win api 音频可视化

　　暂时记录，改天有时间再完善。。。其实写好好久了，但以前的代码丢了，重新写一遍。。

　　原理和 python 的一样，获取输入设备，然后把数据读取到 buffer 中，在绘制出来。

　　这里要注意两点：

　　　　1. waveformat 结构的参数都要填写正确才能打开设备，wavehdr结构必须先初始化才能调用准备函数，官方文档里都有解释。

　　　　2. 读取出来的数据是无符号字符类型（0~255），以及 window 坐标是以左上角为基准，所以，要正确展示波形需要注意下。

　　做了一些修改：

#include "framework.h"
#include "audio_analysis.h"

#define MAX_LOADSTRING 100
#define RATE 44100
#define AUBUFF 2048
#define PIPE 2

HINSTANCE hInst;                                // 当前实例
WCHAR szTitle[MAX_LOADSTRING];                  // 标题栏文本
WCHAR szWindowClass[MAX_LOADSTRING];            // 主窗口类名
WAVEFORMATEX waveformat;
WAVEHDR wavehdr;
HWAVEOUT hWaveOut;
HWAVEIN hWaveIn;
HWND hBtn;
WCHAR szFilter[] = L"ALL Files (*.*)\0*.*\0\0";
WCHAR szButton[] = L"播放";
BYTE waveBuffer[RATE * PIPE];
signed char audioData[AUBUFF];
BOOL playing = TRUE;
INT audioSum = 0;

ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPWSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // TODO: 在此处放置代码。

    // 初始化全局字符串
    LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadStringW(hInstance, IDC_AUDIOANALYSIS, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    // 执行应用程序初始化:
    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

    HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_AUDIOANALYSIS));

    MSG msg;

    // 主消息循环:
    while (GetMessage(&msg, nullptr, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}

ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEXW wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_AUDIOANALYSIS));
    wcex.hCursor        = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground  = CreateSolidBrush(RGB(0, 0, 0));
    wcex.lpszMenuName   = MAKEINTRESOURCEW(IDC_AUDIOANALYSIS);
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassExW(&wcex);
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   hInst = hInstance; // 将实例句柄存储在全局变量中

   HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
	case WM_CREATE:
		{
			HDC hdc = GetDC(hWnd);
			RECT rect;
			TEXTMETRIC textMetric;

			GetTextMetrics(hdc, &textMetric);
			GetClientRect(hWnd, &rect);

			int rWidth = rect.right - rect.left,
				cxChar = textMetric.tmAveCharWidth,
				cyChar = textMetric.tmHeight + textMetric.tmExternalLeading,
				bWidth = 10 * cxChar,
				bHeight = 8 * cyChar / 4;

			hBtn = CreateWindow(TEXT("button"), szButton,
				WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
				rWidth / 2 - bWidth / 2, cyChar, bWidth, bHeight,
				hWnd, (HMENU)MAKEINTRESOURCE(IDM_BUTTON),
				((LPCREATESTRUCT)lParam)->hInstance, NULL);

			waveformat.cbSize = 0;
			waveformat.nAvgBytesPerSec = RATE * 4;
			waveformat.nBlockAlign = 4;
			waveformat.nChannels = PIPE;
			waveformat.nSamplesPerSec = RATE;
			waveformat.wBitsPerSample = 16;
			waveformat.wFormatTag = WAVE_FORMAT_PCM;
			UINT rst = waveInOpen(&hWaveIn, WAVE_MAPPER, &waveformat, (DWORD)hWnd, 0, CALLBACK_WINDOW);
			if (rst != MMSYSERR_NOERROR)
			{
				MessageBox(hWnd, L"Could not find suitable input device",
					L"Error Message", MB_ICONSTOP | MB_OK);
				DestroyWindow(hWnd);
				break;
			}
		}
		break;
    case WM_COMMAND:
        {
            int wmId = LOWORD(wParam);
            switch (wmId)
            {
			case IDM_OPEN:
				{
					OPENFILENAME ofn;
					WCHAR szFile[MAX_PATH];

