How can I save HICON to an .ico file?

Question

I am extracting an icon from .exe/.dll and want to save it in an .ico file. What is the best way to do this?

I have tried to use ::OleCreatePictureIndirect() and then IPicture->SaveAsFile(). It works but transparent parts of the icon are painted black (and obviously are not transparent any more :( ).

I tried manual parsing. It works OK but is cumbersome and I am afraid of complications with Vista icons/.icl files/etc.

Please, help. Thanks.

Answer 1

I had the same problem and therefore I wrote a function to save icons from an HICON handle to a ICO file. The SaveIcon() function shown below support colors depths of 4, 8, 24, and 32 bits. The PNG icon format is not supported.

The function works by constructing the ICO file directly. Fortunately, this is not too difficult, because the ICO format is almost identical to the BMP file format; furthermore, the BMP file format is almost identical to the in-memory representation returned by GetDIBits().

Here is the SaveIcon() function, together with a small test function (_tmain):

#include <afx.h>
#include <afxwin.h>
#include <atlbase.h>

struct ICONDIRENTRY
{
    UCHAR nWidth;
    UCHAR nHeight;
    UCHAR nNumColorsInPalette; // 0 if no palette
    UCHAR nReserved; // should be 0
    WORD nNumColorPlanes; // 0 or 1
    WORD nBitsPerPixel;
    ULONG nDataLength; // length in bytes
    ULONG nOffset; // offset of BMP or PNG data from beginning of file
};

// Helper class to release GDI object handle when scope ends:
class CGdiHandle
{
public:
    CGdiHandle(HGDIOBJ handle) : m_handle(handle) {};
    ~CGdiHandle(){DeleteObject(m_handle);};
private:
    HGDIOBJ m_handle;
};


// Save icon referenced by handle 'hIcon' as file with name 'szPath'.
// The generated ICO file has the color depth specified in 'nColorBits'.
//
bool SaveIcon(HICON hIcon, int nColorBits, const TCHAR* szPath)
{
    ASSERT(nColorBits == 4 || nColorBits == 8 || nColorBits == 24 || nColorBits == 32);

    if (offsetof(ICONDIRENTRY, nOffset) != 12)
    {
        return false;
    }

    CDC dc;
    dc.Attach(::GetDC(NULL)); // ensure that DC is released when function ends

    // Open file for writing:
    CFile file;
    if (!file.Open(szPath, CFile::modeWrite | CFile::modeCreate))
    {
        return false;
    }

    // Write header:
    UCHAR icoHeader[6] = {0, 0, 1, 0, 1, 0}; // ICO file with 1 image
    file.Write(icoHeader, sizeof(icoHeader));

    // Get information about icon:
    ICONINFO iconInfo;
    GetIconInfo(hIcon, &iconInfo);
    CGdiHandle handle1(iconInfo.hbmColor), handle2(iconInfo.hbmMask); // free bitmaps when function ends
    BITMAPINFO bmInfo = {0};
    bmInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bmInfo.bmiHeader.biBitCount = 0;    // don't get the color table     
    if (!GetDIBits(dc, iconInfo.hbmColor, 0, 0, NULL, &bmInfo, DIB_RGB_COLORS))
    {
        return false;
    }

    // Allocate size of bitmap info header plus space for color table:
    int nBmInfoSize = sizeof(BITMAPINFOHEADER);
    if (nColorBits < 24)
    {
        nBmInfoSize += sizeof(RGBQUAD) * (int)(1 << nColorBits);
    }

    CAutoVectorPtr<UCHAR> bitmapInfo;
    bitmapInfo.Allocate(nBmInfoSize);
    BITMAPINFO* pBmInfo = (BITMAPINFO*)(UCHAR*)bitmapInfo;
    memcpy(pBmInfo, &bmInfo, sizeof(BITMAPINFOHEADER));

    // Get bitmap data:
    ASSERT(bmInfo.bmiHeader.biSizeImage != 0);
    CAutoVectorPtr<UCHAR> bits;
    bits.Allocate(bmInfo.bmiHeader.biSizeImage);
    pBmInfo->bmiHeader.biBitCount = nColorBits;
    pBmInfo->bmiHeader.biCompression = BI_RGB;
    if (!GetDIBits(dc, iconInfo.hbmColor, 0, bmInfo.bmiHeader.biHeight, (UCHAR*)bits, pBmInfo, DIB_RGB_COLORS))
    {
        return false;
    }

