Tesseract 3.02

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Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | Static Protected Attributes
tesseract::Bmp8 Class Reference

`#include <bmp_8.h>`

Inheritance diagram for tesseract::Bmp8:

List of all members.

## Public Member Functions

| Bmp8 (unsigned short wid, unsigned short hgt)
| ~Bmp8 ()
bool | Clear ()
unsigned short | Width () const
unsigned short | Stride () const
unsigned short | Height () const
unsigned char * | RawData () const
bool | ScaleFrom (Bmp8 *bmp, bool isotropic=true)
bool | Deslant ()
bool | HorizontalDeslant (double *deslant_angle)
bool | IsIdentical (Bmp8 *pBmp) const
ConComp ** | FindConComps (int *concomp_cnt, int min_size) const
float | ForegroundRatio () const
float | MeanHorizontalHistogramEntropy () const
int * | HorizontalHistogram () const

## Static Public Member Functions

static Bmp8 * | FromCharDumpFile (CachedFile *fp)
static Bmp8 * | FromCharDumpFile (FILE *fp)

## Protected Member Functions

bool | LoadFromCharDumpFile (CachedFile *fp)
bool | LoadFromCharDumpFile (FILE *fp)
bool | LoadFromCharDumpFile (unsigned char **raw_data)
bool | LoadFromRawData (unsigned char *data)
bool | SaveBmp2CharDumpFile (FILE *fp) const
bool | IsBlankColumn (int x) const
bool | IsBlankRow (int y) const
void | Crop (int *xst_src, int *yst_src, int *wid, int *hgt)
void | Copy (int x, int y, int wid, int hgt, Bmp8 *bmp_dest) const

## Protected Attributes

unsigned short | wid_
unsigned short | hgt_
unsigned char ** | line_buff_

## Static Protected Attributes

static const int | kConCompAllocChunk = 16
static const int | kDeslantAngleCount

## Detailed Description

Definition at line 41 of file bmp_8.h.

## Constructor & Destructor Documentation

tesseract::Bmp8::Bmp8 | ( | unsigned short | wid,
|  | unsigned short | hgt
| ) |  |

Definition at line 43 of file bmp_8.cpp.

: wid_(wid)
, hgt_(hgt) {
line_buff_ = CreateBmpBuffer();
}

tesseract::Bmp8::~Bmp8 | ( |  | ) |

Definition at line 49 of file bmp_8.cpp.

{
FreeBmpBuffer(line_buff_);
}

## Member Function Documentation

bool tesseract::Bmp8::Clear | ( |  | ) |

Definition at line 133 of file bmp_8.cpp.

{
if (line_buff_ == NULL) {
return false;
}
memset(line_buff_[0], 0xff, stride_ * hgt_ * sizeof(*line_buff_[0]));
return true;
}

void tesseract::Bmp8::Copy | ( | int | x,
|  | int | y,
|  | int | wid,
|  | int | hgt,
|  | Bmp8 * | bmp_dest
| ) |  | const

protected

Definition at line 584 of file bmp_8.cpp.

{
int x_end = min(x_st + wid, static_cast<int>(wid_)),
y_end = min(y_st + hgt, static_cast<int>(hgt_));
for (int y = y_st; y < y_end; y++) {
for (int x = x_st; x < x_end; x++) {
bmp_dest->line_buff_[y - y_st][x - x_st] =
line_buff_[y][x];
}
}
}

void tesseract::Bmp8::Crop | ( | int * | xst_src,
|  | int * | yst_src,
|  | int * | wid,
|  | int * | hgt
| ) |  |

protected

Definition at line 354 of file bmp_8.cpp.

{
(*xst) = 0;
(*yst) = 0;
int xend = wid_ - 1;
int yend = hgt_ - 1;
while ((*xst) < (wid_ - 1) && (*xst) <= xend) {
// column is not empty
if (!IsBlankColumn((*xst))) {
break;
}
(*xst)++;
}
while (xend > 0 && xend >= (*xst)) {
// column is not empty
if (!IsBlankColumn(xend)) {
break;
}
xend--;
}
while ((*yst) < (hgt_ - 1) && (*yst) <= yend) {
// column is not empty
if (!IsBlankRow((*yst))) {
break;
}
(*yst)++;
}
while (yend > 0 && yend >= (*yst)) {
// column is not empty
if (!IsBlankRow(yend)) {
break;
}
yend--;
}
(*wid) = xend - (*xst) + 1;
(*hgt) = yend - (*yst) + 1;
}

bool tesseract::Bmp8::Deslant | ( |  | ) |

Definition at line 801 of file bmp_8.cpp.

