diff options
Diffstat (limited to 'converter/ppm/spctoppm.c')
| -rw-r--r-- | converter/ppm/spctoppm.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/converter/ppm/spctoppm.c b/converter/ppm/spctoppm.c new file mode 100644 index 00000000..3eea7821 --- /dev/null +++ b/converter/ppm/spctoppm.c @@ -0,0 +1,212 @@ +/* spctoppm.c - read a compressed Spectrum file and produce a portable pixmap +** +** Copyright (C) 1991 by Steve Belczyk and Jef Poskanzer +** +** Permission to use, copy, modify, and distribute this software and its +** documentation for any purpose and without fee is hereby granted, provided +** that the above copyright notice appear in all copies and that both that +** copyright notice and this permission notice appear in supporting +** documentation. This software is provided "as is" without express or +** implied warranty. +*/ + +#include "ppm.h" + +#define ROWS 200 +#define COLS 320 +#define MAXVAL 7 + +static void DoBitmap ARGS(( FILE* ifp )); +static void DoChar ARGS(( int n, char c )); +static void DoColormap ARGS(( FILE* ifp )); + +static char screen[ROWS*COLS/2]; +static short sscreen[ROWS*COLS/4]; +static pixel pal[ROWS][48]; +static long colormap_length, bitmap_length; + +int +main( argc, argv ) + int argc; + char* argv[]; + { + FILE* ifp; + char c1, c2; + pixel* pixelrow; + register pixel* pP; + int row, col; + + + ppm_init( &argc, argv ); + + /* Check args. */ + if ( argc > 2 ) + pm_usage( "[spcfile]" ); + + if ( argc == 2 ) + ifp = pm_openr( argv[1] ); + else + ifp = stdin; + + /* Check SPC file header. */ + c1 = getc( ifp ); + c2 = getc( ifp ); + + if ( ( c1 != 'S' ) || ( c2 != 'P' ) ) + pm_error( "not a Spectrum picture" ); + + /* Skip reserved bytes. */ + getc( ifp ); + getc( ifp ); + + /* Get length of bitmap data. */ + (void) pm_readbiglong( ifp, &bitmap_length ); + + /* and colormap */ + (void) pm_readbiglong( ifp, &colormap_length ); + + /* Process bitmap. */ + DoBitmap( ifp ); + + /* Process colormap. */ + DoColormap( ifp ); + + pm_close( ifp ); + + /* Write the PPM file. */ + ppm_writeppminit( stdout, COLS, ROWS, (pixval) MAXVAL, 0 ); + pixelrow = ppm_allocrow( COLS ); + + for ( row = 0; row < ROWS; ++row ) + { + for ( col = 0, pP = pixelrow; col < COLS; ++col, ++pP ) + { + int c, ind, b, plane, x1; + + /* Compute pixel value. */ + ind = ( 80 * row ) + ( ( col >> 4 ) << 2 ); + b = 0x8000 >> (col & 0xf); + c = 0; + for ( plane = 0; plane < 4; ++plane ) + if ( b & sscreen[ind+plane] ) + c |= (1 << plane); + + /* Compute palette index. */ + x1 = 10 * c; + if ( c & 1 ) + x1 -= 5; + else + ++x1; + if ( ( col >= x1 ) && ( col < ( x1 + 160 ) ) ) + c += 16; + if ( col >= ( x1 + 160 ) ) + c += 32; + + /* Store the proper color. */ + *pP = pal[row][c]; + } + ppm_writeppmrow( stdout, pixelrow, COLS, (pixval) MAXVAL, 0 ); + } + + pm_close( stdout ); + + exit( 0 ); + } + +static void +DoBitmap( ifp ) + FILE* ifp; + { + int i; + long count, data; + signed char h, c; + + /* Zero out first scan line. */ + for ( i = 0; i < 160; ++i ) + screen[i] = 0; + + /* 'count' counts number of input bytes. */ + count = 0; + + /* 'data' counts just data bytes. */ + data = 0; + + while ( count < bitmap_length ) + { + /* Get next record header. */ + h = getc( ifp ); + ++count; + + if ( ( h >= 0 ) && ( count < bitmap_length ) ) + { + for ( i = 0; i <= h; ++i ) + { + c = getc( ifp ); + ++count; + DoChar( data, c ); + ++data; + } + } + else if ( ( h < 0 ) && ( count < bitmap_length ) ) + { + c = getc( ifp ); + ++count; + + for ( i = 0; i < ( 2 - h ); ++i ) + { + DoChar( data, c ); + ++data; + } + } + } + + /* Convert the char version of the screen to short. */ + for ( i = 0; i < ROWS*COLS/4; ++i ) + sscreen[i] = ( screen[i<<1] << 8 ) + ( 0xff & screen[(i<<1)+1] ); + } + +#if __STDC__ +static void +DoChar( int n, char c ) +#else /*__STDC__*/ +static void +DoChar( n, c ) + int n; + char c; +#endif /*__STDC__*/ + { + int i; + + /* Compute screen index. */ + i = 160 + 2 * ( n / 7960 ) + 8 * ( ( n % 7960 ) / 2 ) + ( n & 1 ); + screen[i] = c; + } + +static void +DoColormap( ifp ) + FILE* ifp; + { + int i, j, b; + short mask; + + /* Clear first three palettes. */ + for ( j = 0; j < 48; ++j ) + PPM_ASSIGN( pal[0][j], 0, 0, 0 ); + + /* Read the palettes. */ + for ( i = 1; i < ROWS; ++i ) + for ( j = 0; j < 3; ++j ) + { + (void) pm_readbigshort( ifp, &mask ); + for ( b = 0; b < 15; ++b ) + if ( mask & ( 1 << b ) ) + { + short k; + (void) pm_readbigshort( ifp, &k ); + PPM_ASSIGN( pal[i][(j*16)+b], + ( k & 0x700 ) >> 8, + ( k & 0x070 ) >> 4, + ( k & 0x007 ) ); + } + } + } |