在没有其他库的情况下用纯 c/c++ 编写 BMP 图像
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原文地址: http://stackoverflow.com/questions/2654480/
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Writing BMP image in pure c/c++ without other libraries
提问by den bardadym
In my algorithm, I need to create an information output. I need to write a boolean matrix into a bmp file. It must be a monocromic image, where pixels are white if the matrix on such element is true. Main problem is the bmp header and how to write this.
在我的算法中，我需要创建一个信息输出。我需要将一个布尔矩阵写入 bmp 文件。它必须是单色图像，如果此类元素上的矩阵为真，则像素为白色。主要问题是 bmp 标头以及如何编写它。
采纳答案by Brian R. Bondy
Without the use of any other library you can look at the BMP file format. I've implemented it in the past and it can be done without too much work.
无需使用任何其他库就可以查看BMP 文件格式。我过去已经实现了它，不需要太多工作就可以完成。
Bitmap-File Structures
Each bitmap file contains a bitmap-file header, a bitmap-information header, a color table, and an array of bytes that defines the bitmap bits. The file has the following form:
BITMAPFILEHEADER bmfh;
BITMAPINFOHEADER bmih;
RGBQUAD aColors[];
BYTE aBitmapBits[];
位图文件结构
每个位图文件包含一个位图文件头、一个位图信息头、一个颜色表和一个定义位图位的字节数组。该文件具有以下形式：
位图文件头 bmfh;
BITMAPINFOHEADER bmih;
RGBQUAD aColors[];
BYTE aBitmapBits[];
... see the file format for more details
...查看文件格式了解更多详情
回答by deusmacabre
See if this works for you... In this code, I had 3 2-dimensional arrays, called red,green and blue. Each one was of size [width][height], and each element corresponded to a pixel - I hope this makes sense!
看看这是否适合你...在这段代码中，我有 3 个二维数组，分别称为红色、绿色和蓝色。每个元素的大小为 [width][height]，每个元素对应一个像素 - 我希望这是有道理的！
FILE *f;
unsigned char *img = NULL;
int filesize = 54 + 3*w*h; //w is your image width, h is image height, both int
img = (unsigned char *)malloc(3*w*h);
memset(img,0,3*w*h);
for(int i=0; i<w; i++)
{
for(int j=0; j<h; j++)
{
x=i; y=(h-1)-j;
r = red[i][j]*255;
g = green[i][j]*255;
b = blue[i][j]*255;
if (r > 255) r=255;
if (g > 255) g=255;
if (b > 255) b=255;
img[(x+y*w)*3+2] = (unsigned char)(r);
img[(x+y*w)*3+1] = (unsigned char)(g);
img[(x+y*w)*3+0] = (unsigned char)(b);
}
}
unsigned char bmpfileheader[14] = {'B','M', 0,0,0,0, 0,0, 0,0, 54,0,0,0};
unsigned char bmpinfoheader[40] = {40,0,0,0, 0,0,0,0, 0,0,0,0, 1,0, 24,0};
unsigned char bmppad[3] = {0,0,0};
bmpfileheader[ 2] = (unsigned char)(filesize );
bmpfileheader[ 3] = (unsigned char)(filesize>> 8);
bmpfileheader[ 4] = (unsigned char)(filesize>>16);
bmpfileheader[ 5] = (unsigned char)(filesize>>24);
bmpinfoheader[ 4] = (unsigned char)( w );
bmpinfoheader[ 5] = (unsigned char)( w>> 8);
bmpinfoheader[ 6] = (unsigned char)( w>>16);
bmpinfoheader[ 7] = (unsigned char)( w>>24);
bmpinfoheader[ 8] = (unsigned char)( h );
bmpinfoheader[ 9] = (unsigned char)( h>> 8);
bmpinfoheader[10] = (unsigned char)( h>>16);
bmpinfoheader[11] = (unsigned char)( h>>24);
f = fopen("img.bmp","wb");
fwrite(bmpfileheader,1,14,f);
fwrite(bmpinfoheader,1,40,f);
for(int i=0; i<h; i++)
{
fwrite(img+(w*(h-i-1)*3),3,w,f);
fwrite(bmppad,1,(4-(w*3)%4)%4,f);
}
free(img);
fclose(f);
回答by Minhas Kamal
Clean C Code for Bitmap (BMP) Image Generation
用于位图 (BMP) 图像生成的清洁 C 代码
Generated Image:
生成的图像：
The code does not use any library other than stdio.h. So, the code can be easily incorporated in other languages of C-Family, like- C++, C#, Java.
