windows 读取mp3文件 显示到带时间轴的波形显示控件代码 C++

以下是一个基于 Windows 平台的使用 GDI+ 绘制波形图的示例代码，可以展示 MP3 文件的波形，并将其显示在带时间轴的控件上。

首先需要安装 GDI+，可以在 Visual Studio 中添加依赖项或手动下载安装。然后在代码中包含头文件 `Gdiplus.h` 并在程序初始化时初始化 GDI+。

接下来，我们需要使用一个第三方库来解码 MP3 文件并将其转换为 PCM 数据。这里我们使用了开源库 `libmpg123`，可以在官网下载并安装。安装完成后，在代码中包含头文件 `mpg123.h`，并使用以下代码解码 MP3 文件：

// 打开 MP3 文件
mpg123_handle* mh;
mh = mpg123_new(NULL, NULL);
mpg123_open(mh, "sample.mp3");

// 获取 MP3 文件信息
long rate;
int channels, enc;
mpg123_getformat(mh, &rate, &channels, &enc);

// 分配缓冲区
unsigned char* buffer = new unsigned char[mpg123_outblock(mh)];

// 解码 MP3 文件并转换为 PCM 数据
int samples;
short pcm[4096];
while (mpg123_read(mh, buffer, mpg123_outblock(mh), &samples) == MPG123_OK) {
    mpg123_decode(mh, buffer, samples, pcm, sizeof(pcm), &samples);
    // 将 PCM 数据保存到文件或处理
}

解码并转换完成后，我们可以使用 GDI+ 绘制波形图。我们可以使用 `Graphics::DrawLine()` 方法在控件上绘制线条，以表示波形图。代码如下：

// 绘制波形图
void DrawWaveform(Graphics* graphics, int x, int y, int width, int height, short* pcm, int count) {
    Pen pen(Color(255, 255, 255));
    graphics->SetSmoothingMode(SmoothingModeHighQuality);
    graphics->SetInterpolationMode(InterpolationModeHighQualityBicubic);

    float scaleX = (float)width / count;
    float scaleY = (float)height / 65536;

    for (int i = 0; i < count - 1; i++) {
        float x1 = x + i * scaleX;
        float y1 = y + pcm[i] * scaleY + height / 2;
        float x2 = x + (i + 1) * scaleX;
        float y2 = y + pcm[i + 1] * scaleY + height / 2;
        graphics->DrawLine(&pen, x1, y1, x2, y2);
    }
}

最后，我们需要在窗口中创建一个带时间轴的控件，并在 Windows 消息循环中处理该控件的绘制事件。代码如下：

// 创建控件
HWND hwndTimeline = CreateWindowEx(0, WC_STATIC, NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 10, 10, 400, 100, hwnd, NULL, hInstance, NULL);

// 绘制事件
case WM_PAINT: {
    PAINTSTRUCT ps;
    HDC hdc = BeginPaint(hwnd, &ps);

    // 获取控件尺寸
    RECT rc;
    GetClientRect(hwndTimeline, &rc);

    // 创建 GDI+ Graphics 对象
    Graphics graphics(hdc);
    graphics.SetCompositingQuality(CompositingQualityHighQuality);

    // 绘制波形图
    DrawWaveform(&graphics, rc.left, rc.top + 20, rc.right - rc.left, rc.bottom - rc.top - 20, pcm, count);

    EndPaint(hwnd, &ps);
    break;
}

完整代码示例：

#include <Windows.h>
#include <Gdiplus.h>
#include <mpg123.h>

#pragma comment(lib, "gdiplus.lib")
#pragma comment(lib, "libmpg123.lib")

using namespace Gdiplus;

// 绘制波形图
void DrawWaveform(Graphics* graphics, int x, int y, int width, int height, short* pcm, int count) {
    Pen pen(Color(255, 255, 255));
    graphics->SetSmoothingMode(SmoothingModeHighQuality);
    graphics->SetInterpolationMode(InterpolationModeHighQualityBicubic);

    float scaleX = (float)width / count;
    float scaleY = (float)height / 65536;

    for (int i = 0; i < count - 1; i++) {
        float x1 = x + i * scaleX;
        float y1 = y + pcm[i] * scaleY + height / 2;
        float x2 = x + (i + 1) * scaleX;
        float y2 = y + pcm[i + 1] * scaleY + height / 2;
        graphics->DrawLine(&pen, x1, y1, x2, y2);
    }
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch (msg) {
    case WM_CREATE: {
        // 打开 MP3 文件
        mpg123_handle* mh;
        mh = mpg123_new(NULL, NULL);
        mpg123_open(mh, "sample.mp3");

        // 获取 MP3 文件信息
        long rate;
        int channels, enc;
        mpg123_getformat(mh, &rate, &channels, &enc);

        // 分配缓冲区
        unsigned char* buffer = new unsigned char[mpg123_outblock(mh)];

        // 解码 MP3 文件并转换为 PCM 数据
        int samples;
        short pcm[4096];
        while (mpg123_read(mh, buffer, mpg123_outblock(mh), &samples) == MPG123_OK) {
            mpg123_decode(mh, buffer, samples, pcm, sizeof(pcm), &samples);
            // 将 PCM 数据保存到文件或处理
        }

        // 关闭 MP3 文件
        mpg123_close(mh);
        mpg123_delete(mh);

        delete[] buffer;
        break;
    }
    case WM_PAINT: {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);

        // 获取控件尺寸
        RECT rc;
        GetClientRect(hwndTimeline, &rc);

        // 创建 GDI+ Graphics 对象
        Graphics graphics(hdc);
        graphics.SetCompositingQuality(CompositingQualityHighQuality);

        // 绘制波形图
        DrawWaveform(&graphics, rc.left, rc.top + 20, rc.right - rc.left, rc.bottom - rc.top - 20, pcm, count);

        EndPaint(hwnd, &ps);
        break;
    }
    case WM_DESTROY: {
        PostQuitMessage(0);
        break;
    }
    default:
        return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
    // 初始化 GDI+
    ULONG_PTR gdiplusToken;
    GdiplusStartupInput gdiplusStartupInput;
    GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

    // 创建窗口类
    WNDCLASS wc = {};
    wc.lpfnWndProc = WndProc;
    wc.hInstance = hInstance;
    wc.lpszClassName = "MyWindowClass";
    RegisterClass(&wc);

    // 创建窗口
    HWND hwnd = CreateWindow(wc.lpszClassName, "My Window", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 640, 480, NULL, NULL, hInstance, NULL);
    ShowWindow(hwnd, nCmdShow);

    // 创建控件
    HWND hwndTimeline = CreateWindowEx(0, WC_STATIC, NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 10, 10, 400, 100, hwnd, NULL, hInstance, NULL);

    // Windows 消息循环
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    // 关闭 GDI+
    GdiplusShutdown(gdiplusToken);

    return 0;
}