209 lines
7.2 KiB
C
209 lines
7.2 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include <inttypes.h>
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typedef unsigned char uch;
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// 檔案結構
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#pragma pack(2)
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struct BmpFileHeader {
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uint16_t bfTybe;
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uint32_t bfSize;
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uint16_t bfReserved1;
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uint16_t bfReserved2;
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uint32_t bfOffBits;
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};
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struct BmpInfoHeader {
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uint32_t biSize;
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uint32_t biWidth;
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uint32_t biHeight;
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uint16_t biPlanes; // 1=defeaul, 0=custom
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uint16_t biBitCount;
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uint32_t biCompression;
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uint32_t biSizeImage;
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uint32_t biXPelsPerMeter; // 72dpi=2835, 96dpi=3780
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uint32_t biYPelsPerMeter; // 120dpi=4724, 300dpi=11811
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uint32_t biClrUsed;
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uint32_t biClrImportant;
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};
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#pragma pack()
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void bmpWrite(const char* name, const uch* raw_img, uint32_t width, uint32_t height, uint16_t bits, const char* old_name, double radio)
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{
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if(!(name && raw_img)) {
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perror("Error bmpWrite.");
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return;
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}
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unsigned long oldWidth, oldHeight, oldSize, newWidth, newHeight, newSize;
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oldWidth = width;
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oldHeight = height;
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newWidth = ((int)(oldWidth * radio) + 3) / 4 * 4;//图像显示不出来原因在于图像长或宽不是4的倍数 保证得到的宽高是4的倍数
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newHeight = ((int)(oldHeight * radio) + 3) / 4 * 4;
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// 檔案資訊
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struct BmpFileHeader file_h = {
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.bfTybe=0x4d42,
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.bfReserved1=0,
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.bfReserved2=0,
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.bfOffBits=54,
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};
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file_h.bfSize = file_h.bfOffBits + newWidth*newHeight * bits/8;
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if(bits==8) {file_h.bfSize+= 1024, file_h.bfOffBits+= 1024;}
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// 圖片資訊
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struct BmpInfoHeader info_h = {
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.biSize=40,
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.biPlanes=1,
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.biCompression=0,
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.biXPelsPerMeter=0,
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.biYPelsPerMeter=0,
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.biClrUsed=0,
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.biClrImportant=0,
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};
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info_h.biWidth = newWidth;
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info_h.biHeight = newHeight;
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info_h.biBitCount = bits;
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info_h.biSizeImage = newWidth*newHeight * bits/8;
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if(bits == 8) {info_h.biClrUsed=256;}
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// 寫入檔頭
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FILE *pFile = NULL;
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// pFile = fopen(name,"wb+");
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fopen_s(&pFile, name,"wb+");
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if(!pFile) {
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perror("Error opening file.");
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return;
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}
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fwrite((char*)&file_h, sizeof(char), sizeof(file_h), pFile);
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fwrite((char*)&info_h, sizeof(char), sizeof(info_h), pFile);
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// 寫調色盤
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if(bits == 8) {
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for(unsigned i = 0; i < 256; ++i) {
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uch c = i;
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fwrite((char*)&c, sizeof(char), sizeof(uch), pFile);
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fwrite((char*)&c, sizeof(char), sizeof(uch), pFile);
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fwrite((char*)&c, sizeof(char), sizeof(uch), pFile);
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fwrite("", sizeof(char), sizeof(uch), pFile);
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}
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}
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// 寫入圖片資訊
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size_t alig = ((width*bits/8)*3) % 4;
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for(int j = height-1; j >= 0; --j) {
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for(unsigned i = 0; i < width; ++i) {
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uint32_t idx = j*width +i;
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if(bits == 24) { // RGB圖片
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fwrite((char*)&raw_img[idx*3 +2], sizeof(char), sizeof(uch), pFile);
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fwrite((char*)&raw_img[idx*3 +1], sizeof(char), sizeof(uch), pFile);
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fwrite((char*)&raw_img[idx*3 +0], sizeof(char), sizeof(uch), pFile);
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// unsigned long oldWidth, oldHeight, oldSize, newWidth, newHeight, newSize;
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// oldWidth = width;
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// oldHeight = height;
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unsigned char *sourceData = (unsigned char*)malloc(oldSize);//该指针指向源位图文件图像数据的内存空间
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fseek(old_name, 54, SEEK_SET);//使文件的指针指向文件的第55个字节
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fread(sourceData, oldSize, 1, old_name);//将src_file中的图像数据存储到sourceData指向的内存空间
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// newWidth = ((int)(oldWidth * radio) + 3) / 4 * 4;//图像显示不出来原因在于图像长或宽不是4的倍数 下面这一步可以保证得到的宽高是4的倍数
