Bitmap/Write a PPM file
You are encouraged to solve this task according to the task description, using any language you may know.
Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Ada
<lang ada> with Ada.Characters.Latin_1; with Ada.Streams.Stream_IO; use Ada.Streams.Stream_IO;
procedure Put_PPM (File : File_Type; Picture : Image) is
use Ada.Characters.Latin_1; Size : constant String := Integer'Image (Picture'Length (2)) & Integer'Image (Picture'Length (1)); Buffer : String (1..Picture'Length (2) * 3); Color : Pixel; Index : Positive;
begin
String'Write (Stream (File), "P6" & LF); String'Write (Stream (File), Size (2..Size'Last) & LF); String'Write (Stream (File), "255" & LF); for I in Picture'Range (1) loop Index := Buffer'First; for J in Picture'Range (2) loop Color := Picture (I, J); Buffer (Index) := Character'Val (Color.R); Buffer (Index + 1) := Character'Val (Color.G); Buffer (Index + 2) := Character'Val (Color.B); Index := Index + 3; end loop; String'Write (Stream (File), Buffer); end loop; Character'Write (Stream (File), LF);
end Put_PPM; </lang> The solution writes the image into an opened file. The file format might fail to work on certain OSes, because output might mangle control characters like LF, CR, FF, HT, VT etc. The OS might also limit the line length of a text file. In general it is a bad idea to mix binary and text output in one file. This solution uses stream I/O, which should be as portable as possible.
C
<lang c>#include <stdio.h>
void output_ppm(FILE *fd, image img) {
unsigned int n; fprintf(fd, "P6\n%d %d\n255\n", img->width, img->height); n = img->width * img->height; fwrite(img->buf, sizeof(pixel), n, fd); fflush(fd);
}</lang>
Forth
: write-ppm { bmp fid -- } s" P6" fid write-line throw bmp bdim swap 0 <# bl hold #s #> fid write-file throw 0 <# #s #> fid write-line throw s" 255" fid write-line throw bmp bdata bmp bdim * pixels bounds do i 3 fid write-file throw pixel +loop ;
s" red.ppm" w/o create-file throw test over write-ppm close-file throw
Fortran
It loads RCImageBasic
module, which is defined here.
<lang fortran>module RCImageIO
use RCImageBasic
implicit none
contains
subroutine output_ppm(u, img) integer, intent(in) :: u type(rgbimage), intent(in) :: img integer :: i, j
write(u, '(A2)') 'P6' write(u, '(I0, ,I0)') img%width, img%height write(u, '(A)') '255' do j=1, img%height do i=1, img%width write(u, '(3A1)', advance='no') achar(img%red(i,j)), achar(img%green(i,j)), & achar(img%blue(i,j)) end do end do
end subroutine output_ppm
end module RCImageIO</lang>
Modula-3
Bitmap
is the module from Basic Bitmap Storage.
<lang modula3>INTERFACE PPM;
IMPORT Bitmap, Pathname;
PROCEDURE Create(imgfile: Pathname.T; img: Bitmap.T);
END PPM.</lang> <lang modula3>MODULE PPM;
IMPORT Bitmap, Wr, FileWr, Pathname; FROM Fmt IMPORT F, Int;
<*FATAL ANY*>
VAR imgfilewr: FileWr.T;
PROCEDURE Create(imgfile: Pathname.T; img: Bitmap.T) =
VAR height := LAST(img^); width := LAST(img[0]); color: Bitmap.Pixel; BEGIN imgfilewr := FileWr.Open(imgfile); Wr.PutText(imgfilewr, F("P6\n%s %s\n255\n", Int(height + 1), Int(width + 1))); FOR i := 0 TO height DO FOR j := 0 TO width DO color := img[i,j]; Wr.PutChar(imgfilewr, VAL(color.R, CHAR)); Wr.PutChar(imgfilewr, VAL(color.G, CHAR)); Wr.PutChar(imgfilewr, VAL(color.B, CHAR)); END; END; Wr.PutChar(imgfilewr, '\n'); Wr.Flush(imgfilewr); END Create;
BEGIN END PPM.</lang>
OCaml
<lang ocaml>let output_ppm ~oc ~img:(_, r_channel, g_channel, b_channel) =
let width = Bigarray.Array2.dim1 r_channel and height = Bigarray.Array2.dim2 r_channel in Printf.fprintf oc "P6\n%d %d\n255\n" width height; for y = 0 to pred height do for x = 0 to pred width do output_char oc (char_of_int r_channel.{x,y}); output_char oc (char_of_int g_channel.{x,y}); output_char oc (char_of_int b_channel.{x,y}); done; done; output_char oc '\n'; flush oc;
- </lang>
Vedit macro language
This routine creates a RAW PPM file (binary). Pixel data must be stored in edit buffer pointed by numeric register #10. The data in the buffer is assumed to be in R,G,B order, which is the order used by PPM file.
///////////////////////////////////////////////////////////////////// // // Save image as PPM file. // @10 = filename. Buffer #10 contains the Pixel data. // :SAVE_PPM: Buf_Switch(#10) BOF IT("P6") IN Num_Ins(#11, LEFT) // width of image Num_Ins(#12, LEFT) // height of image Num_Ins(255, LEFT+NOCR) // maxval IC(10) File_Save_As(@10, OK) Return