一种OpenGL局部缩放算法及应用

缩放是OpenGL三维模型展示的基本操作之一，一般缩放时由于整个场景围绕视景体中心缩放，感兴趣区域在视图窗口中的位置会不断变化甚至离开视景体，需要不断地执行平移操作，不断地修正感兴趣区域在视图窗口中的位置，无法集中精力观察工程计算中模型的变化细节。为了解决该问题，从图形学角度提出了一种改进的局部缩放算法，实现了用鼠标滚轮缩放模型时，鼠标选择处的模型不离开视景体而相对视图窗口的位置保持不变，省去了传统算法中用户进行缩放操作时需要不断进行平移的操作．改进了用户体验。该算法在多个可视化项目中得到实际应用．取得了很好的操作体验。

An OpenGL-based local scaling algorithm and its application

Local scaling is one of the most popular operations in OpenGL graphic applications. Normally, the entire scene zooms around the center of the view volume with mouse wheel, making the region of interest unstable in position and even be out of sight. Thus, many translation operations are required to move the target in sight. So, attentions can not be focused on detail deformation of engineering calculation. A new algorithm from the viewpoint of computer graphics is provided, which makes the selected point of the model fixed relative to the viewport while the mouse wheels. Thus, users needn＇t perform translation operations to move the region of interests in sight. The algorithm has been applied in several visualization projects and achieved good operating experience.