SDL_image: An example image loading library for use with SDL

Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>

This software is provided 'as-is', without any express or implied

warranty. In no event will the authors be held liable for any damages

arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,

including commercial applications, and to alter it and redistribute it

freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not

claim that you wrote the original software. If you use this software

in a product, an acknowledgment in the product documentation would be

appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be

misrepresented as being the original software.

3. This notice may not be removed or altered from any source distribution.

*/

/*

* PCX file reader:

* Supports:

* 1..4 bits/pixel in multiplanar format (1 bit/plane/pixel)

* 8 bits/pixel in single-planar format (8 bits/plane/pixel)

* 24 bits/pixel in 3-plane format (8 bits/plane/pixel)

*

* (The <8bpp formats are expanded to 8bpp surfaces)

*

* Doesn't support:

* single-planar packed-pixel formats other than 8bpp

* 4-plane 32bpp format with a fourth "intensity" plane

*/

#include "SDL_endian.h"

#include "SDL_image.h"

#ifdef LOAD_PCX

struct PCXheader {

Uint8 Manufacturer;

Uint8 Version;

Uint8 Encoding;

Uint8 BitsPerPixel;

Sint16 Xmin, Ymin, Xmax, Ymax;

Sint16 HDpi, VDpi;

Uint8 Colormap[48];

Uint8 Reserved;

Uint8 NPlanes;

Sint16 BytesPerLine;

Sint16 PaletteInfo;

Sint16 HscreenSize;

Sint16 VscreenSize;

Uint8 Filler[54];

};

/* See if an image is contained in a data source */

int IMG_isPCX(SDL_RWops *src)

{

int is_PCX;

const int ZSoft_Manufacturer = 10;

const int PC_Paintbrush_Version = 5;

const int PCX_RunLength_Encoding = 1;

struct PCXheader pcxh;

if ( !src )

return 0;

is_PCX = 0;

if ( SDL_RWread(src, &pcxh, sizeof(pcxh), 1) == 1 ) {

if ( (pcxh.Manufacturer == ZSoft_Manufacturer) &&

(pcxh.Version == PC_Paintbrush_Version) &&

(pcxh.Encoding == PCX_RunLength_Encoding ||

pcxh.Encoding == PCX_Uncompressed_Encoding) ) {

is_PCX = 1;

}

}

return(is_PCX);

}

/* Load a PCX type image from an SDL datasource */

SDL_Surface *IMG_LoadPCX_RW(SDL_RWops *src)

{

struct PCXheader pcxh;

Uint32 Rmask;

Uint32 Gmask;

Uint32 Bmask;

Uint32 Amask;

int y, bpl;

Uint8 *row, *buf = NULL;

char *error = NULL;

int bits, src_bits;

if ( !src ) {

/* The error message has been set in SDL_RWFromFile */

return NULL;

}

start = SDL_RWtell(src);

goto done;

}

pcxh.Xmin = SDL_SwapLE16(pcxh.Xmin);

pcxh.Ymin = SDL_SwapLE16(pcxh.Ymin);

pcxh.Xmax = SDL_SwapLE16(pcxh.Xmax);

pcxh.Ymax = SDL_SwapLE16(pcxh.Ymax);

pcxh.BytesPerLine = SDL_SwapLE16(pcxh.BytesPerLine);

/* Create the surface of the appropriate type */

width = (pcxh.Xmax - pcxh.Xmin) + 1;

height = (pcxh.Ymax - pcxh.Ymin) + 1;

Rmask = Gmask = Bmask = Amask = 0;

src_bits = pcxh.BitsPerPixel * pcxh.NPlanes;

if((pcxh.BitsPerPixel == 1 && pcxh.NPlanes >= 1 && pcxh.NPlanes <= 4)

|| (pcxh.BitsPerPixel == 8 && pcxh.NPlanes == 1)) {

bits = 8;

} else if(pcxh.BitsPerPixel == 8 && pcxh.NPlanes == 3) {

bits = 24;

if ( SDL_BYTEORDER == SDL_LIL_ENDIAN ) {

Rmask = 0x000000FF;

Gmask = 0x0000FF00;

Bmask = 0x00FF0000;

} else {

Rmask = 0xFF0000;

Gmask = 0x00FF00;

Bmask = 0x0000FF;

} else {

error = "unsupported PCX format";

goto done;

}

surface = SDL_AllocSurface(SDL_SWSURFACE, width, height,

bits, Rmask, Gmask, Bmask, Amask);

if ( surface == NULL )

goto done;

if (bpl > surface->pitch) {

error = "bytes per line is too large (corrupt?)";

}

buf = (Uint8 *)calloc(SDL_max(bpl, surface->pitch), 1);

row = (Uint8 *)surface->pixels;

/* decode a scan line to a temporary buffer first */

int i, count = 0;

Uint8 ch;

Uint8 *dst = (src_bits == 8) ? row : buf;

if ( pcxh.Encoding == 0 ) {

if(!SDL_RWread(src, dst, bpl, 1)) {

error = "file truncated";

goto done;

}

} else {

for(i = 0; i < bpl; i++) {

if(!count) {

if(!SDL_RWread(src, &ch, 1, 1)) {

error = "file truncated";

goto done;

}

if( (ch & 0xc0) == 0xc0) {

count = ch & 0x3f;

if(!SDL_RWread(src, &ch, 1, 1)) {

error = "file truncated";

goto done;

}

} else

count = 1;

}

dst[i] = ch;

count--;

}

}

if(src_bits <= 4) {

/* expand planes to 1 byte/pixel */

int plane;

for(plane = 0; plane < pcxh.NPlanes; plane++) {

int j, k, x = 0;

for(j = 0; j < pcxh.BytesPerLine; j++) {

Uint8 byte = *innerSrc++;

for(k = 7; k >= 0; k--) {

unsigned bit = (byte >> k) & 1;

row[x++] |= bit << plane;

}

}

} else if(src_bits == 24) {

/* de-interlace planes */

int plane;

for(plane = 0; plane < pcxh.NPlanes; plane++) {

int x;

dst = row + plane;

for(x = 0; x < width; x++) {

}

}

}

row += surface->pitch;

}

int nc = 1 << src_bits;

int i;

surface->format->palette->ncolors = nc;

if(src_bits == 8) {

Uint8 ch;

/* look for a 256-colour palette */

do {

if ( !SDL_RWread(src, &ch, 1, 1)) {

error = "file truncated";

goto done;

}

} while ( ch != 12 );

for(i = 0; i < 256; i++) {

SDL_RWread(src, &colors[i].r, 1, 1);

SDL_RWread(src, &colors[i].g, 1, 1);

SDL_RWread(src, &colors[i].b, 1, 1);

}

} else {

for(i = 0; i < nc; i++) {

colors[i].r = pcxh.Colormap[i * 3];

colors[i].g = pcxh.Colormap[i * 3 + 1];

colors[i].b = pcxh.Colormap[i * 3 + 2];

}

}

}

done:

free(buf);

if ( error ) {

if ( surface ) {

SDL_FreeSurface(surface);

surface = NULL;

}

}

return(surface);

}

#else

/* See if an image is contained in a data source */

int IMG_isPCX(SDL_RWops *src)

{

return(0);

}

/* Load a PCX type image from an SDL datasource */

SDL_Surface *IMG_LoadPCX_RW(SDL_RWops *src)

{

return(NULL);

}

#endif /* LOAD_PCX */