{
int x;
int y;
int des_x;
int des_y;
int ang_idx;
int best_ang;
int min_des_x;
int max_des_x;
int des_wid;
// only do deslanting if bitmap is wide enough
// otherwise it slant estimate might not be reliable
if (wid_ < (hgt_ * 2)) {
return true;
}
// compute tan table if needed
if (tan_table_ == NULL && !ComputeTanTable()) {
return false;
}
// compute min and max values for x after deslant
min_des_x = static_cast<int>(0.5f + (hgt_ - 1) * tan_table_[0]);
max_des_x = (wid_ - 1) +
static_cast<int>(0.5f + (hgt_ - 1) * tan_table_[kDeslantAngleCount - 1]);
des_wid = max_des_x - min_des_x + 1;
// alloc memory for histograms
int **angle_hist = new int*[kDeslantAngleCount];
for (ang_idx = 0; ang_idx < kDeslantAngleCount; ang_idx++) {
angle_hist[ang_idx] = new int[des_wid];
if (angle_hist[ang_idx] == NULL) {
delete[] angle_hist;
return false;
}
memset(angle_hist[ang_idx], 0, des_wid * sizeof(*angle_hist[ang_idx]));
}
// compute histograms
for (y = 0; y < hgt_; y++) {
for (x = 0; x < wid_; x++) {
// find a non-bkgrnd pixel
if (line_buff_[y][x] != 0xff) {
des_y = hgt_ - y - 1;
// stamp all histograms
for (ang_idx = 0; ang_idx < kDeslantAngleCount; ang_idx++) {
des_x = x + static_cast<int>(0.5f + (des_y * tan_table_[ang_idx]));
if (des_x >= min_des_x && des_x <= max_des_x) {
angle_hist[ang_idx][des_x - min_des_x]++;
}
}
}
}
}
// find the histogram with the lowest entropy
float entropy;
double best_entropy = 0.0f;
double norm_val;
best_ang = -1;
for (ang_idx = 0; ang_idx < kDeslantAngleCount; ang_idx++) {
entropy = 0.0f;
for (x = min_des_x; x <= max_des_x; x++) {
if (angle_hist[ang_idx][x - min_des_x] > 0) {
norm_val = (1.0f * angle_hist[ang_idx][x - min_des_x] / hgt_);
entropy += (-1.0f * norm_val * log(norm_val));
}
}
if (best_ang == -1 || entropy < best_entropy) {
best_ang = ang_idx;
best_entropy = entropy;
}
// free the histogram
delete[] angle_hist[ang_idx];
}
delete[] angle_hist;
// deslant
if (best_ang != -1) {
unsigned char **dest_lines;
int old_wid = wid_;
// create a new buffer
wid_ = des_wid;
dest_lines = CreateBmpBuffer();
if (dest_lines == NULL) {
return false;
}
for (y = 0; y < hgt_; y++) {
for (x = 0; x < old_wid; x++) {
// find a non-bkgrnd pixel
if (line_buff_[y][x] != 0xff) {
des_y = hgt_ - y - 1;
// compute new pos
des_x = x + static_cast<int>(0.5f + (des_y * tan_table_[best_ang]));
dest_lines[y][des_x - min_des_x] = 0;
}
}
}
// free old buffer
FreeBmpBuffer(line_buff_);
line_buff_ = dest_lines;
}
return true;
}

ConComp ** tesseract::Bmp8::FindConComps | ( | int * | concomp_cnt,
|  | int | min_size
| ) |  | const

Definition at line 611 of file bmp_8.cpp.