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// newHeight = ((int)(oldHeight * radio) + 3) / 4 * 4;
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//10.使用最邻近插值算法进行图片缩放
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unsigned int x,y,X,Y;//源位图文件像素点宽高和目标位图文件像素点宽高
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unsigned char *destData = (unsigned char*)malloc(newSize);//该指针指向目标位图文件图像数据的内存空间
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unsigned char *sourceWhere, *destWhere;//修改像素的对应位置
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for(Y = 0; Y < newHeight; Y++) {
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y = Y / radio;
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destWhere = destData + Y * newWidth * 3;
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sourceWhere = sourceData + y * oldWidth * 3;
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for(X = 0; X < newWidth; X++) {
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x = X / radio;
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memcpy(destWhere + X * 3, sourceWhere + x * 3, 3);
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}
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}
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}
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else if(bits == 8) { // 灰階圖
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fwrite((char*)&raw_img[idx], sizeof(char), sizeof(uch), pFile);
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}
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}
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// 對齊4byte
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for(size_t i = 0; i < alig; ++i) {
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fwrite("", sizeof(char), sizeof(uch), pFile);
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}
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}
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fclose(pFile);
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}
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void bmpRead(const char* name, uch** raw_img, uint32_t* width, uint32_t* height, uint16_t* bits)
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{
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if(!(name && raw_img && width && height && bits)) {
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perror("Error bmpRead.");
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return;
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}
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// 檔案資訊
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struct BmpFileHeader file_h;
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// 圖片資訊
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struct BmpInfoHeader info_h;
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// 讀取檔頭
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FILE *pFile = NULL;
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// pFile = fopen(name, "rb+");
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fopen_s(&pFile, name, "rb+");
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if(!pFile) {
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perror("Error opening file.");
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return;
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}
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fread((char*)&file_h, sizeof(char), sizeof(file_h), pFile);
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fread((char*)&info_h, sizeof(char), sizeof(info_h), pFile);
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// 讀取長寬
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*width = info_h.biWidth;
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*height = info_h.biHeight;
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*bits = info_h.biBitCount;
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size_t ImgSize = ((size_t)*width) * ((size_t)*height) * 3;
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*raw_img = (uch*)calloc(ImgSize, sizeof(uch));
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// 讀取讀片資訊轉RAW檔資訊
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fseek(pFile, file_h.bfOffBits, SEEK_SET);
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size_t alig = ((info_h.biWidth*info_h.biBitCount/8)*3) % 4;
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for(int j = *height-1; j >= 0; --j) {
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for(unsigned i = 0; i < *width; ++i) {
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uint32_t idx = j*(*width)+i;
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if(*bits == 24) { // RGB圖片
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fread((char*)&(*raw_img)[idx*3 +2],
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sizeof(char), sizeof(uch), pFile);
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fread((char*)&(*raw_img)[idx*3 +1],
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sizeof(char), sizeof(uch), pFile);
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fread((char*)&(*raw_img)[idx*3 +0],
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sizeof(char), sizeof(uch), pFile);
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} else if(*bits == 8) { // 灰階圖
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fread((char*)&(*raw_img)[idx],
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sizeof(char), sizeof(uch), pFile);
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}
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}
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fseek(pFile , (long)alig , SEEK_CUR);
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}
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fclose(pFile);
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}
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// 圖像結構
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typedef struct Imgraw {
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uint32_t width, height;
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uint16_t bits;
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uch* data;
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} Imgraw;
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void Imgraw_Read(const Imgraw* _this, const char* name) {
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const Imgraw* p = _this;
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bmpRead(name, &p->data, &p->width, &p->height, &p->bits);
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}
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void Imgraw_Writ(const Imgraw* _this, const char* name, const char* old_name) {
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const Imgraw* p = _this;
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bmpWrite(name, p->data, p->width, p->height, p->bits, old_name, 1.0);
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}
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/*==============================================================*/
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int main(int argc, char const *argv[]) {
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// 建構
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Imgraw img = {0, 0, 0, NULL};
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// 讀圖
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Imgraw_Read(&img, "./input/bw2x1.bmp");
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// 寫圖
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Imgraw_Writ(&img, "./output/bw2x1(output).bmp", "./input/bw2x1.bmp");
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return 0;
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}
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/*==============================================================*/ |