怎么在C# 中利用SDL2實現(xiàn)一個視頻播放窗口截圖

發(fā)布時間：2020-12-08 14:53:35 來源：億速云閱讀：503 作者：Leah 欄目：開發(fā)技術

本篇文章給大家分享的是有關怎么在C# 中利用SDL2實現(xiàn)一個視頻播放窗口截圖，小編覺得挺實用的，因此分享給大家學習，希望大家閱讀完這篇文章后可以有所收獲，話不多說，跟著小編一起來看看吧。

具體方法如下

 /// <summary>
 /// SDL2截圖操作類
 /// </summary>
 public unsafe class SDLScreenshot
 {
  IntPtr window;// 窗口對象
  IntPtr renderer;// 播放窗口的渲染器（來自于已初始化的播放窗口渲染器） 
  public SDLScreenshot(IntPtr window, IntPtr renderer)
  {
   this.window = window;
   this.renderer = renderer;
  } 
  /// <summary>
  /// 保存截圖
  /// </summary>
  /// <param name="width"></param>
  /// <param name="height"></param>
  /// <param name="path"></param>
  public void SaveBMP(int width, int height,string path)
  {
   // 判斷渲染器是否初始化
   if (renderer == IntPtr.Zero)
   {
    Console.WriteLine("renderer is null ,please call Init() method.");
    return;
   }
   uint Rmask=0x00FF0000, Gmask = 0x0000FF00, Bmask = 0x000000FF, Amask = 0x00000000;
   // 獲取圖像數(shù)據(jù)
   SDL.SDL_Surface* surface= (SDL.SDL_Surface*)SDL.SDL_CreateRGBSurface(0, width, height, 32, Rmask, Gmask, Bmask, Amask);
   //設置紋理的數(shù)據(jù)
   SDL.SDL_Rect destrect;
   destrect.x = 0;
   destrect.y = 0;
   destrect.w = width;
   destrect.h = height; 
 
   // 讀取并渲染圖像數(shù)據(jù)
   SDL.SDL_RenderReadPixels(renderer, ref destrect, SDL.SDL_PIXELFORMAT_ARGB8888, surface->pixels, surface->pitch); 
 
   //保存圖片
   int i = SDL.SDL_SaveBMP((IntPtr)surface, path);
   if (i != 0)
   {
    Console.WriteLine("screenshot failed." + SDL.SDL_GetError());
   } 
 
   SDL.SDL_FreeSurface((IntPtr)surface);
   //SDL.SDL_RenderClear(renderer);
   //SDL.SDL_DestroyRenderer(renderer); 
  } 
 
  /// <summary>
  /// 加載截圖
  /// </summary>
  /// <param name="width"></param>
  /// <param name="height"></param>
  /// <param name="path"></param>
  public void LoadBMP(int width, int height, string path)
  {
   // 判斷渲染器是否初始化
   if (renderer == IntPtr.Zero)
   {
    Console.WriteLine("renderer is null ,please call Init() method.");
    return;
   }
   // 加載圖片
   IntPtr surface = SDL.SDL_LoadBMP(path);
   if (surface == IntPtr.Zero)
   {
    Console.WriteLine("load bmp failed." + SDL.SDL_GetError());
    return;
   }
   IntPtr texture = SDL.SDL_CreateTextureFromSurface(renderer, surface);
   if (texture == IntPtr.Zero)
   {
    Console.WriteLine("create texture failed." + SDL.SDL_GetError());
    return;
   }
   SDL.SDL_FreeSurface(surface); 
 
   //設置紋理的數(shù)據(jù)
   SDL.SDL_Rect destrect;
   destrect.x = 0;
   destrect.y = 0;
   destrect.w = width;
   destrect.h = height; 
 
   SDL.SDL_Rect srcrect = destrect; 
 
   //SDL.SDL_RenderClear(renderer);
   SDL.SDL_RenderCopy(renderer, texture, ref srcrect, ref destrect);
   SDL.SDL_RenderPresent(renderer);
 
 
   //SDL.SDL_Delay(20); 
   SDL.SDL_DestroyTexture(texture);
   //SDL.SDL_DestroyRenderer(renderer);
   //SDL.SDL_DestroyWindow(screen);
   //Quit SDL 
   //SDL.SDL_Quit();
  }
 }

