add rotation, need more tests

genp_tests.f90

@@ -0,0 +1,41 @@
+!
+!           MODULE FOR TESTING THE GENPLOTTING MODULE
+!
+! this crapware is released by tTh under the
+!             DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+!
+! new Sun May 17 11:21:39 AM UTC 2026
+
+module genp_tests
+  use genplotting
+  implicit none
+  contains
+! ---------------------------------------------------------
+subroutine genp_test_rotation()
+
+  real             :: mat(3, 3)
+  real             :: pta(3), ptb(3)
+  integer                :: pass, i, j
+  
+  write(0, '("*** TEST ROTATION ***")' )
+  do pass=1, 90
+    call genp_set_rotation (real(pass)*0.10)
+    write(0, *) "  * the matrix was : "
+    call genp_get_rot_matrix(mat)
+    do i=1, 3
+      do j=1, 3
+        write (0, '("   ", F8.5)', advance='no') mat(i,j)
+      end do
+      write(0, *)
+    end do
+
+    call genp_move(0.0, 0.0)
+    pta(1) = 11.0   ;   pta(2) = 0.0   ;   pta(3) = 0.0
+    ptb = matmul(mat, pta)
+    write(0, '(" got XY: ", F8.5, " ", F8.5)') ptb(1), ptb(2)
+    call genp_draw(ptb(1), ptb(2), 1+mod(pass, 7))
+  end do   ! pass
+
+end subroutine
+! ---------------------------------------------------------
+end module