#include <Windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
 
int main(int argc, char ** argv)
{
	FILE *fp = fopen("C:\\Users\\leong\\Desktop\\bmp_exam\\input\\hello.bmp","rb");
	if (fp == 0)
		return 0;
	BITMAPFILEHEADER fileHead;
	fread(&fileHead, sizeof(BITMAPFILEHEADER), 1, fp);
	BITMAPINFOHEADER infoHead;
	fread(&infoHead, sizeof(BITMAPINFOHEADER), 1, fp);
	int width = infoHead.biWidth;
	int height = infoHead.biHeight;
	int biCount = infoHead.biBitCount;
 
	RGBQUAD *pColorTable;
	int pColorTableSize = 0;
 
	pColorTable = new RGBQUAD[256];
	fread(pColorTable, sizeof(RGBQUAD), 256, fp);
	pColorTableSize = 1024;
 
	unsigned char *pBmpBuf;
	int lineByte = width*floor(biCount/8);
	while(lineByte % 4 != 0){lineByte += 1;}
	pBmpBuf = new unsigned char[lineByte*height];
	fread(pBmpBuf, lineByte*height, 1, fp);
	fclose(fp);
 
	printf("倍：");
	// float lx, ly;
	// scanf("%f%f", &lx, &ly);
	// int dstWidth = round(double(lx*width));
	// int dstHeight = round(double(ly*height));
	float k;
	scanf("%f", &k);
	int dstWidth = round(double(k*width));
	int dstHeight = round(double(k*height));
	int lineByte2 = dstWidth*floor(biCount/8);
	while(lineByte2 % 4 != 0){lineByte2 += 1;}
	
	unsigned char*pBmpBuf2;
	pBmpBuf2 = new unsigned char[lineByte2*dstHeight];
	for (int i = 0; i < dstHeight; ++i){
		for (int j = 0; j < dstWidth; ++j){
			unsigned char *p;
			p = (unsigned char *)(pBmpBuf2 + lineByte2*i + j);
			(*p) = 255;
		}
	}
	int x = 0;
	int y = 0;
	for(int i = 0; i < height; ++i){
		for(int j = 0; j < width; ++j){
			unsigned char *p1, *p2;
			// x = round(double(lx*j));
			// y = round(double(ly*i));
			x = round(double(k*j));
			y = round(double(k*i));
			p1 = (unsigned char *)(pBmpBuf + i*lineByte + j);
			p2 = (unsigned char *)(pBmpBuf2 + y*lineByte2 + x);
			(*p2) = (*p1);
		}
	}
 
	FILE *fpo = fopen("C:\\Users\\leong\\Desktop\\bmp_exam\\output\\output.bmp", "wb");
	if (fpo == 0)
		return 0;
	BITMAPFILEHEADER dstFileHead;
	dstFileHead.bfOffBits = 14 + 40 + pColorTableSize;
	dstFileHead.bfReserved1 = 0;
	dstFileHead.bfReserved2 = 0;
	dstFileHead.bfSize = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+pColorTableSize + lineByte2*dstHeight;
	dstFileHead.bfType = 0x4D42;
	fwrite(&dstFileHead, sizeof(dstFileHead), 1, fpo);
 
	BITMAPINFOHEADER dstInfoHead;
	dstInfoHead.biBitCount = biCount;
	dstInfoHead.biClrImportant = 0;
	dstInfoHead.biClrUsed = 0;
	dstInfoHead.biCompression = 0;
	dstInfoHead.biHeight = dstHeight;
	dstInfoHead.biPlanes = 1;
	dstInfoHead.biSize = 40;
	dstInfoHead.biSizeImage = lineByte2*dstHeight;
	dstInfoHead.biWidth = dstWidth;
	dstInfoHead.biXPelsPerMeter = 0;
	dstInfoHead.biYPelsPerMeter = 0;
	fwrite(&dstInfoHead, sizeof(BITMAPINFOHEADER), 1, fpo);
 
	fwrite(pColorTable, sizeof(RGBQUAD), 256, fpo);
	fwrite(pBmpBuf2, lineByte2*dstHeight, 1, fp);
	fclose(fpo);
 
	system("pause");
	return 0;
}