该代码不使用除stdio.h之外的任何库。因此，代码可以很容易地合并到 C 系列的其他语言中，如 C++、C#、Java。
#include <stdio.h>
const int bytesPerPixel = 3; /// red, green, blue
const int fileHeaderSize = 14;
const int infoHeaderSize = 40;
void generateBitmapImage(unsigned char *image, int height, int width, char* imageFileName);
unsigned char* createBitmapFileHeader(int height, int width, int paddingSize);
unsigned char* createBitmapInfoHeader(int height, int width);
int main(){
int height = 341;
int width = 753;
unsigned char image[height][width][bytesPerPixel];
char* imageFileName = "bitmapImage.bmp";
int i, j;
for(i=0; i<height; i++){
for(j=0; j<width; j++){
image[i][j][2] = (unsigned char)((double)i/height*255); ///red
image[i][j][1] = (unsigned char)((double)j/width*255); ///green
image[i][j][0] = (unsigned char)(((double)i+j)/(height+width)*255); ///blue
}
}
generateBitmapImage((unsigned char *)image, height, width, imageFileName);
printf("Image generated!!");
}
void generateBitmapImage(unsigned char *image, int height, int width, char* imageFileName){
unsigned char padding[3] = {0, 0, 0};
int paddingSize = (4 - (width*bytesPerPixel) % 4) % 4;
unsigned char* fileHeader = createBitmapFileHeader(height, width, paddingSize);
unsigned char* infoHeader = createBitmapInfoHeader(height, width);
FILE* imageFile = fopen(imageFileName, "wb");
fwrite(fileHeader, 1, fileHeaderSize, imageFile);
fwrite(infoHeader, 1, infoHeaderSize, imageFile);
int i;
for(i=0; i<height; i++){
fwrite(image+(i*width*bytesPerPixel), bytesPerPixel, width, imageFile);
fwrite(padding, 1, paddingSize, imageFile);
}
fclose(imageFile);
}
unsigned char* createBitmapFileHeader(int height, int width, int paddingSize){
int fileSize = fileHeaderSize + infoHeaderSize + (bytesPerPixel*width+paddingSize) * height;
static unsigned char fileHeader[] = {
0,0, /// signature
0,0,0,0, /// image file size in bytes
0,0,0,0, /// reserved
0,0,0,0, /// start of pixel array
};
fileHeader[ 0] = (unsigned char)('B');
fileHeader[ 1] = (unsigned char)('M');
fileHeader[ 2] = (unsigned char)(fileSize );
fileHeader[ 3] = (unsigned char)(fileSize>> 8);
fileHeader[ 4] = (unsigned char)(fileSize>>16);
fileHeader[ 5] = (unsigned char)(fileSize>>24);
fileHeader[10] = (unsigned char)(fileHeaderSize + infoHeaderSize);
return fileHeader;
}
unsigned char* createBitmapInfoHeader(int height, int width){
static unsigned char infoHeader[] = {
0,0,0,0, /// header size
0,0,0,0, /// image width
0,0,0,0, /// image height
0,0, /// number of color planes
0,0, /// bits per pixel
0,0,0,0, /// compression
0,0,0,0, /// image size
0,0,0,0, /// horizontal resolution
0,0,0,0, /// vertical resolution
0,0,0,0, /// colors in color table
0,0,0,0, /// important color count
};
infoHeader[ 0] = (unsigned char)(infoHeaderSize);
infoHeader[ 4] = (unsigned char)(width );
