Two BMP Overlays

// Create a 24-bit BMP Region

Hbitmap createbitmapsection (HDC, int CX, int cy, byte ** ppbit)

{

Bitmapinfo BMI;

Memset (& BMI. bmiheader, 0, sizeof (bitmapinfoheader ));

BMI. bmiheader. bisize = sizeof (bitmapinfoheader );

BMI. bmiheader. biplanes = 1;

BMI. bmiheader. bibitcount = 24;

BMI. bmiheader. bicompression = bi_rgb;

BMI. bmiheader. biwidth = Cx;

BMI. bmiheader. biheight = Cy;

Return createdibsection (HDC, & BMI, dib_rgb_colors, (void **) ppbit, null, 0 );

}

// Overlay two BMP images and output them to the specified DC. The Alpha value ranges from 0 ~ 255 (0 indicates full transparency, and 255 indicates opacity)

Void transparentpicture (CDC * PDC, hbitmap honebitmap, hbitmap htwobitmap, crect clientrect, int alpha)

{

Bitmap onebitmap;

Bitmap twobitmap;

GetObject (honebitmap, sizeof (Bitmap), & onebitmap );

GetObject (htwobitmap, sizeof (Bitmap), & twobitmap );

Int noneimagewidth = onebitmap. bmwidth;

Int noneimageheight = onebitmap. bmheight;

Int ntwoimagewidth = twobitmap. bmwidth;

Int ntwoimageheight = twobitmap. bmheight;

If (noneimagewidth <ntwoimagewidth)

{

Noneimagewidth = ntwoimagewidth;

}

Else

{

Ntwoimagewidth = noneimagewidth;

}

If (noneimageheight <ntwoimageheight)

{

Noneimageheight = ntwoimageheight;

}

Else

{

Ntwoimageheight = noneimageheight;

}

Int nimagewidth = noneimagewidth;

Int nimageheight = noneimageheight;

CDC memdc1, memdc2;

Hbitmap holdbitmap1 = NULL, holdbitmap2 = NULL;

Byte * ponebits = NULL;

Memdc1.createcompatibledc (PDC );

Memdc2.createcompatibledc (PDC );

Hbitmap honebmp = NULL;

Honebmp = createbitmapsection (PDC-> m_hdc, nimagewidth, nimageheight, & ponebits );

Holdbitmap1 = (hbitmap) SelectObject (memdc1.m _ HDC, honebmp );

Holdbitmap2 = (hbitmap) SelectObject (memdc2.m _ HDC, honebitmap );

// Bitblt (memdc1.m _ HDC, 0, 0, m_ntwoimage_w, m_ntwoimage_h, memdc2.m _ HDC, 0, 0, srccopy );

Stretchblt (memdc1.m _ HDC, 0, 0, nimagewidth, nimageheight,

Memdc2.m _ HDC, 0, 0, onebitmap. bmwidth, onebitmap. bmheight, srccopy );

CDC memdc3, memdc4;

Hbitmap holdbitmap3 = NULL, holdbitmap4 = NULL;

Byte * ptwobits = NULL;

Memdc3.createcompatibledc (PDC );

Memdc4.createcompatibledc (PDC );

Hbitmap htwobmp = NULL;

Htwobmp = createbitmapsection (PDC-> m_hdc, nimagewidth, nimageheight, & ptwobits );

Holdbitmap3 = (hbitmap) SelectObject (memdc3.m _ HDC, htwobmp );

Holdbitmap4 = (hbitmap) SelectObject (memdc4.m _ HDC, htwobitmap );

// Bitblt (memdc3.m _ HDC, 0, 0, m_ntwoimage_w, m_ntwoimage_h, memdc4.m _ HDC, 0, 0, srccopy );

Stretchblt (memdc3.m _ HDC, 0, 0, nimagewidth, nimageheight,

Memdc4.m _ HDC, 0, 0, twobitmap. bmwidth, twobitmap. bmheight, srccopy );

CDC memdc5;

Hbitmap holdbitmap5 = NULL;

Byte * pnewbits = NULL;

Memdc5.createcompatibledc (PDC );

Hbitmap hnewbitmap = NULL;

Hnewbitmap = createbitmapsection (PDC-> m_hdc, nimagewidth, nimageheight, & pnewbits );

Holdbitmap5 = (hbitmap) SelectObject (memdc5.m _ HDC, hnewbitmap );

Int linebytes = 0;

Int Col = 0;

Int line = (nimagewidth * 24) + 31)> 5) <2;

Linebytes = line;

Col = nimageheight;

For (Int J = 0; j <Col; j ++)

{

For (INT I = 0; I <linebytes; I ++)

{

* (Pnewbits + J * line + I) = (* (ponebits + J * line + I) * Alpha +

* (Ptwobits + J * line + I) * (255-alpha)/255;

}

}

Bitblt (PDC-> m_hdc, 0, 0, clientrect. Width (), clientrect. Height (), memdc5.m _ HDC, 0, 0, srccopy );

// Stretchblt (PDC-> m_hdc, 0, 0, m_clientrect.width (), m_clientrect.height (),

//Memdc5.m _ HDC, 0, 0, m_noneimage_w, m_noneimage_h, srccopy );

SelectObject (memdc5.m _ HDC, holdbitmap5 );

Memdc5.deletedc ();

SelectObject (memdc4.m _ HDC, holdbitmap4 );

Memdc4.deletedc ();

SelectObject (memdc3.m _ HDC, holdbitmap3 );

Memdc3.deletedc ();

SelectObject (memdc2.m _ HDC, holdbitmap2 );

Memdc2.deletedc ();

SelectObject (memdc1.m _ HDC, holdbitmap1 );

Memdc1.deletedc ();

}