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bmp_v1/try.c

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C
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#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>
#include <math.h>
typedef unsigned char uch;
// 檔案結構
#pragma pack(2)
struct BmpFileHeader {
uint16_t bfTybe;
uint32_t bfSize;
uint16_t bfReserved1;
uint16_t bfReserved2;
uint32_t bfOffBits;
};
struct BmpInfoHeader {
uint32_t biSize;
uint32_t biWidth;
uint32_t biHeight;
uint16_t biPlanes; // 1=defeaul, 0=custom
uint16_t biBitCount;
uint32_t biCompression;
uint32_t biSizeImage;
uint32_t biXPelsPerMeter; // 72dpi=2835, 96dpi=3780
uint32_t biYPelsPerMeter; // 120dpi=4724, 300dpi=11811
uint32_t biClrUsed;
uint32_t biClrImportant;
};
#pragma pack()
//辅助计算函数
float linear_single(float x, float x1, float x2, float f1, float f2){
return floor(f1 * (x2 - x) / (x2 - x1) + f2 * (x - x1) / (x2 - x1));
}
// 双线性插值函数
// 参考 https://zh.wikipedia.org/wiki/%E5%8F%8C%E7%BA%BF%E6%80%A7%E6%8F%92%E5%80%BC
char linear_insert(uch** old_pixels, uint32_t row, uint32_t col, uint32_t old_width, uint32_t old_height, float radio_w, float radio_h){
float x = row / radio_h;
float y = col / radio_w;
// 如果整数格点就直接返回
int x1 = floor(x);
int x2 = ceil(x);
int y1 = floor(y);
int y2 = ceil(y);
if (x2 >= old_height){x2 = x1;}
if (y2 >= old_width){y2 = y1;}
if (x1 == x2 && y1 == y2){return old_pixels[x1][y1];}
if (x1 == x2){
int x = x1;
uint32_t idx1 = x*old_width+y;
uint32_t idx2 = x*old_width+y;
float r = linear_single(y, y1, y2, old_pixels[x][idx1 + 0], old_pixels[x][idx2 + 0]);
float g = linear_single(y, y1, y2, old_pixels[x][idx1 + 1], old_pixels[x][idx2 + 1]);
float b = linear_single(y, y1, y2, old_pixels[x][idx1 + 2], old_pixels[x][idx2 + 2]);
return (char)r, (char)g, (char)b;
}
if (y1 == y2){
int y = y1;
uint32_t idx = x*old_width+y;
float r = linear_single(x, x1, x2, old_pixels[x1][idx + 0], old_pixels[x2][idx + 0]);
float g = linear_single(x, x1, x2, old_pixels[x1][idx + 1], old_pixels[x2][idx + 1]);
float b = linear_single(x, x1, x2, old_pixels[x1][idx + 2], old_pixels[x2][idx + 2]);
return (char)r, (char)g, (char)b;
}
uint32_t idx1 = x*old_width+y;
uint32_t idx2 = x*old_width+y;
float fy1_r = linear_single(x, x1, x2, old_pixels[x1][idx1 + 0], old_pixels[x2][idx1 + 0]);
float fy1_g = linear_single(x, x1, x2, old_pixels[x1][idx1 + 1], old_pixels[x2][idx1 + 1]);
float fy1_b = linear_single(x, x1, x2, old_pixels[x1][idx1 + 2], old_pixels[x2][idx1 + 2]);
float fy2_r = linear_single(x, x1, x2, old_pixels[x1][idx2 + 0], old_pixels[x2][idx2 + 0]);
float fy2_g = linear_single(x, x1, x2, old_pixels[x1][idx2 + 1], old_pixels[x2][idx2 + 1]);
float fy2_b = linear_single(x, x1, x2, old_pixels[x1][idx2 + 2], old_pixels[x2][idx2 + 2]);
float r = linear_single(y, y1, y2, fy1_r, fy2_r);
float g = linear_single(y, y1, y2, fy1_g, fy2_g);
float b = linear_single(y, y1, y2, fy1_b, fy2_b);
return (char)r, (char)g, (char)b;
}
void bmpWrite(const char* name, const uch* raw_img, uint32_t width, uint32_t height, uint32_t bits, float radio_w, float radio_h){
