detect true color

3 files changed, 40 insertions, 6 deletions

diff --git a/docs/manual.md b/docs/manual.md
index b794a88b5..5eb1a20df 100644
--- a/docs/manual.md
+++ b/docs/manual.md
@@ -3990,6 +3990,15 @@ if colors.truecolor() then
 end
 ```
 
+xmake对于truecolor的检测支持，是通过`$COLORTERM`环境变量来实现的，如果你的终端支持truecolor，可以手动设置此环境变量，来告诉xmake启用truecolor支持。
+
+可以通过下面的命令来启用和测试：
+
+```bash
+$ export COLORTERM=truecolor
+$ xmake --version
+```
+
 ##### cprintf
 
 ###### 无换行彩色打印终端日志
diff --git a/docs/zh/manual.md b/docs/zh/manual.md
index f20a94079..0008c546e 100644
--- a/docs/zh/manual.md
+++ b/docs/zh/manual.md
@@ -4007,6 +4007,15 @@ if colors.truecolor() then
 end
 ```
 
+xmake对于truecolor的检测支持，是通过`$COLORTERM`环境变量来实现的，如果你的终端支持truecolor，可以手动设置此环境变量，来告诉xmake启用truecolor支持。
+
+可以通过下面的命令来启用和测试：
+
+```bash
+$ export COLORTERM=truecolor
+$ xmake --version
+```
+
 ##### cprintf
 
 ###### 无换行彩色打印终端日志
diff --git a/xmake/core/base/colors.lua b/xmake/core/base/colors.lua
index d0fedcd81..9fe7790ae 100644
--- a/xmake/core/base/colors.lua
+++ b/xmake/core/base/colors.lua
@@ -116,16 +116,32 @@ function colors.has256()
     end
 
     -- this is supported if exists ANSICON envirnoment variable on windows
-    return os.getenv("ANSICON") 
+    colors._ANSICON = colors._ANSICON or os.getenv("ANSICON")
+    return colors._ANSICON
 end
 
--- support 24bits true colors
+-- support 24bits true color
+--
+-- There's no reliable way, and ncurses/terminfo's maintainer expressed he has no intent on introducing support. 
+-- S-Lang author added a check for $COLORTERM containing either "truecolor" or "24bit" (case sensitive).
+-- In turn, VTE, Konsole and iTerm2 set this variable to "truecolor" (it's been there in VTE for a while, 
+-- it's relatively new and maybe still git-only in Konsole and iTerm2).
+--
+-- This is obviously not a reliable method, and is not forwarded via sudo, ssh etc. However, whenever it errs, 
+-- it errs on the safe side: does not advertise support whereas it's actually supported. 
+-- App developers can freely choose to check for this same variable, or introduce their own method
+-- (e.g. an option in their config file), whichever matches better the overall design of the given app. 
+-- Checking $COLORTERM is recommended though, since that would lead to a more unique desktop experience 
+-- where the user has to set one variable only and it takes effect across all the apps, rather than something 
+-- separately for each app.
+--
 function colors.truecolor()
 
-    -- this is supported if be not windows
-    if os.host() ~= "windows" then
---        return true
-    end
+    -- get $COLORTERM
+    colors._COLORTERM = colors._COLORTERM or os.getenv("COLORTERM") or ""
+
+    -- support true color?
+    return colors._COLORTERM:find("truecolor", 1, true) or colors._COLORTERM:find("24bit", 1, true)
 end
 
 -- make rainbow color code by the index of characters