add a new useless graphic

.gitignore

@@ -9,4 +9,4 @@
 spirale
 starfield
 randomwalk
-
+oscilloscope

Makefile

@@ -28,6 +28,16 @@ randomwalk.png:	randomwalk Makefile
 
 # -----------------------------------------------
 
+oscilloscope:	oscilloscope.f90 Makefile genplotting.o
+	gfortran -Wall $< genplotting.o -o $@
+
+oscilloscope.png:	oscilloscope Makefile
+	./oscilloscope
+	genplot2 -s 512x512 WS/oscilloscope.scratch a.tga
+	convert a.tga $@
+
+# -----------------------------------------------
+
 spirale:	spirale.f90 Makefile genplotting.o
 	gfortran -Wall $< genplotting.o -o $@
 

oscilloscope.f90

@@ -0,0 +1,62 @@
+program oscilloscope
+  use genplotting
+  implicit none
+
+  real, dimension(4)    :: frequences
+
+  write (0, '(A)') "----[ genplotting oscilloscope ]----"
+  call srand(time())
+  call genp_init (0, 'WS/oscilloscope.scratch')
+
+  frequences(1) = 0.86
+  frequences(2) = 1.77
+  frequences(3) = 1.56
+  frequences(4) = 3.04
+
+  call do_oscilloscope(frequences, 1)
+  call genp_end (0)
+contains
+! ---------------------------------------------------------
+subroutine plot_axes(amp)
+  real, intent(in)     :: amp
+  call genp_move(0.0, -amp)
+  call genp_draw(0.0,  amp, 7)
+  call genp_move(-amp, 0.0)
+  call genp_draw( amp, 0.0, 7)
+end subroutine
+! ---------------------------------------------------------
+subroutine plot_a_trace(freq, phy, nbsteps, ypos)
+  real, intent(in)        :: freq, phy, ypos
+  integer, intent(in)     :: nbsteps
+
+  integer          idx
+  real             rstep, px, py
+  logical          firstdot
+
+  firstdot = .true.
+  do idx=0, nbsteps
+    rstep = (real(idx)/real(nbsteps)) 
+    px    = -10.0 + (20.0 * rstep)
+    py    = ypos + sin(15*(rstep+phy)*freq) 
+    if (firstdot) then
+      call genp_move(px, py)   ;   firstdot = .false.
+    else
+      call genp_draw(px, py, 2)
+    endif
+  enddo
+
+end subroutine
+! ---------------------------------------------------------
+subroutine do_oscilloscope(freqs, col)
+  real, intent(in), dimension(4)   :: freqs
+  integer, intent(in)              :: col
+
+  call plot_a_trace(freqs(1), 0.2, 90,  6.66)
+  call plot_a_trace(freqs(2), 1.0, 90,  3.33)
+  call plot_a_trace(freqs(3), 2.6, 90, -3.33)
+  call plot_a_trace(freqs(4), 3.9, 90, -6.66)
+  call plot_axes(10.0)
+
+end subroutine
+! ---------------------------------------------------------
+end program