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bmp.cpp
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bmp.cpp
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//
// Created by 96351 on 2020/2/28.
//
#include "bmp.h"
Bmp::Bmp(char *sFileName) {
fileName = sFileName;
rgb = NULL;
ycbcr = NULL;
readBMP();
}
bool Bmp::readBMP() {
FILE* fp = fopen(fileName,"rb");
if(!fp)
return false;
BITMAPFILEHEADER fileHeader;//文件头
BITMAPINFOHEADER infoHeader;//信息头
fread(&fileHeader, sizeof(BITMAPFILEHEADER),1,fp);
fread(&infoHeader, sizeof(BITMAPINFOHEADER),1,fp);
size = fileHeader.bfSize;
height = infoHeader.biHeight;
width = infoHeader.biWidth;
nBitCount = infoHeader.biBitCount;
_height = (height+31)/32*32;
_width = (width+31)/32*32;
cout<<_height<<" "<<_width<<endl;
rgb = (Pixel**)malloc(sizeof(Pixel*)*_height);
for(int i=0;i<_height;i++)
rgb[i] = (Pixel*)malloc(sizeof(Pixel)*_width);
int offset = ((width*3+3)/4*4) - width*3;
for(int i=height-1;i>=0;i--) {
for (int j = 0; j < width; j++) {
fread(&rgb[i][j], 3, 1, fp);
}
fseek(fp,offset,SEEK_CUR);
}
fclose(fp);
return true;
}
void Bmp::show() {
cout<<"图片大小："<<size<<"Byte"<<endl;
cout<<"图片高度："<<height<<endl;
cout<<"图片宽度："<<width<<endl;
cout<<"图片位数："<<(int)nBitCount<<endl;
}
void Bmp::save() {
ofstream r("E:\\Project_clion\\BmpToJpg\\data\\r.csv");
ofstream y("E:\\Project_clion\\BmpToJpg\\data\\g.csv");
ofstream dct_y("E:\\Project_clion\\BmpToJpg\\data\\b.csv");
for(int i=0;i<height;i++){
for(int j=0;j<width;j++) {
r << ycbcr[i][j].nY << " ";
y << (int)rgb[i][j].byGreen<<" ";
dct_y<<(int)rgb[i][j].byBlue<<" ";
}
r<<endl;y<<endl;dct_y<<endl;
}
r.close();y.close();dct_y.close();
}
void Bmp::convert2YCbCr(int x,int y,int flag) {
for(int i=x;i<x+8;i++)
for(int j=y;j<y+8;j++){
if(flag==1)
ycbcr[i][j].nY = round(0.299*rgb[i][j].byRed + 0.587*rgb[i][j].byGreen + 0.114*rgb[i][j].byBlue);
else if(flag==2)
ycbcr[i][j].nCb = round(-0.1687*rgb[i][j].byRed - 0.3313*rgb[i][j].byGreen + 0.5*rgb[i][j].byBlue+128);
else if(flag==3)
ycbcr[i][j].nCr = round(0.5*rgb[i][j].byRed - 0.4187*rgb[i][j].byGreen -0.0813*rgb[i][j].byBlue+128);
}
}
void Bmp::forwardDCT(int x, int y,int flag,int* data) {
float s = 1/sqrt(8.0f);
for(int i=0;i<8;i++)
for(int j=0;j<8;j++){
float sum=0;
for(int u=0;u<8;u++)
for(int v=0;v<8;v++){
if(flag==1)
sum+=dctTable[u][i]*dctTable[v][j]*(ycbcr[x+u][y+v].nY-128);
else if(flag==2)
sum+=dctTable[u][i]*dctTable[v][j]*(ycbcr[x+u][y+v].nCb-128);
else if(flag==3)
sum+=dctTable[u][i]*dctTable[v][j]*(ycbcr[x+u][y+v].nCr-128);
}
float alphaU = i==0?s:0.5f;
float alphaV = j==0?s:0.5f;
float temp = alphaU*alphaV;
if(flag==1)
data[ZigZag[i][j]] = round(temp*sum/QyTable[ZigZag[i][j]]);
else
data[ZigZag[i][j]] = round(temp*sum/QcTable[ZigZag[i][j]]);
}
}
