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在ScaleGesture中,android如何计算比例因子detector.getScaleFactor();在哪个范围内?

private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
            @Override
            public boolean onScale(ScaleGestureDetector detector) {
                mScaleFactor *= detector.getScaleFactor();

                // Don't let the object get too small or too large.
                mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 15.0f));
                _renderer.z=-mScaleFactor;
                invalidate();
                return true;
            }
       }
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1 回答 1

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如果你搜索 pinch 你会发现基本上和源代码相同的公式:

mScaleFactor = getCurrentSpan() / getPreviousSpan();

它是当前夹点的距离除以第一个/旧夹点。

于 2012-08-27T19:10:00.760 回答