    // Get mask data:
    BITMAPINFO maskInfo = {0};
    maskInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    maskInfo.bmiHeader.biBitCount = 0;  // don't get the color table     
    if (!GetDIBits(dc, iconInfo.hbmMask, 0, 0, NULL, &maskInfo, DIB_RGB_COLORS))
    {
        return false;
    }
    ASSERT(maskInfo.bmiHeader.biBitCount == 1);
    CAutoVectorPtr<UCHAR> maskBits;
    maskBits.Allocate(maskInfo.bmiHeader.biSizeImage);
    CAutoVectorPtr<UCHAR> maskInfoBytes;
    maskInfoBytes.Allocate(sizeof(BITMAPINFO) + 2 * sizeof(RGBQUAD));
    BITMAPINFO* pMaskInfo = (BITMAPINFO*)(UCHAR*)maskInfoBytes;
    memcpy(pMaskInfo, &maskInfo, sizeof(maskInfo));
    if (!GetDIBits(dc, iconInfo.hbmMask, 0, maskInfo.bmiHeader.biHeight, (UCHAR*)maskBits, pMaskInfo, DIB_RGB_COLORS))
    {
        return false;
    }

    // Write directory entry:
    ICONDIRENTRY dir;
    dir.nWidth = (UCHAR) pBmInfo->bmiHeader.biWidth;
    dir.nHeight = (UCHAR) pBmInfo->bmiHeader.biHeight;
    dir.nNumColorsInPalette = (nColorBits == 4 ? 16 : 0);
    dir.nReserved = 0;
    dir.nNumColorPlanes = 0;
    dir.nBitsPerPixel = pBmInfo->bmiHeader.biBitCount;
    dir.nDataLength = pBmInfo->bmiHeader.biSizeImage + pMaskInfo->bmiHeader.biSizeImage + nBmInfoSize;
    dir.nOffset = sizeof(dir) + sizeof(icoHeader);
    file.Write(&dir, sizeof(dir));

    // Write DIB header (including color table):
    int nBitsSize = pBmInfo->bmiHeader.biSizeImage;
    pBmInfo->bmiHeader.biHeight *= 2; // because the header is for both image and mask
    pBmInfo->bmiHeader.biCompression = 0;
    pBmInfo->bmiHeader.biSizeImage += pMaskInfo->bmiHeader.biSizeImage; // because the header is for both image and mask
    file.Write(&pBmInfo->bmiHeader, nBmInfoSize);

    // Write image data:
    file.Write((UCHAR*)bits, nBitsSize);

    // Write mask data:
    file.Write((UCHAR*)maskBits, pMaskInfo->bmiHeader.biSizeImage);

    file.Close();

    return true;
}

// Test program for SaveIcon() function.
//
// Usage: first argument is input ICO file (must be 32x32 pixels); second argument is output ICO file
//
int _tmain(int argc, _TCHAR* argv[])
{
    ASSERT(argc == 3);

    // Load a 32x32 icon:
    HICON hIcon = (HICON)LoadImage(0, argv[1], IMAGE_ICON, 32, 32, LR_LOADFROMFILE | LR_CREATEDIBSECTION);
    ASSERT(hIcon != NULL);

    // Save with 24-bits colors:
    if (!SaveIcon(hIcon, 24, argv[2]))
    {
        _ftprintf(stderr, _T("Error: saving icon to %s failed"), argv[2]);
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}

Answer 2

You can save HICONs with the IPicture::SaveAsFile() method. Here's a sample C++ program that uses it:

#include "stdafx.h"
#include <windows.h>
#include <olectl.h>
#pragma comment(lib, "oleaut32.lib")

HRESULT SaveIcon(HICON hIcon, const wchar_t* path) {
    // Create the IPicture intrface
    PICTDESC desc = { sizeof(PICTDESC) };
    desc.picType = PICTYPE_ICON;
    desc.icon.hicon = hIcon;
    IPicture* pPicture = 0;
    HRESULT hr = OleCreatePictureIndirect(&desc, IID_IPicture, FALSE, (void**)&pPicture);
    if (FAILED(hr)) return hr;

