CCLabel: fix fontName attribute (#19095)

* add  method for FontAtlas

* break empty font

* reduce string constrution

cocos/2d/CCFontAtlas.cpp

@@ -477,11 +477,22 @@ Texture2D* FontAtlas::getTexture(int slot)
     return _atlasTextures[slot];
 }
 
-void  FontAtlas::setLineHeight(float newHeight)
+void FontAtlas::setLineHeight(float newHeight)
 {
     _lineHeight = newHeight;
 }
 
+std::string FontAtlas::getFontName() const
+{
+    std::string fontName = _fontFreeType ? _fontFreeType->getFontName() : "";
+    if(fontName.empty()) return fontName;
+    auto idx = fontName.rfind("/");
+    if (idx != std::string::npos) { return fontName.substr(idx + 1); }
+    idx = fontName.rfind("\\");
+    if (idx != std::string::npos) { return fontName.substr(idx + 1); }
+    return fontName;
+}
+
 void FontAtlas::setAliasTexParameters()
 {
     if (_antialiasEnabled)

cocos/2d/CCFontAtlas.h

@@ -84,6 +84,8 @@ public:
     float getLineHeight() const { return _lineHeight; }
     void  setLineHeight(float newHeight);
     
+    std::string getFontName() const;
+
     Texture2D* getTexture(int slot);
     const Font* getFont() const { return _font; }
 

cocos/2d/CCFontFreeType.h

@@ -73,6 +73,7 @@ public:
     
     int getFontAscender() const;
     const char* getFontFamily() const;
+    std::string getFontName() const { return _fontName; }
 
     virtual FontAtlas* createFontAtlas() override;
     virtual int getFontMaxHeight() const override { return _lineHeight; }

cocos/2d/CCLabel.cpp

@@ -2084,7 +2084,11 @@ void Label::removeChild(Node* child, bool cleanup /* = true */)
 FontDefinition Label::_getFontDefinition() const
 {
     FontDefinition systemFontDef;
-    systemFontDef._fontName = _systemFont;
+
+    std::string fontName = _systemFont;
+    if (_fontAtlas && !_fontAtlas->getFontName().empty()) fontName = _fontAtlas->getFontName();
+
+    systemFontDef._fontName = fontName;
     systemFontDef._fontSize = _systemFontSize;
     systemFontDef._alignment = _hAlignment;
     systemFontDef._vertAlignment = _vAlignment;