{
(*concomp_cnt) = 0;
unsigned int **out_bmp_array = CreateBmpBuffer(wid_, hgt_, 0);
if (out_bmp_array == NULL) {
fprintf(stderr, "Cube ERROR (Bmp8::FindConComps): could not allocate "
"bitmap array\n");
return NULL;
}
// listed of connected components
ConComp **concomp_array = NULL;
int x;
int y;
int x_nbr;
int y_nbr;
int concomp_id;
int alloc_concomp_cnt = 0;
// neighbors to check
const int nbr_cnt = 4;
// relative coordinates of nbrs
int x_del[nbr_cnt] = {-1, 0, 1, -1},
y_del[nbr_cnt] = {-1, -1, -1, 0};
for (y = 0; y < hgt_; y++) {
for (x = 0; x < wid_; x++) {
// is this a foreground pix
if (line_buff_[y][x] != 0xff) {
int master_concomp_id = 0;
ConComp *master_concomp = NULL;
// checkout the nbrs
for (int nbr = 0; nbr < nbr_cnt; nbr++) {
x_nbr = x + x_del[nbr];
y_nbr = y + y_del[nbr];
if (x_nbr < 0 || y_nbr < 0 || x_nbr >= wid_ || y_nbr >= hgt_) {
continue;
}
// is this nbr a foreground pix
if (line_buff_[y_nbr][x_nbr] != 0xff) {
// get its concomp ID
concomp_id = out_bmp_array[y_nbr][x_nbr];
// this should not happen
if (concomp_id < 1 || concomp_id > alloc_concomp_cnt) {
fprintf(stderr, "Cube ERROR (Bmp8::FindConComps): illegal "
"connected component id: %d\n", concomp_id);
FreeBmpBuffer(out_bmp_array);
delete []concomp_array;
return NULL;
}
// if we has previously found a component then merge the two
// and delete the latest one
if (master_concomp != NULL && concomp_id != master_concomp_id) {
// relabel all the pts
ConCompPt *pt_ptr = concomp_array[concomp_id - 1]->Head();
while (pt_ptr != NULL) {
out_bmp_array[pt_ptr->y()][pt_ptr->x()] = master_concomp_id;
pt_ptr = pt_ptr->Next();
}
// merge the two concomp
if (!master_concomp->Merge(concomp_array[concomp_id - 1])) {
fprintf(stderr, "Cube ERROR (Bmp8::FindConComps): could not "
"merge connected component: %d\n", concomp_id);
FreeBmpBuffer(out_bmp_array);
delete []concomp_array;
return NULL;
}
// delete the merged concomp
delete concomp_array[concomp_id - 1];
concomp_array[concomp_id - 1] = NULL;
} else {
// this is the first concomp we encounter
master_concomp_id = concomp_id;
master_concomp = concomp_array[master_concomp_id - 1];
out_bmp_array[y][x] = master_concomp_id;
if (!master_concomp->Add(x, y)) {
fprintf(stderr, "Cube ERROR (Bmp8::FindConComps): could not "
"add connected component (%d,%d)\n", x, y);
FreeBmpBuffer(out_bmp_array);
delete []concomp_array;
return NULL;
}
}
} // foreground nbr
} // nbrs
// if there was no foreground pix, then create a new concomp
if (master_concomp == NULL) {
master_concomp = new ConComp();
if (master_concomp == NULL || master_concomp->Add(x, y) == false) {
fprintf(stderr, "Cube ERROR (Bmp8::FindConComps): could not "
"allocate or add a connected component\n");
FreeBmpBuffer(out_bmp_array);
delete []concomp_array;
return NULL;
}
// extend the list of concomps if needed
if ((alloc_concomp_cnt % kConCompAllocChunk) == 0) {
ConComp **temp_con_comp =
new ConComp *[alloc_concomp_cnt + kConCompAllocChunk];
if (temp_con_comp == NULL) {
fprintf(stderr, "Cube ERROR (Bmp8::FindConComps): could not "
"extend array of connected components\n");
FreeBmpBuffer(out_bmp_array);
delete []concomp_array;
return NULL;
}
if (alloc_concomp_cnt > 0) {
memcpy(temp_con_comp, concomp_array,
alloc_concomp_cnt * sizeof(*concomp_array));
delete []concomp_array;
}
concomp_array = temp_con_comp;
}
concomp_array[alloc_concomp_cnt++] = master_concomp;
out_bmp_array[y][x] = alloc_concomp_cnt;
}
} // foreground pix
} // x
} // y
// free the concomp bmp
FreeBmpBuffer(out_bmp_array);
if (alloc_concomp_cnt > 0 && concomp_array != NULL) {
// scan the array of connected components and color
// the o/p buffer with the corresponding concomps
(*concomp_cnt) = 0;
ConComp *concomp = NULL;
for (int concomp_idx = 0; concomp_idx < alloc_concomp_cnt; concomp_idx++) {
concomp = concomp_array[concomp_idx];
// found a concomp
if (concomp != NULL) {
// add the connected component if big enough
if (concomp->PtCnt() > min_size) {
concomp->SetLeftMost(true);
concomp->SetRightMost(true);
concomp->SetID((*concomp_cnt));
concomp_array[(*concomp_cnt)++] = concomp;
} else {
delete concomp;
}
}
}
}
return concomp_array;
}

