palette: add necessary predicates #230

include/notcurses.h

@@ -932,12 +932,18 @@ channel_set_alpha(unsigned* channel, int alpha){
   return 0;
 }
 
-// Is this channel using the "default color" rather than its RGB?
+// Is this channel using the "default color" rather than RGB/palette-indexed?
 static inline bool
 channel_default_p(unsigned channel){
   return !(channel & CELL_BGDEFAULT_MASK);
 }
 
+// Is this channel using palette-indexed color rather than RGB?
+static inline bool
+channel_palindex_p(unsigned channel){
+  return !channel_default_p(channel) && (channel & CELL_BG_PALETTE);
+}
+
 // Mark the channel as using its default color, which also marks it opaque.
 static inline unsigned
 channel_set_default(unsigned* channel){
@@ -1096,6 +1102,12 @@ channels_fg_default_p(uint64_t channels){
   return channel_default_p(channels_fchannel(channels));
 }
 
+// Is the foreground using indexed palette color?
+static inline bool
+channels_fg_palindex_p(uint64_t channels){
+  return channel_palindex_p(channels_fchannel(channels));
+}
+
 // Is the background using the "default background color"? The "default
 // background color" must generally be used to take advantage of
 // terminal-effected transparency.
@@ -1104,6 +1116,12 @@ channels_bg_default_p(uint64_t channels){
   return channel_default_p(channels_bchannel(channels));
 }
 
+// Is the background using indexed palette color?
+static inline bool
+channels_bg_palindex_p(uint64_t channels){
+  return channel_palindex_p(channels_bchannel(channels));
+}
+
 // Mark the foreground channel as using its default color.
 static inline uint64_t
 channels_set_fg_default(uint64_t* channels){
@@ -1301,6 +1319,11 @@ cell_fg_default_p(const cell* cl){
   return channels_fg_default_p(cl->channels);
 }
 
+static inline bool
+cell_fg_palindex_p(const cell* cl){
+  return channels_fg_palindex_p(cl->channels);
+}
+
 // Is the background using the "default background color"? The "default
 // background color" must generally be used to take advantage of
 // terminal-effected transparency.
@@ -1309,6 +1332,11 @@ cell_bg_default_p(const cell* cl){
   return channels_bg_default_p(cl->channels);
 }
 
+static inline bool
+cell_bg_palindex_p(const cell* cl){
+  return channels_bg_palindex_p(cl->channels);
+}
+
 // Get the current channels or attribute word for ncplane 'n'.
 API uint64_t ncplane_channels(const struct ncplane* n);
 API uint32_t ncplane_attr(const struct ncplane* n);

src/lib/render.c

@@ -271,6 +271,7 @@ paint(notcurses* nc, ncplane* p, struct crender* rvec, cell* fb){
           cell_set_wide(targc);
         }
       }
+      // FIXME blend in palette-indexed colors?
       if(cell_fg_alpha(targc) > CELL_ALPHA_OPAQUE && cell_fg_alpha(vis) < CELL_ALPHA_TRANSPARENT){
         cell_blend_fchannel(targc, cell_fchannel(vis), crender->fgblends);
         ++crender->fgblends;