This function does a good bit of position-munging, but it all boils down to a simple idea: Keep constant the precise distance between the mouse cursor and the target object.

该函数做很多位置整理(position - munging)工作，但都可归结为一个简单的思想：不断保存鼠标光标与目标对象之间的精确的距离。

youdao

Said proximity corresponds to a distance (relative position) between the target object (2) and the reference object (6, 8) wherein the reference object is located substantially at the focal plane.

所述接近程度对应于目标物体(2)与参考物体(6、8)之间的距离(相对位置)，其中，参考物体基本位于焦平面上。

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On the NCI chip, the phase, frequency, andintensity of the reflected light from different points on the object isdetected and used to determine the exact distance of the target point.

NCI测量并分析不同点的反射光，通过相位、频率和亮度三个参数来精准确定目标点与镜头的距离。

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Looking through the rifle's telescopic sight, the gunman then estimates the distance from this object to the target.

ECONOMIST: Military technology