					ZeroMemory(&ofn, sizeof(ofn));
					ofn.hwndOwner = hWnd;
					ofn.lStructSize = sizeof(ofn);
					ofn.lpstrFilter = szFilter;
					ofn.nMaxFile = _MAX_PATH;
					ofn.lpstrFile = szFile;
					ofn.lpstrFile[0] = '\0';
					ofn.nFilterIndex = 1;
					ofn.lpstrFileTitle = NULL;
					ofn.nMaxFileTitle = 0;
					ofn.lpstrInitialDir = NULL;
					ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
					if (GetOpenFileName(&ofn) == TRUE)
					{
						WCHAR wComd[MAX_PATH];
						_stprintf_s(wComd, TEXT("open cdaudio!%s"), szFile);
						mciSendString(wComd, NULL, 0, 0);
						_stprintf_s(wComd, TEXT("play cdaudio!%s"), szFile);
						mciSendString(wComd, NULL, 0, 0);
					}
					else
					{
						MessageBoxW(NULL, TEXT("打开文件失败"), TEXT("错误"), MB_OK);
					}
				}
				break;
			case IDM_BUTTON:
				{
					if (playing == TRUE)
					{
						playing = FALSE;
						waveInStop(hWaveIn);
						SetWindowText(hBtn, TEXT("播放"));
					}
					else
					{
						playing = TRUE;
						waveInStart(hWaveIn);
						SetWindowText(hBtn, TEXT("暂停"));
					}
				}
				break;
            case IDM_ABOUT:
                DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                break;
            case IDM_EXIT:
                DestroyWindow(hWnd);
                break;
            default:
                return DefWindowProc(hWnd, message, wParam, lParam);
            }
        }
        break;
    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);
			RECT rect;
			TEXTMETRIC textMetric;

			GetTextMetrics(hdc, &textMetric);
			GetClientRect(hWnd, &rect);

			int rWidth = rect.right - rect.left,
				rHeight = rect.bottom - rect.top,
				cxChar = textMetric.tmAveCharWidth,
				cyChar = textMetric.tmHeight + textMetric.tmExternalLeading,
				bWidth = 10 * cxChar,
				bHeight = 8 * cyChar / 4,
				waveAxis = rHeight / 2;

			SetWindowPos(hBtn, HWND_TOP, rWidth / 2 - bWidth / 2,
				cyChar, bWidth, bHeight, SWP_SHOWWINDOW | SWP_NOREDRAW);
			HGDIOBJ hPen = SelectObject(hdc, GetStockObject(DC_PEN));
			SetDCPenColor(hdc, RGB(0, 245, 0));
			for (int i = 0; i < rWidth - 1; i++)
			{
				MoveToEx(hdc, 1 + 4 * i, audioData[i] + waveAxis, NULL);
				LineTo(hdc, 1 + 4 * (i + 1), audioData[i + 1] + waveAxis);
			}
			SelectObject(hdc, hPen);
			DeleteObject(hPen);
            EndPaint(hWnd, &ps);
        }
        break;
	case MM_WIM_OPEN:
		{
			ZeroMemory(&wavehdr, sizeof(wavehdr));
			ZeroMemory(waveBuffer, sizeof(waveBuffer));
			wavehdr.lpData = (LPSTR)waveBuffer;
			wavehdr.dwBufferLength = sizeof(waveBuffer);
			wavehdr.dwFlags = 0;
			wavehdr.dwLoops = 0;
			wavehdr.dwUser = 0;
			if (waveInPrepareHeader(hWaveIn, &wavehdr, sizeof(wavehdr)) != MMSYSERR_NOERROR)
			{
				MessageBox(hWnd, L"Could not prepare wave header",
					L"Warning Message", MB_ICONWARNING | MB_OK);
				waveInClose(hWaveIn);
				break;
			}
			if (waveInStart(hWaveIn) != MMSYSERR_NOERROR)
			{
				MessageBox(hWnd, L"Could not start input device",
					L"Warning Message", MB_ICONWARNING | MB_OK);
				waveInClose(hWaveIn);
				break;
			}
			if (waveInAddBuffer(hWaveIn, &wavehdr, sizeof(wavehdr)) != MMSYSERR_NOERROR)
			{
				MessageBox(hWnd, L"Could not add buffer",
					L"Warning Message", MB_ICONWARNING | MB_OK);
				waveInClose(hWaveIn);
				break;
			}
			SetWindowText(hBtn, TEXT("暂停"));
		}
		break;
	case MM_WIM_DATA:
		{
			RECT rect;
			GetClientRect(hWnd, &rect);
			int width = rect.right - rect.left;

			for (int i = 0; i < width; i++)
				audioData[i] = wavehdr.lpData[i + audioSum];
			audioSum += 4;

			RedrawWindow(hWnd, NULL, NULL, RDW_INVALIDATE);
			HBRUSH wb = (HBRUSH)GetStockObject(BLACK_BRUSH);
			RECT r = rect;
			HDC hdc = GetDC(hWnd);
			r.top += 56;
			FillRect(hdc, &r, wb);
			ReleaseDC(hWnd, hdc);
			if (audioSum > RATE * PIPE)
			{
				audioSum = 0;
				ZeroMemory(waveBuffer, sizeof(waveBuffer));
			}
			waveInAddBuffer(hWaveIn, &wavehdr, sizeof(wavehdr));
		}
		break;
	case MM_WIM_CLOSE:
		{
			playing = FALSE;
		}
		break;
    case WM_DESTROY:
		{
			if (playing)
			{
				waveInStop(hWaveIn);
				waveInClose(hWaveIn);
			}
			PostQuitMessage(0);
		}
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}

　　截图：

　　原截图：