From 860d06384dedb228e62ffcb702b7e624b3991439 Mon Sep 17 00:00:00 2001
From: nick black <dankamongmen@gmail.com>
Date: Sun, 23 Jan 2022 18:15:53 -0500
Subject: [PATCH] ncchannels_bchannel: operate only on alpha+coloring bits
 #2571

---
 NEWS.md                       | 6 +++++-
 USAGE.md                      | 9 ++++++---
 include/notcurses/notcurses.h | 9 ++++++---
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 018bd6f94..81730d343 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -2,7 +2,11 @@ This document attempts to list user-visible changes and any major internal
 rearrangements of Notcurses.
 
 * 3.0.6 (not yet released)
-  * Remove the unsafe `ncplane_set_bchannel()` and `ncplane_set_fchannel()`.
+  * `ncplane_set_[fb]channel()`, `ncplane_[fb]channel()`,
+    `ncplane_channels()`, `ncplane_set_channels()`,
+    `ncchannels_set_[fb]channel()`, and `ncchannels_[fb]channel()` now
+    function only on the 28 alpha + coloring bits of their respective
+    channels, which is almost certainly what you wanted in the first place.
 
 * 3.0.5 (2022-01-21)
   * The Hyper and Super modifiers are now supported. CapsLock and NumLock
diff --git a/USAGE.md b/USAGE.md
index f254146fc..1d5767b86 100644
--- a/USAGE.md
+++ b/USAGE.md
@@ -3124,13 +3124,16 @@ ncchannel_set_default(uint32_t* channel){
   return *channel &= ~NC_BGDEFAULT_MASK;
 }
 
-// Extract the 32-bit background channel from a channel pair.
+// Extract the background alpha and coloring bits from a 64-bit channel
+// pair as a single 32-bit value.
 static inline unsigned
 ncchannels_bchannel(uint64_t channels){
-  return channels & 0xfffffffflu;
+  return channels & (NC_BG_RGB_MASK | NC_BG_PALETTE |
+                     NC_BGDEFAULT_MASK | NC_BG_ALPHA_MASK);
 }
 
-// Extract the 32-bit foreground channel from a channel pair.
+// Extract the foreground alpha and coloring bits from a 64-bit channel
+// pair as a single 32-bit value.
 static inline uint32_t
 ncchannels_fchannel(uint64_t channels){
   return ncchannels_bchannel(channels >> 32u);
diff --git a/include/notcurses/notcurses.h b/include/notcurses/notcurses.h
index 1cb18d7ce..d7e82eeed 100644
--- a/include/notcurses/notcurses.h
+++ b/include/notcurses/notcurses.h
@@ -296,13 +296,16 @@ ncchannel_set_rgb8_clipped(uint32_t* channel, int r, int g, int b){
   *channel = (*channel & ~(NC_BG_RGB_MASK | NC_BG_PALETTE)) | NC_BGDEFAULT_MASK | c;
 }
 
-// Extract the 32-bit background channel from a channel pair.
+// Extract the background alpha and coloring bits from a 64-bit channel
+// pair as a single 32-bit value.
 static inline uint32_t
 ncchannels_bchannel(uint64_t channels){
-  return channels & 0xfffffffflu;
+  return channels & (NC_BG_RGB_MASK | NC_BG_PALETTE |
+                     NC_BGDEFAULT_MASK | NC_BG_ALPHA_MASK);
 }
 
-// Extract the 32-bit foreground channel from a channel pair.
+// Extract the foreground alpha and coloring bits from a 64-bit channel
+// pair as a single 32-bit value.
 static inline uint32_t
 ncchannels_fchannel(uint64_t channels){
   return ncchannels_bchannel(channels >> 32u);