    // Create a stream and save the image
    IStream* pStream = 0;
    CreateStreamOnHGlobal(0, TRUE, &pStream);
    LONG cbSize = 0;
    hr = pPicture->SaveAsFile(pStream, TRUE, &cbSize);

    // Write the stream content to the file
    if (!FAILED(hr)) {
        HGLOBAL hBuf = 0;
        GetHGlobalFromStream(pStream, &hBuf);
        void* buffer = GlobalLock(hBuf);
        HANDLE hFile = CreateFile(path, GENERIC_WRITE, 0, 0, CREATE_ALWAYS, 0, 0);
        if (!hFile) hr = HRESULT_FROM_WIN32(GetLastError());
        else {
            DWORD written = 0;
            WriteFile(hFile, buffer, cbSize, &written, 0);
            CloseHandle(hFile);
        }
        GlobalUnlock(buffer);
    }
    // Cleanup
    pStream->Release();
    pPicture->Release();
    return hr;

}
int _tmain(int argc, _TCHAR* argv[])
{
    HICON hIcon = (HICON)LoadImage(0, L"c:\\windows\\system32\\perfcentercpl.ico", IMAGE_ICON, 32, 32, LR_LOADFROMFILE);
    if (!hIcon) return GetLastError();
    HRESULT hr = SaveIcon(hIcon, L"c:\\temp\\test.ico");
    return hr;
}

Answer 3

This code handles transparency correctly.

#include <windows.h>
#include <stdio.h>
#include <tchar.h>

//
// ICONS (.ICO type 1) are structured like this:
//
// ICONHEADER (just 1)
// ICONDIR [1...n] (an array, 1 for each image)
// [BITMAPINFOHEADER+COLOR_BITS+MASK_BITS] [1...n] (1 after the other, for each image)
//
// CURSORS (.ICO type 2) are identical in structure, but use
// two monochrome bitmaps (real XOR and AND masks, this time).
//

typedef struct
{
    WORD idReserved; // must be 0
    WORD idType; // 1 = ICON, 2 = CURSOR
    WORD idCount; // number of images (and ICONDIRs)

    // ICONDIR [1...n]
    // ICONIMAGE [1...n]

} ICONHEADER;

//
// An array of ICONDIRs immediately follow the ICONHEADER
//
typedef struct
{
    BYTE bWidth;
    BYTE bHeight;
    BYTE bColorCount;
    BYTE bReserved;
    WORD wPlanes; // for cursors, this field = wXHotSpot
    WORD wBitCount; // for cursors, this field = wYHotSpot
    DWORD dwBytesInRes;
    DWORD dwImageOffset; // file-offset to the start of ICONIMAGE

} ICONDIR;

//
// After the ICONDIRs follow the ICONIMAGE structures -
// consisting of a BITMAPINFOHEADER, (optional) RGBQUAD array, then
// the color and mask bitmap bits (all packed together
//
typedef struct
{
    BITMAPINFOHEADER biHeader; // header for color bitmap (no mask header)
    //RGBQUAD rgbColors[1...n];
    //BYTE bXOR[1]; // DIB bits for color bitmap
    //BYTE bAND[1]; // DIB bits for mask bitmap

} ICONIMAGE;

//
// Write the ICO header to disk
//
static UINT WriteIconHeader(HANDLE hFile, int nImages)
{
    ICONHEADER iconheader;
    DWORD nWritten;

    // Setup the icon header
    iconheader.idReserved = 0; // Must be 0
    iconheader.idType = 1; // Type 1 = ICON (type 2 = CURSOR)
    iconheader.idCount = nImages; // number of ICONDIRs

    // Write the header to disk
    WriteFile( hFile, &iconheader, sizeof(iconheader), &nWritten, 0);

    // following ICONHEADER is a series of ICONDIR structures (idCount of them, in fact)
    return nWritten;
}

//
// Return the number of BYTES the bitmap will take ON DISK
//
static UINT NumBitmapBytes(BITMAP *pBitmap)
{
    int nWidthBytes = pBitmap->bmWidthBytes;

