* [Caml-list] Problem with Graph module
@ 2002-06-17 1:12 Nicolas FRANCOIS
2002-06-17 13:23 ` Jun P.FURUSE
0 siblings, 1 reply; 6+ messages in thread
From: Nicolas FRANCOIS @ 2002-06-17 1:12 UTC (permalink / raw)
To: Caml List
A strange thing, under Linux : this piece of code :
open Graphics;;
open Random;;
type t_fourmi = {mutable dir : int;
mutable x : int;
mutable y : int};;
let trace_fourmi_deux_etats n =
let mouvement = [|(0, 5); (-5, 0); (0, -5); (5, 0)|] in
let init = open_graph " 800x800+50-50" in
let ma_fourmi = {dir = 0; x = 349; y = 349} in
let onestep () =
if (point_color ma_fourmi.x ma_fourmi.y) = white
then
begin
set_color black;
ma_fourmi.dir <-
if ma_fourmi.dir + 1 > 3 then 0 else ma_fourmi.dir + 1
end
else
begin
set_color white;
ma_fourmi.dir <-
if ma_fourmi.dir - 1 < 0 then 3 else ma_fourmi.dir - 1
end;
fill_rect ma_fourmi.x ma_fourmi.y 5 5;
let (dx, dy) = mouvement.(ma_fourmi.dir) in
ma_fourmi.x <- ma_fourmi.x + dx;
ma_fourmi.y <- ma_fourmi.y + dy;
in
init;
for i = 0 to n do
onestep ();
for j = 1 to 10000 do begin end done
done;;
trace_fourmi_deux_etats 10000;;
works perfectly in camllight (with a few modifications to adapt the code),
but not in Ocaml. The graphic window opens well, but the test
if (point_color ma_fourmi.x ma_fourmi.y) = white
is allways false under Ocaml.
Can you see the problem ?????
Thanks.
--
Nicolas FRANCOIS
http://nicolas.francois.free.fr
A TRUE Klingon programmer does NOT comment his code
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^ permalink raw reply [flat|nested] 6+ messages in thread* (no subject) 2002-06-17 1:12 [Caml-list] Problem with Graph module Nicolas FRANCOIS @ 2002-06-17 13:23 ` Jun P.FURUSE 2002-06-17 17:47 ` [Caml-list] Nicolas FRANCOIS 0 siblings, 1 reply; 6+ messages in thread From: Jun P.FURUSE @ 2002-06-17 13:23 UTC (permalink / raw) To: nicolas.francois; +Cc: caml-list Hello, > if (point_color ma_fourmi.x ma_fourmi.y) = white > is allways false under Ocaml. If the following code says "BUG" in your environment, I am afraid that there is a bug inside the graphics library. In such case, could you send me the result of the command xdpyinfo in your environment ? (* ocamlc -o testgraphics graphics.cma testgraphics.ml *) open Graphics let _ = open_graph ""; if point_color 0 0 = white then prerr_endline "OK" else prerr_endline "BUG" ;; -- Jun ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Caml-list] Re: 2002-06-17 13:23 ` Jun P.FURUSE @ 2002-06-17 17:47 ` Nicolas FRANCOIS 2002-06-18 9:48 ` [Caml-list] Re: Problem with Graph module Jun P.FURUSE 0 siblings, 1 reply; 6+ messages in thread From: Nicolas FRANCOIS @ 2002-06-17 17:47 UTC (permalink / raw) To: Jun P.FURUSE; +Cc: caml-list [-- Attachment #1: Type: text/plain, Size: 876 bytes --] Le Mon, 17 Jun 2002 15:23:09 +0200 (CEST) "Jun P.FURUSE" <Jun.Furuse@inria.fr> a écrit : > Hello, > > > if (point_color ma_fourmi.x ma_fourmi.y) = white > > is allways false under Ocaml. > > If the following code says "BUG" in your environment, I am afraid that > there is a bug inside the graphics library. In such case, could you > send me the result of the command xdpyinfo in your environment ? > > (* ocamlc -o testgraphics graphics.cma testgraphics.ml *) > open Graphics > let _ = > open_graph ""; > if point_color 0 0 = white then > prerr_endline "OK" > else prerr_endline "BUG" > ;; I received the bad answer :-( You'll find the xdpyinfo output in attachment. What can I do, boss ? Please !!!!! \bye -- Nicolas FRANCOIS http://nicolas.francois.free.fr A TRUE Klingon programmer does NOT comment his code [-- Attachment #2: xdpyinfo.out --] [-- Type: application/octet-stream, Size: 9720 bytes --] name of display: :0.0 version number: 11.0 vendor string: The XFree86 Project, Inc vendor release number: 40100000 XFree86 version: 4.1.0 maximum request size: 4194300 bytes motion buffer size: 256 bitmap unit, bit order, padding: 32, LSBFirst, 32 image byte order: LSBFirst number of supported pixmap formats: 7 supported pixmap formats: depth 1, bits_per_pixel 1, scanline_pad 32 depth 4, bits_per_pixel 8, scanline_pad 32 depth 8, bits_per_pixel 8, scanline_pad 32 depth 15, bits_per_pixel 16, scanline_pad 32 depth 16, bits_per_pixel 16, scanline_pad 32 depth 24, bits_per_pixel 32, scanline_pad 32 depth 32, bits_per_pixel 32, scanline_pad 32 keycode range: minimum 8, maximum 255 focus: window 0x180000e, revert to Parent number of extensions: 26 BIG-REQUESTS DOUBLE-BUFFER DPMS Extended-Visual-Information FontCache GLX LBX MIT-SCREEN-SAVER MIT-SHM MIT-SUNDRY-NONSTANDARD RENDER SECURITY SGI-GLX SHAPE SYNC TOG-CUP XC-APPGROUP XC-MISC XFree86-Bigfont XFree86-DRI XFree86-Misc XFree86-VidModeExtension XInputExtension XKEYBOARD XTEST XVideo default screen number: 0 number of screens: 1 screen #0: dimensions: 1280x1024 pixels (433x347 millimeters) resolution: 75x75 dots per inch depths (7): 16, 1, 4, 8, 15, 24, 32 root window id: 0x4d depth of root window: 16 planes number of colormaps: minimum 1, maximum 1 default colormap: 0x20 