From 06942089b70ac3748a40b2eca4f8df77e44cb17f Mon Sep 17 00:00:00 2001
From: "Gregory J. Ward" <gregoryjward@gmail.com>
Date: Fri, 7 Jan 2022 23:01:01 +0000
Subject: [PATCH] perf: minor performance improvement in grayscale mode to
 24-bit output

---
 src/common/tmap16bit.c | 6 ++++--
 src/common/tmapcolrs.c | 6 ++++--
 src/common/tonemap.c   | 6 ++++--
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/common/tmap16bit.c b/src/common/tmap16bit.c
index 697c75c83..ea155ab95 100644
--- a/src/common/tmap16bit.c
+++ b/src/common/tmap16bit.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: tmap16bit.c,v 1.10 2011/05/20 02:06:38 greg Exp $";
+static const char RCSid[] = "$Id: tmap16bit.c,v 1.11 2022/01/07 23:01:01 greg Exp $";
 #endif
 /*
  * Routines for tone-mapping 16-bit/primary pixels
@@ -257,7 +257,9 @@ tmCvRGB48(TMstruct *tms, TMbright *ls, uby8 *cs,
 				cmon[BLU] = slum + pf*cmon[BLU];
 			}
 		} else if (tms->flags & TM_F_BW) {
-			cmon[RED] = cmon[GRN] = cmon[BLU] = lum;
+			int	j = 3;
+			while (j--) cs[3*i+j] = tms->cdiv[j]/(TM_BRES>>8);
+			continue;
 		}
 		bi = (double)MONGAMTSZ*tms->clf[RED]*cmon[RED]/lum;
 		cs[3*i  ] = bi>=MONGAMTSZ ? 255 : mongamtab[bi];
diff --git a/src/common/tmapcolrs.c b/src/common/tmapcolrs.c
index 6e4219223..36a7d6b91 100644
--- a/src/common/tmapcolrs.c
+++ b/src/common/tmapcolrs.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: tmapcolrs.c,v 3.35 2020/10/13 00:08:46 greg Exp $";
+static const char	RCSid[] = "$Id: tmapcolrs.c,v 3.36 2022/01/07 23:01:01 greg Exp $";
 #endif
 /*
  * Routines for tone mapping on Radiance RGBE and XYZE pictures.
@@ -122,7 +122,9 @@ int	len
 				}
 			}
 		} else if (tms->flags & TM_F_BW) {
-			cmon[RED] = cmon[GRN] = cmon[BLU] = li;
+			for (j = 3; j--; )
+				cs[3*i+j] = tms->cdiv[j]/(TM_BRES>>8);
+			continue;
 		} else {
 			for (j = 3; j--; )
 				cmon[j] *= (cmon[j] > 0);
diff --git a/src/common/tonemap.c b/src/common/tonemap.c
index b3a84eb7d..e74afeda5 100644
--- a/src/common/tonemap.c
+++ b/src/common/tonemap.c
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: tonemap.c,v 3.52 2021/05/26 17:50:26 greg Exp $";
+static const char	RCSid[] = "$Id: tonemap.c,v 3.53 2022/01/07 23:01:01 greg Exp $";
 #endif
 /*
  * Tone mapping functions.
@@ -321,7 +321,9 @@ int	len
 				cmon[BLU] += d;
 			}
 		} else if (tms->flags & TM_F_BW) {
-			cmon[RED] = cmon[GRN] = cmon[BLU] = lum;
+			int	j = 3;
+			while (j--) cs[3*i+j] = tms->cdiv[j]/(TM_BRES>>8);
+			continue;
 		}
 		d = tms->clf[RED]*cmon[RED]/lum;
 		cs[3*i  ] = d>=.999f ? 255 : gamtab[(int)(1024.f*d)];