infoHeader[ 5] = (unsigned char)(width>> 8);
infoHeader[ 6] = (unsigned char)(width>>16);
infoHeader[ 7] = (unsigned char)(width>>24);
infoHeader[ 8] = (unsigned char)(height );
infoHeader[ 9] = (unsigned char)(height>> 8);
infoHeader[10] = (unsigned char)(height>>16);
infoHeader[11] = (unsigned char)(height>>24);
infoHeader[12] = (unsigned char)(1);
infoHeader[14] = (unsigned char)(bytesPerPixel*8);
return infoHeader;
}
回答by ralf htp
this is the best low level example i know, written by Evercat. copied from https://en.wikipedia.org/wiki/User:Evercat/Buddhabrot.c
这是我所知道的最好的低级示例，由 Evercat 编写。复制自 https://en.wikipedia.org/wiki/User:Evercat/Buddhabrot.c
void drawbmp (char * filename) {
unsigned int headers[13];
FILE * outfile;
int extrabytes;
int paddedsize;
int x; int y; int n;
int red, green, blue;
extrabytes = 4 - ((WIDTH * 3) % 4); // How many bytes of padding to add to each
// horizontal line - the size of which must
// be a multiple of 4 bytes.
if (extrabytes == 4)
extrabytes = 0;
paddedsize = ((WIDTH * 3) + extrabytes) * HEIGHT;
// Headers...
// Note that the "BM" identifier in bytes 0 and 1 is NOT included in these "headers".
headers[0] = paddedsize + 54; // bfSize (whole file size)
headers[1] = 0; // bfReserved (both)
headers[2] = 54; // bfOffbits
headers[3] = 40; // biSize
headers[4] = WIDTH; // biWidth
headers[5] = HEIGHT; // biHeight
// Would have biPlanes and biBitCount in position 6, but they're shorts.
// It's easier to write them out separately (see below) than pretend
// they're a single int, especially with endian issues...
headers[7] = 0; // biCompression
headers[8] = paddedsize; // biSizeImage
headers[9] = 0; // biXPelsPerMeter
headers[10] = 0; // biYPelsPerMeter
headers[11] = 0; // biClrUsed
headers[12] = 0; // biClrImportant
outfile = fopen(filename, "wb");
//
// Headers begin...
// When printing ints and shorts, we write out 1 character at a time to avoid endian issues.
//
fprintf(outfile, "BM");
for (n = 0; n <= 5; n++)
{
fprintf(outfile, "%c", headers[n] & 0x000000FF);
fprintf(outfile, "%c", (headers[n] & 0x0000FF00) >> 8);
fprintf(outfile, "%c", (headers[n] & 0x00FF0000) >> 16);
fprintf(outfile, "%c", (headers[n] & (unsigned int) 0xFF000000) >> 24);
}
// These next 4 characters are for the biPlanes and biBitCount fields.
fprintf(outfile, "%c", 1);
fprintf(outfile, "%c", 0);
fprintf(outfile, "%c", 24);
fprintf(outfile, "%c", 0);
for (n = 7; n <= 12; n++)
{
fprintf(outfile, "%c", headers[n] & 0x000000FF);
fprintf(outfile, "%c", (headers[n] & 0x0000FF00) >> 8);
fprintf(outfile, "%c", (headers[n] & 0x00FF0000) >> 16);
fprintf(outfile, "%c", (headers[n] & (unsigned int) 0xFF000000) >> 24);
}
//
// Headers done, now write the data...
//
for (y = HEIGHT - 1; y >= 0; y--) // BMP image format is written from bottom to top...