bool Bmp::encode2JPG(char* fileName,int qualityScale,unsigned char YHV, unsigned char CbHV, unsigned char CrHV) {
FILE* fp = fopen(fileName,"wb");
if(!fp) {
cout<<"false"<<endl;
return false;
}
_initQualityTable(qualityScale);//初始化量化表
writeJpgHeader(fp,YHV,CbHV,CrHV);//写文件
int lastY=0,lastCb=0,lastCr=0;
int byte=0, bytepos=7;
_init(YHV,CbHV,CrHV);//分配内存
_initHuffmanTable();//初始化哈夫曼表
int x1=0,y1=0,x2=0,y2=0,x3=0,y3=0;
while(1){
//Y分量
handleMCU(1,x1,y1,yHV.H,yHV.V,yHV.hInterval,yHV.vInterval,lastY,byte,bytepos,fp);
//Cb分量
handleMCU(2,x2,y2,cbHV.H,cbHV.V,cbHV.hInterval,cbHV.vInterval,lastCb,byte,bytepos,fp);
//Cr分量
handleMCU(3,x3,y3,crHV.H,crHV.V,crHV.hInterval,crHV.vInterval,lastCr,byte,bytepos,fp);
if(x1>=_height)
break;
}
//EOI
_writeWord(0xFFD9,fp); //图片结束标志
fclose(fp);
return true;
}
void Bmp::handleMCU(int flag, int &x, int& y, int H, int V, int _H, int _V,int &last,int& byte,int& bytepos,FILE* fp) {
int data[64];BitString output[128];
int count;
for(int i=0;i<H;i++) {
for (int j = 0; j < V; j++) {
convert2YCbCr(x + i * 8 * _H, y + 8 * j * _V, flag);
forwardDCT(x + i * 8 * _H, y + 8 * j * _V, flag, data);
if (flag == 1)
count = huffmanCoding(last, data, hY_DC, hY_AC, output);
else
count = huffmanCoding(last, data, hC_DC, hC_AC, output);
writeBitString(output, count, byte, bytepos, fp);
}
}
y+=V*8*_V;
if(y>=_width){
y=0;
x+=H*8*_H;
}
return ;
}
void Bmp::_init(unsigned char YHV, unsigned char CbHV, unsigned char CrHV) {
//初试化YCbCr采样因子
yHV.H= (YHV&0xf0)>>4;
cbHV.H = (CbHV&0xf0)>>4;
crHV.H = (CrHV&0xf0)>>4;
int maxH = max(max(yHV.H,cbHV.H),crHV.H);
yHV.hInterval = maxH/yHV.H;
cbHV.hInterval = maxH/cbHV.H;
crHV.hInterval = maxH/crHV.H;
yHV.V = YHV&0x0f;
cbHV.V = CbHV&0x0f;
crHV.V = CrHV&0x0f;
int maxV = max(max(yHV.V,cbHV.V),crHV.V);
yHV.vInterval = maxV/yHV.V;
cbHV.vInterval = maxV/cbHV.V;
crHV.vInterval = maxV/crHV.V;
_height = (height+maxH*8-1)/(maxH*8)*maxH*8;
_width = (width+maxV*8-1)/(maxV*8)*maxV*8;
//为ycbcr分配内存
ycbcr = (Node**)malloc(sizeof(Node*)*_height);
for(int i=0;i<_height;i++)
ycbcr[i] = (Node *) malloc(sizeof(Node) * _width);
//初始化dctTable
const float PI = 3.1415926f;
for(int i=0;i<8;i++)
for(int j=0;j<8;j++)
dctTable[i][j] = cos((2*i+1)*j*PI/16);
}
void Bmp::_initQualityTable(int qualityScale) {
if(qualityScale<=0) qualityScale=1;
if(qualityScale>=100) qualityScale=99;
for(int i=0;i<8;i++)
for(int j=0;j<8;j++){
int temp = ((int)(yQualityTable[i][j]*qualityScale + 50) / 100);
if (temp<=0) temp = 1;
if (temp>0xFF) temp = 0xFF;
QyTable[ZigZag[i][j]] = (unsigned char)temp;
temp = ((int)(cQualityTable[i][j]*qualityScale + 50) / 100);
if (temp<=0) temp = 1;
if (temp>0xFF) temp = 0xFF;
QcTable[ZigZag[i][j]] = (unsigned char)temp;
}
}
void Bmp::_initHuffmanTable() {
memset(hY_DC,0, sizeof(hY_DC));