if(!(name && raw_img)){
perror("Error bmpWrite.");
return;
}
// 檔案資訊
struct BmpFileHeader file_h = {
.bfTybe=0x4d42,
.bfReserved1=0,
.bfReserved2=0,
.bfOffBits=54,
};
uint32_t new_width = floor(width*radio_w);
uint32_t new_height = floor(height*radio_h);
file_h.bfSize = file_h.bfOffBits + new_width*new_height * bits/8;
if(bits==8) {file_h.bfSize+= 1024, file_h.bfOffBits+= 1024;}
// 圖片資訊
struct BmpInfoHeader info_h = {
.biSize=40,
.biPlanes=1,
.biCompression=0,
.biXPelsPerMeter=0,
.biYPelsPerMeter=0,
.biClrUsed=0,
.biClrImportant=0,
};
info_h.biWidth = new_width;
info_h.biHeight = new_height;
info_h.biBitCount = bits;// 多少位的圖
info_h.biSizeImage = new_width*new_height * bits/8;
if(bits == 8) {info_h.biClrUsed=256;}
// 寫入檔頭
FILE *pFile = NULL;
// pFile = fopen(name,"wb+");
fopen_s(&pFile, name,"wb+");
if(!pFile) {
perror("Error opening file.");
return;
}
fwrite((char*)&file_h, sizeof(char), sizeof(file_h), pFile);
fwrite((char*)&info_h, sizeof(char), sizeof(info_h), pFile);
// 寫調色盤
if(bits == 8) {
for(unsigned i = 0; i < 256; ++i) {
uch c = i;
fwrite((char*)&c, sizeof(char), sizeof(uch), pFile);
fwrite((char*)&c, sizeof(char), sizeof(uch), pFile);
fwrite((char*)&c, sizeof(char), sizeof(uch), pFile);
fwrite("", sizeof(char), sizeof(uch), pFile);
}
}
// char newpixels[new_width*new_height];
unsigned char **newpixels=(unsigned char**)malloc(new_width*new_height*3);// 沒用到
// 寫入圖片資訊
size_t alig = ((new_width*bits/8)*3) % 4;
// for(int j = new_height-1; j >= 0; --j) {
// for(unsigned i = 0; i < new_width; ++i) {
// uint32_t idx = j*new_width +i;
// if(bits == 24) { // RGB圖片
// fwrite((char*)&raw_img[idx*3 +2], sizeof(char), sizeof(uch), pFile);
// fwrite((char*)&raw_img[idx*3 +1], sizeof(char), sizeof(uch), pFile);
// fwrite((char*)&raw_img[idx*3 +0], sizeof(char), sizeof(uch), pFile);
// } else if(bits == 8) { // 灰階圖
// fwrite((char*)&raw_img[idx], sizeof(char), sizeof(uch), pFile);
// }
// }
for(int j = new_height-1; j >= 0; --j) {
for(unsigned i = 0; i < new_width; ++i) {
uint32_t idx = j*new_width +i;
if(bits == 24) { // RGB圖片
char* r, g, b = linear_insert(&raw_img, j, i, width, height, radio_w, radio_h);
fwrite(b, sizeof(char), sizeof(uch), pFile);
fwrite(g, sizeof(char), sizeof(uch), pFile);
fwrite(r, sizeof(char), sizeof(uch), pFile);
} else if(bits == 8) { // 灰階圖
fwrite((char*)&raw_img[idx], sizeof(char), sizeof(uch), pFile);
}
}
//# 计算新像素
// 對齊4byte
for(size_t i = 0; i < alig; ++i) {
fwrite("", sizeof(char), sizeof(uch), pFile);
}
}
fclose(pFile);
free(newpixels); //記得釋放空間
}
void bmpRead(const char* name, uch** oldpixels, uint32_t* width, uint32_t* height, uint16_t* bits)
{
if(!(name && oldpixels && width && height && bits)) {
perror("Error bmpRead.");
return;
}
// 檔案資訊
struct BmpFileHeader file_h;
// 圖片資訊
struct BmpInfoHeader info_h;
// 讀取檔頭
FILE *pFile = NULL;
// pFile = fopen(name, "rb+");
fopen_s(&pFile, name, "rb+");
if(!pFile) {
perror("Error opening file.");
return;
}
fread((char*)&file_h, sizeof(char), sizeof(file_h), pFile);
fread((char*)&info_h, sizeof(char), sizeof(info_h), pFile);
// 讀取長寬
*width = info_h.biWidth;
