Microsoft KB Archive/128786

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HOWTO: How to Shade Images to Look Like Windows 95 Active Icon

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Q128786

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The information in this article applies to:


 * Microsoft Win32 Application Programming Interface (API), used with:
 * Microsoft Windows NT Server versions 3.51, 4.0
 * Microsoft Windows NT Workstation versions 3.51, 4.0
 * Microsoft Windows 95
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Professional

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SUMMARY
This article shows by example how to display an image or an icon in a shaded state, as Windows 95 does for the active icon.

Step-by-Step Procedure
To obtain the shaded look for your image or icon, follow these six steps:


 * 1) Create a compatible DC and bitmap.
 * 2) Create a monochrome pattern brush with every other pixel on.
 * 3) Fill the memory image with the pattern.
 * 4) BitBlt the source image over the pattern using SRCAND so that only the "on" destination pixels are transferred.
 * 5) Color the destination with the pattern, using the highlight color for the "off" pixels and using black for the 'on' pixels.
 * 6) Copy the filtered original from the memory DC to the destination using SRCPAINT so that only the "on" pixels are transferred.

This results in the destination having the original image with every other pixel colored with the highlight color.

Sample Code
The following function implements these six steps to shade a rectangular area on a device context:

  // ShadeRect // hDC   : the DC on which the area is to be shaded // lpRect : the coordinates within which to shade

BOOL ShadeRect( HDC hDC, LPRECT lpRect ) {

COLORREF crHighlightColor, crOldBkColor, crOldTextColor; HBRUSH   hBrush, hOldBrush; HBITMAP  hBitmap, hBrushBitmap, hOldMemBitmap; int      OldBkMode, nWidth, nHeight; HDC      hMemDC; RECT     rcRect = { 0, 0, 0, 0}; // The bitmap bits are for a monochrome "every-other-pixel" //    bitmap (for a pattern brush) WORD     Bits[8] = { 0x0055, 0x00aa, 0x0055, 0x00aa,

0x0055, 0x00aa, 0x0055, 0x00aa };

// The Width and Height of the target area nWidth = lpRect->right - lpRect->left + 1; nHeight = lpRect->bottom - lpRect->top + 1;

// Need a pattern bitmap hBrushBitmap = CreateBitmap( 8, 8, 1, 1, &Bits ); // Need to store the original image hBitmap = CreateCompatibleBitmap( hDC, nWidth, nHeight ); // Need a memory DC to work in  hMemDC = CreateCompatibleDC( hDC ); // Create the pattern brush hBrush = CreatePatternBrush( hBrushBitmap );

// Has anything failed so far? If so, abort! if( (hBrushBitmap==NULL) || (hBitmap==NULL) ||      (hMemDC==NULL) || (hBrush==NULL) ) {     if( hBrushBitmap != NULL ) DeleteObject(hBrushBitmap); if( hBitmap != NULL ) DeleteObject( hBitmap ); if( hMemDC != NULL ) DeleteDC( hMemDC ); if( hBrush != NULL ) DeleteObject( hBrush ); return FALSE; }

// Select the bitmap into the memory DC  hOldMemBitmap = SelectObject( hMemDC, hBitmap );

// How wide/tall is the original? rcRect.right = nWidth; rcRect.bottom = nHeight;

// Lay down the pattern in the memory DC  FillRect( hMemDC, &rcRect, hBrush );

// Fill in the non-color pixels with the original image BitBlt( hMemDC, 0, 0, nWidth, nHeight, hDC,  lpRect->left, lpRect->top, SRCAND );

// For the "Shutdown" look, use black or gray here instead crHighlightColor = GetSysColor( COLOR_HIGHLIGHT );

// Set the color scheme crOldTextColor = SetTextColor( hDC, crHighlightColor ); crOldBkColor = SetBkColor( hDC, RGB(0,0,0) ); SetBkMode( hDC, OPAQUE );

// Select the pattern brush hOldBrush = SelectObject( hDC, hBrush ); // Fill in the color pixels, and set the others to black FillRect( hDC, lpRect, hBrush ); // Fill in the black ones with the original image BitBlt( hDC, lpRect->left, lpRect->top, nWidth, nHeight,          hMemDC, 0, 0, SRCPAINT );

// Restore target DC settings SetBkMode( hDC, OldBkMode ); SetBkColor( hDC, crOldBkColor ); SetTextColor( hDC, crOldTextColor );

// Clean up  SelectObject( hMemDC, hOldMemBitmap ); DeleteObject( hBitmap ); DeleteDC( hMemDC ); DeleteObject( hBrushBitmap ); SelectObject( hDC, hOldBrush ); DeleteObject( hBrush );

return TRUE;

} Additional query words: 4.00 hatch darken shadow

Keywords : kbOSWinNT351 kbOSWinNT400 kbOSWin2000 kbSDKWin32 kbDSupport kbGDIFAQ

Issue type : kbhowto

Technology : kbAudDeveloper kbWin32sSearch kbWin32API