{
for (x = 0; x <= WIDTH - 1; x++)
{
red = reduce(redcount[x][y] + COLOUR_OFFSET) * red_multiplier;
green = reduce(greencount[x][y] + COLOUR_OFFSET) * green_multiplier;
blue = reduce(bluecount[x][y] + COLOUR_OFFSET) * blue_multiplier;
if (red > 255) red = 255; if (red < 0) red = 0;
if (green > 255) green = 255; if (green < 0) green = 0;
if (blue > 255) blue = 255; if (blue < 0) blue = 0;
// Also, it's written in (b,g,r) format...
fprintf(outfile, "%c", blue);
fprintf(outfile, "%c", green);
fprintf(outfile, "%c", red);
}
if (extrabytes) // See above - BMP lines must be of lengths divisible by 4.
{
for (n = 1; n <= extrabytes; n++)
{
fprintf(outfile, "%c", 0);
}
}
}
fclose(outfile);
return;
}
drawbmp(filename);
回答by codymanix
Note that the lines are saved from down to up and not the other way around.
请注意，线条是从下到上保存的，而不是相反。
Additionally, the scanlines must have a byte-length of multiples of four, you should insert fill bytes at the end of the lines to ensure this.
此外，扫描线的字节长度必须是四的倍数，您应该在行尾插入填充字节以确保这一点。
回答by Cullen Fluffy Jennings
Here is a C++ variant of the code that works for me. Note I had to change the size computation to account for the line padding.
这是适用于我的代码的 C++ 变体。请注意，我必须更改大小计算以考虑行填充。
// mimeType = "image/bmp";
unsigned char file[14] = {
'B','M', // magic
0,0,0,0, // size in bytes
0,0, // app data
0,0, // app data
40+14,0,0,0 // start of data offset
};
unsigned char info[40] = {
40,0,0,0, // info hd size
0,0,0,0, // width
0,0,0,0, // heigth
1,0, // number color planes
24,0, // bits per pixel
0,0,0,0, // compression is none
0,0,0,0, // image bits size
0x13,0x0B,0,0, // horz resoluition in pixel / m
0x13,0x0B,0,0, // vert resolutions (0x03C3 = 96 dpi, 0x0B13 = 72 dpi)
0,0,0,0, // #colors in pallete
0,0,0,0, // #important colors
};
int w=waterfallWidth;
int h=waterfallHeight;
int padSize = (4-(w*3)%4)%4;
int sizeData = w*h*3 + h*padSize;
int sizeAll = sizeData + sizeof(file) + sizeof(info);
file[ 2] = (unsigned char)( sizeAll );
file[ 3] = (unsigned char)( sizeAll>> 8);
file[ 4] = (unsigned char)( sizeAll>>16);
file[ 5] = (unsigned char)( sizeAll>>24);
info[ 4] = (unsigned char)( w );
info[ 5] = (unsigned char)( w>> 8);
info[ 6] = (unsigned char)( w>>16);
info[ 7] = (unsigned char)( w>>24);
info[ 8] = (unsigned char)( h );
info[ 9] = (unsigned char)( h>> 8);
info[10] = (unsigned char)( h>>16);
info[11] = (unsigned char)( h>>24);
info[20] = (unsigned char)( sizeData );
info[21] = (unsigned char)( sizeData>> 8);
info[22] = (unsigned char)( sizeData>>16);
info[23] = (unsigned char)( sizeData>>24);
stream.write( (char*)file, sizeof(file) );
stream.write( (char*)info, sizeof(info) );
unsigned char pad[3] = {0,0,0};
for ( int y=0; y<h; y++ )
{
for ( int x=0; x<w; x++ )
{
long red = lround( 255.0 * waterfall[x][y] );
if ( red < 0 ) red=0;
if ( red > 255 ) red=255;
long green = red;
long blue = red;
unsigned char pixel[3];
pixel[0] = blue;
pixel[1] = green;
pixel[2] = red;
stream.write( (char*)pixel, 3 );
}
stream.write( (char*)pad, padSize );
}
回答by Ignacio Hermosilla
I edited ralf's htp code so that it would compile (on gcc, running ubuntu 16.04 lts). It was just a matter of initializing the variables.
