Windows位图和DIBSection之间有什么区别？

我正在从包含以下内容的文件加载DIBSection：

HBITMAP bmpIn = (HBITMAP) LoadImage(NULL, _T("c:\\Temp\\Temp.bmp"), IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE);

根据经验，我发现加载的位图和我过去使用的位图之间存在以下差异，但我找不到任何说明应该存在差异的文档

• 这些行在内存中的顺序是自上而下，而不是自下而上。我已经验证了.bmp文件本身是自下而上排序的
• 行填充是2字节的倍数，而不是4字节

我还发现，当您使用从头开始创建DIBSection时，有一个记录在案的差异

• GetObject

  返回的DIBSECTION.dsHandle和BITMAP.bmBits值将为空

前两个差异的文档在哪里？我是否遗漏了什么？这是Windows7，但我无法想象其他版本的Windows会有什么不同

编辑：一些其他详细信息。这里是一个十六进制转储的

temp.bmp

；这是一个7x7的图像，右侧有白色条纹，左侧有蓝色值（0x10、0x20等）递增。您可以看到底线（00,00,70）是第一行，有3个字节的填充

00: 42 4d de 00 00 00 00 00 00 00 36 00 00 00 28 00
10: 00 00 07 00 00 00 07 00 00 00 01 00 18 00 00 00
20: 00 00 a8 00 00 00 00 00 00 00 00 00 00 00 00 00
30: 00 00 00 00 00 00 70 00 00 00 00 00 00 00 00 00
40: 00 00 00 00 00 00 00 00 ff ff ff 00 00 00 60 00
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60: ff ff ff 00 00 00 50 00 00 00 00 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 ff ff ff 00 00 00 40 00
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: ff ff ff 00 00 00 30 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 ff ff ff 00 00 00 20 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c0: ff ff ff 00 00 00 10 00 00 00 00 00 00 00 00 00
d0: 00 00 00 00 00 00 00 00 ff ff ff 00 00 00

下面是一个读取.bmp文件并写出内容的示例程序。为了简洁起见，我删除了错误检查

int _tmain(int argc, _TCHAR* argv[])
{
   HBITMAP bmpIn = (HBITMAP) LoadImage(NULL, argv[1], IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE);
   FILE * out = _tfopen(argv[2], _T("wb"));
   DIBSECTION obj = {0};
   GetObject(bmpIn, sizeof(obj), &obj);
   cout << "dsBm.bmHeight = " << obj.dsBm.bmHeight << endl;
   cout << "dsBmih.biHeight = " << obj.dsBmih.biHeight << endl;
   cout << "sizeof(DIBSECTION) = " << sizeof(DIBSECTION) << endl;
   fwrite(&obj, sizeof(DIBSECTION), 1, out);
   int stride = (((obj.dsBmih.biWidth * obj.dsBmih.biBitCount) + 15) / 16) * 2;
   int bytecount = abs(obj.dsBmih.biHeight) * stride;
   vector<BYTE> bits(bytecount);
   GetBitmapBits(bmpIn, bytecount, &bits[0]);
   fwrite(&bits[0], 1, bytecount, out);
   fclose(out);
   return 0;
}

---

调用GetDIBits而不是GetBitmapBits。GetBitmapBits（）的文档表明，这是为依赖于设备的位图返回数据，而您有一个独立于设备的位图。它们还表示不应使用此调用，只是为了实现16位兼容性。因此，使用GetDIBits应该可以做到这一点。

有关更多信息，请参阅。@Nerdtron，该链接直接与我的观察结果相矛盾-它声明自上而下的DIB将具有负高度，但在本例中它没有。那么，您是要返回具有正高度的自上而下的DIB吗？在你调用LoadImage之后，你用HBITMAP做什么来经验性地发现这一点？我猜您遗漏了一些细节，而不是API实际上返回了错误的数据。只是好奇加载后调用的API。@Nerdtron，我使用了GetObject和GetBitmapBits，并用自己的代码将结果直接写回一个文件。我还检查了调试器中的内存以进行双重检查。GetBitmapBits（）的文档说它“将指定的依赖于设备的位图的位图位复制到缓冲区”。在这里，您已经加载了一个独立于设备的位图。因此，可能正在进行转换，因为GetBitmapBits的调用者希望从上到下实现某种功能。我只是在猜测，因为我总是叫GetDIBits。请注意，我链接到的文档说，无论如何都不应该调用它，应该调用GetDIBits。我打赌如果你打电话给GetDIBits，你会得到你想要的。

dsBm.bmHeight = 7
dsBmih.biHeight = 7
sizeof(DIBSECTION) = 84
00: 00 00 00 00 07 00 00 00 07 00 00 00 18 00 00 00
10: 01 00 18 00 00 00 11 00 28 00 00 00 07 00 00 00
20: 07 00 00 00 01 00 18 00 00 00 00 00 a8 00 00 00
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50: 00 00 00 00 10 00 00 00 00 00 00 00 00 00 00 00
60: 00 00 00 00 00 00 ff ff ff 00 20 00 00 00 00 00
70: 00 00 00 00 00 00 00 00 00 00 00 00 ff ff ff 00
80: 30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: 00 00 ff ff ff 00 40 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 ff ff ff 00 50 00 00 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff ff
c0: ff 00 60 00 00 00 00 00 00 00 00 00 00 00 00 00
d0: 00 00 00 00 ff ff ff 00 70 00 00 00 00 00 00 00
e0: 00 00 00 00 00 00 00 00 00 00 ff ff ff 00