float tesseract::Bmp8::ForegroundRatio | ( |  | ) | const

Definition at line 976 of file bmp_8.cpp.

{
int fore_cnt = 0;
if (wid_ <= 0 || hgt_ <= 0) {
return 1.0;
}
for (int y = 0; y < hgt_; y++) {
for (int x = 0; x < wid_; x++) {
fore_cnt += (line_buff_[y][x] == 0xff ? 0 : 1);
}
}
return (1.0 * (fore_cnt / hgt_) / wid_);
}

Bmp8 * tesseract::Bmp8::FromCharDumpFile | ( | CachedFile * | fp | ) |

static

Reimplemented in tesseract::CharSamp.

Definition at line 222 of file bmp_8.cpp.

{
// create a Bmp8 object
Bmp8 *bmp_obj = new Bmp8(0, 0);
if (bmp_obj == NULL) {
return NULL;
}
if (bmp_obj->LoadFromCharDumpFile(fp) == false) {
delete bmp_obj;
}
return bmp_obj;
}

Bmp8 * tesseract::Bmp8::FromCharDumpFile | ( | FILE * | fp | ) |

static

Reimplemented in tesseract::CharSamp.

Definition at line 319 of file bmp_8.cpp.

{
// create a Bmp8 object
Bmp8 *bmp_obj = new Bmp8(0, 0);
if (bmp_obj == NULL) {
return NULL;
}
if (bmp_obj->LoadFromCharDumpFile(fp) == false) {
delete bmp_obj;
}
return bmp_obj;
}

unsigned short tesseract::Bmp8::Height | ( |  | ) | const

inline

Definition at line 50 of file bmp_8.h.

{ return hgt_; }

bool tesseract::Bmp8::HorizontalDeslant | ( | double * | deslant_angle | ) |

Definition at line 993 of file bmp_8.cpp.