    // bitmap scanlines MUST be a multiple of 4 bytes when stored
    // inside a bitmap resource, so round up if necessary
    if(nWidthBytes & 3)
        nWidthBytes = (nWidthBytes + 4) & ~3;

    return nWidthBytes * pBitmap->bmHeight;
}

//
// Return number of bytes written
//
static UINT WriteIconImageHeader(HANDLE hFile, BITMAP *pbmpColor, BITMAP *pbmpMask)
{
    BITMAPINFOHEADER biHeader;
    DWORD nWritten;
    UINT nImageBytes;

    // calculate how much space the COLOR and MASK bitmaps take
    nImageBytes = NumBitmapBytes(pbmpColor) + NumBitmapBytes(pbmpMask);

    // write the ICONIMAGE to disk (first the BITMAPINFOHEADER)
    ZeroMemory(&biHeader, sizeof(biHeader));

    // Fill in only those fields that are necessary
    biHeader.biSize = sizeof(biHeader);
    biHeader.biWidth = pbmpColor->bmWidth;
    biHeader.biHeight = pbmpColor->bmHeight * 2; // height of color+mono
    biHeader.biPlanes = pbmpColor->bmPlanes;
    biHeader.biBitCount = pbmpColor->bmBitsPixel;
    biHeader.biSizeImage = nImageBytes;

    // write the BITMAPINFOHEADER
    WriteFile(hFile, &biHeader, sizeof(biHeader), &nWritten, 0);

    // write the RGBQUAD color table (for 16 and 256 colour icons)
    if(pbmpColor->bmBitsPixel == 2 || pbmpColor->bmBitsPixel == 8)
    {

    }

    return nWritten;
}

//
// Wrapper around GetIconInfo and GetObject(BITMAP)
//
static BOOL GetIconBitmapInfo(HICON hIcon, ICONINFO *pIconInfo, BITMAP *pbmpColor, BITMAP *pbmpMask)
{
    if(!GetIconInfo(hIcon, pIconInfo))
        return FALSE;

    if(!GetObject(pIconInfo->hbmColor, sizeof(BITMAP), pbmpColor))
        return FALSE;

    if(!GetObject(pIconInfo->hbmMask, sizeof(BITMAP), pbmpMask))
        return FALSE;

    return TRUE;
}

//
// Write one icon directory entry - specify the index of the image
//
static UINT WriteIconDirectoryEntry(HANDLE hFile, int nIdx, HICON hIcon, UINT nImageOffset)
{
    ICONINFO iconInfo;
    ICONDIR iconDir;

    BITMAP bmpColor;
    BITMAP bmpMask;

    DWORD nWritten;
    UINT nColorCount;
    UINT nImageBytes;

    GetIconBitmapInfo(hIcon, &iconInfo, &bmpColor, &bmpMask);

    nImageBytes = NumBitmapBytes(&bmpColor) + NumBitmapBytes(&bmpMask);

    if(bmpColor.bmBitsPixel >= 8)
        nColorCount = 0;
    else
        nColorCount = 1 << (bmpColor.bmBitsPixel * bmpColor.bmPlanes);

    // Create the ICONDIR structure
    iconDir.bWidth = (BYTE)bmpColor.bmWidth;
    iconDir.bHeight = (BYTE)bmpColor.bmHeight;
    iconDir.bColorCount = nColorCount;
    iconDir.bReserved = 0;
    iconDir.wPlanes = bmpColor.bmPlanes;
    iconDir.wBitCount = bmpColor.bmBitsPixel;
    iconDir.dwBytesInRes = sizeof(BITMAPINFOHEADER) + nImageBytes;
    iconDir.dwImageOffset = nImageOffset;

    // Write to disk
    WriteFile(hFile, &iconDir, sizeof(iconDir), &nWritten, 0);

    // Free resources
    DeleteObject(iconInfo.hbmColor);
    DeleteObject(iconInfo.hbmMask);

    return nWritten;
}

static UINT WriteIconData(HANDLE hFile, HBITMAP hBitmap)
{
    BITMAP bmp;
    int i;
    BYTE * pIconData;

    UINT nBitmapBytes;
    DWORD nWritten;

