Rework after review

doc/tigrc.5.adoc

@@ -280,7 +280,7 @@ The following variables can be set:
 	to false. When set to true then 'diff-highlight' is used, else the option
 	value is used as the path. When this option is in effect, highlighted
 	regions are governed by `color diff-add-highlight` and
-	`color diff-del-highlight`. git-delta is also supported.
+	`color diff-del-highlight`.
 
 'ignore-space' (mixed) [no|all|some|at-eol|<bool>]::
 

include/tig/line.h

@@ -17,7 +17,9 @@
 #include "tig/tig.h"
 struct ref;
 
+#if defined(NCURSES_VERSION_PATCH) && NCURSES_VERSION_PATCH >= 20180127
 extern short color_pairs_map[257][257];
+#endif
 
 /*
  * Line-oriented content detection.

src/ansi.c

@@ -63,9 +63,8 @@ draw_ansi(struct view *view, int *ansi_num, char **ansi_ptrs, int max_width, siz
 			waddnstr(view->win, text, len);
 			continue;
 		}
-		// delta won't add moving ansi codes which are
-		// A, B, C, D, E, F, G, H, f, S, T.
-		// J, K exists for filling lines with a color, but ncurses can't do.
+
+		// ncurses can't handle J and K of ANSI code behavior.
 		if ((text[3] == 'J') || (text[3] == 'K'))
 			continue;
 
@@ -219,15 +218,14 @@ convert_ansi_into_256_color(char **save_ptr) {
 	}
 
 	// WONTFIX: You can't init_color with numerous RGB code in ncurses.
-	// I decided to force delta users to use "true-color = never" when using tig,
-	// so the process never comes to this condition.
-	// I leave the code for someone who wants to implements in the future.
+	// Therefore, \e[(3 or 4)8;2;r;g;bm syntax is disabled currently.
+	// The below code is left for when it is someday implemented.
 	// if (strcmp(color_method_mark, "2") == 0) {
 		// char *r = strtok(NULL, ";");
 		// char *g = strtok(NULL, ";");
 		// char *b = strtok(NULL, ";");
 	// }
-	// Do some process to convert those color infos for ncurses.
+	// Return a color pair ID that matches this rgb combination.
 
 	return c256;
 }

src/draw.c

@@ -13,11 +13,14 @@
 
 #include "tig/tig.h"
 #include "tig/graph.h"
-#include "tig/ansi.h"
 #include "tig/draw.h"
 #include "tig/options.h"
 #include "compat/hashtab.h"
 
+#if defined(NCURSES_VERSION_PATCH) && NCURSES_VERSION_PATCH >= 20180127
+#include "tig/ansi.h"
+#endif
+
 static const enum line_type palette_colors[] = {
 	LINE_PALETTE_0,
 	LINE_PALETTE_1,
@@ -172,13 +175,18 @@ draw_text_expanded(struct view *view, enum line_type type, const char *string, i
 		size_t pos = string_expand(text, sizeof(text), string, length, opt_tab_size);
 		size_t col = view->col;
 
-		if (opt_diff_highlight && *opt_diff_highlight && strcmp(opt_diff_highlight, "delta") == 0 && strstr(string, "\033[") != NULL) {
+#if defined(NCURSES_VERSION_PATCH) && NCURSES_VERSION_PATCH >= 20180127
+		if (strstr(string, "\033[") != NULL) {
 			if (draw_chars_with_ansi(view, type, text, -1, max_width, use_tilde))
 				return true;
 		} else {
 			if (draw_chars(view, type, text, -1, max_width, use_tilde))
 				return true;
 		}
+#else
+		if (draw_chars(view, type, text, -1, max_width, use_tilde))
+			return true;
+#endif
 
 		string += pos;
 		length -= pos;

src/line.c

@@ -23,7 +23,9 @@ static size_t line_rules;
 static struct line_info **color_pair;
 static size_t color_pairs;
 
+#if defined(NCURSES_VERSION_PATCH) && NCURSES_VERSION_PATCH >= 20180127
 short color_pairs_map[257][257];
+#endif
 
 DEFINE_ALLOCATOR(realloc_line_rule, struct line_rule, 8)
 DEFINE_ALLOCATOR(realloc_color_pair, struct line_info *, 8)
@@ -243,6 +245,7 @@ init_colors(void)
 		}
 	}
 
+#if defined(NCURSES_VERSION_PATCH) && NCURSES_VERSION_PATCH >= 20180127
 	// Because init_extended_pair can't accept more than 32768 pairs,
 	// we skip the colors with color codes odd numbered and greater than 15 currently.
 	short cnt = COLOR_ID(LINE_NONE) + 1;
@@ -264,6 +267,7 @@ init_colors(void)
 	}
 	init_extended_pair(++cnt, COLOR_DEFAULT, COLOR_DEFAULT);
 	color_pairs_map[256][256] = cnt;
+#endif
 }
 
 /* vim: set ts=8 sw=8 noexpandtab: */