Info Catalog elisp: PostScript Images elisp: Images elisp: Other Image Types

elisp: ImageMagick Images

 
 37.17.6 ImageMagick Images
 --------------------------
 
 If you build Emacs with ImageMagick support, you can use the ImageMagick
 library to load many image formats ((emacs)File Conveniences).
 The image type symbol for images loaded via ImageMagick is
 ‘imagemagick’, regardless of the actual underlying image format.
 
    To check for ImageMagick support, use the following:
 
      (image-type-available-p 'imagemagick)
 
  -- Function: imagemagick-types
      This function returns a list of image file extensions supported by
      the current ImageMagick installation.  Each list element is a
      symbol representing an internal ImageMagick name for an image type,
      such as ‘BMP’ for ‘.bmp’ images.
 
  -- User Option: imagemagick-enabled-types
      The value of this variable is a list of ImageMagick image types
      which Emacs may attempt to render using ImageMagick.  Each list
      element should be one of the symbols in the list returned by
      ‘imagemagick-types’, or an equivalent string.  Alternatively, a
      value of ‘t’ enables ImageMagick for all possible image types.
      Regardless of the value of this variable,
      ‘imagemagick-types-inhibit’ (see below) takes precedence.
 
  -- User Option: imagemagick-types-inhibit
      The value of this variable lists the ImageMagick image types which
      should never be rendered using ImageMagick, regardless of the value
      of ‘imagemagick-enabled-types’.  A value of ‘t’ disables
      ImageMagick entirely.
 
  -- Variable: image-format-suffixes
      This variable is an alist mapping image types to file name
      extensions.  Emacs uses this in conjunction with the ‘:format’
      image property (see below) to give a hint to the ImageMagick
      library as to the type of an image.  Each element has the form
      ‘(TYPE EXTENSION)’, where TYPE is a symbol specifying an image
      content-type, and EXTENSION is a string that specifies the
      associated file name extension.
 
    Images loaded with ImageMagick support the following additional image
 descriptor properties:
 
 ‘:background BACKGROUND’
      BACKGROUND, if non-‘nil’, should be a string specifying a color,
      which is used as the image’s background color if the image supports
      transparency.  If the value is ‘nil’, it defaults to the frame’s
      background color.
 
 ‘:width WIDTH, :height HEIGHT’
      The ‘:width’ and ‘:height’ keywords are used for scaling the image.
      If only one of them is specified, the other one will be calculated
      so as to preserve the aspect ratio.  If both are specified, aspect
      ratio may not be preserved.
 
 ‘:max-width MAX-WIDTH, :max-height MAX-HEIGHT’
      The ‘:max-width’ and ‘:max-height’ keywords are used for scaling if
      the size of the image of the image exceeds these values.  If
      ‘:width’ is set it will have precedence over ‘max-width’, and if
      ‘:height’ is set it will have precedence over ‘max-height’, but you
      can otherwise mix these keywords as you wish.  ‘:max-width’ and
      ‘:max-height’ will always preserve the aspect ratio.
 
 ‘:format TYPE’
      The value, TYPE, should be a symbol specifying the type of the
      image data, as found in ‘image-format-suffixes’.  This is used when
      the image does not have an associated file name, to provide a hint
      to ImageMagick to help it detect the image type.
 
 ‘:rotation ANGLE’
      Specifies a rotation angle in degrees.
 
 ‘:index FRAME’
      Multi-Frame Images.
 

Info Catalog elisp: PostScript Images elisp: Images elisp: Other Image Types