Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
304 views
in Technique[技术] by (71.8m points)

java - Java2D: Is it always safe to cast Graphics into Graphics2D

Assuming we always use a Sun JVM (say, 1.5+), is it always safe to cast a Graphics reference to Graphics2D?

I haven't seen it cause any problems yet and, to my understanding, the Graphics class is legacy code but the Java designers didn't want to change the interfaces for Swing and AWT classes in order to preserver backwards compatibility.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

According to the discussion here, it is always safe to cast from Graphics to Graphics2D. However I am not able to quickly find the official Sun statement on this.

The reason it is valid to cast from Graphics to Graphics2D, is because Sun have said that all Graphics objects returned by the API in Java 1.2 or above will be a subclass of Graphics2D.

Another hint here with the same conclusion.

Graphics Object can always be cast Graphics2D g2d = (Graphics2D)g;


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...