support for color formatting

include/spdlog/details/log_msg.h

@@ -40,6 +40,9 @@ struct log_msg
     fmt::MemoryWriter raw;
     fmt::MemoryWriter formatted;
     size_t msg_id{0};
+    // wrap this range with color codes
+    size_t color_range_start{0};
+    size_t color_range_end{0};
 };
 } // namespace details
 } // namespace spdlog

include/spdlog/details/os.h

@@ -238,7 +238,7 @@ inline size_t filesize(FILE *f)
     int fd = fileno(f);
     // 64 bits(but not in osx or cygwin, where fstat64 is deprecated)
 #if !defined(__FreeBSD__) && !defined(__APPLE__) && (defined(__x86_64__) || defined(__ppc64__)) && !defined(__CYGWIN__)
-    struct stat64 st;   
+    struct stat64 st;
     if (fstat64(fd, &st) == 0)
     {
         return static_cast<size_t>(st.st_size);

include/spdlog/details/pattern_formatter_impl.h

@@ -421,7 +421,24 @@ private:
     std::string _str;
 };
 
+// set the color range. expect it to be in the form of "%^colored text%$"
+class start_color_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.color_range_start = msg.formatted.size();
+    }
+};
+class stop_color_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.color_range_end = msg.formatted.size();
+    }
+};
+
 // Full info formatter
+
 // pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] %v
 class full_formatter SPDLOG_FINAL : public flag_formatter
 {
@@ -462,8 +479,13 @@ class full_formatter SPDLOG_FINAL : public flag_formatter
         msg.formatted << '[' << *msg.logger_name << "] ";
 #endif
 
-        msg.formatted << '[' << level::to_str(msg.level) << "] ";
+        const char *level_name = level::to_str(msg.level);
+        size_t level_name_size = strlen(level_name);
+        msg.formatted << '[' << fmt::StringRef(level_name, level_name_size) << "] ";
         msg.formatted << fmt::StringRef(msg.raw.data(), msg.raw.size());
+        // wrap the level with color
+        msg.color_range_start = 37;
+        msg.color_range_end = 37 + level_name_size;
     }
 };
 
@@ -491,6 +513,7 @@ inline void spdlog::pattern_formatter::compile_pattern(const std::string &patter
             {
                 _formatters.push_back(std::move(user_chars));
             }
+            // if(
             if (++it != end)
             {
                 handle_flag(*it);
@@ -644,6 +667,12 @@ inline void spdlog::pattern_formatter::handle_flag(char flag)
     case ('i'):
         _formatters.emplace_back(new details::i_formatter());
         break;
+    case ('^'):
+        _formatters.emplace_back(new details::start_color_formatter());
+        break;
+    case ('$'):
+        _formatters.emplace_back(new details::stop_color_formatter());
+        break;
 
     default: // Unknown flag appears as is
         _formatters.emplace_back(new details::ch_formatter('%'));

include/spdlog/sinks/ansicolor_sink.h

@@ -28,9 +28,9 @@ public:
         : target_file_(file)
     {
         should_do_colors_ = details::os::in_terminal(file) && details::os::is_color_terminal();
-        colors_[level::trace] = cyan;
+        colors_[level::trace] = magenta;
         colors_[level::debug] = cyan;
-        colors_[level::info] = reset;
+        colors_[level::info] = green;
         colors_[level::warn] = yellow + bold;
         colors_[level::err] = red + bold;
         colors_[level::critical] = bold + on_red;
@@ -83,17 +83,20 @@ protected:
     {
         // Wrap the originally formatted message in color codes.
         // If color is not supported in the terminal, log as is instead.
-        if (should_do_colors_)
+        if (should_do_colors_ && msg.color_range_end > msg.color_range_start)
         {
-            const std::string &prefix = colors_[msg.level];
-            fwrite(prefix.data(), sizeof(char), prefix.size(), target_file_);
-            fwrite(msg.formatted.data(), sizeof(char), msg.formatted.size(), target_file_);
-            fwrite(reset.data(), sizeof(char), reset.size(), target_file_);
-            fwrite(clear_line.data(), sizeof(char), clear_line.size(), target_file_);
+            // before color range
+            _print_range(msg, 0, msg.color_range_start);
+            // in color range
+            _print_ccode(colors_[msg.level]);
+            _print_range(msg, msg.color_range_start, msg.color_range_end);
+            _print_ccode(reset);
+            // after color range
+            _print_range(msg, msg.color_range_end, msg.formatted.size());
         }
         else
         {
-            fwrite(msg.formatted.data(), sizeof(char), msg.formatted.size(), target_file_);
+            _print_range(msg, 0, msg.formatted.size());
         }
         _flush();
     }
@@ -103,6 +106,15 @@ protected:
         fflush(target_file_);
     }
 
+private:
+    void _print_ccode(const std::string &color_code)
+    {
+        fwrite(color_code.data(), sizeof(char), color_code.size(), target_file_);
+    }
+    void _print_range(const details::log_msg &msg, size_t start, size_t end)
+    {
+        fwrite(msg.formatted.data() + start, sizeof(char), end - start, target_file_);
+    }
     FILE *target_file_;
     bool should_do_colors_;
     std::unordered_map<level::level_enum, std::string, level::level_hasher> colors_;