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+    The .ggr file format.
+
+GGR files are used to store GIMP gradients.  A gradient consists of a
+series of consecutive *segments* spanning the range from 0.0 to 1.0.  Each
+segment has the following attributes:
+
+Left Endpoint coordinate: (double)
+Left Endpoint color (RGBA color)
+Right Endpoint coordinate (double)
+Right Endpoint color (RGBA color)
+Midpoint coordinate (double)
+Blending function (enum; values are:
+                   0 = "linear"
+                   1 = "curved"
+                   2 = "sinusoidal"
+                   3 = "spherical (increasing)"
+                   4 = "spherical (decreasing)"
+                   5 = "step")
+Coloring type (enum; values are:
+               0 = "RGB"
+               1 = "HSV CCW"
+               2 = "HSV CW")
+Left and right Endpoint Color type (enum; values are:
+                                    0 = "fixed"
+                                    1 = "foreground",
+                                    2 = "foreground transparent"
+                                    3 = "background",
+                                    4 = "background transparent")
+
+
+A GGR file is an ASCII file structured as follows:
+
+Line 1: "GIMP Gradient"
+Line 2: "Name: " followed by the name of the gradient
+Line 3: the number of segments 
+
+The remaining lines consist of segment specifications.  There must be
+one line for each segment.  Each line contains 15 numbers -- the first
+11 are floats, the remaining 4 are ints.  Here is what each field
+encodes:
+
+Field      Meaning
+  0          Left endpoint coordinate
+  1          Midpoint coordinate 
+  2          Right endpoint coordinate
+  3          Left endpoint R
+  4          Left endpoint G
+  5          Left endpoint B
+  6          Left endpoint A
+  7          Right endpoint R
+  8          Right endpoint G
+  9          Right endpoint B
+ 10          Right endpoint A
+ 11          Blending function type
+ 12          Coloring type
+ 13          Left endpoint color type
+ 14          Right endpoint color type
+
+The left endpoint coordinate of each segment must equal the right
+endpoint coordinate of the preceding segment.
+
+Note 1: This is a description of the *new* gradient file format.  In
+earlier versions of GIMP a different format was used.
+
+Note 2: In GIMP versions prior to 2.3.11 the file format didn't contain
+the color types of the endpoints, thus it was impossible to get the
+behavior of the special "FG to BG" etc. gradients in custom gradients.
+
+Note 3: Starting with version 2.1, GIMP now has the ability to load
+gradients in SVG gradient format, if the file is placed in the user's
+personal "gradients" directory, or some other location in the
+gradients search path.
+