Bitmap.cpp: grayscaling toolbar bitmap did not work on XP

diff --git a/Src/Common/Bitmap.cpp b/Src/Common/Bitmap.cpp
index 1c9330e..0ceefe3 100644 (file)
--- a/Src/Common/Bitmap.cpp
+++ b/Src/Common/Bitmap.cpp
@@ -129,30 +129,58 @@ bool GrayScale(CBitmap *pBitmap)
 {
        BITMAP bm;
        pBitmap->GetBitmap(&bm);
-       if (bm.bmBitsPixel < 24)
-               return false;
        const int nCount = bm.bmWidthBytes * bm.bmHeight;
        const int bypp = bm.bmBitsPixel / 8;
        std::unique_ptr<BYTE[]> pbuf(new BYTE[nCount]);
        pBitmap->GetBitmapBits(nCount, pbuf.get());
-       for (int i = 0, x = 0, y = 0; i < nCount - bypp; i += bypp, x += bypp)
+       if (bm.bmBitsPixel >= 24)
+       {
+               for (int i = 0, x = 0, y = 0; i < nCount - bypp; i += bypp, x += bypp)
+               {
+                       const BYTE b = pbuf[i];
+                       const BYTE g = pbuf[i + 1];
+                       const BYTE r = pbuf[i + 2];
+                       const BYTE gray = static_cast<BYTE>(
+                                (static_cast<int>(0.114 * 256) * (((255 - b) >> 1) + b)
+                               + static_cast<int>(0.587 * 256) * (((255 - g) >> 1) + g)
+                               + static_cast<int>(0.299 * 256) * (((255 - r) >> 1) + r)) >> 8);
+                       pbuf[i] = gray;
+                       pbuf[i + 1] = gray;
+                       pbuf[i + 2] = gray;
+                       if (x >= bm.bmWidthBytes - bypp)
+                       {
+                               ++y;
+                               x = 0;
+                               i = y * bm.bmWidthBytes;
+                       }
+               }
+       }
+       else if (bm.bmBitsPixel == 16)
        {
-               const BYTE b = pbuf[i];
-               const BYTE g = pbuf[i + 1];
-               const BYTE r = pbuf[i + 2];
-               const BYTE gray = static_cast<BYTE>(
-                        (static_cast<int>(0.114 * 256) * (((255 - b) >> 1) + b)
-                       + static_cast<int>(0.587 * 256) * (((255 - g) >> 1) + g)
-                       + static_cast<int>(0.299 * 256) * (((255 - r) >> 1) + r)) >> 8);
-               pbuf[i] = gray;
-               pbuf[i + 1] = gray;
-               pbuf[i + 2] = gray;
-               if (x >= bm.bmWidthBytes - bypp)
+               static const int RGB565Table5[32] = { 0, 8, 16, 25, 33, 41, 49, 58, 66, 74, 82, 90, 99, 107, 115, 123, 132, 140, 148, 156, 165, 173, 181, 189, 197, 206, 214, 222, 230, 239, 247, 255 };
+               static const int RGB565Table6[64] = { 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190, 194, 198, 202, 206, 210, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251, 255 };
+               for (int i = 0, x = 0, y = 0; i < nCount - bypp; i += bypp, x += bypp)
                {
-                       ++y;
-                       x = 0;
-                       i = y * bm.bmWidthBytes;
+                       const WORD w = (pbuf[i + 1] << 8) | pbuf[i];
+                       const BYTE b = static_cast<BYTE>(RGB565Table5[(w & 0xf800) >> 11]);
+                       const BYTE g = static_cast<BYTE>(RGB565Table6[(w & 0x07e0) >> 5]);
+                       const BYTE r = static_cast<BYTE>(RGB565Table5[w & 0x001f]);
+                       const BYTE gray = static_cast<BYTE>(
+                                (static_cast<int>(0.114 * 256) * (((255 - b) >> 1) + b)
+                               + static_cast<int>(0.587 * 256) * (((255 - g) >> 1) + g)
+                               + static_cast<int>(0.299 * 256) * (((255 - r) >> 1) + r)) >> 8);
+                       const WORD wo = ((gray >> 3) << 11) | ((gray >> 2) << 5) | ((gray >> 3) << 0);
+                       pbuf[i] = static_cast<BYTE>(wo & 0xff);
+                       pbuf[i + 1] = static_cast<BYTE>((wo >> 8));
+                       if (x >= bm.bmWidthBytes - bypp)
+                       {
+                               ++y;
+                               x = 0;
+                               i = y * bm.bmWidthBytes;
+                       }
                }
        }
+       else
+               return false;
        return pBitmap->SetBitmapBits(nCount, pbuf.get()) != 0;
 }
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