getHuffmanTable(Standard_DC_Luminance_NRCodes,Standard_DC_Luminance_Values,hY_DC);
memset(hY_AC,0, sizeof(hY_AC));
getHuffmanTable(Standard_AC_Luminance_NRCodes,Standard_AC_Luminance_Values,hY_AC);
memset(hC_DC, 0, sizeof(hC_DC));
getHuffmanTable(Standard_DC_Chrominance_NRCodes,Standard_DC_Chrominance_Values,hC_DC);
memset(hC_AC,0, sizeof(hC_AC));
getHuffmanTable(Standard_AC_Chrominance_NRCodes,Standard_AC_Chrominance_Values,hC_AC);
}
void Bmp::getHuffmanTable(const char *numTable,const unsigned char *posTable, BitString *huffmanTable) {
int index = 0;
int code = 0;
for(int i=0;i<16;i++) {
for (int j = 0; j < numTable[i]; j++) {
huffmanTable[posTable[index]].length = i + 1;
huffmanTable[posTable[index]].value = code;
code++;
index++;
}
code<<=1;
}
}
int Bmp::huffmanCoding(int &last, int *data, BitString* HD, BitString* HA, BitString *output) {
int index = 0;
//DC分量处理
int diff = data[0] - last;
last = data[0];
if(diff == 0){
output[index++] = HD[0x00];
}else{
BitString bs = getValueBit(diff);
output[index++] = HD[bs.length];
output[index++] = bs;
}
//AC分量处理
BitString EOB = HA[0x00];
BitString SIXTEENZEROS = HA[0xf0];
int endpos = 63;
while(data[endpos]==0&&endpos>0)
endpos--;
for(int i=1;i<=endpos;i++){
int startpos = i;
while(data[i]==0&&i<=endpos)
i++;
int count = i - startpos;
while(count>=16){
output[index++] = SIXTEENZEROS;
count -= 16;
}
BitString bs = getValueBit(data[i]);
output[index++] = HA[count<<4|bs.length];
output[index++] = bs;
}
if(endpos!=63)
output[index++] = EOB;
return index;
}
void Bmp::writeBitString(BitString *data, int count, int &byte, int &bytepos, FILE* fp) {
unsigned short mask[] = {1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768};
for(int i=0;i<count;i++){
int value = data[i].value;
int pos = data[i].length - 1;
while(pos>=0){
if(value&mask[pos]){
byte = byte|mask[bytepos];
}
pos--;
bytepos--;
if(bytepos<0){
_writeByte((unsigned char)byte,fp);
if(byte==0xff)
_writeByte((unsigned char)0,fp);
byte=0;
bytepos=7;
}
}
}
}
BitString Bmp::getValueBit(int value) {
int v = value>0?value:-value;
int length = 0;
while(v>0){
length++;
v>>=1;
}
BitString bs;
bs.length = length;
bs.value = value>0?value:(1<<length)+value-1;
return bs;
}
void Bmp::_writeByte(unsigned char value, FILE* fp)
{
_write(&value, 1, fp);
}
void Bmp::_writeWord(unsigned short value, FILE* fp)
{
unsigned short _value = ((value>>8)&0xFF) | ((value&0xFF)<<8);
_write(&_value, 2, fp);
}
void Bmp::_write(const void* p, int byteSize, FILE* fp)
{
fwrite(p, 1, byteSize, fp);
}
void Bmp::writeJpgHeader(FILE *fp, unsigned char YHV, unsigned char CbHV, unsigned char CrHV) {
//SOI
_writeWord(0xFFD8, fp); // marker = 0xFFD8 图像开始标志
//APPO
_writeWord(0xFFE0,fp); // marker = 0xFFE0
_writeWord(16, fp); // 应用标志长度
_write("JFIF", 5, fp); // 'JFIF\0'
