如何在WinCE中创建.bmp [英] How to create a .bmp in WinCE
问题描述
我有一个照相机返回原始图像，这些原始图像可以很容易地转换为可以通过以下C#方法(我没有写过)保存到文件中的位图.从各种来源来看，我确定这些图片每个像素有8位，并且可能是灰度，也可能不是灰度.
I have a camera that returns raw images that can easily be converted to a bitmap that can be saved to a file by the following C# method (that I did not write). From various sources, I have determined that the pictures have 8 bits per pixel, and may or may not be grayscale.
private void rawImgToBmp(byte[] imgData, String fname) {
Bitmap bmp = new Bitmap(getWidth(), getHeight(),
System.Drawing.Imaging.PixelFormat.Format8bppIndexed);
for (int i = 0; i < 256; i++)
{ bmp.Palette.Entries[i] = Color.FromArgb(255, i, i, i); }
//Copy the data from the byte array into the bitmap
BitmapData bmpData =
bmp.LockBits( new Rectangle(0, 0, bmp.Width, bmp.Height),
ImageLockMode.WriteOnly, bmp.PixelFormat);
Marshal.Copy(imgData, 0, bmpData.Scan0, getWidth() * getHeight());
bmp.UnlockBits(bmpData); //Unlock the pixels
bmp.Save(FileName);
}
我的问题是:我将如何使用Windows CE 4.2的内置功能以C ++编写等效方法?
My question is: how would I go about writing the equivalent method in C++, using built in functions of Windows CE 4.2?
erisu:感谢您提供的调色板代码，我认为是正确的.根据 Wikipedia 页的介绍，我不得不手动填充其余结构.
erisu: thanks for the palette code, I think it's right. I've resorted to filling in the rest of the structs manually, according to the Wikipedia page.
推荐答案
这是对我有用的代码.它基于erisu的答案和 Wikipedia对BMP格式的描述.对于使用此答案的其他任何人，我建议您尽可能全面地了解BMP格式，以便可以相应地调整标题字段.
This is the code that works for me. It is based on erisu's answer and Wikipedia's description of the BMP format. For anyone else using this answer, I recommend that you understand the BMP format as fully as possible, so you can adjust the header fields accordingly.
最后的复杂循环是我针对硬件/操作系统问题的解决方法，在该问题中，它不会写入我提供给fwrite的所有数据.不过，它应该可以在任何环境下工作.
The complicated loop at the end is my workaround for an issue with my hardware/OS, where it would not write all of the data I supplied to fwrite. It should work in any environment, though.
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <tchar.h>
#define NPAL_ENT 256
INT WINAPI WinMain( HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPTSTR lpCmdLine,
INT nShowCmd )
{
int w = 1920, h = 1080; // My values, yours may vary
//////////////////////// File Operations ///////////////////////////////
// Reading raw img
FILE* f = fopen("\\FlashDisk\\raw_img.bin","r");
if(NULL == f){printf("BAD");exit(1);}
// Obtaining size of raw img
fseek (f , 0L , SEEK_END);
DWORD fsize = (DWORD)ftell (f);
fseek (f , 0L , SEEK_SET);
char *imgData = (char*) malloc (sizeof(char)*fsize);
if(NULL == imgData) {printf("NOT imgData");exit(2);}
// Copy contents of file into buffer
DWORD result = fread(imgData,1,fsize,f);
if (result != fsize) {
printf ("Reading error. Expected: %d, Got: %d\n",fsize, result );
if(ferror(f)){printf("An error: %d\n", ferror(f)); }
if(feof(f)) {printf("EOF\n");}
delete[] imgData;
fclose(f);
