Loading a bitmap from a *.BMP file
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Hello, I am trying to load a bitmap into one of my dialog boxes in the program I am coding. I have found much help in this area provided that the file I am going to load is already defined as a resource. However, my problem is that the *.BMP that I have to load will be selected by the user. I was wondering if anyone could give me a little instruction on how I am able to take a Bitmap from a *.BMP whose properities I am unaware of and get it to appear in the dialog box. Thank you, Joe
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Hello, I am trying to load a bitmap into one of my dialog boxes in the program I am coding. I have found much help in this area provided that the file I am going to load is already defined as a resource. However, my problem is that the *.BMP that I have to load will be selected by the user. I was wondering if anyone could give me a little instruction on how I am able to take a Bitmap from a *.BMP whose properities I am unaware of and get it to appear in the dialog box. Thank you, Joe
take a look at ::LoadImage
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take a look at ::LoadImage
Yes I understand that Load Image is the function I am going to be using, however, it returns a HANDLE, can I cast that as an HBITMAP and just move on?
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Yes I understand that Load Image is the function I am going to be using, however, it returns a HANDLE, can I cast that as an HBITMAP and just move on?
yep. it's a HANDLE because you can load cursors and icons with that function, too. but, if you're using the IMAGE_BITMAP flag, you get a HANDLE to a bitmap (aka HBITMAP) back.
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yep. it's a HANDLE because you can load cursors and icons with that function, too. but, if you're using the IMAGE_BITMAP flag, you get a HANDLE to a bitmap (aka HBITMAP) back.
Ok but when I load a BMP from a file, it has to be a DIB? Could you possibly point out what doesn't seem to work here? BOOL LoadBitmapFromBMPFile( LPTSTR szFileName, HBITMAP hBitmap,HPALETTE hPalette ) { BITMAP bm; //*phBitmap = NULL; //*phPalette = NULL; // Use LoadImage() to get the image loaded into a DIBSection hBitmap = (HBITMAP)LoadImage( NULL, szFileName, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE ); if (hBitmap == NULL ) return FALSE; // Get the color depth of the DIBSection GetObject(hBitmap, sizeof(BITMAP), &bm ); // If the DIBSection is 256 color or less, it has a color table if (( bm.bmBitsPixel * bm.bmPlanes ) <= 8 ) { HDC hMemDC; HBITMAP hOldBitmap; RGBQUAD rgb[256]; LPLOGPALETTE pLogPal; WORD i; // Create a memory DC and select the DIBSection into it hMemDC = CreateCompatibleDC( NULL ); hOldBitmap = (HBITMAP)SelectObject( hMemDC, hBitmap ); // Get the DIBSection's color table GetDIBColorTable( hMemDC, 0, 256, rgb ); // Create a palette from the color tabl pLogPal = (LOGPALETTE *)malloc( sizeof(LOGPALETTE) + (256*sizeof(PALETTEENTRY)) ); pLogPal->palVersion = 0x300; pLogPal->palNumEntries = 256; for (i = 0 ; i < 256 ; i++) { pLogPal->palPalEntry[i].peRed = rgb[i].rgbRed; pLogPal->palPalEntry[i].peGreen = rgb[i].rgbGreen; pLogPal->palPalEntry[i].peBlue = rgb[i].rgbBlue; pLogPal->palPalEntry[i].peFlags = 0; } hPalette = CreatePalette( pLogPal ); // Clean up free(pLogPal); SelectObject(hMemDC, hOldBitmap); DeleteDC(hMemDC); } else // It has no color table, so use a halftone palette { HDC hRefDC; hRefDC = GetDC( NULL ); hPalette = CreateHalftonePalette( hRefDC ); ReleaseDC( NULL, hRefDC ); } return TRUE; } Thanks a bunch in advance, Joe
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Ok but when I load a BMP from a file, it has to be a DIB? Could you possibly point out what doesn't seem to work here? BOOL LoadBitmapFromBMPFile( LPTSTR szFileName, HBITMAP hBitmap,HPALETTE hPalette ) { BITMAP bm; //*phBitmap = NULL; //*phPalette = NULL; // Use LoadImage() to get the image loaded into a DIBSection hBitmap = (HBITMAP)LoadImage( NULL, szFileName, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE ); if (hBitmap == NULL ) return FALSE; // Get the color depth of the DIBSection GetObject(hBitmap, sizeof(BITMAP), &bm ); // If the DIBSection is 256 color or less, it has a color table if (( bm.bmBitsPixel * bm.bmPlanes ) <= 8 ) { HDC hMemDC; HBITMAP hOldBitmap; RGBQUAD rgb[256]; LPLOGPALETTE pLogPal; WORD i; // Create a memory DC and select the DIBSection into it hMemDC = CreateCompatibleDC( NULL ); hOldBitmap = (HBITMAP)SelectObject( hMemDC, hBitmap ); // Get the DIBSection's color table GetDIBColorTable( hMemDC, 0, 256, rgb ); // Create a palette from the color tabl pLogPal = (LOGPALETTE *)malloc( sizeof(LOGPALETTE) + (256*sizeof(PALETTEENTRY)) ); pLogPal->palVersion = 0x300; pLogPal->palNumEntries = 256; for (i = 0 ; i < 256 ; i++) { pLogPal->palPalEntry[i].peRed = rgb[i].rgbRed; pLogPal->palPalEntry[i].peGreen = rgb[i].rgbGreen; pLogPal->palPalEntry[i].peBlue = rgb[i].rgbBlue; pLogPal->palPalEntry[i].peFlags = 0; } hPalette = CreatePalette( pLogPal ); // Clean up free(pLogPal); SelectObject(hMemDC, hOldBitmap); DeleteDC(hMemDC); } else // It has no color table, so use a halftone palette { HDC hRefDC; hRefDC = GetDC( NULL ); hPalette = CreateHalftonePalette( hRefDC ); ReleaseDC( NULL, hRefDC ); } return TRUE; } Thanks a bunch in advance, Joe
TheDelChop wrote:
Ok but when I load a BMP from a file, it has to be a DIB?