    GetObject(hBitmap, sizeof(BITMAP), &bmp);

    nBitmapBytes = NumBitmapBytes(&bmp);

    pIconData = (BYTE *)malloc(nBitmapBytes);

    GetBitmapBits(hBitmap, nBitmapBytes, pIconData);

    // bitmaps are stored inverted (vertically) when on disk..
    // so write out each line in turn, starting at the bottom + working
    // towards the top of the bitmap. Also, the bitmaps are stored in packed
    // in memory - scanlines are NOT 32bit aligned, just 1-after-the-other
    for(i = bmp.bmHeight - 1; i >= 0; i--)
    {
        // Write the bitmap scanline
        WriteFile(
            hFile,
            pIconData + (i * bmp.bmWidthBytes), // calculate offset to the line
            bmp.bmWidthBytes, // 1 line of BYTES
            &nWritten,
            0);

        // extend to a 32bit boundary (in the file) if necessary
        if(bmp.bmWidthBytes & 3)
        {
            DWORD padding = 0;
            WriteFile(hFile, &padding, 4 - bmp.bmWidthBytes, &nWritten, 0);
        }
    }

    free(pIconData);

    return nBitmapBytes;
}

//
// Create a .ICO file, using the specified array of HICON images
//
BOOL SaveIcon3(TCHAR *szIconFile, HICON hIcon[], int nNumIcons)
{
    HANDLE hFile;
    int i;
    int * pImageOffset;

    if(hIcon == 0 || nNumIcons < 1)
        return FALSE;

    // Save icon to disk:
    hFile = CreateFile(szIconFile, GENERIC_WRITE, 0, 0, CREATE_ALWAYS, 0, 0);

    if(hFile == INVALID_HANDLE_VALUE)
        return FALSE;

    //
    // Write the iconheader first of all
    //
    WriteIconHeader(hFile, nNumIcons);

    //
    // Leave space for the IconDir entries
    //
    SetFilePointer(hFile, sizeof(ICONDIR) * nNumIcons, 0, FILE_CURRENT);

    pImageOffset = (int *)malloc(nNumIcons * sizeof(int));

    //
    // Now write the actual icon images!
    //
    for(i = 0; i < nNumIcons; i++)
    {
        ICONINFO iconInfo;
        BITMAP bmpColor, bmpMask;

        GetIconBitmapInfo(hIcon[i], &iconInfo, &bmpColor, &bmpMask);

        // record the file-offset of the icon image for when we write the icon directories
        pImageOffset[i] = SetFilePointer(hFile, 0, 0, FILE_CURRENT);

        // bitmapinfoheader + colortable
        WriteIconImageHeader(hFile, &bmpColor, &bmpMask);

        // color and mask bitmaps
        WriteIconData(hFile, iconInfo.hbmColor);
        WriteIconData(hFile, iconInfo.hbmMask);

        DeleteObject(iconInfo.hbmColor);
        DeleteObject(iconInfo.hbmMask);
    }

    //
    // Lastly, skip back and write the icon directories.
    //
    SetFilePointer(hFile, sizeof(ICONHEADER), 0, FILE_BEGIN);

    for(i = 0; i < nNumIcons; i++)
    {
        WriteIconDirectoryEntry(hFile, i, hIcon[i], pImageOffset[i]);
    }

    free(pImageOffset);

    // finished!
    CloseHandle(hFile);

    return TRUE;
}


int saveIcon(TCHAR* filename, TCHAR* iconFile) {
    HICON hIconLarge;
    HICON hIconSmall;
    BOOL ret;


    if ( ExtractIconEx(filename, 0, &hIconLarge, &hIconSmall, 1) == 0 ) {
        return 1;
    }

    ret = SaveIcon3(iconFile, &hIconSmall, 1);
    if ( ret ) {
        return 0;
    }
    return -1;
}

int _tmain(int argc, TCHAR* argv[]) {
    if ( argc < 3 ) {
        printf("Usage: <exe/dll file> <output ico file>");
        return EXIT_FAILURE;
    }
    _tprintf(_T("src = %s\n"), argv[1]);
    _tprintf(_T("dest = %s\n"), argv[2]);
    saveIcon(argv[1], argv[2]);

    return 0;
}