exit (3);
}
fclose(f);
//////////////////////// BMP Operations ///////////////////////////////
/* A bitmap has the following components:
* 1. BMP file header
* 2. Bitmap Information (DIB) header
* 3. Color Palette
* 4. Raw Data
*/
BITMAPFILEHEADER bmfh;
ZeroMemory( &bmfh, sizeof( bmfh ) );
bmfh.bfType = 0x4D42; // Magic #
bmfh.bfSize = sizeof( bmfh ) + sizeof( BITMAPINFOHEADER )
+ NPAL_ENT*sizeof(PALETTEENTRY) + w*h; // Or total file size if w/h not known
bmfh.bfOffBits = sizeof( bmfh ) + sizeof( BITMAPINFOHEADER )
+ NPAL_ENT*sizeof(PALETTEENTRY);
BITMAPINFOHEADER bmih;
ZeroMemory( &bmih, sizeof( bmih ) );
bmih.biWidth = w;
bmih.biHeight = h;
bmih.biSize = sizeof(bmih);
bmih.biPlanes = 1;
bmih.biBitCount = 8;
bmih.biCompression = BI_RGB;
bmih.biSizeImage = w * h;
int palSize = NPAL_ENT*sizeof(PALETTEENTRY);
LOGPALETTE *logpal=(LOGPALETTE*)new BYTE[sizeof(LOGPALETTE)+palSize];
if(!logpal) {delete [] imgData; printf("!logpal\n"); exit(4);}
logpal->palVersion=0x300;
logpal->palNumEntries=NPAL_ENT;
int i=0;
do { // Exact palette format varies. This is what worked for me
logpal->palPalEntry[i].peRed=i;
logpal->palPalEntry[i].peGreen=i;
logpal->palPalEntry[i].peBlue=i;
logpal->palPalEntry[i].peFlags=NULL;
} while(++i<NPAL_ENT);
// Complete bitmap is now in memory, time to save it
TCHAR bmpfname[80];
wsprintf( bmpfname, (TCHAR*) TEXT( "\\USBDisk\\out.bmp" ) );
// open the file for writing
FILE *bmpFile = _wfopen(bmpfname,L"wb");
if(!bmpFile) { delete[] imgData; delete[] logpal; exit(6); }
// write the bitmap to file, in whatever chunks WinCE allows
size_t totWrit = 0, offset = 0, writeAmt = 0;
while(totWrit < bmfh.bfSize){
if(totWrit < sizeof(bmfh)){ // File header
offset = totWrit;
totWrit += fwrite( ((char*)&bmfh)+offset, 1, sizeof(bmfh)-offset, bmpFile );
}
else if(totWrit<sizeof(bmfh)+sizeof(bmih)){ // Image header
offset = totWrit - sizeof(bmfh);
totWrit += fwrite( ((char*)&bmih)+offset, 1, sizeof(bmih)-offset, bmpFile );
}
else if(totWrit<sizeof(bmfh)+sizeof(bmih)+palSize) { // Pallette
offset = totWrit - sizeof(bmfh) - sizeof(bmih);
totWrit += fwrite( ((char*)&logpal->palPalEntry)+offset, 1, palSize-offset, bmpFile );
}
else { // Image data
offset = totWrit - sizeof(bmfh) - sizeof(bmih) - palSize;
if(bmfh.bfSize-totWrit >= IO_SIZE) {
writeAmt = IO_SIZE;
}
else {
writeAmt = bmfh.bfSize-totWrit;
}
totWrit += fwrite( &imageBuffer[offset], 1, writeAmt, bmpFile );
}
// Close and open after each iteration to please WinCE
fflush(bmpFile);
fclose(bmpFile);
Sleep(4000);
bmpFile = _wfopen(bmpfname,L"ab");
if(!bmpFile) {flog->lprintf("Couldn't reopen bmpfile"); delete [] logpal; return 0;}
}
fclose(bmpFile);
if(totWrit != bmfh.bfSize) {
printf("BMP Size mismatch: %d/%d.",totWrit,bmfh.bfSize);
delete [] imgData;
delete [] logpal;
exit(-1);
}
// Cleanup
delete [] imgData;
delete [] logpal;
return 0;
}
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