If your Emacs build has ImageMagick support, you can use the
ImageMagick library to load many image formats (see 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:
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
BMPfor .bmp images.
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
tenables ImageMagick for all possible image types. Regardless of the value of this variable,
imagemagick-types-inhibit(see below) takes precedence.
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
tdisables ImageMagick entirely.
This variable is an alist mapping image types to file name extensions. Emacs uses this in conjunction with the
:formatimage property (see below) to give a hint to the ImageMagick library as to the type of an image. Each element has the form
), 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:
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.
:heightkeywords 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-heightkeywords are used for scaling if the size of the image of the image exceeds these values. If
:widthis set it will have precedence over
max-width, and if
:heightis set it will have precedence over
max-height, but you can otherwise mix these keywords as you wish.
:max-heightwill always preserve the aspect ratio.
:max-height has been set (but
:height has not been set), then
:max-height will have
precedence. The same is the case for the opposite combination: The
“max” keyword has precedence. That is, if you have a 200x100 image
and specify that
:width should be 400 and
should be 150, you'll end up with an image that is 300x150: Preserving
the aspect ratio and not exceeding the “max” setting. This
combination of parameters is a useful way of saying “display this
image as large as possible, but no larger than the available display
:max-height, the resulting size will not exceed those two values. If both
:widthare specified, the height/width will be adjusted by the specified scaling factor.
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.