_writeByte(1, fp); // 主版本号
_writeByte(1, fp); // 次版本号
_writeByte(1, fp); // 单位：0表示：无单位；1表示：英寸/点数；2表示：厘米/点数
_writeWord(0x78, fp); // 水平分辨率
_writeWord(0x78, fp); // 竖直分辨率
_writeByte(0, fp); // 水平点数
_writeByte(0, fp); // 竖直点数
//DQT
_writeWord(0xFFDB, fp); //marker = 0xFFDB 量化表标志
_writeWord(132, fp); //size=132 标志长度
_writeByte(0x00, fp); //高4位是量化表精度，0表示8位，1表示16位；低四位定义量化表标识
_write(QyTable, 64, fp); //YTable 按z字形存储
_writeByte(0x01, fp); //高4位是量化表精度，0表示8位，1表示16位；低四位定义量化表标识
_write(QcTable, 64, fp); //CbCrTable
//SOFO
_writeWord(0xFFC0, fp); //marker = 0xFFC0 帧开始标记
_writeWord(17, fp); //length = 17 for a truecolor YCbCr JPG 参数长度
_writeByte(8, fp); //precision = 8: 8 bits/sample 采样精度
_writeWord(height&0xFFFF, fp); //height 行数
_writeWord(width&0xFFFF, fp); //width 列数
_writeByte(3, fp); //Nr= 3: We encode a truecolor JPG 分量数
_writeByte(1, fp); //IdY = 1 分量标志
_writeByte(YHV, fp); //HVY sampling factors for Y (bit 0-3 vert., 4-7 hor.)(SubSamp 1x1)竖直水平采样因子
_writeByte(0, fp); //QTY Quantization Table number for Y = 0 使用的量化表
_writeByte(2, fp); //IdCb = 2
_writeByte(CbHV, fp); //HVCb = 0x11(SubSamp 1x1)
_writeByte(1, fp); //QTCb = 1
_writeByte(3, fp); //IdCr = 3
_writeByte(CrHV, fp); //HVCr = 0x11 (SubSamp 1x1)
_writeByte(1, fp); //QTCr Normally equal to QTCb = 1
//DHT
_writeWord(0xFFC4, fp); //marker = 0xFFC4 哈夫曼表标志
_writeWord(0x01A2, fp); //length = 0x01A2 标志长度
_writeByte(0x00, fp); //高4位：0表示DC，1表示AC；低四位：表标志，0表示Y
_write(Standard_DC_Luminance_NRCodes, sizeof(Standard_DC_Luminance_NRCodes), fp); //DC_L_NRC
_write(Standard_DC_Luminance_Values, sizeof(Standard_DC_Luminance_Values), fp); //DC_L_VALUE
_writeByte(0x10, fp); //HTYAC
_write(Standard_AC_Luminance_NRCodes, sizeof(Standard_AC_Luminance_NRCodes), fp);
_write(Standard_AC_Luminance_Values, sizeof(Standard_AC_Luminance_Values), fp); //we'll use the standard Huffman tables
_writeByte(0x01, fp); //高4位：0表示DC，1表示AC；低四位：表标志，1表示C
_write(Standard_DC_Chrominance_NRCodes, sizeof(Standard_DC_Chrominance_NRCodes), fp);
_write(Standard_DC_Chrominance_Values, sizeof(Standard_DC_Chrominance_Values), fp);
_writeByte(0x11, fp); //HCAC
_write(Standard_AC_Chrominance_NRCodes, sizeof(Standard_AC_Chrominance_NRCodes), fp);
_write(Standard_AC_Chrominance_Values, sizeof(Standard_AC_Chrominance_Values), fp);
//SOS
_writeWord(0xFFDA, fp); //marker = 0xFFC4 扫描头标志
_writeWord(12, fp); //length = 12 扫描头长度
_writeByte(3, fp); //nrofcomponents, Should be 3: truecolor JPG 扫描分量
_writeByte(1, fp); //Idy=1
_writeByte(0x00, fp); //HTY bits 0..3: AC table (0..3)
// bits 4..7: DC table (0..3)
_writeByte(2, fp); //IdCb
_writeByte(0x11, fp); //HTCb
_writeByte(3, fp); //IdCr
_writeByte(0x11, fp); //HTCr
_writeByte(0, fp); //Ss not interesting, they should be 0,63,0
_writeByte(0x3F, fp); //Se
_writeByte(0, fp); //Bf
}