nap-time commit

docs/usage.md

@@ -5,7 +5,8 @@ The genplotting library use, as a backend, an external
 who can be installed with the [libtthimage](https://git.tetalab.org/tTh/libtthimage) and convert scratchfiles to
 [Targa](https://en.wikipedia.org/wiki/Truevision_TGA) image file. 
 
-Three steps : initialize, use and terminating.
+For drawing an *useless graphic*, you have to follow three steps:
+initialize, use and terminating.
 
 ## Initialize
 

exemples.md

@@ -1,24 +0,0 @@
-# Genplotting exemples
-
-## Spiral
-
-Code source : [spirale.f90](spirale.f90) / if you change the parameter
-in the call to `do_spirale`, you can see some nice variations on the
-spiraling thing.
-
-![#UselessGraphic : la spirale](picz/spirale.png)
-
-This was my first testbed for this new *disruptive* technology, but
-there was so many variations of spirales, and i'm thinking about
-a powerfull spiral generator. *Stay tuned, film at 11*.
-
-## Dessins numériques
-
-By the way, I'm using all that *futilo-technology* for trying to
-make some
-[numeric pictures](http://maison.tth.netlib.re/dessins/numerique.html)
-(aka #UselessGraphic). I try to use various mathematic fundations, and
-I hack and divert and modify and ignore all that for just make
-[UselessGraphic](https://mastodon.tetaneutral.net/tags/uselessgraphic).
-*Feel free to share and enjoy*.
-

genplotting.f90

@@ -11,16 +11,25 @@ module genplotting
   real      ::    xoffset, yoffset, xscale, yscale
   private   ::    xoffset, yoffset, xscale, yscale
 
-  integer   ::    outunit
+  real      ::    rotation
+  private   ::    rotation
+
+  integer   ::    outunit = 6
   private   ::    outunit
 
 contains
 ! ---------------------------------------------------------
+! the first parameter _must_ be 0.
+! the second can be
+!    - the name of a file for recoding plot instructions
+!  or
+!    - an empty string for send plot command to stdout
+!
 subroutine genp_init (foo, fname)
   integer, intent(in)             :: foo
   character (len=*), intent(in)   :: fname
 
-  if (FOO .NE. 0)   THEN
+  IF (FOO .NE. 0)   THEN
     WRITE(0, '("FOO .NE. 0")')
     CALL EXIT(1) 
   END IF
@@ -35,6 +44,8 @@ subroutine genp_init (foo, fname)
   ymin = 9e9       ;       ymax = -9e9
   xoffset = 0.0    ;       yoffset = 0.0
   xscale  = 0.0    ;       yscale  = 0.0
+  rotation = 0.0
+
 end subroutine
 ! ---------------------------------------------------------
 subroutine genp_set_offset(ox, oy)
@@ -76,6 +87,14 @@ subroutine genp_line(xa, ya, xb, yb, color)
   call genp_draw(xb, yb, color)
 end subroutine
 ! ---------------------------------------------------------
+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 genp_end (foo)
   integer, intent(in)    :: foo
 

oscilloscope.f90

@@ -1,3 +1,9 @@
+!
+!                    OSCILLOSCOPE EXPERIMENT
+!
+! this crapware is released by tTh under the
+!             DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+!
 program oscilloscope
   use genplotting
   implicit none
@@ -8,40 +14,41 @@ program oscilloscope
   call srand(time())
   call genp_init (0, 'WS/oscilloscope.scratch')
 
-  frequences(1) = 0.86
+  frequences(1) = 24.86
-  frequences(2) = 1.77
+  frequences(2) = 29.77
-  frequences(3) = 1.56
+  frequences(3) = 37.56
-  frequences(4) = 3.04
+  frequences(4) = 49.3
+
+  call do_oscilloscope(frequences, 2)
 
-  call do_oscilloscope(frequences, 1)
   call genp_end (0)
 contains
 ! ---------------------------------------------------------
-subroutine plot_axes(amp)
+real function compute_a_value(clk, freq, phase)
-  real, intent(in)     :: amp
+  real, intent(in)    :: clk, freq, phase
-  call genp_move(0.0, -amp)
+  real                :: v, f
-  call genp_draw(0.0,  amp, 7)
+  f = freq*(clk+phase)
-  call genp_move(-amp, 0.0)
+  v = sin(f) + (0.3 * sin(3*f)) + (0.1 * sin(5*f))
-  call genp_draw( amp, 0.0, 7)
+  compute_a_value = v
-end subroutine
+end function
 ! ---------------------------------------------------------
-subroutine plot_a_trace(freq, phy, nbsteps, ypos)
+subroutine plot_a_trace(freq, phy, nbsteps, ypos, col)
   real, intent(in)        :: freq, phy, ypos
-  integer, intent(in)     :: nbsteps
+  integer, intent(in)     :: nbsteps, col
 
   integer          idx
   real             rstep, px, py
   logical          firstdot
 
