When a MIDlet uses multiple threads to access a record store, it is the MIDlet's responsibility to coordinate this access; if it fails to do so, unintended consequences may result.
Then, you create a new coordinate system that's centered within your display using translate and store this matrix.
然后,您可以使用 translate 创建一个位于显示器中央的新坐标系统。
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Next, rotate and store this matrix; then, offset from the current coordinate system with translate (which is applied from the previously rotated and translated matrices), and draw a red ellipse.