如何将像素数组转换为HBITMAP

How to convert an Array of pixels to HBITMAP

本文关键字：转换 HBITMAP 数组 像素数 像素      更新时间：2023-10-16

我有一个像素数组，我需要将其转换为HBITMAP以便在窗口中显示它。我试图使用CreateDIBitmap()，但我没有BMP头。我试图根据MSDN文档手动构建它们，但这不起作用。

我的代码是这样的

HBITMAP hBitmap
char pixels[160*120]; // White grayscale image of size 160x120
memset(pixels,255,sizeof(pixels));
BITMAPINFOHEADER bmih;
bmih.biSize     = sizeof(BITMAPINFOHEADER);
bmih.biWidth    = 160;
bmih.biHeight   = -120;
bmih.biPlanes   = 1;
bmih.biBitCount = 8;
bmih.biCompression  = BI_RGB ;
bmih.biSizeImage    = 0;
bmih.biXPelsPerMeter    =   10;
bmih.biYPelsPerMeter    =   10;
bmih.biClrUsed  =0;
bmih.biClrImportant =0;
BITMAPINFO dbmi;
dbmi.bmiHeader = bmih;
dbmi.bmiColors->rgbBlue = 0;
dbmi.bmiColors->rgbGreen = 0;
dbmi.bmiColors->rgbRed = 0;
dbmi.bmiColors->rgbReserved = 0;
void* bits = (void*)&(pixels[0]); 
hBitmap = CreateDIBitmap(localDC, &bmih, CBM_INIT, qB.bmBits, &dbmi, DIB_RGB_COLORS);

现在我得到了一个非NULL的hBitmap，这很好，但它总是显示黑色图像，好像它没有指向像素数组。我使用代码

检查它
BITMAP qB;
GetObject(reinterpret_cast<HGDIOBJ>(hBitmap),sizeof(BITMAP),reinterpret_cast<LPVOID>(&qB));

确实qB。bmBits为NULL。问题是什么?如何解决?

我知道怎么做了。我们需要用CreateDIBSection()代替CreateDIBitmap()下面是工作代码

HBITMAP hBitmap = NULL;
    unsigned char pixels[160*120*3]; 
    for (int i=0; i<160*120*3; i++){
        pixels[i] = (i%4==1)*255;        // An BGR (not RGB) 160x120 image.
    }
BITMAPINFOHEADER bmih;
bmih.biSize     = sizeof(BITMAPINFOHEADER);
bmih.biWidth    = 160;
bmih.biHeight   = -120;
bmih.biPlanes   = 1;
bmih.biBitCount = 24;
bmih.biCompression  = BI_RGB ;
bmih.biSizeImage    = 0;
bmih.biXPelsPerMeter    =   10;
bmih.biYPelsPerMeter    =   10;
bmih.biClrUsed    =0;
bmih.biClrImportant =0;
BITMAPINFO dbmi;
ZeroMemory(&dbmi, sizeof(dbmi));  
dbmi.bmiHeader = bmih;
dbmi.bmiColors->rgbBlue = 0;
dbmi.bmiColors->rgbGreen = 0;
dbmi.bmiColors->rgbRed = 0;
dbmi.bmiColors->rgbReserved = 0;
void* bits = (void*)&(pixels[0]); 
// Create DIB
hBitmap = CreateDIBSection(localDC, &dbmi, DIB_RGB_COLORS, &bits, NULL, 0);
if (hBitmap == NULL) {
    ::MessageBox(NULL, __T("Could not load the desired image image"), __T("Error"), MB_OK);
    return;
}
// copy pixels into DIB.
memcpy(bits,pixels,sizeof(pixels));

对于灰度级图像，在循环中将像素复制到DIB，而不是使用memcpy()

#define INTENSITY unsigned char
INTENSITY* dest = (INTENSITY*)bits;
const INTENSITY* src  = .. Put your char array of pixels;
for (int j=0; j<imageWidth; j++){
    for (int i=0; i<imageHeight; i++, src++){
        *dest++ = *src;
        *dest++ = *src;
        *dest++ = *src;
    }
    // Padd the line to round WORD.
    if (imageWidth%2)
        *dest++ = 0;
}

你的帖子很有帮助(答案)，但它不适合我，这里是代码与小更正:

    // creating input
    unsigned char pixels[160*120*3]; 
    for (int i=0; i<160*120*3; i++)
        pixels[i] = (i%4==1)*255;        // An BGR (not RGB) 160x120 image.
    // at this point we have some input
    BITMAPINFOHEADER bmih;
    bmih.biSize     = sizeof(BITMAPINFOHEADER);
    bmih.biWidth    = 160;
    bmih.biHeight   = -120;
    bmih.biPlanes   = 1;
    bmih.biBitCount = 24;
    bmih.biCompression  = BI_RGB ;
    bmih.biSizeImage    = 0;
    bmih.biXPelsPerMeter    =   10;
    bmih.biYPelsPerMeter    =   10;
    bmih.biClrUsed    =0;
    bmih.biClrImportant =0;
    BITMAPINFO dbmi;
    ZeroMemory(&dbmi, sizeof(dbmi));  
    dbmi.bmiHeader = bmih;
    dbmi.bmiColors->rgbBlue = 0;
    dbmi.bmiColors->rgbGreen = 0;
    dbmi.bmiColors->rgbRed = 0;
    dbmi.bmiColors->rgbReserved = 0;
    HDC hdc = ::GetDC(NULL);
    HBITMAP hbmp = CreateDIBitmap(hdc, &bmih, CBM_INIT, pixels, &dbmi, DIB_RGB_COLORS);
    if (hbmp == NULL) {
        ::MessageBox(NULL, L"Could not load the desired image image", L"Error", MB_OK);
        return;
    }
    ::ReleaseDC(NULL, hdc);
    // a little test if everything is OK
    OpenClipboard(NULL);
    EmptyClipboard();
    SetClipboardData(CF_BITMAP, hbmp);
    CloseClipboard();
    // cleanup
    DeleteObject(hbmp);

这里的其他答案非常有用，但我最终只用了一行就能实现它。

HBITMAP hBm = CreateBitmap(width,height,1,32,pixels); // 1 plane, 32 bits

希望对将来的读者有帮助。

此外，如果您需要使用设备上下文，还有CreateCompatibleBitmap和SetDIBits。

CreateDIBitmap的MSDN上写着:

使用fdwInit作为CBM_INIT调用CreateDIBitmap相当于调用CreateCompatibleBitmap函数在设备的格式，然后调用SetDIBits函数来将DIB位转换为DDB。

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