我编辑了 ralf 的 htp 代码，以便它可以编译（在 gcc 上，运行 ubuntu 16.04 lts）。这只是初始化变量的问题。
int w = 100; /* Put here what ever width you want */
int h = 100; /* Put here what ever height you want */
int red[w][h];
int green[w][h];
int blue[w][h];
FILE *f;
unsigned char *img = NULL;
int filesize = 54 + 3*w*h; //w is your image width, h is image height, both int
if( img )
free( img );
img = (unsigned char *)malloc(3*w*h);
memset(img,0,sizeof(img));
int x;
int y;
int r;
int g;
int b;
for(int i=0; i<w; i++)
{
for(int j=0; j<h; j++)
{
x=i; y=(h-1)-j;
r = red[i][j]*255;
g = green[i][j]*255;
b = blue[i][j]*255;
if (r > 255) r=255;
if (g > 255) g=255;
if (b > 255) b=255;
img[(x+y*w)*3+2] = (unsigned char)(r);
img[(x+y*w)*3+1] = (unsigned char)(g);
img[(x+y*w)*3+0] = (unsigned char)(b);
}
}
unsigned char bmpfileheader[14] = {'B','M', 0,0,0,0, 0,0, 0,0, 54,0,0,0};
unsigned char bmpinfoheader[40] = {40,0,0,0, 0,0,0,0, 0,0,0,0, 1,0, 24,0};
unsigned char bmppad[3] = {0,0,0};
bmpfileheader[ 2] = (unsigned char)(filesize );
bmpfileheader[ 3] = (unsigned char)(filesize>> 8);
bmpfileheader[ 4] = (unsigned char)(filesize>>16);
bmpfileheader[ 5] = (unsigned char)(filesize>>24);
bmpinfoheader[ 4] = (unsigned char)( w );
bmpinfoheader[ 5] = (unsigned char)( w>> 8);
bmpinfoheader[ 6] = (unsigned char)( w>>16);
bmpinfoheader[ 7] = (unsigned char)( w>>24);
bmpinfoheader[ 8] = (unsigned char)( h );
bmpinfoheader[ 9] = (unsigned char)( h>> 8);
bmpinfoheader[10] = (unsigned char)( h>>16);
bmpinfoheader[11] = (unsigned char)( h>>24);
f = fopen("img.bmp","wb");
fwrite(bmpfileheader,1,14,f);
fwrite(bmpinfoheader,1,40,f);
for(int i=0; i<h; i++)
{
fwrite(img+(w*(h-i-1)*3),3,w,f);
fwrite(bmppad,1,(4-(w*3)%4)%4,f);
}
fclose(f);
回答by blueshogun96
I just wanted to share an improved version of Minhas Kamal's code because although it worked well enough for most applications, I had a few issues with it still. Two highly important things to remember:
我只是想分享 Minhas Kamal 代码的改进版本，因为尽管它对于大多数应用程序来说已经足够好了，但我仍然遇到了一些问题。要记住两件非常重要的事情：
- The code (at the time of writing) calls free() on two static arrays. This will cause your program to crash. So I commented out those lines.
- NEVER assume that your pixel data's pitch is always (Width*BytesPerPixel). It's best to let the user specify the pitch value. Example: when manipulating resources in Direct3D, the RowPitch is never guaranteed to be an even multiple of the byte depth being used. This can cause errors in your generated bitmaps (especially at odd resolutions such as 1366x768).
