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本篇文章給大家分享的是有關怎么在C# 中利用SDL2實現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;
// 獲取圖像數據
SDL.SDL_Surface* surface= (SDL.SDL_Surface*)SDL.SDL_CreateRGBSurface(0, width, height, 32, Rmask, Gmask, Bmask, Amask);
//設置紋理的數據
SDL.SDL_Rect destrect;
destrect.x = 0;
destrect.y = 0;
destrect.w = width;
destrect.h = height;
// 讀取并渲染圖像數據
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);
//設置紋理的數據
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：
注：此處截圖是直接獲取的播放窗口的圖像像素來實現的。
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();
//設置紋理的數據
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容
sdlTTF.ShowText("simkai.ttf",12, text);
}測試效果圖：
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 視頻數據渲染播放
//設置紋理的數據
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 視頻數據渲染播放
//設置紋理的數據
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);
//設置紋理的數據
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：
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日常工作會見到或用到的。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資訊頻道。
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