Added GetGlyphRangesVietnamese() helper. (#2403)

docs/CHANGELOG.txt

@@ -85,6 +85,7 @@ Other Changes:
 - Log/Capture: Fixed LogXXX functions 'auto_open_depth' parameter being treated as an absolute
   tree depth instead of a relative one.
 - Log/Capture: Fixed CollapsingHeader trailing ascii representation being "#" instead of "##".
+- ImFont: Added GetGlyphRangesVietnamese() helper. (#2403)
 - Misc: Asserting in NewFrame() if style.WindowMinSize is zero or smaller than (1.0f,1.0f).
 - Demo: Using GetBackgroundDrawList() and GetForegroundDrawList() in "Custom Rendering" demo.
 - Examples: OpenGL: Fix to be able to run on ES 2.0 / WebGL 1.0. [@rmitton, @gabrielcuvillier]

imgui.h

@@ -2047,6 +2047,7 @@ struct ImFontAtlas
     IMGUI_API const ImWchar*    GetGlyphRangesChineseSimplifiedCommon();// Default + Half-Width + Japanese Hiragana/Katakana + set of 2500 CJK Unified Ideographs for common simplified Chinese
     IMGUI_API const ImWchar*    GetGlyphRangesCyrillic();               // Default + about 400 Cyrillic characters
     IMGUI_API const ImWchar*    GetGlyphRangesThai();                   // Default + Thai characters
+    IMGUI_API const ImWchar*    GetGlyphRangesVietnamese();             // Default + Vietname characters
 
     //-------------------------------------------
     // Custom Rectangles/Glyphs API

imgui_draw.cpp

@@ -2346,6 +2346,23 @@ const ImWchar*  ImFontAtlas::GetGlyphRangesThai()
     return &ranges[0];
 }
 
+const ImWchar*  ImFontAtlas::GetGlyphRangesVietnamese()
+{
+    static const ImWchar ranges[] =
+    {
+        0x0020, 0x00FF, // Basic Latin
+        0x0102, 0x0103,
+        0x0110, 0x0111,
+        0x0128, 0x0129,
+        0x0168, 0x0169,
+        0x01A0, 0x01A1,
+        0x01AF, 0x01B0,
+        0x1EA0, 0x1EF9,
+        0,
+    };
+    return &ranges[0];
+}
+
 //-----------------------------------------------------------------------------
 // [SECTION] ImFontGlyphRangesBuilder
 //-----------------------------------------------------------------------------