- 代码（在撰写本文时）在两个静态数组上调用 free()。这将导致您的程序崩溃。所以我注释掉了这些行。
- 永远不要假设你的像素数据的间距总是 (Width*BytesPerPixel)。最好让用户指定音高值。示例：在 Direct3D 中操作资源时，RowPitch 永远不能保证是所用字节深度的偶数倍。这可能会导致生成的位图出现错误（尤其是在奇数分辨率下，例如 1366x768）。
Below, you can see my revisions to his code:
下面，你可以看到我对他的代码的修改：
const int bytesPerPixel = 4; /// red, green, blue
const int fileHeaderSize = 14;
const int infoHeaderSize = 40;
void generateBitmapImage(unsigned char *image, int height, int width, int pitch, const char* imageFileName);
unsigned char* createBitmapFileHeader(int height, int width, int pitch, int paddingSize);
unsigned char* createBitmapInfoHeader(int height, int width);
void generateBitmapImage(unsigned char *image, int height, int width, int pitch, const char* imageFileName) {
unsigned char padding[3] = { 0, 0, 0 };
int paddingSize = (4 - (/*width*bytesPerPixel*/ pitch) % 4) % 4;
unsigned char* fileHeader = createBitmapFileHeader(height, width, pitch, paddingSize);
unsigned char* infoHeader = createBitmapInfoHeader(height, width);
FILE* imageFile = fopen(imageFileName, "wb");
fwrite(fileHeader, 1, fileHeaderSize, imageFile);
fwrite(infoHeader, 1, infoHeaderSize, imageFile);
int i;
for (i = 0; i < height; i++) {
fwrite(image + (i*pitch /*width*bytesPerPixel*/), bytesPerPixel, width, imageFile);
fwrite(padding, 1, paddingSize, imageFile);
}
fclose(imageFile);
//free(fileHeader);
//free(infoHeader);
}
unsigned char* createBitmapFileHeader(int height, int width, int pitch, int paddingSize) {
int fileSize = fileHeaderSize + infoHeaderSize + (/*bytesPerPixel*width*/pitch + paddingSize) * height;
static unsigned char fileHeader[] = {
0,0, /// signature
0,0,0,0, /// image file size in bytes
0,0,0,0, /// reserved
0,0,0,0, /// start of pixel array
};
fileHeader[0] = (unsigned char)('B');
fileHeader[1] = (unsigned char)('M');
fileHeader[2] = (unsigned char)(fileSize);
fileHeader[3] = (unsigned char)(fileSize >> 8);
fileHeader[4] = (unsigned char)(fileSize >> 16);
fileHeader[5] = (unsigned char)(fileSize >> 24);
fileHeader[10] = (unsigned char)(fileHeaderSize + infoHeaderSize);
return fileHeader;
}
unsigned char* createBitmapInfoHeader(int height, int width) {
static unsigned char infoHeader[] = {
0,0,0,0, /// header size
0,0,0,0, /// image width
0,0,0,0, /// image height
0,0, /// number of color planes
0,0, /// bits per pixel
0,0,0,0, /// compression
0,0,0,0, /// image size
0,0,0,0, /// horizontal resolution
0,0,0,0, /// vertical resolution
0,0,0,0, /// colors in color table
0,0,0,0, /// important color count
};
infoHeader[0] = (unsigned char)(infoHeaderSize);
infoHeader[4] = (unsigned char)(width);
infoHeader[5] = (unsigned char)(width >> 8);
infoHeader[6] = (unsigned char)(width >> 16);
infoHeader[7] = (unsigned char)(width >> 24);
infoHeader[8] = (unsigned char)(height);
infoHeader[9] = (unsigned char)(height >> 8);
infoHeader[10] = (unsigned char)(height >> 16);
infoHeader[11] = (unsigned char)(height >> 24);
infoHeader[12] = (unsigned char)(1);
infoHeader[14] = (unsigned char)(bytesPerPixel * 8);
return infoHeader;
}
回答by IInspectable
The best bitmap encoder is the one you do not write yourself. The file format is a lot more involved, than one might expect. This is evidenced by the fact, that all proposed answers do not create a monochrome (1bpp) bitmap, but rather write out 24bpp files, that happen to only use 2 colors.
