Merge pull request #11683 from WenhaiLin/v3-label-i10576

Label:Fixed the character positions could be wrong if `getLetter(letterIndex)` get called.

cocos/2d/CCLabel.cpp

@@ -628,13 +628,15 @@ void Label::alignText()
                 letterSprite = dynamic_cast<Sprite*>(child);
                 if (letterSprite)
                 {
-                    uvRect.size.height = _lettersInfo[tag].def.height;
-                    uvRect.size.width = _lettersInfo[tag].def.width;
-                    uvRect.origin.x = _lettersInfo[tag].def.U;
-                    uvRect.origin.y = _lettersInfo[tag].def.V;
+                    auto& letterDef = _lettersInfo[tag].def;
+                    uvRect.size.height = letterDef.height;
+                    uvRect.size.width = letterDef.width;
+                    uvRect.origin.x = letterDef.U;
+                    uvRect.origin.y = letterDef.V;
 
-                    letterSprite->setTexture(textures.at(_lettersInfo[tag].def.textureID));
+                    letterSprite->setTexture(textures.at(letterDef.textureID));
                     letterSprite->setTextureRect(uvRect);
+                    letterSprite->setPosition(_lettersInfo[tag].position);
                 }
                 ++index;
             }

tests/cpp-tests/Classes/LabelTest/LabelTestNew.cpp

@@ -76,6 +76,7 @@ NewLabelTests::NewLabelTests()
     ADD_TEST_CASE(LabelIssue10089Test);
     ADD_TEST_CASE(LabelSystemFontColor);
     ADD_TEST_CASE(LabelIssue10773Test);
+    ADD_TEST_CASE(LabelIssue10576Test);
 };
 
 LabelTTFAlignmentNew::LabelTTFAlignmentNew()
@@ -1884,3 +1885,31 @@ std::string LabelIssue10773Test::subtitle() const
 {
     return "Should not crash!";
 }
+
+LabelIssue10576Test::LabelIssue10576Test()
+{
+    auto center = VisibleRect::center();
+
+    auto label = Label::createWithTTF("abcdefg", "fonts/arial.ttf", 24);
+    for (int index = 0; index < label->getStringLength(); ++index)
+    {
+        label->getLetter(index);
+    }
+
+    this->runAction(Sequence::create(DelayTime::create(2.0f), CallFunc::create([label](){
+        label->setString("Hello World!");
+    }), nullptr));
+
+    label->setPosition(center.x, center.y);
+    addChild(label);
+}
+
+std::string LabelIssue10576Test::title() const
+{
+    return "Test for Issue #10576";
+}
+
+std::string LabelIssue10576Test::subtitle() const
+{
+    return "You should see another string displayed correctly after 2 seconds.";
+}

tests/cpp-tests/Classes/LabelTest/LabelTestNew.h

@@ -565,4 +565,15 @@ public:
     virtual std::string subtitle() const override;
 };
 
+class LabelIssue10576Test : public AtlasDemoNew
+{
+public:
+    CREATE_FUNC(LabelIssue10576Test);
+
+    LabelIssue10576Test();
+
+    virtual std::string title() const override;
+    virtual std::string subtitle() const override;
+};
+
 #endif