如何将像素阵列转换为HBITMAP [英] How to convert an Array of pixels to HBITMAP

问题描述

我有一个像素数组，我需要转换为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，但是这不工作。

I have an array of pixels which I need to convert to HBITMAP in order to display it in a window. I tried to use CreateDIBitmap() but I don't have the BMP headers. I tried to construct them manually according to MSDN documentation but this didn't work.

这里我的代码看起来

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);

现在我得到一个非NULL的hBitmap是好的，但它总是显示黑色图像， t指向像素阵列。
我使用代码检查它

Now I get a non NULL hBitmap which is good but it shows always black image as if it doesn't point to the array of pixels. I checked it using the code

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

确实qB.bmBits为NULL。
问题和如何解决？

And indeed qB.bmBits is NULL. What is the problem and how to fix it?

推荐答案

我找到了如何做。
我们需要使用 CreateDIBSection（）而不是 CreateDIBitmap（）
工作代码

I found how to do it. We need to use CreateDIBSection() instead of CreateDIBitmap() So here is the working code

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，将像素复制到DIB，而不是使用memcpy（）

For grey level images, copy the pixels to DIB in a loop instead of with 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;
}  

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