img_xcf.c

sdl的image开发包

/*
    SDL_image:  An example image loading library for use with SDL
    Copyright (C) 1999, 2000, 2001  Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    [e-mail]
*/

/* $Id: IMG_xcf.c,v 1.5 2003/02/21 17:24:03 slouken Exp $ */

/* This is a XCF image file loading framework */

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>

#include "SDL_endian.h"
#include "SDL_image.h"

#ifdef LOAD_XCF

#if DEBUG
static char prop_names [][30] = {
  "end",
  "colormap",
  "active_layer",
  "active_channel",
  "selection",
  "floating_selection",
  "opacity",
  "mode",
  "visible",
  "linked",
  "preserve_transparency",
  "apply_mask",
  "edit_mask",
  "show_mask",
  "show_masked",
  "offsets",
  "color",
  "compression",
  "guides",
  "resolution",
  "tattoo",
  "parasites",
  "unit",
  "paths",
  "user_unit"
};
#endif


typedef enum
{
  PROP_END = 0,
  PROP_COLORMAP = 1,
  PROP_ACTIVE_LAYER = 2,
  PROP_ACTIVE_CHANNEL = 3,
  PROP_SELECTION = 4,
  PROP_FLOATING_SELECTION = 5,
  PROP_OPACITY = 6,
  PROP_MODE = 7,
  PROP_VISIBLE = 8,
  PROP_LINKED = 9,
  PROP_PRESERVE_TRANSPARENCY = 10,
  PROP_APPLY_MASK = 11,
  PROP_EDIT_MASK = 12,
  PROP_SHOW_MASK = 13,
  PROP_SHOW_MASKED = 14,
  PROP_OFFSETS = 15,
  PROP_COLOR = 16,
  PROP_COMPRESSION = 17,
  PROP_GUIDES = 18,
  PROP_RESOLUTION = 19,
  PROP_TATTOO = 20,
  PROP_PARASITES = 21,
  PROP_UNIT = 22,
  PROP_PATHS = 23,
  PROP_USER_UNIT = 24
} xcf_prop_type;

typedef enum {
  COMPR_NONE    = 0,
  COMPR_RLE     = 1,
  COMPR_ZLIB    = 2,
  COMPR_FRACTAL = 3
} xcf_compr_type;

typedef enum {
  IMAGE_RGB       = 0,
  IMAGE_GREYSCALE = 1,
  IMAGE_INDEXED   = 2
} xcf_image_type;

typedef struct {
  Uint32 id;
  Uint32 length;
  union {
    struct {
      Uint32 num;
      char * cmap;
    } colormap; // 1
    struct {
      Uint32 drawable_offset;
    } floating_selection; // 5
    Sint32 opacity;
    Sint32 mode;
    int    visible;
    int    linked;
    int    preserve_transparency;
    int    apply_mask;
    int    show_mask;
    struct {
      Sint32 x;
      Sint32 y;
    } offset;
    unsigned char color [3];
    Uint8 compression;
    struct {
      Sint32 x;
      Sint32 y;
    } resolution;
    struct {
      char * name;
      Uint32 flags;
      Uint32 size;
      char * data;
    } parasite;
  } data;
} xcf_prop;

typedef struct {
  char   sign [14];
  Uint32 width;
  Uint32 height;
  Sint32 image_type;
  xcf_prop * properties;

  Uint32 * layer_file_offsets;
  Uint32 * channel_file_offsets;

  xcf_compr_type compr;
  Uint32         cm_num;
  unsigned char * cm_map;
} xcf_header;

typedef struct {
  Uint32 width;
  Uint32 height;
  Sint32 layer_type;
  char * name;
  xcf_prop * properties;

  Uint32 hierarchy_file_offset;
  Uint32 layer_mask_offset;

  Uint32 offset_x;
  Uint32 offset_y;
  int visible;
} xcf_layer;

typedef struct {
  Uint32 width;
  Uint32 height;
  char * name;
  xcf_prop * properties;

  Uint32 hierarchy_file_offset;

  Uint32 color;
  Uint32 opacity;
  int selection;
  int visible;
} xcf_channel;

typedef struct {
  Uint32 width;
  Uint32 height;
  Uint32 bpp;

  Uint32 * level_file_offsets;
} xcf_hierarchy;

typedef struct {
  Uint32 width;
  Uint32 height;

  Uint32 * tile_file_offsets;
} xcf_level;

typedef unsigned char * xcf_tile;

typedef unsigned char * (* load_tile_type) (SDL_RWops *, Uint32, int, int, int);


/* See if an image is contained in a data source */
int IMG_isXCF(SDL_RWops *src) {
  int is_XCF;
  char magic[14];

  is_XCF = 0;
  if ( SDL_RWread(src, magic, 14, 1) ) {
    if (strncmp(magic, "gimp xcf ", 9) == 0) {
      is_XCF = 1;
    }
  }

  return(is_XCF);
}

static char * read_string (SDL_RWops * src) {
  Uint32 tmp;
  char * data;

  tmp = SDL_ReadBE32 (src);
  if (tmp > 0) {
    data = (char *) malloc (sizeof (char) * tmp);
    SDL_RWread (src, data, tmp, 1);
  }
  else {
    data = NULL;
  }

  return data;
}


static Uint32 Swap32 (Uint32 v) {
  return
    ((v & 0x000000FF) << 16)
    |  ((v & 0x0000FF00))
    |  ((v & 0x00FF0000) >> 16)
    |  ((v & 0xFF000000));
}

void xcf_read_property (SDL_RWops * src, xcf_prop * prop) {
  prop->id = SDL_ReadBE32 (src);
  prop->length = SDL_ReadBE32 (src);

