improved lisp interface to scaling, doc changed acordingly

1 files changed, 38 insertions, 18 deletions

diff --git a/README.imagemagick b/README.imagemagick
index a4910d212ee..ff1831e8c8f 100644
--- a/README.imagemagick
+++ b/README.imagemagick
@@ -76,9 +76,41 @@ This means imagemagick will be used also to load jpeg files, if you
 have both jpeg and imagemagick libraries linked. Add 'JPG to
 imagemagick-types-inhibit if you do not want this.
 
+imagemagick-render-type is a new variable which can be set to choose
+between screen render methods.
+
+- 0 is a conservative metod which works with older ImageMagick
+  versions. It is a bit slow, but robust.
+
+- 1 utilizes a newer ImageMagick method   
+
+
 Images loaded with imagemagick will support a couple of new display
-specifications:
+specification behaviours:
+
+- if the :width and :height keywords are specified, these values are
+used for scaling the image. If only one of :width or :height is
+specified, the other one will be calculated so as to preserve the
+aspect ratio.If both :width and :height are specified, aspect ratio
+will not be preserved.
+
+- :rotation specifies a rotation angle in degrees.
+
+- :index specifies which image inside an image bundle file format, such
+as TIFF or DJVM, to view.
+
+The image-metadata function can be used to retrieve the total number
+of images in an image bundle. This is simmilar to how GIF files work.
+
+- :crop is used to specify a croping area: (width height x y).  This
+is similar to the slice image specification, but has a different
+purpose. :crop removes the croped areas from memory, so its memory
+efficient if you only need to view a certain part of the image. The
+slice specification can be used to pick diferent parts of the same
+image, so its more disk and display efficient.
+
 
+* experimental
 - :geometry takes a geometry string as defined by ImageMagick:
 
 scale%            
@@ -96,24 +128,12 @@ area@
 
 See the ImageMagick manual for more information.
 
-Furthermore, if the :width and :height keywords are specified, these
-values are used for scaling the image.
-
-- :rotation specifies a rotation angle in degrees.
-
-- :index specifies which image inside an image bundle file format, such
-as TIFF or DJVM, to view.
-
-The image-metadata function can be used to retrieve the total number
-of images in an image bundle. This is simmilar to how GIF files work.
-
-- :crop is used to specify a croping area, with the {size}{offset}
-syntax.  This is similar to the slice image specification, but has a
-different purpose. :crop removes the croped areas from memory, so its
-memory efficient if you only need to view a certain part of the
-image. :slice can be used to pick diferent parts of the same image, so
-its more disk and display efficient.
+- :crop is used to specify a croping area, with the "{size}{offset}" syntax.
 
+:geometry and :crop with a string argument, are both particular to
+ImageMagick, whereas the lisp interface is more general. Currently it
+seems like the lisp interface is good enough, so the string argument
+interface will probably be removed.
 
 * Changelog entry
 2010-06-12 Joakim Verona <joakim@verona.se>