nope. you can read it to a 'normal' HBITMAP.
TheDelChop wrote:
Could you possibly point out what doesn't seem to work here?
the hBitmap and hPalette parameters should probably be references or pointers, if you want to set them so the calling function can use them.
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TheDelChop wrote:
Ok but when I load a BMP from a file, it has to be a DIB?
nope. you can read it to a 'normal' HBITMAP.
TheDelChop wrote:
Could you possibly point out what doesn't seem to work here?
the hBitmap and hPalette parameters should probably be references or pointers, if you want to set them so the calling function can use them.
Assuming that the resourse IDB_BITMAP1 is stored in C:\BITMAP1.BMP, any difference on what these two functions will return? hbm = (HBITMAP)LoadImage(NULL,"C:\BITMAP1.BMP",IMAGE_BITMAP,0,0, LR_LOADFROMFILE); hbm = LoadBitmap(hInstance,MAKEINTRESOURCE(IDB_BITMAP1));
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Assuming that the resourse IDB_BITMAP1 is stored in C:\BITMAP1.BMP, any difference on what these two functions will return? hbm = (HBITMAP)LoadImage(NULL,"C:\BITMAP1.BMP",IMAGE_BITMAP,0,0, LR_LOADFROMFILE); hbm = LoadBitmap(hInstance,MAKEINTRESOURCE(IDB_BITMAP1));
should be the same thing
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Ok but when I load a BMP from a file, it has to be a DIB? Could you possibly point out what doesn't seem to work here? BOOL LoadBitmapFromBMPFile( LPTSTR szFileName, HBITMAP hBitmap,HPALETTE hPalette ) { BITMAP bm; //*phBitmap = NULL; //*phPalette = NULL; // Use LoadImage() to get the image loaded into a DIBSection hBitmap = (HBITMAP)LoadImage( NULL, szFileName, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE ); if (hBitmap == NULL ) return FALSE; // Get the color depth of the DIBSection GetObject(hBitmap, sizeof(BITMAP), &bm ); // If the DIBSection is 256 color or less, it has a color table if (( bm.bmBitsPixel * bm.bmPlanes ) <= 8 ) { HDC hMemDC; HBITMAP hOldBitmap; RGBQUAD rgb[256]; LPLOGPALETTE pLogPal; WORD i; // Create a memory DC and select the DIBSection into it hMemDC = CreateCompatibleDC( NULL ); hOldBitmap = (HBITMAP)SelectObject( hMemDC, hBitmap ); // Get the DIBSection's color table GetDIBColorTable( hMemDC, 0, 256, rgb ); // Create a palette from the color tabl pLogPal = (LOGPALETTE *)malloc( sizeof(LOGPALETTE) + (256*sizeof(PALETTEENTRY)) ); pLogPal->palVersion = 0x300; pLogPal->palNumEntries = 256; for (i = 0 ; i < 256 ; i++) { pLogPal->palPalEntry[i].peRed = rgb[i].rgbRed; pLogPal->palPalEntry[i].peGreen = rgb[i].rgbGreen; pLogPal->palPalEntry[i].peBlue = rgb[i].rgbBlue; pLogPal->palPalEntry[i].peFlags = 0; } hPalette = CreatePalette( pLogPal ); // Clean up free(pLogPal); SelectObject(hMemDC, hOldBitmap); DeleteDC(hMemDC); } else // It has no color table, so use a halftone palette { HDC hRefDC; hRefDC = GetDC( NULL ); hPalette = CreateHalftonePalette( hRefDC ); ReleaseDC( NULL, hRefDC ); } return TRUE; } Thanks a bunch in advance, Joe
The returned handle is ALWAYS a DDB if you dont set the flag LR_CREATEDIBSECTION and a DIB if u do set the flag. So, if your working on 24+ bits per pixel display you dont even have to worry abou the palette and other stuff.. just load it and enjoy :cool: Peace!
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Hello, I am trying to load a bitmap into one of my dialog boxes in the program I am coding. I have found much help in this area provided that the file I am going to load is already defined as a resource. However, my problem is that the *.BMP that I have to load will be selected by the user. I was wondering if anyone could give me a little instruction on how I am able to take a Bitmap from a *.BMP whose properities I am unaware of and get it to appear in the dialog box. Thank you, Joe
If you want to load file you can use
LoadImageor CImage class
WhiteSky
