Additional work towards "forcing" term256 mode on supported terms

common.h

@@ -328,12 +328,12 @@ inline wcstring to_string(const long &x) {
 
 template<>
 inline bool from_string(const std::string &x) {
-    return ! x.empty() && strchr("YTyt", x.at(0));
+    return ! x.empty() && strchr("YTyt1", x.at(0));
 }
 
 template<>
 inline bool from_string(const wcstring &x) {
-    return ! x.empty() && wcschr(L"YTyt", x.at(0));
+    return ! x.empty() && wcschr(L"YTyt1", x.at(0));
 }
 
 template<>

output.cpp

@@ -130,6 +130,11 @@ int (*output_get_writer())(char)
 	return out;
 }
 
+static bool term256_support_is_native(void) {
+    /* Return YES if we think the term256 support is "native" as opposed to forced. */
+    return max_colors == 256;
+}
+
 bool output_get_supports_term256() {
     return support_term256;
 }
@@ -146,6 +151,48 @@ static unsigned char index_for_color(rgb_color_t c) {
     }
 }
 
+
+static bool write_color(char *todo, unsigned char idx, bool is_fg) {
+    bool result = false;
+    if (idx < 16 || term256_support_is_native()) {
+        /* Use tparm */
+        writembs( tparm( todo, idx ) );
+        result = true;
+    } else {
+        /* We are attempting to bypass the term here. Generate the ANSI escape sequence ourself. */
+        char stridx[128];
+        format_long_safe(stridx, (long)idx);
+        char buff[128] = "\x1b[";
+        strcat(buff, is_fg ? "38;5;" : "48;5;");
+        strcat(buff, stridx);
+        strcat(buff, "m");
+        write_loop(STDOUT_FILENO, buff, strlen(buff));
+        result = true;
+    }
+    return result;
+}
+
+static bool write_foreground_color(unsigned char idx) {
+    if (set_a_foreground && set_a_foreground[0]) {
+        return write_color(set_a_foreground, idx, true);
+    } else if (set_foreground && set_foreground[0]) {
+        return write_color(set_foreground, idx, true);
+    } else {
+        return false;
+    }
+}
+
+static bool write_background_color(unsigned char idx) {
+    if (set_a_background && set_a_background[0]) {
+        return write_color(set_a_background, idx, false);
+    } else if (set_background && set_background[0]) {
+        return write_color(set_background, idx, false);
+    } else {
+        return false;
+    }
+}
+
+
 void set_color(rgb_color_t c, rgb_color_t c2)
 {
     
@@ -162,7 +209,6 @@ void set_color(rgb_color_t c, rgb_color_t c2)
 	static int was_bold=0;
 	static int was_underline=0;
 	int bg_set=0, last_bg_set=0;
-	char *fg = 0, *bg=0;
     
 	int is_bold = 0;
 	int is_underline = 0;
@@ -183,31 +229,17 @@ void set_color(rgb_color_t c, rgb_color_t c2)
 	is_underline |= c.is_underline();
 	is_underline |= c2.is_underline();
     
-	if( (set_a_foreground != 0) && (strlen( set_a_foreground) != 0 ) )
-	{
-		fg = set_a_foreground;
-		bg = set_a_background;
-	}
-	else if( (set_foreground != 0) && (strlen( set_foreground) != 0 ) )
-	{
-		fg = set_foreground;
-		bg = set_background;
-	}
-
 	if( c.is_reset() || c2.is_reset())
 	{
 		c = c2 = normal;
 		was_bold=0;
 		was_underline=0;
-		if( fg )
-		{
         /*
          If we exit attibute mode, we must first set a color, or
          previously coloured text might lose it's
          color. Terminals are weird...
          */
-			writembs( tparm( fg, 0 ) );
+        write_foreground_color(0);
-		}
 		writembs( exit_attribute_mode );
 		return;
 	}
@@ -268,9 +300,8 @@ void set_color(rgb_color_t c, rgb_color_t c2)
              We don't know if exit_attribute_mode resets colors, so
              we set it to something known.
              */
-			if( fg )
+			if( write_foreground_color(0))
 			{
-				writembs( tparm( fg, 0 ) );
 				last_color=rgb_color_t::black();
 			}
 		}
@@ -280,10 +311,7 @@ void set_color(rgb_color_t c, rgb_color_t c2)
 	{
 		if( c.is_normal() )
 		{
-			if( fg )
+			write_foreground_color(0);
-			{
-				writembs( tparm( fg, 0 ) );
-			}
 			writembs( exit_attribute_mode );
             
 			last_color2 = rgb_color_t::normal();
@@ -292,10 +320,7 @@ void set_color(rgb_color_t c, rgb_color_t c2)
 		}
 		else if( ! c.is_special() )
 		{
-			if( fg )
+            write_foreground_color(index_for_color(c));
-			{
-                writembs( tparm(fg, index_for_color(c)) );
-			}
 		}
 	}
     
@@ -305,15 +330,12 @@ void set_color(rgb_color_t c, rgb_color_t c2)
 	{
 		if( c2.is_normal() )
 		{
-			if( bg )
+            write_background_color(0);
-			{
-				writembs( tparm( bg, 0 ) );
-			}
             
 			writembs( exit_attribute_mode );
-			if( ! last_color.is_normal() && fg )
+			if( ! last_color.is_normal())
 			{
-                writembs( tparm( fg, index_for_color(last_color) ));
+                write_foreground_color(index_for_color(last_color));
 			}
 			
             
@@ -323,10 +345,7 @@ void set_color(rgb_color_t c, rgb_color_t c2)
 		}
 		else if ( ! c2.is_special() )
 		{
-			if( bg )
+            write_background_color(index_for_color(c2));
-			{
-				writembs( tparm( bg, index_for_color(c2) ));
-			}
 			last_color2 = c2;
 		}
 	}