#if DEBUG
  printf ("%.8X: %s: %d\n", SDL_RWtell (src), prop->id < 25 ? prop_names [prop->id] : "unknown", prop->length);
#endif

  switch (prop->id) {
  case PROP_COLORMAP:
    prop->data.colormap.num = SDL_ReadBE32 (src);
    prop->data.colormap.cmap = (char *) malloc (sizeof (char) * prop->data.colormap.num * 3);
    SDL_RWread (src, prop->data.colormap.cmap, prop->data.colormap.num*3, 1);
    break;

  case PROP_OFFSETS:
    prop->data.offset.x = SDL_ReadBE32 (src);
    prop->data.offset.y = SDL_ReadBE32 (src);
    break;
  case PROP_OPACITY:
    prop->data.opacity = SDL_ReadBE32 (src);
    break;
  case PROP_COMPRESSION:
  case PROP_COLOR:
    SDL_RWread (src, &prop->data, prop->length, 1);
    break;
  case PROP_VISIBLE:
    prop->data.visible = SDL_ReadBE32 (src);
    break;
  default:
    //    SDL_RWread (src, &prop->data, prop->length, 1);
    SDL_RWseek (src, prop->length, SEEK_CUR);
  }
}

void free_xcf_header (xcf_header * h) {
  if (h->cm_num)
    free (h->cm_map);

  free (h);
}

xcf_header * read_xcf_header (SDL_RWops * src) {
  xcf_header * h;
  xcf_prop prop;

  h = (xcf_header *) malloc (sizeof (xcf_header));
  SDL_RWread (src, h->sign, 14, 1);
  h->width       = SDL_ReadBE32 (src);
  h->height      = SDL_ReadBE32 (src);
  h->image_type  = SDL_ReadBE32 (src);

  h->properties = NULL;
  h->compr      = COMPR_NONE;
  h->cm_num = 0;
  h->cm_map = NULL;

  // Just read, don't save
  do {
    xcf_read_property (src, &prop);
    if (prop.id == PROP_COMPRESSION)
      h->compr = prop.data.compression;
    else if (prop.id == PROP_COLORMAP) {
      // unused var: int i;

      h->cm_num = prop.data.colormap.num;
      h->cm_map = (char *) malloc (sizeof (char) * 3 * h->cm_num);
      memcpy (h->cm_map, prop.data.colormap.cmap, 3*sizeof (char)*h->cm_num);
      free (prop.data.colormap.cmap);
    }
  } while (prop.id != PROP_END);

  return h;
}

void free_xcf_layer (xcf_layer * l) {
  free (l->name);
  free (l);
}

xcf_layer * read_xcf_layer (SDL_RWops * src) {
  xcf_layer * l;
  xcf_prop    prop;

  l = (xcf_layer *) malloc (sizeof (xcf_layer));
  l->width  = SDL_ReadBE32 (src);
  l->height = SDL_ReadBE32 (src);
  l->layer_type = SDL_ReadBE32 (src);

  l->name = read_string (src);

  do {
    xcf_read_property (src, &prop);
    if (prop.id == PROP_OFFSETS) {
      l->offset_x = prop.data.offset.x;
      l->offset_y = prop.data.offset.y;
    } else if (prop.id == PROP_VISIBLE) {
      l->visible = prop.data.visible ? 1 : 0;
    }
  } while (prop.id != PROP_END);

  l->hierarchy_file_offset = SDL_ReadBE32 (src);
  l->layer_mask_offset     = SDL_ReadBE32 (src);

  return l;
}

void free_xcf_channel (xcf_channel * c) {
  free (c->name);
  free (c);
}

xcf_channel * read_xcf_channel (SDL_RWops * src) {
  xcf_channel * l;
  xcf_prop    prop;

  l = (xcf_channel *) malloc (sizeof (xcf_channel));
  l->width  = SDL_ReadBE32 (src);
  l->height = SDL_ReadBE32 (src);

  l->name = read_string (src);

  l->selection = 0;
  do {
    xcf_read_property (src, &prop);
    switch (prop.id) {
    case PROP_OPACITY:
      l->opacity = prop.data.opacity << 24;
      break;
    case PROP_COLOR:
      l->color = ((Uint32) prop.data.color[0] << 16)
	| ((Uint32) prop.data.color[1] << 8)
	| ((Uint32) prop.data.color[2]);
      break;
    case PROP_SELECTION:
      l->selection = 1;
      break;
    case PROP_VISIBLE:
      l->visible = prop.data.visible ? 1 : 0;
      break;
    default:
        ;
    }
  } while (prop.id != PROP_END);

  l->hierarchy_file_offset = SDL_ReadBE32 (src);

  return l;
}

void free_xcf_hierarchy (xcf_hierarchy * h) {
  free (h->level_file_offsets);
  free (h);
}

xcf_hierarchy * read_xcf_hierarchy (SDL_RWops * src) {
  xcf_hierarchy * h;
  int i;