最好的位图编码器不是您自己编写的。文件格式比人们想象的要复杂得多。事实证明，所有建议的答案都不会创建单色 (1bpp) 位图，而是写出 24bpp 文件，而这些文件恰好仅使用 2 种颜色。
The following is a Windows-only solution, using the Windows Imaging Component. It doesn't rely on any external/3rd party libraries, other than what ships with Windows.
以下是使用Windows Imaging Component的仅限 Windows 的解决方案。除了 Windows 附带的库之外，它不依赖于任何外部/第 3 方库。
Like every C++ program, we need to include several header files. And link to Windowscodecs.libwhile we're at it:
像每个 C++ 程序一样，我们需要包含几个头文件。并在我们使用它时链接到Windowscodecs.lib：
#include <Windows.h>
#include <comdef.h>
#include <comip.h>
#include <comutil.h>
#include <wincodec.h>
#include <vector>
#pragma comment(lib, "Windowscodecs.lib")
Next up, we declare our container (a vector, of vectors! Of bool!), and a few smart pointers for convenience:
接下来，我们声明我们的容器（一个向量，向量！的bool！），以及一些为方便起见的智能指针：
using _com_util::CheckError;
using container = std::vector<std::vector<bool>>;
_COM_SMARTPTR_TYPEDEF(IWICImagingFactory, __uuidof(IWICImagingFactory));
_COM_SMARTPTR_TYPEDEF(IWICBitmapEncoder, __uuidof(IWICBitmapEncoder));
_COM_SMARTPTR_TYPEDEF(IWICBitmapFrameEncode, __uuidof(IWICBitmapFrameEncode));
_COM_SMARTPTR_TYPEDEF(IWICStream, __uuidof(IWICStream));
_COM_SMARTPTR_TYPEDEF(IWICPalette, __uuidof(IWICPalette));
With that all settled, we can jump right into the implementation. There's a bit of setup required to get a factory, an encoder, a frame, and get everything prepared:
一切都解决了之后，我们就可以直接进入实施阶段了。要获得工厂、编码器、框架并准备好一切，需要进行一些设置：
void write_bitmap(wchar_t const* pathname, container const& data)
{
// Create factory
IWICImagingFactoryPtr sp_factory { nullptr };
CheckError(sp_factory.CreateInstance(CLSID_WICImagingFactory, nullptr,
CLSCTX_INPROC_SERVER));
// Create encoder
IWICBitmapEncoderPtr sp_encoder { nullptr };
CheckError(sp_factory->CreateEncoder(GUID_ContainerFormatBmp, nullptr, &sp_encoder));
// Create stream
IWICStreamPtr sp_stream { nullptr };
CheckError(sp_factory->CreateStream(&sp_stream));
CheckError(sp_stream->InitializeFromFilename(pathname, GENERIC_WRITE));
// Initialize encoder with stream
CheckError(sp_encoder->Initialize(sp_stream, WICBitmapEncoderNoCache));
// Create new frame
IWICBitmapFrameEncodePtr sp_frame { nullptr };
IPropertyBag2Ptr sp_properties { nullptr };
CheckError(sp_encoder->CreateNewFrame(&sp_frame, &sp_properties));
// Initialize frame with default properties
CheckError(sp_frame->Initialize(sp_properties));
// Set pixel format
// SetPixelFormat() requires a pointer to non-const
auto pf { GUID_WICPixelFormat1bppIndexed };
CheckError(sp_frame->SetPixelFormat(&pf));
if (!::IsEqualGUID(pf, GUID_WICPixelFormat1bppIndexed))
{
// Report unsupported pixel format
CheckError(WINCODEC_ERR_UNSUPPORTEDPIXELFORMAT);
}
// Set size derived from data argument
auto const width { static_cast<UINT>(data.size()) };
auto const height { static_cast<UINT>(data[0].size()) };
CheckError(sp_frame->SetSize(width, height));
// Set palette on frame. This is required since we use an indexed pixel format.