-  firstdot = .true.
+  firstdot = .TRUE.
   do idx=0, nbsteps
     rstep = (real(idx)/real(nbsteps)) 
     px    = -10.0 + (20.0 * rstep)
-    py    = ypos + sin(15*(rstep+phy)*freq) 
+    py = ypos + compute_a_value (rstep, freq, phy)
     if (firstdot) then
       call genp_move(px, py)   ;   firstdot = .false.
     else
-      call genp_draw(px, py, 2)
+      call genp_draw(px, py, col)
     endif
   enddo
 
@@ -51,10 +58,10 @@ 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(1), 0.2, 120,  6.66, col)
-  call plot_a_trace(freqs(2), 1.0, 90,  3.33)
+  call plot_a_trace(freqs(2), 1.0, 120,  3.33, col)
-  call plot_a_trace(freqs(3), 2.6, 90, -3.33)
+  call plot_a_trace(freqs(3), 2.6, 120, -3.33, col)
-  call plot_a_trace(freqs(4), 3.9, 90, -6.66)
+  call plot_a_trace(freqs(4), 3.1, 120, -6.66, col)
   call plot_axes(10.0)
 
 end subroutine

starfield.f90

@@ -1,24 +1,30 @@
 !
 !         BUILD A STAR FIELD
+
+! this crapware is released by tTh under the
+!             DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
 !
 program starfield
   use genplotting
   implicit none
   write (0, '(A)') "----[ genplotting starfield ]----"
   call genp_init (0, 'WS/starfield.scratch')
-  call do_starfield (451)
+  call do_starfield (200)
   call genp_end (0)
 contains
 ! ---------------------------------------------------------
 subroutine plot_a_star(at_x, at_y, sz, color)
   real, intent(in)        :: at_x, at_y, sz
   integer, intent(in)     :: color
+
   integer                 :: idx
   real                    :: rad, xv, yv
+
   write(0, '("plot a star ", 2F8.3)') at_x, at_y
   call genp_set_offset(at_x, at_y)
   do idx=0, 360, 36
-    rad = 0.042 + (real(idx) * (3.14159 / 180))
+    !   convert index to radians
+    rad = real(idx) * (3.14159 / 180)
     xv = sz * sin(rad)    ;    yv = sz * cos(rad)
     call genp_move(0.0, 0.0)
     call genp_draw(xv, yv, color)
@@ -27,12 +33,13 @@ end subroutine
 ! ---------------------------------------------------------
 subroutine do_starfield (nbstar)
   integer, intent(in)     :: nbstar
+
   integer         idx, color
   real            px, py, sz
   do idx=1, nbstar
     px = (rand(0) * 10.00) - 5.00
     py = (rand(0) * 10.00) - 5.00
-    sz = (rand(0) *  0.16) + 0.16
+    sz = (rand(0) *  0.30) + 0.12
     color = 1 + mod(idx, 7)
     call plot_a_star(px, py, sz, color)
   end do

usage.md

@@ -1,30 +0,0 @@
-# Usage
-
-The genplotting library use, as a backend, an external 
-[software](https://git.tetalab.org/tTh/libtthimage/src/branch/master/Tools/genplot2.c)
-who can be installed with the [libtthimage](https://git.tetalab.org/tTh/libtthimage) and convert scratchfiles to
-[Targa](https://en.wikipedia.org/wiki/Truevision_TGA) image file. 
-
-Three steps : initialize, use and terminating.
-
-## Initialize
-
-Call the subroutine `genp_init` with two parameters.
-The first is an integer and must be 0. 
-The second is the filename for recording the plottings instructions,
-if this filename is an empty string, *stdout* will be used.
-
-## Use it
-
-- real xa, ya, xb, yb
-- integer color
-- call genp_move(xa, ya)
-- call genp_draw(xa, ya, color)
-- call genp_line(xa, ya, xb, yb, color)
-
-## Terminator
-
-- call genp_end(0)
-
-
-