113 lines
2.5 KiB
C++
113 lines
2.5 KiB
C++
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/*++
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Copyright (c) 2000 Microsoft Corporation
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Module Name:
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EmulateBitmapStride.cpp
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Abstract:
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When GetObjectA is called, modify the returned width of scan lines
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so that it is DWORD aligned for Bitmaps. This is a bug in GetObjectA
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that will be fixed in whistler, but this shim is still needed for
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win2k.
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If a program is using the width of scan lines to determine if the bitmap
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is mono, 16, 24 bit, etc... it may cause the program to incorrectly display
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the bitmap. Symptoms will be a skewed bitmap with colors shifted.
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Notes:
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This is a general purpose shim.
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This bug is fixed in Whistler, so this shim is for Win2k.
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History:
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10/16/2000 mnikkel Created
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--*/
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#include "precomp.h"
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IMPLEMENT_SHIM_BEGIN(EmulateBitmapStride)
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#include "ShimHookMacro.h"
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APIHOOK_ENUM_BEGIN
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APIHOOK_ENUM_ENTRY(GetObjectA)
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APIHOOK_ENUM_END
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/*++
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Hook GetObjectA and align the stride if required.
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--*/
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int
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APIHOOK(GetObjectA)(
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HGDIOBJ hgdiobj, // handle to graphics object
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int cbBuffer, // size of buffer for object information
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LPVOID lpvObject // buffer for object information
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)
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{
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int iRet= 0;
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iRet = ORIGINAL_API(GetObjectA)(
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hgdiobj,
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cbBuffer,
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lpvObject);
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// If the call failed or the object is not a bitmap, pass through
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if (iRet != 0 &&
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GetObjectType(hgdiobj) == OBJ_BITMAP &&
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lpvObject != NULL)
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{
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BITMAP *pBitmap;
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LONG lOrgSize, lSizeMod;
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// Check to see if the is a compatible bitmap or a DIB
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if (cbBuffer == sizeof(BITMAP))
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{
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pBitmap= (PBITMAP)lpvObject;
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}
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else
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{
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pBitmap= &(((PDIBSECTION)lpvObject)->dsBm);
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}
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// Check the width of scan lines to see if it is DWORD aligned
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lOrgSize = pBitmap->bmWidthBytes;
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lSizeMod = 4 - (lOrgSize & 3);
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if (lSizeMod == 4)
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{
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lSizeMod = 0;
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}
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// If a change is necessary mod the size and log it.
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if (lSizeMod > 0)
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{
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pBitmap->bmWidthBytes += lSizeMod;
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LOGN( eDbgLevelInfo, "[GetObjectA] width of scan lines from %d to %d",
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lOrgSize, pBitmap->bmWidthBytes );
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}
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}
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return iRet;
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}
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/*++
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Register hooked functions
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--*/
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HOOK_BEGIN
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APIHOOK_ENTRY(GDI32.DLL, GetObjectA)
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HOOK_END
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IMPLEMENT_SHIM_END
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