default number of colormap cells: 64 preallocated pixels: black 0, white 65535 options: backing-store NO, save-unders NO largest cursor: 64x64 current input event mask: 0x58007f KeyPressMask KeyReleaseMask ButtonPressMask ButtonReleaseMask EnterWindowMask LeaveWindowMask PointerMotionMask SubstructureNotifyMask SubstructureRedirectMask PropertyChangeMask number of visuals: 32 default visual id: 0x23 visual: visual id: 0x23 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x24 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x25 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x26 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x27 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x28 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x29 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x2a class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x2b class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x2c class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x2d class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x2e class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x2f class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x30 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x31 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x32 class: TrueColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x33 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x34 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x35 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x36 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x37 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x38 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x39 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x3a class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x3b class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x3c class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x3d class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x3e class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x3f class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x40 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x41 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits visual: visual id: 0x42 class: DirectColor depth: 16 planes available colormap entries: 64 per subfield red, green, blue masks: 0xf800, 0x7e0, 0x1f significant bits in color specification: 6 bits ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Caml-list] Re: Problem with Graph module 2002-06-17 17:47 ` [Caml-list] Nicolas FRANCOIS @ 2002-06-18 9:48 ` Jun P.FURUSE 2002-06-18 17:01 ` Nicolas FRANCOIS 0 siblings, 1 reply; 6+ messages in thread From: Jun P.FURUSE @ 2002-06-18 9:48 UTC (permalink / raw) To: nicolas.francois; +Cc: caml-list, ecc, Andreas.Eder Hello, I thank people who sent their xdpyinfo result. > Le Mon, 17 Jun 2002 15:23:09 +0200 (CEST) "Jun P.FURUSE" > <Jun.Furuse@inria.fr> a écrit : > > > Hello, > > > > > if (point_color ma_fourmi.x ma_fourmi.y) = white > > > is allways false under Ocaml. > > > > If the following code says "BUG" in your environment, I am afraid that > > there is a bug inside the graphics library. In such case, could you > > send me the result of the command xdpyinfo in your environment ? > > > > (* ocamlc -o testgraphics graphics.cma testgraphics.ml *) > > open Graphics > > let _ = > > open_graph ""; > > if point_color 0 0 = white then > > prerr_endline "OK" > > else prerr_endline "BUG" > > ;; I verified that this code prints out "BUG" when X display has less than 24bits color depth. In such environment, the colour mapping from Graphics to X is not one-to-one. This means that point_color may not always return the exact colour which you drew on the screen. For example, in an X display of 15bpp, the Graphics colour 0xffffff and 0xf8f8f8 are translated to the same X white colour. This is also true for the default white background color of Graphics. point_color returns 0xf8f8f8, not 0xffffff, this is why the above code prints out "BUG". In Camllight, the translation between Caml colour and X colour performs communication between programs and the X server. Since it is highly expensive operation, the colour translation of O'Caml Graphics is rewritten, so that it would never ask the X server about colours. It improves the speed of colour query impressively. Unfortunately, the both colour translation code do not return always the same result. The different behavior of the Nicolas' O'Caml and Camllight programs can be explained by this difference of colour translation. I think this does not mean the new colour translation of O'Caml is buggy. Even in Camllight, the same things can happen, unless the colour translation is one-to-one. (It happens less, but not never.) The important things (which should be noted in graphics.mli) are that * you may get different colour index from one you draw, * the colour indices predefined in Graphics for the basic colours