effects.idl

来自「winddk src目录下的WDM源码压缩!」· IDL 代码 · 共 120 行

///////////////////////////////////////////////////////////////////////////////
// Microsoft Windows Media Player
// Copyright (C) Microsoft Corporation, 1999-2000
//
// Filename:    effects.idl
//
// Abstract:    Interface implemented by all Windows Media Player effects.
//
///////////////////////////////////////////////////////////////////////////////

#include <olectl.h>

import "oaidl.idl";
import "ocidl.idl";


// These flags are to be returned in the GetCapabilities method.  They
// indicate to the effects host what the effect supports

const DWORD EFFECT_CANGOFULLSCREEN  = 0x00000001;   // can the effect go full screen?
const DWORD EFFECT_HASPROPERTYPAGE  = 0x00000002;   // does the effect have a property page?
const DWORD EFFECT_VARIABLEFREQSTEP = 0x00000004;   // should effect return frequency data with variable size steps?

// This structure is passed to the Render() method of the effect. It holds the frequency,
// waveform and state data need to render the effect.
//
// The first dimension of each array corresponds to the channel: 0-left/mono 1-right(stereo only)
// The second dimension contains the sampled levels.  The frequency data ranges
// from 0..255.  The wave form data represents -128..127 but is stored as 
// 0..255. The state contains the current audio playback state. The time stamp provides
// the relative time of these samples in the audio stream.

const int SA_BUFFER_SIZE    = 1024;  // number of frequency/waveform samples

enum PlayerState                    // audio playback states
{
    stop_state              = 0,    // audio is currently stopped
    pause_state             = 1,    // audio is currently paused
    play_state              = 2     // audio is currently playing
};

cpp_quote("")
cpp_quote("//**********************************************************************")
cpp_quote("// Define the minimum and maximum frequency ranges returned in our")
cpp_quote("// TimedLevel frequency array (i.e. first index in TimedLevel.frequency")
cpp_quote("// is at 20Hz and last is at 22050Hz).")
cpp_quote("//**********************************************************************")
cpp_quote("const float kfltTimedLevelMaximumFrequency = 22050.0F;")
cpp_quote("const float kfltTimedLevelMinimumFrequency = 20.0F;")
cpp_quote("")
cpp_quote("/*")
cpp_quote(" * FREQUENCY_INDEX() returns the index into TimedLevel.frequency[] where ")
cpp_quote(" * the specified frequency is located in the power spectrum")
cpp_quote(" */")
cpp_quote("#define FREQUENCY_INDEX(FREQ)\\")
cpp_quote("  (int)(((FREQ) - kfltTimedLevelMinimumFrequency) /\\")
cpp_quote("    (((kfltTimedLevelMaximumFrequency - kfltTimedLevelMinimumFrequency) / SA_BUFFER_SIZE)))")
cpp_quote("")

typedef struct tagTimedLevel
{
    unsigned char   frequency[2][SA_BUFFER_SIZE];
    unsigned char   waveform [2][SA_BUFFER_SIZE]; 
    int             state;
    hyper           timeStamp;
} TimedLevel;

[
    object,
    uuid(D3984C13-C3CB-48e2-8BE5-5168340B4F35),
    helpstring("IEffects Interface"),
    pointer_default(unique)
]
interface IWMPEffects : IUnknown
{
    // render effect to the rectangle on the provided dc - the dc is normalized
    [helpstring("method Render")] 
    HRESULT Render([in] TimedLevel *pLevels, [in] HDC hdc, [in] RECT *prc);

    // provides the no. channels, sample rate and title of the audio currently playing
    [helpstring("method MediaInfo")] 
    HRESULT MediaInfo([in] LONG lChannelCount, [in] LONG lSampleRate, [in] BSTR bstrTitle );

    // called to retrieive the capabilities of the effect (fullscreen? property page?, etc.)
    [helpstring("method GetCapabilities")]
    HRESULT GetCapabilities([out] DWORD * pdwCapabilities);

    // retrieve the display title of the effect
    [helpstring("method GetTitle")]
    HRESULT GetTitle([out] BSTR *bstrTitle);

    // retrieve the title for a preset
    [helpstring("method GetPresetTitle")]
    HRESULT GetPresetTitle([in] LONG nPreset, [out] BSTR *bstrPresetTitle);

    // retrieve the number of presets this effect supports
    [helpstring("method GetPresetCount")]
    HRESULT GetPresetCount([out] LONG * pnPresetCount);

    // set / get the current preset
    [helpstring("method SetPreset")]
    HRESULT SetCurrentPreset([in] LONG nPreset);
    [helpstring("method GetPreset")]
    HRESULT GetCurrentPreset([out] LONG * pnPreset);

    // display the property page of the effect (if there is one)
    [helpstring("method DisplayPropertyPage")] 
    HRESULT DisplayPropertyPage([in] HWND hwndOwner);

    // This method will be called when the effect is to start and stop full screen
    // rendering (if supported)
    [helpstring("method GoFullscreen")] 
    HRESULT GoFullscreen([in] BOOL fFullScreen);

    // This method will get called after a successful call to GoFullScreen to render
    // the effect.  Return failure from this method to signal loss of full screen.
    [helpstring("method RenderFullScreen")] 
    HRESULT RenderFullScreen([in] TimedLevel *pLevels);
};