Started Typefacet Autokern; added references.md.

README.md

@@ -49,29 +49,20 @@ AutoSpace by Andres Torresi of Huerta Tipográfica is an add-on for the
 Glyphs font editor.  It has been demonstrated in several widely
 shared online videos, but has not yet been formally released.
 
-[Spacing Macro](http://www.impallari.com/projects/overview/spacing-macro) by Pablo
-Impallari is a macro for FontLab.  It is based on discussions
-[http://typedrawers.com/discussion/52/spacing-macro] at the
-TypeDrawers forum, and was initially inspired by Frank E. Blokland's LetterModel.
+Pablo Impallari's [Spacing Macro](impallari.md) is a macro for FontLab.  It was initially inspired by Frank E. Blokland's LetterModel.
 
-[Kernagic](https://github.com/hodefoting/kernagic) by Øyvind Kolås is a
+[Kernagic](kernagic.md) by Øyvind Kolås is a
 standalone software tool that can automatically letterspace a UFO
-font.  It implements several different letterspacing approaches:
-* LetterModel by Frank E. Blokland
-* Snap Gap, which snaps "rhythm points" of glyphs to a desired grid
-* Interactivos Average, a simple approach expressed in
-https://gitorious.org/libregraphicsmag/interactivosbook .
-
-Note that the Average method was dropped from later Kernagic releases,
-as it did not produce results as satisfactory as the other methods.
-It is mentioned here for the sake of completeness.
+font.  It implements several different letterspacing approaches
 
 Kerning
 -------
 
 [Typefacet
 Autokern](http://charlesmchen.github.io/typefacet/topics/autokern/index.html)
-is a Python program using Robofab.
+is a Python program by Charles M. Chen that can automatically adjust
+side-bearings 
+of kerning pairs in a font based on a set of user-supplied general arguments.
 
 [BubbleKern](https://github.com/Tosche/BubbleKern) is an add-on for the
 Glyphs font editor.

impallari.md

@@ -0,0 +1,7 @@
+Pablo Impallari's Spacing Macro
+===============================
+[Spacing Macro](http://www.impallari.com/projects/overview/spacing-macro) by Pablo
+Impallari is a macro for FontLab.  It is based on discussions
+[http://typedrawers.com/discussion/52/spacing-macro] at the
+TypeDrawers forum, and was initially inspired by Frank E. Blokland's LetterModel.
+

kernagic.md

@@ -0,0 +1,14 @@
+Kernagic
+========
+
+[Kernagic](https://github.com/hodefoting/kernagic) by Øyvind Kolås is a
+standalone software tool that can automatically letterspace a UFO
+font.  It implements several different letterspacing approaches:
+* LetterModel by Frank E. Blokland
+* Snap Gap, which snaps "rhythm points" of glyphs to a desired grid
+* Interactivos Average, a simple approach expressed in
+https://gitorious.org/libregraphicsmag/interactivosbook .
+
+Note that the Average method was dropped from later Kernagic releases,
+as it did not produce results as satisfactory as the other methods.
+It is mentioned here for the sake of completeness.

kindersley.md

@@ -137,6 +137,27 @@ photocell through the gradient masks is the equivalent of computing
 the "first," "second," and "third" moments directly.
 
 
+
+
+Kindersley's observations
+-------------------------
+
+Kindersley reported that using the quadratic gradient masks produced results
+"close" to what was expected.  He also made several other observations
+along the way.
+
+First, he noted that ascenders and descenders do not seem to contribute to the
+location of the optical center (i.e., h and n have the same center, as
+do v and y).  Instead, the optical centering happens within the
+x-height rectangle. 
+
+Second, he tested italic and slanted typefaces using the same method
+as uprights, and determined that the gradient mask needed to be tilted
+at the same angle as the italic in order to produce satisfactory
+results.
+
+
+
 Implementation talk
 -------------------
 
@@ -199,25 +220,6 @@ era.  More could surely be done with the computing resources available today.
 
 
 
-
-Kindersley's observations
--------------------------
-
-Kindersley reported that using the quadratic gradient masks produced results
-"close" to what was expected.  He also made several other observations
-along the way.
-
-First, he noted that ascenders and descenders do not seem to contribute to the
-location of the optical center (i.e., h and n have the same center, as
-do v and y).  Instead, the optical centering happens within the
-x-height rectangle. 
-
-Second, he tested italic and slanted typefaces using the same method
-as uprights, and determined that the gradient mask needed to be tilted
-at the same angle as the italic in order to produce satisfactory
-results.
-
-
 Limitations
 -----------
 

