图像变形计算方法，三角变形的计算，将图像分割成四个三角形，鼠标拖动中间的三角形顶点，实现画面的变形。三角变形的精度高于矩形变形-Image deformation calculation method, the deformation of the triangle, the image is divided into four triangles, drag the mouse in the middle of the triangle vertices to achieve the dist