*height = info_h.biHeight;
*bits = info_h.biBitCount;
unsigned char **oldpixels=(unsigned char**)malloc((*width)*(*height)*3);
// size_t ImgSize = ((size_t)*width) * ((size_t)*height) * 3;
// *raw_img = (uch*)calloc(ImgSize, sizeof(uch));
// 讀取讀片資訊轉RAW檔資訊
fseek(pFile, file_h.bfOffBits, SEEK_SET);
size_t alig = ((info_h.biWidth*info_h.biBitCount/8)*3) % 4;
for(int j = *height-1; j >= 0; --j) {
for(unsigned i = 0; i < *width; ++i) {
uint32_t idx = j*(*width)+i;
if(*bits == 24) { // RGB圖片
fread((char*)&(*oldpixels)[idx*3 +2], sizeof(char), sizeof(uch), pFile);
fread((char*)&(*oldpixels)[idx*3 +1], sizeof(char), sizeof(uch), pFile);
fread((char*)&(*oldpixels)[idx*3 +0], sizeof(char), sizeof(uch), pFile);
} else if(*bits == 8) { // 灰階圖
fread((char*)&(*oldpixels)[idx], sizeof(char), sizeof(uch), pFile);
}
}
fseek(pFile , (long)alig , SEEK_CUR);
}
fclose(pFile);
//---------------------------------------------------------------------------
// size_t ImgSize = ((size_t)*width) * ((size_t)*height) * 3;
// *raw_img = (uch*)calloc(ImgSize, sizeof(uch));
// // 讀取讀片資訊轉RAW檔資訊
// fseek(pFile, file_h.bfOffBits, SEEK_SET);
// size_t alig = ((info_h.biWidth*info_h.biBitCount/8)*3) % 4;
// for(int j = *height-1; j >= 0; --j) {
// for(unsigned i = 0; i < *width; ++i) {
// uint32_t idx = j*(*width)+i;
// if(*bits == 24) { // RGB圖片
// fread((char*)&(*raw_img)[idx*3 +2], sizeof(char), sizeof(uch), pFile);
// fread((char*)&(*raw_img)[idx*3 +1], sizeof(char), sizeof(uch), pFile);
// fread((char*)&(*raw_img)[idx*3 +0], sizeof(char), sizeof(uch), pFile);
// } else if(*bits == 8) { // 灰階圖
// fread((char*)&(*raw_img)[idx], sizeof(char), sizeof(uch), pFile);
// }
// }
// fseek(pFile , (long)alig , SEEK_CUR);
// }
// fclose(pFile);
//----------------------------------------------------------------------------
// for(int j = *height-1; j >= 0; --j) {
// for(unsigned i = 0; i < *width; ++i) {
// uint32_t idx = j*(*width)+i;
// for(int k = 0; k < 3; k++){
// printf((char*)&(*raw_img)[idx*3 + k]);
// printf("\t");
// }
// printf("\t done \t");
// }
// printf("\n");
// }
}
// 圖像結構
typedef struct Imgraw {
uint32_t width, height;
uint16_t bits;
uch* data;
} Imgraw;
void Imgraw_Read(const Imgraw* _this, const char* name) {
const Imgraw* p = _this;
bmpRead(name, &p->data, &p->width, &p->height, &p->bits);
}
void Imgraw_Writ(const Imgraw* _this, const char* name, float radio_w, float radio_h) {
const Imgraw* p = _this;
bmpWrite(name, p->data, p->width, p->height, p->bits, radio_w, radio_h);
}
/*==============================================================*/
int main(int argc, char const *argv[]) {
float radio_w, radio_h;
printf("Enter a radio of width :") ;
scanf("%f", &radio_w);
printf("Enter a radio of height :") ;
scanf("%f", &radio_h);
printf("%f :: %f\n", radio_w, radio_h);
// 建構
Imgraw img = {0, 0, 0, NULL};
// 讀圖
Imgraw_Read(&img, "./input/bw2x1.bmp");
// 寫圖
Imgraw_Writ(&img, "./output/bw2x1(output).bmp", radio_w, radio_h);
return 0;
}
/*==============================================================*/
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