references.md

@@ -0,0 +1,53 @@
+Research papers and other references
+====================================
+
+"An escape from crowding", Jeremy Freeman, Denis J. Pelli. Journal of
+Vision (2007) 7(2):22, 1–14.
+
+"Crowding: a cortical constraint on object recognition", Denis
+G. Pelli. Current Opinion in Neurobiology (2008), 18:445-451.
+
+"Crowding and eccentricity determine reading rate", Denis G. Pelli,
+Katharine A. Tillman, Jeremy Freeman, Michael Su, Tracey D. Berger,
+Najib J. Majaj.  Journal of Vision (2007) 7(2):20, 1-36.
+
+"Crowding is unlike ordinary masking: Distinguishing feature
+integration from detection", Denis G. Pelli, Melanie Palomares, Najib
+J. Majaj. Journal of Vision (2004) 4, 1136-1169.
+
+"Feature detection and letter identification", Denis G. Pelli,
+Catherine W. Burns, Bart Farell, Deborah C. Moore-Page. Vision Research 46 (2006) 4646–4674.
+
+"The golden ratio predicted: vision, cognition and locomotion as a
+single design in nature", Adrian Bejan. International Journal of Design & Nature and Ecodynamics. Vol. 4, No. 2 (2009) 97–104.
+
+"Gray-scale Hough transform for think line detection in gray-scale
+images", Rong-Chin Lo, Wen-Hsiang Tsai. Pattern Recognition, Vol 28
+Number 5 (1995), p 647-661.
+
+"The lowest spatial frequency channel determines brightness
+perception", A. Perna, M. C. Morrone. Vision Research 47 (2007) 1282–1291.
+
+"Modeling the Shape of the Scene: A Holistic Representation
+of the Spatial Envelope", Aude Oliva, Antonio Torralba. International Journal of Computer Vision 42(3), 145–175, 2001.
+
+"Real-time line detection through an improved Hough transform
+voting scheme", Leandro A.F. Fernandes, Manuel M. Oliveira. Pattern Recognition 41 (2008) 299 – 314.
+
+"The role of spatial frequency channels in letter identification",
+Najib J. Majaj, Denis G. Pelli, Peri Kurshan, Melanie Palomares. Vision Research 42 (2002) 1165–1184.
+
+"Size Adaptation to Visual Texture and Print: Evidence for
+Spatial-Frequency Analysis", S. M. Anstis. The American Journal of Psychology, Vol. 87, No. 1/2 (Mar. - Jun., 1974), pp. 261-267.
+
+"Spatial-frequency and contrast properties of crowding", Susana
+T.L. Chung, Dennis M. Levi, Gordon E. Legge.  Vision Research 41
+(2001) 1833-1850.
+
+"Towards quantification of the effects of typographic variation on
+readability", Robert A. Morris, Karl Berry, Kathryn
+A. Hargreaves. 1993 SID Digest of Technical Papers, Special Session on
+Text Quality. Society for Information Display 1993.
+
+"Two Decades of Typographic Research at URW: A Retrospective", Peter
+Karow. URW.

typefacet.md

@@ -0,0 +1,111 @@
+TypeFacet Autokern
+==================
+
+Charles M. Chen's [Autokern](http://charlesmchen.github.io/typefacet/topics/autokern/index.html) is a command-line Python tool released as
+part of Chen's *TypeFacet* software collection.  It reads in UFO font
+files and takes a set of user-supplied arguments, then outputs a
+modified UFO file with adjusted side-bearings and, optionally, kerning
+values.
+
+
+
+Arguments
+---------
+
+### Basic operation
+
+`--ufo-src-path` *foo.ufo* Sets the font file to be processed.
+
+`--ufo-dst-path` *bar.ufo* Designates the name of the modified output
+file to create.
+
+`--log-path` *logs* Designates where output logs should be written.
+
+
+### Common tunable settings
+
+`--min-distance-ems` Sets a minimum allowable distance between the
+contours of adjacent glyphs.
+
+`--max-distance-ems` Sets the maximum distance allowed between any two glyphs. 
+
+
+`--intrusion-tolerance-ems` Sets the maximum amount to which glyphs can "intrude" into the spacing between them. 
+
+`--max-x-extrema-overlap-ems`
+
+`--precision-ems` Sets the numeric precision to use for calculations.
+Smaller values are more CPU intensive.
+
+
+### Glyph selection
+
+`--sample-texts`
+
+`--kern-samples-only`
+
+`--glyph-pairs-to-kern`
+
+`--glyphs-to-kern`
+
+`--glyphs-to-ignore`
+
+
+### Additional tunable settings
+
+`--do-not-modify-side-bearings` Tells Autokern to preserve the font's
+original side bearings.
+
+`--allow-negative-side-bearings` Tells Autokern to permit side
+bearings to take on negative values.
+
+`--kerning-threshold-ems` *N* Tells Autokern to discard any kerning
+values less than N.
+
+`--max-kerning-pairs` *N* Tells Autokern to only output the N largest
+kerning values and discard the rest. 
+
+`--x-extrema-overlap-scaling`
+
+`--tracking-ems` *N* (mentioned in the documentation as `--tracking`)
+Tells Autokern to add a constant N value to all kerning values.
+
+`--ignore-x-extrema-overlap-outside-ascender`  Tells Autokern to
+ignore x-extrema overlaps that occur below the baseline or above the
+ascender.
+
+
+### Glyph selection by category
+
+`--glyph-categories-to-ignore`
+
+`--max-x-extrema-overlap-ems-per-category`
+
+`--max-distance-ems-per-category`
+
+`--min-distance-ems-per-category`
+
+`--intrusion-tolerance-ems-per-category`
+
+`--tracking-ems-per-category`
+
+
+### Additional logging options
+
+`--log-basic-pairs` Tells Autokern to log the "basic" set of glyph
+pairs, for use proofreading or troubleshooting.
+
+`--write-kerning-pair-logs` Tells Autokern to log every kerning-pair combination.
+
+`--disparity-log-count` Tells Autokern to log which kerning pairs were
+changed by the greatest amount.
+
+
+
+Usage
+-----
+
+Chen advises users to run the Autorkern tool several times, employing
+a different subset of the arguments for each run.  First, he suggests
+running with `--min-distance-ems` and `--max-distance-ems` on a pair
+of glyphs such as "Tt", "TT", or "rf".