{
int x;
int y;
int des_y;
int ang_idx;
int best_ang;
int min_des_y;
int max_des_y;
int des_hgt;
// compute tan table if necess.
if (tan_table_ == NULL && !ComputeTanTable()) {
return false;
}
// compute min and max values for x after deslant
min_des_y = min(0, static_cast<int>((wid_ - 1) * tan_table_[0]));
max_des_y = (hgt_ - 1) +
max(0, static_cast<int>((wid_ - 1) * tan_table_[kDeslantAngleCount - 1]));
des_hgt = max_des_y - min_des_y + 1;
// alloc memory for histograms
int **angle_hist = new int*[kDeslantAngleCount];
for (ang_idx = 0; ang_idx < kDeslantAngleCount; ang_idx++) {
angle_hist[ang_idx] = new int[des_hgt];
if (angle_hist[ang_idx] == NULL) {
delete[] angle_hist;
return false;
}
memset(angle_hist[ang_idx], 0, des_hgt * sizeof(*angle_hist[ang_idx]));
}
// compute histograms
for (y = 0; y < hgt_; y++) {
for (x = 0; x < wid_; x++) {
// find a non-bkgrnd pixel
if (line_buff_[y][x] != 0xff) {
// stamp all histograms
for (ang_idx = 0; ang_idx < kDeslantAngleCount; ang_idx++) {
des_y = y - static_cast<int>(x * tan_table_[ang_idx]);
if (des_y >= min_des_y && des_y <= max_des_y) {
angle_hist[ang_idx][des_y - min_des_y]++;
}
}
}
}
}
// find the histogram with the lowest entropy
float entropy;
float best_entropy = 0.0f;
float norm_val;
best_ang = -1;
for (ang_idx = 0; ang_idx < kDeslantAngleCount; ang_idx++) {
entropy = 0.0f;
for (y = min_des_y; y <= max_des_y; y++) {
if (angle_hist[ang_idx][y - min_des_y] > 0) {
norm_val = (1.0f * angle_hist[ang_idx][y - min_des_y] / wid_);
entropy += (-1.0f * norm_val * log(norm_val));
}
}
if (best_ang == -1 || entropy < best_entropy) {
best_ang = ang_idx;
best_entropy = entropy;
}
// free the histogram
delete[] angle_hist[ang_idx];
}
delete[] angle_hist;
(*deslant_angle) = 0.0;
// deslant
if (best_ang != -1) {
unsigned char **dest_lines;
int old_hgt = hgt_;
// create a new buffer
min_des_y = min(0, static_cast<int>((wid_ - 1) * -tan_table_[best_ang]));
max_des_y = (hgt_ - 1) +
max(0, static_cast<int>((wid_ - 1) * -tan_table_[best_ang]));
hgt_ = max_des_y - min_des_y + 1;
dest_lines = CreateBmpBuffer();
if (dest_lines == NULL) {
return false;
}
for (y = 0; y < old_hgt; y++) {
for (x = 0; x < wid_; x++) {
// find a non-bkgrnd pixel
if (line_buff_[y][x] != 0xff) {
// compute new pos
des_y = y - static_cast<int>((x * tan_table_[best_ang]));
dest_lines[des_y - min_des_y][x] = 0;
}
}
}
// free old buffer
FreeBmpBuffer(line_buff_);
line_buff_ = dest_lines;
(*deslant_angle) = kMinDeslantAngle + (best_ang * kDeslantAngleDelta);
}
return true;
}

int * tesseract::Bmp8::HorizontalHistogram | ( |  | ) | const

Definition at line 1129 of file bmp_8.cpp.

{
int *hist = new int[hgt_];
if (hist == NULL) {
return NULL;
}
// compute histograms
for (int y = 0; y < hgt_; y++) {
hist[y] = 0;
for (int x = 0; x < wid_; x++) {
// find a non-bkgrnd pixel
if (line_buff_[y][x] != 0xff) {
hist[y]++;
}
}
}
return hist;
}

bool tesseract::Bmp8::IsBlankColumn | ( | int | x | ) | const

protected

Definition at line 333 of file bmp_8.cpp.

{
for (int y = 0; y < hgt_; y++) {
if (line_buff_[y][x] != 0xff) {
return false;
}
}
return true;
}

bool tesseract::Bmp8::IsBlankRow | ( | int | y | ) | const

protected

Definition at line 343 of file bmp_8.cpp.

{
for (int x = 0; x < wid_; x++) {
if (line_buff_[y][x] != 0xff) {
return false;
}
}
return true;
}

bool tesseract::Bmp8::IsIdentical | ( | Bmp8 * | pBmp | ) | const

Definition at line 596 of file bmp_8.cpp.

{
if (wid_ != pBmp->wid_ || hgt_ != pBmp->hgt_) {
return false;
}
for (int y = 0; y < hgt_; y++) {
if (memcmp(line_buff_[y], pBmp->line_buff_[y], wid_) != 0) {
return false;
}
}
return true;
}

bool tesseract::Bmp8::LoadFromCharDumpFile | ( | CachedFile * | fp | ) |

protected

Definition at line 142 of file bmp_8.cpp.

