.</p> 104 105 <p>The format of the CombineImages method is:</p> 106 107 <pre class="text"> 108 Image *CombineImages(const Image *images,const ColorspaceType colorspace, 109 ExceptionInfo *exception) 110 </pre> 111 112 <p>A description of each parameter follows:</p> 113 114 <dd> 115 </dd> 116 117 <dd> </dd> 118 <dl class="dl-horizontal"> 119 <dt>images</dt> 120 <dd>the image sequence. </dd> 121 122 <dd> </dd> 123 <dt>colorspace</dt> 124 <dd>the image colorspace. </dd> 125 126 <dd> </dd> 127 <dt>exception</dt> 128 <dd>return any errors or warnings in this structure. </dd> 129 130 <dd> </dd> 131 </dl> 132 <h2><a href="http://nextgen.imagemagick.org/api/MagickCore/channel_8c.html" id="GetImageAlphaChannel">GetImageAlphaChannel</a></h2> 133 134 <p>GetImageAlphaChannel() returns MagickFalse if the image alpha channel is not activated. That is, the image is RGB rather than RGBA or CMYK rather than CMYKA.</p> 135 136 <p>The format of the GetImageAlphaChannel method is:</p> 137 138 <pre class="text"> 139 MagickBooleanType GetImageAlphaChannel(const Image *image) 140 </pre> 141 142 <p>A description of each parameter follows:</p> 143 144 <dd> 145 </dd> 146 147 <dd> </dd> 148 <dl class="dl-horizontal"> 149 <dt>image</dt> 150 <dd>the image. </dd> 151 152 <dd> </dd> 153 </dl> 154 <h2><a href="http://nextgen.imagemagick.org/api/MagickCore/channel_8c.html" id="SeparateImage">SeparateImage</a></h2> 155 156 <p>SeparateImage() separates a channel from the image and returns it as a grayscale image.</p> 157 158 <p>The format of the SeparateImage method is:</p> 159 160 <pre class="text"> 161 Image *SeparateImage(const Image *image,const ChannelType channel, 162 ExceptionInfo *exception) 163 </pre> 164 165 <p>A description of each parameter follows:</p> 166 167 <dd> 168 </dd> 169 170 <dd> </dd> 171 <dl class="dl-horizontal"> 172 <dt>image</dt> 173 <dd>the image. </dd> 174 175 <dd> </dd> 176 <dt>channel</dt> 177 <dd>the image channel. </dd> 178 179 <dd> </dd> 180 <dt>exception</dt> 181 <dd>return any errors or warnings in this structure. </dd> 182 183 <dd> </dd> 184 </dl> 185 <h2><a href="http://nextgen.imagemagick.org/api/MagickCore/channel_8c.html" id="SeparateImages">SeparateImages</a></h2> 186 187 <p>SeparateImages() returns a separate grayscale image for each channel specified.</p> 188 189 <p>The format of the SeparateImages method is:</p> 190 191 <pre class="text"> 192 Image *SeparateImages(const Image *image,ExceptionInfo *exception) 193 </pre> 194 195 <p>A description of each parameter follows:</p> 196 197 <dd> 198 </dd> 199 200 <dd> </dd> 201 <dl class="dl-horizontal"> 202 <dt>image</dt> 203 <dd>the image. </dd> 204 205 <dd> </dd> 206 <dt>exception</dt> 207 <dd>return any errors or warnings in this structure. </dd> 208 209 <dd> </dd> 210 </dl> 211 <h2><a href="http://nextgen.imagemagick.org/api/MagickCore/channel_8c.html" id="SetImageAlphaChannel">SetImageAlphaChannel</a></h2> 212 213 <p>SetImageAlphaChannel() activates, deactivates, resets, or sets the alpha channel.</p> 214 215 <p>The format of the SetImageAlphaChannel method is:</p> 216 217 <pre class="text"> 218 MagickBooleanType SetImageAlphaChannel(Image *image, 219 const AlphaChannelOption alpha_type,ExceptionInfo *exception) 220 </pre> 221 222 <p>A description of each parameter follows:</p> 223 224 <dd> 225 </dd> 226 227 <dd> </dd> 228 <dl class="dl-horizontal"> 229 <dt>image</dt> 230 <dd>the image. </dd> 231 232 <dd> </dd> 233 <dt>alpha_type</dt> 234 <dd> The alpha channel type: ActivateAlphaChannel, AssociateAlphaChannel, CopyAlphaChannel, DeactivateAlphaChannel, DisassociateAlphaChannel, ExtractAlphaChannel, OffAlphaChannel, OnAlphaChannel, OpaqueAlphaChannel, SetAlphaChannel, ShapeAlphaChannel, and TransparentAlphaChannel. </dd> 235 236 <dd> </dd> 237 <dt>exception</dt> 238 <dd>return any errors or warnings in this structure. </dd> 239 240 <dd> </dd> 241 </dl> 242 </div> 243 <footer class="magick-footer"> 244 <p><a href="../script/support.php">Donate</a> 245 <a href="../script/sitemap.php">Sitemap</a> 246 <a href="../script/links.php">Related</a> 247 <a href="../script/architecture.php">Architecture</a> 248 </p> 249 <p><a href="channel.php#">Back to top</a> 250 <a href="http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x89AB63D48277377A">Public Key</a> 251 <a href="../script/contact.php">Contact Us</a></p> 252 <p><small> 1999-2016 ImageMagick Studio LLC</small></p> 253 </footer> 254 </div><!-- /.container --> 255 256 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script> 257 <script src="http://nextgen.imagemagick.org/js/magick.php"></script> 258 </div> 259 </body> 260 </html> 261
