我决定自己动手,用一个快速脏的端口完成这个任务。
我只是采用了文件加载 BMP 函数,并创建了虚拟 fread/fseek,因为我真的很懒。
可以正常运行。
如果有人需要,我会在下面发布它。
令人困惑的是, leptonica 开发人员没有正确地为 Windows 完成它。
#include <cstring>
#include <leptonica/allheaders.h>
#include "leptonica_hack.h"
#include "bmp.h"
int fake_file_tracker = 0;
size_t fake_fread ( void * ptr, size_t size, size_t count, char * buffer, size_t buflen)
{
if (fake_file_tracker >= buflen)
{
return 0;
}
if (fake_file_tracker + size * count > buflen)
{
(void)memcpy(ptr, (void *)(buffer+fake_file_tracker), (size_t)(buflen - fake_file_tracker));
fake_file_tracker = buflen+1;
return (size_t)((buflen - fake_file_tracker) / size);
}
(void)memcpy(ptr, (void *)(buffer+fake_file_tracker), size * count);
fake_file_tracker += size * count;
return count;
}
int fake_fseek ( char * buffer, long int offset, int origin, size_t buflen)
{
if (origin + offset >= buflen)
return 0;
fake_file_tracker = origin + offset;
return 0;
}
PIX *
pixReadBmpFromBuffer(char *fp, size_t buflen)
{
fake_file_tracker = 0;
l_uint16 sval;
l_uint32 ival;
l_int16 bfType, bfSize, bfFill1, bfReserved1, bfReserved2;
l_int16 offset, bfFill2, biPlanes, depth, d;
l_int32 biSize, width, height, xres, yres, compression, ignore;
l_int32 imagebytes, biClrUsed, biClrImportant;
l_uint8 *colormapBuf = NULL;
l_int32 colormapEntries;
l_int32 fileBpl, extrabytes, readerror;
l_int32 pixWpl, pixBpl;
l_int32 i, j, k;
l_uint8 pel[4];
l_uint8 *data;
l_uint32 *line, *pword;
PIX *pix, *pixt;
PIXCMAP *cmap;
PROCNAME("pixReadBmpFromBuffer");
if (!fp)
return (PIX *)ERROR_PTR("fp not defined", procName, NULL);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
bfType = convertOnBigEnd16(sval);
if (bfType != BMP_ID)
return (PIX *)ERROR_PTR("not bmf format", procName, NULL);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
bfSize = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
bfFill1 = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
bfReserved1 = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
bfReserved2 = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
offset = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
bfFill2 = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
biSize = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
width = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
height = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
biPlanes = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&sval, 1, 2, fp, buflen);
depth = convertOnBigEnd16(sval);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
compression = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
imagebytes = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
xres = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
yres = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
biClrUsed = convertOnBigEnd32(ival);
ignore = fake_fread((char *)&ival, 1, 4, fp, buflen);
biClrImportant = convertOnBigEnd32(ival);
if (compression != 0)
return (PIX *)ERROR_PTR("cannot read compressed BMP files",
procName,NULL);
if (width < 1)
return (PIX *)ERROR_PTR("width < 1", procName,NULL);
if (height < 1)
return (PIX *)ERROR_PTR("height < 1", procName,NULL);
if (depth < 1 || depth > 32)
return (PIX *)ERROR_PTR("depth not in [1 ... 32]", procName,NULL);
fileBpl = 4 * ((width * depth + 31)/32);
if (imagebytes != 0 && imagebytes != fileBpl * height)
return (PIX *)ERROR_PTR("invalid imagebytes", procName,NULL);
if (offset < BMP_FHBYTES + BMP_IHBYTES)
return (PIX *)ERROR_PTR("invalid offset: too small", procName,NULL);
if (offset > BMP_FHBYTES + BMP_IHBYTES + 4 * 256)
return (PIX *)ERROR_PTR("invalid offset: too large", procName,NULL);
colormapEntries = (offset - BMP_FHBYTES - BMP_IHBYTES) / sizeof(RGBA_QUAD);
if (colormapEntries > 0) {
if ((colormapBuf = (l_uint8 *)CALLOC(colormapEntries,
sizeof(RGBA_QUAD))) == NULL)
return (PIX *)ERROR_PTR("colormapBuf alloc fail", procName, NULL );
if (fake_fread(colormapBuf, sizeof(RGBA_QUAD), colormapEntries, fp, buflen)
!= colormapEntries) {
FREE(colormapBuf);
return (PIX *)ERROR_PTR( "colormap read fail", procName, NULL);
}
}
d = depth;
if (depth == 24)
d = 32;
if ((pix = pixCreate(width, height, d)) == NULL)
return (PIX *)ERROR_PTR( "pix not made", procName, NULL);
pixSetXRes(pix, (l_int32)((l_float32)xres / 39.37 + 0.5));
pixSetYRes(pix, (l_int32)((l_float32)yres / 39.37 + 0.5));
pixWpl = pixGetWpl(pix);
pixBpl = 4 * pixWpl;
cmap = NULL;
if (colormapEntries > 256)
L_WARNING("more than 256 colormap entries!", procName);
if (colormapEntries > 0) {
cmap = pixcmapCreate(L_MIN(d, 8));
FREE(cmap->array);
cmap->array = (void *)colormapBuf;
cmap->n = L_MIN(colormapEntries, 256);
}
pixSetColormap(pix, cmap);
fake_fseek(fp, offset, 0, buflen);
if (depth != 24) {
data = (l_uint8 *)pixGetData(pix) + pixBpl * (height - 1);
for (i = 0; i < height; i++) {
if (fake_fread(data, 1, fileBpl, fp, buflen) != fileBpl) {
pixDestroy(&pix);
return (PIX *)ERROR_PTR("BMP read fail", procName, NULL);
}
data -= pixBpl;
}
}
else {
readerror = 0;
extrabytes = fileBpl - 3 * width;
line = pixGetData(pix) + pixWpl * (height - 1);
for (i = 0; i < height; i++) {
for (j = 0; j < width; j++) {
pword = line + j;
if (fake_fread(&pel, 1, 3, fp, buflen) != 3)
readerror = 1;
*((l_uint8 *)pword + COLOR_RED) = pel[2];
*((l_uint8 *)pword + COLOR_GREEN) = pel[1];
*((l_uint8 *)pword + COLOR_BLUE) = pel[0];
}
if (extrabytes) {
for (k = 0; k < extrabytes; k++)
ignore = fake_fread(&pel, 1, 1, fp, buflen);
}
line -= pixWpl;
}
if (readerror) {
pixDestroy(&pix);
return (PIX *)ERROR_PTR("BMP read fail", procName, NULL);
}
}
pixEndianByteSwap(pix);
if (depth == 1 && cmap) {
pixt = pixRemoveColormap(pix, REMOVE_CMAP_BASED_ON_SRC);
pixDestroy(&pix);
pix = pixt;
}
return pix;
}
pixReadMemBmp
。 - Brandon