{
unsigned short wid;
unsigned short hgt;
unsigned short x;
unsigned short y;
int buf_size;
int pix;
int pix_cnt;
unsigned int val32;
unsigned char *buff;
// read and check 32 bit marker
if (fp->Read(&val32, sizeof(val32)) != sizeof(val32)) {
return false;
}
if (val32 != kMagicNumber) {
return false;
}
// read wid and hgt
if (fp->Read(&wid, sizeof(wid)) != sizeof(wid)) {
return false;
}
if (fp->Read(&hgt, sizeof(hgt)) != sizeof(hgt)) {
return false;
}
// read buf size
if (fp->Read(&buf_size, sizeof(buf_size)) != sizeof(buf_size)) {
return false;
}
// validate buf size: for now, only 3 channel (RBG) is supported
pix_cnt = wid * hgt;
if (buf_size != (3 * pix_cnt)) {
return false;
}
// alloc memory & read the 3 channel buffer
buff = new unsigned char[buf_size];
if (buff == NULL) {
return false;
}
if (fp->Read(buff, buf_size) != buf_size) {
delete []buff;
return false;
}
// create internal buffers
wid_ = wid;
hgt_ = hgt;
line_buff_ = CreateBmpBuffer();
if (line_buff_ == NULL) {
delete []buff;
return false;
}
// copy the data
for (y = 0, pix = 0; y < hgt_; y++) {
for (x = 0; x < wid_; x++, pix += 3) {
// for now we only support gray scale,
// so we expect R = G = B, it this is not the case, bail out
if (buff[pix] != buff[pix + 1] || buff[pix] != buff[pix + 2]) {
delete []buff;
return false;
}
line_buff_[y][x] = buff[pix];
}
}
// delete temp buffer
delete[]buff;
return true;
}

bool tesseract::Bmp8::LoadFromCharDumpFile | ( | FILE * | fp | ) |

protected

Definition at line 236 of file bmp_8.cpp.

{
unsigned short wid;
unsigned short hgt;
unsigned short x;
unsigned short y;
int buf_size;
int pix;
int pix_cnt;
unsigned int val32;
unsigned char *buff;
// read and check 32 bit marker
if (fread(&val32, 1, sizeof(val32), fp) != sizeof(val32)) {
return false;
}
if (val32 != kMagicNumber) {
return false;
}
// read wid and hgt
if (fread(&wid, 1, sizeof(wid), fp) != sizeof(wid)) {
return false;
}
if (fread(&hgt, 1, sizeof(hgt), fp) != sizeof(hgt)) {
return false;
}
// read buf size
if (fread(&buf_size, 1, sizeof(buf_size), fp) != sizeof(buf_size)) {
return false;
}
// validate buf size: for now, only 3 channel (RBG) is supported
pix_cnt = wid * hgt;
if (buf_size != (3 * pix_cnt)) {
return false;
}
// alloc memory & read the 3 channel buffer
buff = new unsigned char[buf_size];
if (buff == NULL) {
return false;
}
if (fread(buff, 1, buf_size, fp) != buf_size) {
delete []buff;
return false;
}
// create internal buffers
wid_ = wid;
hgt_ = hgt;
line_buff_ = CreateBmpBuffer();
if (line_buff_ == NULL) {
delete []buff;
return false;
}
// copy the data
for (y = 0, pix = 0; y < hgt_; y++) {
for (x = 0; x < wid_; x++, pix += 3) {
// for now we only support gray scale,
// so we expect R = G = B, it this is not the case, bail out
if ( buff[pix] != buff[pix + 1] ||
buff[pix] != buff[pix + 2]
) {
delete []buff;
return false;
}
line_buff_[y][x] = buff[pix];
}
}
// delete temp buffer
delete[]buff;
return true;
}

bool tesseract::Bmp8::LoadFromCharDumpFile | ( | unsigned char ** | raw_data | ) |

protected

Definition at line 916 of file bmp_8.cpp.

{
unsigned short wid;
unsigned short hgt;
unsigned short x;
unsigned short y;
unsigned char *raw_data = (*raw_data_ptr);
int buf_size;
int pix;
unsigned int val32;
// read and check 32 bit marker
memcpy(&val32, raw_data, sizeof(val32));
raw_data += sizeof(val32);
if (val32 != kMagicNumber) {
return false;
}
// read wid and hgt
memcpy(&wid, raw_data, sizeof(wid));
raw_data += sizeof(wid);
memcpy(&hgt, raw_data, sizeof(hgt));
raw_data += sizeof(hgt);
// read buf size
memcpy(&buf_size, raw_data, sizeof(buf_size));
raw_data += sizeof(buf_size);
// validate buf size: for now, only 3 channel (RBG) is supported
if (buf_size != (3 * wid * hgt)) {
return false;
}
wid_ = wid;
hgt_ = hgt;
line_buff_ = CreateBmpBuffer();
if (line_buff_ == NULL) {
return false;
}
// copy the data
for (y = 0, pix = 0; y < hgt_; y++) {
for (x = 0; x < wid_; x++, pix += 3) {
// for now we only support gray scale,
// so we expect R = G = B, it this is not the case, bail out
if (raw_data[pix] != raw_data[pix + 1] ||
raw_data[pix] != raw_data[pix + 2]) {
return false;
}
line_buff_[y][x] = raw_data[pix];
}
}
(*raw_data_ptr) = raw_data + buf_size;
return true;
}