such as white, blue, red, etc can be just canonical candidate indices for them. You should not compare these colour indices against the colours got from the screen. For example, in Nicolas' program, instead of comparing Graphics.white, we should use the colour index obtained from the screen at the begining of the program: let screen_white = point_color 0 0 (* this can be different from Graphics.white *) Regards, -- Jun ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Caml-list] Re: Problem with Graph module 2002-06-18 9:48 ` [Caml-list] Re: Problem with Graph module Jun P.FURUSE @ 2002-06-18 17:01 ` Nicolas FRANCOIS 2002-06-18 23:21 ` Nicolas FRANCOIS 0 siblings, 1 reply; 6+ messages in thread From: Nicolas FRANCOIS @ 2002-06-18 17:01 UTC (permalink / raw) To: Jun P.FURUSE; +Cc: Caml List Le Tue, 18 Jun 2002 11:48:31 +0200 (CEST) "Jun P.FURUSE" <Jun.Furuse@inria.fr> a écrit : > I verified that this code prints out "BUG" when X display has less > than 24bits color depth. In such environment, the colour mapping from > Graphics to X is not one-to-one. This means that point_color may not > always return the exact colour which you drew on the screen. > For example, in an X display of 15bpp, the Graphics colour 0xffffff > and 0xf8f8f8 are translated to the same X white colour. > This is also true for the default white background color of Graphics. > point_color returns 0xf8f8f8, not 0xffffff, this is why the above > code prints out "BUG". OK. Now I have this simple problem : I can use Direct Rendering from X with my Voodoo card in 15 bits, and correct color translation in 24 bits. is that right ? > In Camllight, the translation between Caml colour and X colour > performs communication between programs and the X server. Since it is > highly expensive operation, the colour translation of O'Caml Graphics > is rewritten, so that it would never ask the X server about > colours. It improves the speed of colour query impressively. > Unfortunately, the both colour translation code do not return always > the same result. The different behavior of the Nicolas' O'Caml and > Camllight programs can be explained by this difference of colour > translation. Who said computer science is not an exact one ? > I think this does not mean the new colour translation of O'Caml is > buggy. Even in Camllight, the same things can happen, unless the colour > translation is one-to-one. (It happens less, but not never.) > > The important things (which should be noted in graphics.mli) are that > > * you may get different colour index from one you draw, > > * the colour indices predefined in Graphics for the basic colours > such as white, blue, red, etc can be just canonical candidate > indices for them. > > You should not compare these colour indices against the colours > got from the screen. For example, in Nicolas' program, instead of > comparing Graphics.white, we should use the colour index obtained > from the screen at the begining of the program: > > let screen_white = point_color 0 0 > (* this can be different from Graphics.white *) Great. Thanks for the tip. Euh, and what if I have to test several colors ? Oh, yes, here it is : let screen_from_color c = set_color x; plot 0 0; point_color 0 0;; Right ? I'll try it now. \bye, and thanks again. -- Nicolas FRANCOIS http://nicolas.francois.free.fr A TRUE Klingon programmer does NOT comment his code ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Caml-list] Re: Problem with Graph module 2002-06-18 17:01 ` Nicolas FRANCOIS @ 2002-06-18 23:21 ` Nicolas FRANCOIS 0 siblings, 0 replies; 6+ messages in thread From: Nicolas FRANCOIS @ 2002-06-18 23:21 UTC (permalink / raw) To: caml-list Le Tue, 18 Jun 2002 19:01:39 +0200 Nicolas FRANCOIS (AKA El Bofo) <nicolas.francois@free.fr> a écrit : > Great. Thanks for the tip. Euh, and what if I have to test several > colors? Oh, yes, here it is : > > let screen_from_color c = > set_color x; > plot 0 0; > point_color 0 0;; > > Right ? I'll try it now. A better version (known to work, it ran just a few seconds ago in front of my eyes ;-) : let color_from_screen c = let o = point_color 0 0 in set_color c; plot 0 0; let s = point_color 0 0 in set_color o; plot 0 0; s;; Just keep the place exactly in the same state you would like to find it... Release 1.0 for monday. Anyway, if you don't know the Langton ant, you should try it. It's amazing. And the generalizes ones are not bad, too. \bye -- Nicolas FRANCOIS http://nicolas.francois.free.fr A TRUE Klingon programmer does NOT comment his code ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2002-06-18 23:13 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2002-06-17 1:12 [Caml-list] Problem with Graph module Nicolas FRANCOIS 2002-06-17 13:23 ` Jun P.FURUSE 2002-06-17 17:47 ` [Caml-list] Nicolas FRANCOIS 2002-06-18 9:48 ` [Caml-list] Re: Problem with Graph module Jun P.FURUSE 2002-06-18 17:01 ` Nicolas FRANCOIS 2002-06-18 23:21 ` Nicolas FRANCOIS
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