How to determine the size of an icon from a HICON?

问题

I have an icon identified by an HICON handle that I want to draw centered on a custom control.

How do I determine the size of the icon so that I can calculate the correct drawing position?

回答1:

The Win32 GetIconInfo call will return, as part of its response, the icon's source bitmap. You can get the icon image size from this.

Dim IconInf As IconInfo
Dim BMInf As Bitmap

If (GetIconInfo(hIcon, IconInf)) Then
    If (IconInf.hbmColor) Then ' Icon has colour plane
        If (GetObject(IconInf.hbmColor, Len(BMInf), BMInf)) Then
            Width = BMInf.bmWidth
            Height = BMInf.bmHeight
            BitDepth = BMInf.bmBitsPixel
        End If

        Call DeleteObject(IconInf.hbmColor)
    Else ' Icon has no colour plane, image data stored in mask
        If (GetObject(IconInf.hbmMask, Len(BMInf), BMInf)) Then
            Width = BMInf.bmWidth
            Height = BMInf.bmHeight \ 2
            BitDepth = 1
        End If
    End If

    Call DeleteObject(IconInf.hbmMask)
End If 

回答2:

Here is a C++ version of code:

struct MYICON_INFO
{
    int     nWidth;
    int     nHeight;
    int     nBitsPerPixel;
};

MYICON_INFO MyGetIconInfo(HICON hIcon);

// =======================================

MYICON_INFO MyGetIconInfo(HICON hIcon)
{
    MYICON_INFO myinfo;
    ZeroMemory(&myinfo, sizeof(myinfo));

    ICONINFO info;
    ZeroMemory(&info, sizeof(info));

    BOOL bRes = FALSE;

    bRes = GetIconInfo(hIcon, &info);
    if(!bRes)
        return myinfo;

    BITMAP bmp;
    ZeroMemory(&bmp, sizeof(bmp));

    if(info.hbmColor)
    {
        const int nWrittenBytes = GetObject(info.hbmColor, sizeof(bmp), &bmp);
        if(nWrittenBytes > 0)
        {
            myinfo.nWidth = bmp.bmWidth;
            myinfo.nHeight = bmp.bmHeight;
            myinfo.nBitsPerPixel = bmp.bmBitsPixel;
        }
    }
    else if(info.hbmMask)
    {
        // Icon has no color plane, image data stored in mask
        const int nWrittenBytes = GetObject(info.hbmMask, sizeof(bmp), &bmp);
        if(nWrittenBytes > 0)
        {
            myinfo.nWidth = bmp.bmWidth;
            myinfo.nHeight = bmp.bmHeight / 2;
            myinfo.nBitsPerPixel = 1;
        }
    }

    if(info.hbmColor)
        DeleteObject(info.hbmColor);
    if(info.hbmMask)
        DeleteObject(info.hbmMask);

    return myinfo;
}

来源：https://stackoverflow.com/questions/1913468/how-to-determine-the-size-of-an-icon-from-a-hicon