bool tesseract::Bmp8::LoadFromRawData | ( | unsigned char * | data | ) |

protected

Definition at line 510 of file bmp_8.cpp.

{
unsigned char *pline_data = data;
// copy the data
for (int y = 0; y < hgt_; y++, pline_data += wid_) {
memcpy(line_buff_[y], pline_data, wid_ * sizeof(*pline_data));
}
return true;
}

float tesseract::Bmp8::MeanHorizontalHistogramEntropy | ( |  | ) | const

Definition at line 1106 of file bmp_8.cpp.

{
float entropy = 0.0f;
// compute histograms
for (int y = 0; y < hgt_; y++) {
int pix_cnt = 0;
for (int x = 0; x < wid_; x++) {
// find a non-bkgrnd pixel
if (line_buff_[y][x] != 0xff) {
pix_cnt++;
}
}
if (pix_cnt > 0) {
float norm_val = (1.0f * pix_cnt / wid_);
entropy += (-1.0f * norm_val * log(norm_val));
}
}
return entropy / hgt_;
}

unsigned char* tesseract::Bmp8::RawData | ( |  | ) | const

inline

Definition at line 51 of file bmp_8.h.

{
return (line_buff_ == NULL ? NULL : line_buff_[0]);
}

bool tesseract::Bmp8::SaveBmp2CharDumpFile | ( | FILE * | fp | ) | const

protected

Definition at line 521 of file bmp_8.cpp.

{
unsigned short wid;
unsigned short hgt;
unsigned short x;
unsigned short y;
int buf_size;
int pix;
int pix_cnt;
unsigned int val32;
unsigned char *buff;
// write and check 32 bit marker
val32 = kMagicNumber;
if (fwrite(&val32, 1, sizeof(val32), fp) != sizeof(val32)) {
return false;
}
// write wid and hgt
wid = wid_;
if (fwrite(&wid, 1, sizeof(wid), fp) != sizeof(wid)) {
return false;
}
hgt = hgt_;
if (fwrite(&hgt, 1, sizeof(hgt), fp) != sizeof(hgt)) {
return false;
}
// write buf size
pix_cnt = wid * hgt;
buf_size = 3 * pix_cnt;
if (fwrite(&buf_size, 1, sizeof(buf_size), fp) != sizeof(buf_size)) {
return false;
}
// alloc memory & write the 3 channel buffer
buff = new unsigned char[buf_size];
if (buff == NULL) {
return false;
}
// copy the data
for (y = 0, pix = 0; y < hgt_; y++) {
for (x = 0; x < wid_; x++, pix += 3) {
buff[pix] =
buff[pix + 1] =
buff[pix + 2] = line_buff_[y][x];
}
}
if (fwrite(buff, 1, buf_size, fp) != buf_size) {
delete []buff;
return false;
}
// delete temp buffer
delete[]buff;
return true;
}

bool tesseract::Bmp8::ScaleFrom | ( | Bmp8 * | bmp,
|  | bool | isotropic = `true`
| ) |  |

Definition at line 399 of file bmp_8.cpp.