// Only GIF files support global palettes, so make sure to set it on the frame
// rather than the encoder.
IWICPalettePtr sp_palette { nullptr };
CheckError(sp_factory->CreatePalette(&sp_palette));
CheckError(sp_palette->InitializePredefined(WICBitmapPaletteTypeFixedBW, FALSE));
CheckError(sp_frame->SetPalette(sp_palette));
At that point everything is set up, and we have a frame to dump our data into. For 1bpp files, every byte stores the information of 8 pixels. The left-most pixel is stored in the MSB, with pixels following all the way down to the right-most pixel stored in the LSB.
到那时，一切都已设置完毕，我们有一个框架可以将数据转储到其中。对于 1bpp 的文件，每个字节存储 8 个像素的信息。最左边的像素存储在 MSB 中，像素一直到最右边的像素存储在 LSB 中。
The code isn't entirely important; you'll be replacing that with whatever suits your needs, when you replace the data layout of your input anyway:
代码并不完全重要；无论如何，当您替换输入的数据布局时，您将使用适合您需要的任何内容替换它：
// Write data to frame
auto const stride { (width * 1 + 7) / 8 };
auto const size { height * stride };
std::vector<unsigned char> buffer(size, 127u);
// Convert data to match required layout. Each byte stores 8 pixels, with the
// MSB being the leftmost, the LSB the right-most.
for (size_t x { 0 }; x < data.size(); ++x)
{
for (size_t y { 0 }; y < data[x].size(); ++y)
{
auto shift { x % 8 };
auto mask { 0x80 >> shift };
auto bit { mask * data[x][y] };
auto& value { buffer[y * stride + x / 8] };
value &= ~mask;
value |= bit;
}
}
CheckError(sp_frame->WritePixels(height, stride,
static_cast<UINT>(buffer.size()), buffer.data()));
What's left is to commit the changes to the frame and the encoder, which will ultimately write the image file to disk:
剩下的就是提交对帧和编码器的更改，最终将图像文件写入磁盘：
// Commit frame
CheckError(sp_frame->Commit());
// Commit image
CheckError(sp_encoder->Commit());
}
This is a test program, writing out an image to a file passed as the first command-line argument:
这是一个测试程序，将图像写入作为第一个命令行参数传递的文件：
#include <iostream>
int wmain(int argc, wchar_t* argv[])
try
{
if (argc != 2)
{
return -1;
}
CheckError(::CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED));
// Create 64x64 matrix
container data(64, std::vector<bool>(64, false));
// Fill with arrow pointing towards the upper left
for (size_t i { 0 }; i < data.size(); ++i)
{
data[0][i] = true;
data[i][0] = true;
data[i][i] = true;
}
::write_bitmap(argv[1], data);
::CoUninitialize();
}
catch (_com_error const& e)
{
std::wcout << L"Error!\n" << L" Message: " << e.ErrorMessage() << std::endl;
}
It produces the following image (true 1bpp, 574 bytes in size):
它生成以下图像（真正的 1bpp，大小为 574 字节）：
回答by Hadrien Milano
If you get strange colors switches in the middle of your image using the above C++ function. Be sure to open the outstream in binary mode:
imgFile.open(filename, std::ios_base::out | std::ios_base::binary);
Otherwise windows inserts unwanted characters in the middle of your file! (been banging my head on this issue for hours)
如果使用上述 C++ 函数在图像中间出现奇怪的颜色切换。确保以二进制模式打开外流：
imgFile.open(filename, std::ios_base::out | std::ios_base::binary);
否则 Windows 会在文件中间插入不需要的字符！（几个小时以来一直在这个问题上敲我的头）
See related question here: Why does ofstream insert a 0x0D byte before 0x0A?
请参阅此处的相关问题：为什么 ofstream 在 0x0A 之前插入 0x0D 字节？
