In the section 8.7.6 (OpenvG Specification 1.1) indicated that
if the user-to-surface tansformation includes non-uniform scaling, the geometry to be stroked must be transformed into surface coordinates prior to stroking. The paint transformation must also be set to the concatenation of the paint-to-user and user-to-surface transformations in order to allow correct painting of the stroked geometry.
According to the sample code, i wrote my code as below, but had no effect to the line width.Why?

Code :
VGPath path;
VGubyte segments[] = {VG_MOVE_TO_ABS, VG_LINE_TO_ABS};
VGfloat coords[] = {20.0f, 20.0f, 20.0f, 50.0f};
path = vgCreatePath(VG_PATH_FORMAT_STANDARD, VG_PATH_DATATYPE_F, 1.0, 0.0f, 0, 0, VG_PATH_CAPABILITY_ALL);
vgAppendPathData(path, 2, segments, coods);
vgSeti(VG_MATRIX_MODE, VG_MATRIX_STROKE_PAINT_TO_USER);
vgScale(5.0f, 5.0f);
vgDrawPath(path, VG_STROKE_PATH);