{
int x_num;
int x_denom;
int y_num;
int y_denom;
int xoff;
int yoff;
int xsrc;
int ysrc;
int xdest;
int ydest;
int xst_src = 0;
int yst_src = 0;
int xend_src = bmp->wid_ - 1;
int yend_src = bmp->hgt_ - 1;
int wid_src;
int hgt_src;
// src dimensions
wid_src = xend_src - xst_src + 1,
hgt_src = yend_src - yst_src + 1;
// scale to maintain aspect ratio if required
if (isotropic) {
if ((wid_ * hgt_src) > (hgt_ * wid_src)) {
x_num = y_num = hgt_;
x_denom = y_denom = hgt_src;
} else {
x_num = y_num = wid_;
x_denom = y_denom = wid_src;
}
} else {
x_num = wid_;
y_num = hgt_;
x_denom = wid_src;
y_denom = hgt_src;
}
// compute offsets needed to center new bmp
xoff = (wid_ - ((x_num * wid_src) / x_denom)) / 2;
yoff = (hgt_ - ((y_num * hgt_src) / y_denom)) / 2;
// scale up
if (y_num > y_denom) {
for (ydest = yoff; ydest < (hgt_ - yoff); ydest++) {
// compute un-scaled y
ysrc = static_cast<int>(0.5 + (1.0 * (ydest - yoff) *
y_denom / y_num));
if (ysrc < 0 || ysrc >= hgt_src) {
continue;
}
for (xdest = xoff; xdest < (wid_ - xoff); xdest++) {
// compute un-scaled y
xsrc = static_cast<int>(0.5 + (1.0 * (xdest - xoff) *
x_denom / x_num));
if (xsrc < 0 || xsrc >= wid_src) {
continue;
}
line_buff_[ydest][xdest] =
bmp->line_buff_[ysrc + yst_src][xsrc + xst_src];
}
}
} else {
// or scale down
// scaling down is a bit tricky: we'll accumulate pixels
// and then compute the means
unsigned int **dest_line_buff = CreateBmpBuffer(wid_, hgt_, 0),
**dest_pix_cnt = CreateBmpBuffer(wid_, hgt_, 0);
for (ysrc = 0; ysrc < hgt_src; ysrc++) {
// compute scaled y
ydest = yoff + static_cast<int>(0.5 + (1.0 * ysrc * y_num / y_denom));
if (ydest < 0 || ydest >= hgt_) {
continue;
}
for (xsrc = 0; xsrc < wid_src; xsrc++) {
// compute scaled y
xdest = xoff + static_cast<int>(0.5 + (1.0 * xsrc * x_num / x_denom));
if (xdest < 0 || xdest >= wid_) {
continue;
}
dest_line_buff[ydest][xdest] +=
bmp->line_buff_[ysrc + yst_src][xsrc + xst_src];
dest_pix_cnt[ydest][xdest]++;
}
}
for (ydest = 0; ydest < hgt_; ydest++) {
for (xdest = 0; xdest < wid_; xdest++) {
if (dest_pix_cnt[ydest][xdest] > 0) {
unsigned int pixval =
dest_line_buff[ydest][xdest] / dest_pix_cnt[ydest][xdest];
line_buff_[ydest][xdest] =
(unsigned char) min((unsigned int)255, pixval);
}
}
}
// we no longer need these temp buffers
FreeBmpBuffer(dest_line_buff);
FreeBmpBuffer(dest_pix_cnt);
}
return true;
}

unsigned short tesseract::Bmp8::Stride | ( |  | ) | const

inline

Definition at line 49 of file bmp_8.h.

{ return stride_; }

unsigned short tesseract::Bmp8::Width | ( |  | ) | const

inline

Definition at line 48 of file bmp_8.h.

{ return wid_; }

## Member Data Documentation

unsigned short tesseract::Bmp8::hgt_

protected

Definition at line 96 of file bmp_8.h.

const int tesseract::Bmp8::kConCompAllocChunk = 16

staticprotected

Definition at line 100 of file bmp_8.h.

const int tesseract::Bmp8::kDeslantAngleCount

staticprotected

Initial value:
(1 + static_cast<int>(0.5f +
(kMaxDeslantAngle - kMinDeslantAngle) / kDeslantAngleDelta))

Definition at line 101 of file bmp_8.h.

unsigned char** tesseract::Bmp8::line_buff_

protected

Definition at line 98 of file bmp_8.h.

unsigned short tesseract::Bmp8::wid_

protected

Definition at line 95 of file bmp_8.h.

The documentation for this class was generated from the following files:

- /mnt/data/src/tesseract-ocr/cube/bmp_8.h
- /mnt/data/src/tesseract-ocr/cube/bmp_8.cpp