JDK的代码：抱怨FreeType的斜体不好用，自行处理

// values used by FreeType (as of version 2.10.1) for italics transformation matrix in FT_GlyphSlot_Oblique
#define FT_MATRIX_ONE        0x10000
#define FT_MATRIX_OBLIQUE_XY 0x0366A
static void setupTransform(FT_Matrix* target, FTScalerContext *context) {
    FT_Matrix* transform = &context->transform;
    if (context->doItalize) {
        // we cannot use FT_GlyphSlot_Oblique as it doesn't work well with arbitrary transforms,
        // so we add corresponding shear transform to the requested glyph transformation
        target->xx = FT_MATRIX_ONE;
        target->xy = FT_MATRIX_OBLIQUE_XY;
        target->yx = 0;
        target->yy = FT_MATRIX_ONE;
        FT_Matrix_Multiply(transform, target);
    } else {
        target->xx = transform->xx;
        target->xy = transform->xy;
        target->yx = transform->yx;
        target->yy = transform->yy;
    }
}