播放測試代碼：

 if (isSaveScreenshot)
       {
        SDLScreenshot screenshot = new SDLScreenshot(sdlVideo.window, sdlVideo.sdlrenderer);
        screenshot.SaveBMP(nvVideoframe.VideoFrame->width, nvVideoframe.VideoFrame->height, "screenshot.bmp");
        isSaveScreenshot = false;
     }

測試效果圖：

怎么在C# 中利用SDL2實現(xiàn)一個視頻播放窗口截圖

注：此處截圖是直接獲取的播放窗口的圖像像素來實現(xiàn)的。

視頻字幕

 /// <summary>
 /// SDL2字幕顯示類
 /// </summary>
 public unsafe class SDLTTF
 {
  IntPtr renderer;// 播放窗口的渲染器（來自于已初始化的播放窗口渲染器）
 
  public SDLTTF(IntPtr renderer)
	{
   this.renderer = renderer;
  }
 
  /// <summary>
  /// 展示字幕文字
  /// </summary>
  /// <param name="text"></param>
  public void ShowText(string ttfPath, int fontSize,string text)
  {
   // 初始化 ttf
   if (SDL_ttf.TTF_Init() < 0)
   {
    Console.WriteLine("SDL_ttf.TTF_Init() failed.");
    return;
   }
   // 是否初始化完成
   int was_init = SDL_ttf.TTF_WasInit();
 
   if (was_init == 1)
    // SDL_ttf was already initialized
    Console.WriteLine("SDL_ttf was already initialized");
   else if (was_init == 0)
    // SDL_ttf was not already initialized
    Console.WriteLine("SDL_ttf was not already initialized");
 
   // 判斷是否初始化
   if (renderer == IntPtr.Zero)
   {
    Console.WriteLine("Not initialized by SDL_ttf.TTF_Init() ,please call Init() method.");
    return;
   }
 
   //如：打開ttfPath=simfang.ttf 字庫，設字體為fontSize=20號
   IntPtr font = SDL_ttf.TTF_OpenFont(ttfPath, fontSize);
   if (font == IntPtr.Zero)
   {
    Console.WriteLine("open font failed." + SDL.SDL_GetError());
    return;
   }
 
   // 設置文字顏色
   SDL.SDL_Color color;
   color.a = 255;
   color.r = 255;
   color.g = 255;
   color.b = 255;
 
   // 渲染文字效果
   //IntPtr surface = SDL_ttf.TTF_RenderUTF8_Blended(font, text, color);
   IntPtr surface = SDL_ttf.TTF_RenderUNICODE_Blended(font, text, color);
   if (surface == IntPtr.Zero)
   {
    Console.WriteLine("show surface failed." + SDL.SDL_GetError());
   }
   IntPtr texture = SDL.SDL_CreateTextureFromSurface(renderer, surface);
   if (texture == IntPtr.Zero)
   {
    Console.WriteLine("create texture failed." + SDL.SDL_GetError());
   }
   SDL.SDL_FreeSurface(surface);
   // 關閉字體
   SDL_ttf.TTF_CloseFont(font);
 
   // 停止顯示
   SDL_ttf.TTF_Quit();
 
   //設置紋理的數(shù)據(jù)
   SDL.SDL_Rect destrect;
   destrect.x = 0;
   destrect.y = 0;
   destrect.w = text.Length * 20;
   destrect.h = 20;
 
   SDL.SDL_Rect srcrect = destrect; 
   SDL.SDL_RenderClear(renderer);
   SDL.SDL_RenderCopy(renderer, texture, ref srcrect, ref destrect);
   SDL.SDL_RenderPresent(renderer);
   SDL.SDL_DestroyTexture(texture);
   SDL.SDL_DestroyRenderer(renderer);
  }
 }

事件測試字幕添加：

需要的引用庫下載：https://www.libsdl.org/projects/SDL_ttf/

 /// <summary>
  /// 字幕疊加****需要添加三個dll庫：SDL2_ttf.dll 、libfreetype-6.dll 、zlib1.dll
  /// </summary>
  /// <param name="sender"></param>
  /// <param name="e"></param>
  private void mbtnAddFontText_Click(object sender, EventArgs e)
  {
   Console.WriteLine("疊加字幕...............");
 
   sdlTTF = new SDLTTF(sdlVideo.sdlrenderer);
   // 中英文都需要兼容
   string text = "Hello 世界!";
   // 設置一個字體庫并設置字體大小和顯示文字內(nèi)容
   sdlTTF.ShowText("simkai.ttf",12, text);
  }

