How to convert HICON to HBITMAP in VC++?

How to convert HICON to HBITMAP in VC++?

I know this is an FAQ but all the solutions I've found on Google don't work. What I need is a function which takes a parameter HICON and returns HBITMAP.

Greatest if possible to make conversion to 32-bit bitmap even the icon is 24-bit, 16-bit or 8-bit.

This is the code, I don't know where it goes wrong:

HBITMAP icon_to_bitmap(开发者_运维知识库HICON Icon_Handle) {
  HDC Screen_Handle = GetDC(NULL);
  HDC Device_Handle = CreateCompatibleDC(Screen_Handle);

  HBITMAP Bitmap_Handle = 
  CreateCompatibleBitmap(Device_Handle,GetSystemMetrics(SM_CXICON),
  GetSystemMetrics(SM_CYICON));

  HBITMAP Old_Bitmap = (HBITMAP)SelectObject(Device_Handle,Bitmap_Handle);
  DrawIcon(Device_Handle, 0,0, Icon_Handle);
  SelectObject(Device_Handle,Old_Bitmap);

  DeleteDC(Device_Handle);
  ReleaseDC(NULL,Screen_Handle);
  return Bitmap_Handle;
}

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this code do it:

HICON hIcon = (HICON)LoadImage(instance, MAKEINTRESOURCEW(IDI_ICON), IMAGE_ICON, width, height, 0);
ICONINFO iconinfo;
GetIconInfo(hIcon, &iconinfo);
HBITMAP hBitmap = iconinfo.hbmColor;

and this is the code in the *.rc file:

IDI_ICON ICON "example.ico"

and this is the code in the *.h file:

#define IDI_ICON 4000

---

HDC hDC = GetDC(NULL);
HDC hMemDC = CreateCompatibleDC(hDC);
HBITMAP hMemBmp = CreateCompatibleBitmap(hDC, x, y);
HBITMAP hResultBmp = NULL;
HGDIOBJ hOrgBMP = SelectObject(hMemDC, hMemBmp);

DrawIconEx(hMemDC, 0, 0, hIcon, x, y, 0, NULL, DI_NORMAL);

hResultBmp = hMemBmp;
hMemBmp = NULL;

SelectObject(hMemDC, hOrgBMP);
DeleteDC(hMemDC);
ReleaseDC(NULL, hDC);
DestroyIcon(hIcon);
return hResultBmp;

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I don't have code readily available to share, but I think this is pretty easy. You have to create the HBITMAP, create a device context, select the bitmap into the DC (this will make the bitmap the drawing area for this DC). Finally call the DrawIcon() function to draw your icon on this DC. After that detach the bitmap from the DC and destroy the DC. Your bitmap now should be ready to go.

Update after looking at your code:

I believe the problem is in the createCompatibleBitmap call. You are asking for a bitmap compatible with the memory DC, but memory DCs start with a 1 bit/pixel bitmap selected into them. Try asking for a bitmap compatible with the screen DC instead.

Update 2: you may want to look at this question as it seems related to your problem.

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I found this(similar code works for me - 32x32 icons with or without alpha data):
  used CopyImage (msdn link)

HICON hICON = /*your code here*/
HBITMAP hBITMAPcopy;
ICONINFOEX IconInfo;
BITMAP BM_32_bit_color;
BITMAP BM_1_bit_mask;

// 1. From HICON to HBITMAP for color and mask separately
//.cbSize required
//memset((void*)&IconInfo, 0, sizeof(ICONINFOEX));
IconInfo.cbSize = sizeof(ICONINFOEX);
GetIconInfoEx( hICON , &IconInfo);


//HBITMAP IconInfo.hbmColor is 32bit per pxl, however alpha bytes can be zeroed or can be not.
//HBITMAP IconInfo.hbmMask is 1bit per pxl

// 2. From HBITMAP to BITMAP for color
//    (HBITMAP without raw data -> HBITMAP with raw data)
//         LR_CREATEDIBSECTION - DIB section will be created,
//         so .bmBits pointer will not be null
hBITMAPcopy = (HBITMAP)CopyImage(IconInfo.hbmColor, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION);
//    (HBITMAP to BITMAP)
GetObject(hBITMAPcopy, sizeof(BITMAP), &BM_32_bit_color);
//Now: BM_32_bit_color.bmBits pointing to BGRA data.(.bmWidth * .bmHeight * (.bmBitsPixel/8))

// 3. From HBITMAP to BITMAP for mask
hBITMAPcopy = (HBITMAP)CopyImage(IconInfo.hbmMask, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION);
GetObject(hBITMAPcopy, sizeof(BITMAP), &BM_1_bit_mask);
//Now: BM_1_bit_mask.bmBits pointing to mask data (.bmWidth * .bmHeight Bits!)

BM_32_bit_color bitmap may be have Alpha *channel*(each 4th byte) already set! So - check for it before u add mask bit to color data.