From 9c3adaaea3fff495e34424436c3089837d633ebc Mon Sep 17 00:00:00 2001
From: nick black <dankamongmen@gmail.com>
Date: Fri, 17 Dec 2021 03:17:56 -0500
Subject: [PATCH] add ncchannel_rgb(), use it in channels_blend()

---
 USAGE.md                             | 22 ++++++++++++++++++++--
 doc/man/man3/notcurses_channels.3.md |  2 ++
 include/notcurses/notcurses.h        | 13 ++++++++++---
 src/lib/internal.h                   |  8 +++-----
 4 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/USAGE.md b/USAGE.md
index 7df8855e6..25d7ed161 100644
--- a/USAGE.md
+++ b/USAGE.md
@@ -3174,14 +3174,32 @@ ncchannels_bg_alpha(uint64_t channels){
   return ncchannel_alpha(channels_bchannel(channels));
 }
 
+// Extract the 24-bit RGB value from a 32-bit channel.
+// Only valid if ncchannel_rgb_p() would return true for the channel.
+static inline uint32_t
+ncchannel_rgb(uint32_t channel){
+  return channel & NC_BG_RGB_MASK;
+}
+
+// Extract the three 8-bit R/G/B components from a 32-bit channel.
+// Only valid if ncchannel_rgb_p() would return true for the channel.
+static inline uint32_t
+ncchannel_rgb8(uint32_t channel, unsigned* restrict r, unsigned* restrict g,
+               unsigned* restrict b){
+  *r = ncchannel_r(channel);
+  *g = ncchannel_g(channel);
+  *b = ncchannel_b(channel);
+  return channel;
+}
+
 // Extract 24 bits of foreground RGB from 'channels', split into subchannels.
-static inline unsigned
+static inline uint32_t
 ncchannels_fg_rgb8(uint64_t channels, unsigned* r, unsigned* g, unsigned* b){
   return ncchannel_rgb8(channels_fchannel(channels), r, g, b);
 }
 
 // Extract 24 bits of background RGB from 'channels', split into subchannels.
-static inline unsigned
+static inline uint32_t
 ncchannels_bg_rgb8(uint64_t channels, unsigned* r, unsigned* g, unsigned* b){
   return ncchannel_rgb8(channels_bchannel(channels), r, g, b);
 }
diff --git a/doc/man/man3/notcurses_channels.3.md b/doc/man/man3/notcurses_channels.3.md
index 99dc30879..5851fd2a5 100644
--- a/doc/man/man3/notcurses_channels.3.md
+++ b/doc/man/man3/notcurses_channels.3.md
@@ -25,6 +25,8 @@ notcurses_channels - operations on notcurses channels
 
 **uint32_t ncchannel_b(uint32_t ***channel***);**
 
+**uint32_t ncchannel_rgb(uint32_t ***channel***);**
+
 **uint32_t ncchannel_rgb8(uint32_t ***channel***, uint32_t* restrict ***r***, uint32_t* restrict ***g***, uint32_t* restrict ***b***);**
 
 **int ncchannel_set_rgb8(uint32_t* ***channel***, unsigned ***r***, unsigned ***g***, unsigned ***b***);**
diff --git a/include/notcurses/notcurses.h b/include/notcurses/notcurses.h
index 16d60b6a1..8ea60fa33 100644
--- a/include/notcurses/notcurses.h
+++ b/include/notcurses/notcurses.h
@@ -222,9 +222,16 @@ ncchannel_b(uint32_t channel){
   return (channel & 0x0000ffu);
 }
 
+// Extract the 24-bit RGB value from a 32-bit channel.
+// Only valid if ncchannel_rgb_p() would return true for the channel.
+static inline uint32_t
+ncchannel_rgb(uint32_t channel){
+  return channel & NC_BG_RGB_MASK;
+}
+
 // Extract the three 8-bit R/G/B components from a 32-bit channel.
 // Only valid if ncchannel_rgb_p() would return true for the channel.
-static inline unsigned
+static inline uint32_t
 ncchannel_rgb8(uint32_t channel, unsigned* RESTRICT r, unsigned* RESTRICT g,
                unsigned* RESTRICT b){
   *r = ncchannel_r(channel);
@@ -404,13 +411,13 @@ ncchannels_bg_palindex(uint64_t channels){
 // Extract 24 bits of foreground RGB from 'channels', shifted to LSBs.
 static inline uint32_t
 ncchannels_fg_rgb(uint64_t channels){
-  return ncchannels_fchannel(channels) & NC_BG_RGB_MASK;
+  return ncchannel_rgb(ncchannels_fchannel(channels));
 }
 
 // Extract 24 bits of background RGB from 'channels', shifted to LSBs.
 static inline uint32_t
 ncchannels_bg_rgb(uint64_t channels){
-  return ncchannels_bchannel(channels) & NC_BG_RGB_MASK;
+  return ncchannel_rgb(ncchannels_bchannel(channels));
 }
 
 // Extract 24 bits of foreground RGB from 'channels', split into subchannels.
diff --git a/src/lib/internal.h b/src/lib/internal.h
index 9cba3ecf3..f6de1776c 100644
--- a/src/lib/internal.h
+++ b/src/lib/internal.h
@@ -1353,16 +1353,14 @@ channels_blend(notcurses* nc, unsigned c1, unsigned c2, unsigned* blends){
     }else if(c2palette){
       ncchannel_set_palindex(&c1, ncchannel_palindex(c2));
     }else{
-      ncchannel_set(&c1, c2 & NC_BG_RGB_MASK);
+      ncchannel_set(&c1, ncchannel_rgb(c2));
     }
     ncchannel_set_alpha(&c1, ncchannel_alpha(c2));
   }else if(!c2default && !ncchannel_default_p(c1)){
     unsigned rsum, gsum, bsum;
     if(c2palette){
-      uint32_t rgb = nc->palette.chans[ncchannel_palindex(c2)];
-      bsum = rgb & 0xff;
-      gsum = (rgb >> 8u) & 0xff;
-      rsum = (rgb >> 16u) & 0xff;
+      ncchannel_rgb8(nc->palette.chans[ncchannel_palindex(c2)],
+                     &rsum, &gsum, &bsum);
     }else{
       ncchannel_rgb8(c2, &rsum, &gsum, &bsum);
     }