測試效果圖：

怎么在C# 中利用SDL2實現(xiàn)一個視頻播放窗口截圖

如果是播放過程中顯示字幕一定要在視頻渲染完成后渲染字幕，如下面工具類的方法：

/// <summary>
  /// 播放視頻
  /// </summary>
  /// <param name="width"></param>
  /// <param name="height"></param>
  /// <param name="pixels"></param>
  /// <param name="pixelsSize"></param>
  /// <param name="pitch"></param>
  /// <returns></returns>
  public int SDL_Display(int width, int height, IntPtr pixels, int pixelsSize,
   int pitch)
  {
   lock (this)
   {
    while (isPause)
    {
     SDL.SDL_Delay(20);//延遲播放
    }
 
    #region SDL 視頻數(shù)據(jù)渲染播放
    //設置紋理的數(shù)據(jù)
    sdlrect.x = 0;
    sdlrect.y = 0;
    sdlrect.w = width;
    sdlrect.h = height;
    SDL.SDL_UpdateTexture(sdltexture, ref sdlrect, pixels, pitch);
    //SDL.SDL_UpdateTexture(sdltexture, IntPtr.Zero, pixels, pitch);//此處代碼導致播放窗口綠色陰影
    //復制紋理信息到渲染器目標
    SDL.SDL_RenderClear(sdltexture);
    //SDL.SDL_Rect srcRect = sdlrect;
    //SDL.SDL_RenderCopy(sdlrenderer, sdltexture, ref srcRect, ref sdlrect);
 
    SDL.SDL_RenderCopy(sdlrenderer, sdltexture, IntPtr.Zero, IntPtr.Zero);
    //字幕渲染顯示-特別提醒：此處必須放置于視頻渲染之后，否則字幕不會顯示
    if (ttfText!=null&&!ttfText.Equals(""))
    {
     RenderToShowTTF(ttfText);
    }
    //else
    //{
    // RenderToShowTTF( "未設置字幕內(nèi)容");
    //}
    //視頻渲染顯示
    SDL.SDL_RenderPresent(sdlrenderer);
    //SDL.SDL_Delay(40);
    //SDL.SDL_PollEvent(out sdlevent);
    //switch (sdlevent.type)
    //{
    // case SDL.SDL_EventType.SDL_QUIT:
    //  SDL.SDL_Quit();
    //  return -1;
    // default:
    //  break;
    //}
    return 0;
   } 
 
   //SDL.SDL_RenderClear(sdlrenderer);
   //SDL.SDL_RenderCopy(sdlrenderer, sdltexture, ref srcRect, ref sdlrect);
   //SDL.SDL_RenderPresent(sdlrenderer);
   Delay 40ms 
   //SDL.SDL_Delay(40);
   #endregion 
 
   //#region SDL 視頻數(shù)據(jù)渲染播放
   //設置紋理的數(shù)據(jù)
   sdlrect.x = 0;
   sdlrect.y = 0;
   sdlrect.w = width;
   sdlrect.h = height;
   SDL.SDL_UpdateTexture(sdltexture, ref sdlrect, pixels, pitch);
   //復制紋理信息到渲染器目標
   SDL.SDL_Rect srcRect = sdlrect;
   SDL.SDL_RenderCopy(sdlrenderer, sdltexture, ref srcRect, ref sdlrect);
   //視頻渲染顯示
   SDL.SDL_RenderPresent(sdlrenderer);
   //SDL.SDL_Delay(40);
   SDL.SDL_PollEvent(out sdlevent);
   switch (sdlevent.type)
   {
    case SDL.SDL_EventType.SDL_QUIT:
     SDL.SDL_Quit();
     return -1;
    default:
     break;
   }
   return 0;
   //#endregion
  }
 
  /// <summary>
  /// 設置字幕顯示內(nèi)容
  /// </summary>
  /// <param name="ttfPath"></param>
  /// <param name="fontSize"></param>
  public void SDL_TTF_TEXT(string ttfPath, string text, int fontSize)
  {
   this.ttfPath = ttfPath;
   this.ttfText = text;
   this.ttfFontSize = fontSize;
  }
 
