Flutter کی rendering میں تین درخت شامل ہیں — Widget tree (configuration)، Element tree (فوری شدہ، منظم widgets)، اور RenderObject tree (layout اور painting)۔ اس pipeline کو سمجھنا واضح کرتا ہے کہ Flutter کس طرح موثر طریقے سے widgets کو pixels میں تبدیل کرتا ہے۔
تین درخت
WIDGET tree → immutable CONFIGURATION (what you write: the description of the UI)
→ cheap to create/recreate; rebuilt often (build() returns new widgets)
ELEMENT tree → the INSTANTIATED widgets; manages lifecycle and LINKS widgets to render
objects; PERSISTS across rebuilds (this is the key to efficiency)
RENDEROBJECT tree → does the actual LAYOUT, PAINTING, and hit-testing (the heavy objects)
→ expensive; REUSED and updated (not recreated) across rebuilds
