I read in this webpage that below two are differences between a light weight component / heavy weight component.
A lightweight component can have transparent pixels; a heavyweight is always opaque. A lightweight component can appear to be non-rectangular because of its ability to set transparent areas; a heavyweight can only be rectangular.
Could you please share your thoughts on the texts in bold in the above quote.
1. What is a transparent pixel, how it will appear on the GUI screen.
2. What is opaque
3. What is the meaning of appearing non-rectangular and rectangular.