From: Ben Harris <bjh21@bjh21.me.uk>
Date: Wed, 28 Jun 2017 21:15:02 +0000 (+0100)
Subject: Generate PANOSE classification.
X-Git-Tag: bedstead-001.003~29
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~bjharris/git?a=commitdiff_plain;h=4ca14615e4e0d004faf26eb16780ed212f2e9384;p=bedstead.git

Generate PANOSE classification.

This is a mandatory part of the 'OS/2' table, so we may as well get it
right.  Gratuitously generalised across all possible character widths.
---

diff --git a/bedstead.c b/bedstead.c
index c9e445b..832a95c 100644
--- a/bedstead.c
+++ b/bedstead.c
@@ -157,6 +157,7 @@ struct param *param = &default_param;
 void doprologue(void);
 void dochar(char const data[YSIZE], unsigned flags);
 static void domosaic(unsigned code, bool sep);
+static void dopanose();
 
 struct glyph {
 	char data[YSIZE];
@@ -1263,6 +1264,7 @@ main(int argc, char **argv)
 	printf("OS2SubYOff: %d\n", 2 * YPIX);
 	printf("OS2SupYOff: %d\n", 2 * YPIX);
 	printf("TTFWidth: %d\n", param->ttfwidth);
+	dopanose();
 	printf("LayerCount: 2\n");
 	printf("Layer: 0 0 \"Back\" 1\n");
 	printf("Layer: 1 0 \"Fore\" 0\n");
@@ -1323,6 +1325,114 @@ main(int argc, char **argv)
 	return 0;
 }
 
+static void
+dopanose()
+{
+	/*
+	 * PANOSE is a complex font categorisation scheme.  I suspect
+	 * no-one uses it, but it's a mandatory part of the 'OS/2'
+	 * table, so it would be nice to get it right.  This procedure
+	 * calculates the PANOSE code for a Bedstead variant based on
+	 * its design parameters.
+	 *
+	 * See <http://panose.com> for the full details.
+	 */
+	int panose[10];
+	/* Common digits */
+	/* WeightRat == 700/XPIX */
+	if (XPIX <= 20) /* WeightRat >= 35 */
+		panose[2] = 2; /* Very Light */
+	else if (XPIX < 39) /* WeightRat > 17.9 */
+		panose[2] = 3; /* Light */
+	else if (XPIX <= 70) /* WeightRat >= 10 */
+		panose[2] = 4; /* Thin */
+	else if (XPIX <= 94) /* WeightRat > 7.44 */
+		panose[2] = 5; /* Book */
+	else if (XPIX < 128) /* WeightRat > 5.5 */
+		panose[2] = 6; /* Medium */
+	else if (XPIX < 156) /* WeightRat > 4.5 */
+		panose[2] = 7; /* Demi */
+	else if (XPIX <= 200) /* WeightRat >= 3.5 */
+		panose[2] = 8; /* Bold */
+	else if (XPIX <= 280) /* WeightRat >= 2.5 */
+		panose[2] = 9; /* Heavy */
+	else if (XPIX <= 350) /* WeightRat >= 2.0 */
+		panose[2] = 10; /* Black */
+	else
+		panose[2] = 11; /* Extra Black */
+	/*
+	 * To make life simpler, ignore diagonals when calculating
+	 * ConRat.
+	 */
+	/* ConRat == min(XPIX / 100, 100 / XPIX) */
+	if (XPIX > 80 && XPIX < 125)
+		panose[4] = 2; /* None */
+	else if (XPIX > 65 && XPIX < 154)
+		panose[4] = 3; /* Very Low */
+	else if (XPIX > 48 && XPIX < 209)
+		panose[4] = 4; /* Low */
+	else if (XPIX > 30 && XPIX < 334)
+		panose[4] = 5; /* Medium Low */
+	else if (XPIX > 20 && XPIX < 500)
+		panose[4] = 6; /* Medium */
+	else if (XPIX > 15 && XPIX < 667)
+		panose[4] = 7; /* Medium High */
+	else if (XPIX > 8 && XPIX < 1250)
+		panose[4] = 8; /* High */
+	else
+		panose[4] = 9; /* Very High */
+	/*
+	 * First digit is overall style.  Bedstead is a text font, but
+	 * PANOSE says that fonts with horizontal stress and extreme
+	 * aspect ratios should be classified as decorative.
+	 */
+	if (XPIX < 100 || /* ConRat > 1.00 */
+	    XPIX > 164) { /* ORat < 0.85 */
+		panose[0] = 4; /* Latin Decorative */
+		panose[1] = 2; /* Derivative */
+		/* ORat == 140/XPIX */
+		if (XPIX <= 53)
+			panose[3] = 2; /* Super Condensed */
+		else if (XPIX <= 66)
+			panose[3] = 3; /* Very Condensed */
+		else if (XPIX <= 110)
+			panose[3] = 4; /* Condensed */
+		else if (XPIX <= 152)
+			panose[3] = 5; /* Normal */
+		else if (XPIX <= 155)
+			panose[3] = 6; /* Extended */
+		else if (XPIX <= 164)
+			panose[3] = 7; /* Very Extended */
+		else
+			panose[3] = 8; /* Super Extended */
+		panose[5] = 11; /* Normal Sans Serif */
+		panose[6] = 2; /* Standard Solid Fill */
+		panose[7] = 2; /* No Lining */
+		panose[8] = 3; /* Square */
+		panose[9] = 2; /* Extended Collection */
+	} else {
+		panose[0] = 2; /* Latin Text */
+		panose[1] = 11; /* Normal Sans Serif */
+		/* J and M are the same width. */
+		panose[3] = 9; /* Monospaced */
+		if (panose[4] == 2)
+			panose[5] = 2; /* No Variation */
+		else if (XPIX > 100)
+			panose[5] = 5; /* Gradual/Vertical */
+		else
+			panose[5] = 6; /* Gradual/Hoizontal */
+		/* Unusually shaped 'A' means no fit here. */
+		panose[6] = 1; /* No Fit */
+		/* OutCurv == 0.791 */
+		panose[7] = 5; /* Normal/Boxed */
+		panose[8] = 3; /* Standard/Pointed */
+		panose[9] = 7; /* Ducking/Large */
+	}
+	printf("Panose: %d %d %d %d %d %d %d %d %d %d\n",
+	       panose[0], panose[1], panose[2], panose[3], panose[4], 
+	       panose[5], panose[6], panose[7], panose[8], panose[9]);
+}
+
 static void
 dopalt(struct glyph const *g)
 {