Flutter को rendering मा तीन वटा trees समावेश छन् — Widget tree (configuration), Element tree (instantiated, managed widgets), र RenderObject tree (layout र painting)। यो pipeline बुझ्नुले Flutter ले कसरी efficiently widgets लाई pixels मा परिणत गर्छ भनेर स्पष्ट गर्छ।
तीन वटा trees
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