  /// <summary>
  /// 渲染字幕
  /// </summary>
  /// <param name="text"></param>
  private void RenderToShowTTF(string text)
  {
   // 初始化 ttf
   if (SDL_ttf.TTF_Init() < 0)
   {
    Console.WriteLine("SDL_ttf.TTF_Init() failed.");
    return;
   }
   // 是否初始化完成
   int was_init = SDL_ttf.TTF_WasInit();
 
   if (was_init == 1)
    // SDL_ttf was already initialized
    Console.WriteLine("SDL_ttf was already initialized");
   else if (was_init == 0)
    // SDL_ttf was not already initialized
    Console.WriteLine("SDL_ttf was not already initialized");
 
   //如：打開ttfPath=simfang.ttf 字庫，設字體為fontSize=20號
   IntPtr font = SDL_ttf.TTF_OpenFont(ttfPath, ttfFontSize);
   if (font == IntPtr.Zero)
   {
    Console.WriteLine("open font failed." + SDL.SDL_GetError());
    return;
   }
 
   // 設置文字字體
   SDL_ttf.TTF_SetFontStyle(font, SDL_ttf.TTF_STYLE_BOLD);
 
   // 設置文字顏色
   SDL.SDL_Color color;
   color.a = 255;
   color.r = 255;
   color.g = 255;
   color.b = 255;
 
   // 渲染文字效果
   //IntPtr surface = SDL_ttf.TTF_RenderText_Blended(font, text, color);
   IntPtr surface = SDL_ttf.TTF_RenderUTF8_Blended(font, text, color);
   //IntPtr surface = SDL_ttf.TTF_RenderUNICODE_Blended(font, text, color);
   if (surface == IntPtr.Zero)
   {
    Console.WriteLine("show surface failed." + SDL.SDL_GetError());
   }
   IntPtr texture = SDL.SDL_CreateTextureFromSurface(sdlrenderer, surface);
   if (texture == IntPtr.Zero)
   {
    Console.WriteLine("create texture failed." + SDL.SDL_GetError());
   }
 
   SDL.SDL_FreeSurface(surface);
   // 關閉字體
   SDL_ttf.TTF_CloseFont(font);
 
   // 停止顯示
   SDL_ttf.TTF_Quit();
 
   // 計算合適的寬度和高度
   int texWidth = 0;
   int texHeight = 0;
   uint format = 0;
   int access = 0;
   // 下面這行代碼解決字體虛浮不清問題
   SDL.SDL_QueryTexture(texture, out format, out access, out texWidth, out texHeight);
   //設置紋理的數(shù)據(jù)
   SDL.SDL_Rect destrect;
   destrect.x = 0;
   destrect.y = 0;
   destrect.w = texWidth;
   destrect.h = texHeight;
 
   SDL.SDL_Rect srcrect = destrect;
   SDL.SDL_RenderCopy(sdlrenderer, texture, ref srcrect, ref destrect);
  }

效果就會好很多：

怎么在C# 中利用SDL2實現(xiàn)一個視頻播放窗口截圖

請看這里的“中華人民共和國”

注意：

常用中英文ttf字體包中包含了：times new roman，中山行書百年紀念版，calibri，Christopherhand，DejaVuSansMono，方正蘭亭黑，James Fajardo，Monaco，微軟雅黑，仿宋，黑體，楷體，宋體，yahei_mono，仿宋_GB2312，楷體_GB2312，迷你簡行楷碑等。

本文使用的是simkai.ttf。

下面是部分字體文件名：

bb1550.ttf
calibri.ttf
calibrib.ttf
calibrii.ttf
calibriz.ttf
comesinhandy.ttf
DejaVuSansMono-Bold.ttf
DejaVuSansMono-BoldOblique.ttf
DejaVuSansMono-Oblique.ttf
DejaVuSansMono.ttf
DroidSansFallback.ttf
James_Fajardo.ttf
Monaco.ttf
msyh.ttf
msyhbd.ttf
simfang.ttf
simhei.ttf
simkai.ttf
simsun.ttc
times.ttf
timesbd.ttf
timesbi.ttf
timesi.ttf
yahei_mono.ttf

以上就是怎么在C# 中利用SDL2實現(xiàn)一個視頻播放窗口截圖，小編相信有部分知識點可能是我們?nèi)粘９ぷ鲿姷交蛴玫降?。希望你能通過這篇文章學到更多知識。更多詳情敬請關注億速云行業(yè)資訊頻道。

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怎么在C# 中利用SDL2實現(xiàn)一個視頻播放窗口截圖

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