CONTRAST.H

//==========================================================================; 
// 
//  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY 
//  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR 
//  PURPOSE. 
// 
//  Copyright (c) 1992 - 1997  Microsoft Corporation.  All Rights Reserved. 
// 
//--------------------------------------------------------------------------; 
 
const signed char MaxContrastLevel = 127; 
const signed char MinContrastLevel = -127; 
 
class CContrast : public CTransformFilter, 
  public IContrast, 
  public ISpecifyPropertyPages 
{ 
 
public: 
 
    static CUnknown * WINAPI CreateInstance(LPUNKNOWN punk, HRESULT *phr); 
 
    // Reveals IContrast & ISpecifyPropertyPages 
    STDMETHODIMP NonDelegatingQueryInterface(REFIID riid, void ** ppv); 
 
    DECLARE_IUNKNOWN; 
 
    HRESULT Transform(IMediaSample *pIn, IMediaSample *pOut); 
    HRESULT CheckInputType(const CMediaType *mtIn); 
    HRESULT CheckTransform(const CMediaType *mtIn,const CMediaType *mtOut); 
    HRESULT GetMediaType(int iPosition, CMediaType *pMediaType); 
    HRESULT DecideBufferSize(IMemAllocator *pAlloc, 
                             ALLOCATOR_PROPERTIES *pProperties); 
 
    // IContrast methods 
 
    STDMETHODIMP get_ContrastLevel(signed char *ContrastLevel); 
    STDMETHODIMP put_ContrastLevel(signed char ContrastLevel, unsigned long ChangeTime); 
    STDMETHODIMP put_DefaultContrastLevel(void); 
 
    // ISpecifyPropertyPages method 
 
    STDMETHODIMP GetPages(CAUUID *pPages); 
 
private: 
 
    // Constructor 
    CContrast(TCHAR *tszName, LPUNKNOWN punk, HRESULT *phr); 
 
    // Look after the transformation of media samples 
    BOOL CanChangeContrastLevel(const CMediaType *pMediaType) const; 
    HRESULT Copy(IMediaSample *pSource, IMediaSample *pDest) const; 
    HRESULT Transform(IMediaSample *pMediaSample); 
    HRESULT Transform(AM_MEDIA_TYPE *pType, const signed char ContrastLevel) const; 
 
    // Handle increasing and decreasing contrast 
    void IncreaseContrast(RGBQUAD *pElem, const int Low, const int High, const float Grad) const; 
    void IncreaseContrast(BYTE *pByte, const int Low, const int High, const float Grad) const; 
    void DecreaseContrast(RGBQUAD *pElem, const int Level, const float Grad) const; 
    void DecreaseContrast(BYTE *pByte, const int Level, const float Grad) const; 
 
    // The default (no-change) level 
    const signed char m_DefaultContrastLevel; 
 
    // The current level to set the palette to 
    signed charm_ContrastLevel; 
 
    // The level the last frame's palette was set at 
    signed charm_PrevLevel; 
 
    // The number of buffers to request on the output allocator 
    const long m_lBufferRequest; 
 
    // Non interface locking critical section 
    CCritSec m_ContrastLock; 
 
}; // CContrast