Golang C.TTF_RenderUTF8_Blended函數代碼示例

// Renders UTF-8 text in the specified color and returns an SDL surface.
// Blended rendering is the slowest of the three methods, although it produces
// the best results, especially when blitted over another image.
func RenderUTF8_Blended(font *Font, text string, color sdl.Color) *sdl.Surface {
	ctext := C.CString(text)
	ccol := C.SDL_Color{C.Uint8(color.R), C.Uint8(color.G), C.Uint8(color.B), C.Uint8(color.Unused)}
	surface := C.TTF_RenderUTF8_Blended(font.cfont, ctext, ccol)
	C.free(unsafe.Pointer(ctext))
	return (*sdl.Surface)(unsafe.Pointer(surface))
}

// RenderUTF8_Blended (https://www.libsdl.org/projects/SDL_ttf/docs/SDL_ttf_52.html#SEC52)
func (f *Font) RenderUTF8_Blended(text string, color sdl.Color) (*sdl.Surface, error) {
	_text := C.CString(text)
	defer C.free(unsafe.Pointer(_text))
	_c := C.SDL_Color{C.Uint8(color.R), C.Uint8(color.G), C.Uint8(color.B), C.Uint8(color.A)}
	surface := (*sdl.Surface)(unsafe.Pointer(C.TTF_RenderUTF8_Blended(f.f, _text, _c)))
	if surface == nil {
		return nil, GetError()
	}
	return surface, nil
}

func (this Font) RenderTextBlended(text string, fg sdl.Color) (sdl.Surface, error) {
	c_font := (*C.TTF_Font)(this.Ptr)
	c_text := C.CString(text)
	defer C.free(unsafe.Pointer(c_text))
	c_fg := *(*C.SDL_Color)(unsafe.Pointer(&fg))
	ret := C.TTF_RenderUTF8_Blended(c_font, c_text, c_fg)
	if ret == nil {
		return sdl.Surface{}, sdl.GetError()
	}
	return sdl.Surface{unsafe.Pointer(ret)}, nil
}

// Renders UTF-8 text in the specified color and returns an SDL surface.
// Blended rendering is the slowest of the three methods, although it produces
// the best results, especially when blitted over another image.
func RenderUTF8_Blended(font *Font, text string, color sdl.Color) *sdl.Surface {
	sdl.GlobalMutex.Lock() // Because 'C.TTF_Render*' uses 'C.SDL_CreateRGBSurface'
	font.mutex.Lock()      // Use a write lock, because 'C.TTF_Render*' may update font's internal caches

	ctext := C.CString(text)
	ccol := C.SDL_Color{C.Uint8(color.R), C.Uint8(color.G), C.Uint8(color.B), C.Uint8(color.Unused)}
	surface := C.TTF_RenderUTF8_Blended(font.cfont, ctext, ccol)
	C.free(unsafe.Pointer(ctext))

	font.mutex.Unlock()
	sdl.GlobalMutex.Unlock()

	return wrap(surface)
}

func main() {
	runtime.GOMAXPROCS(32)

	// sdl
	C.SDL_Init(C.SDL_INIT_AUDIO | C.SDL_INIT_VIDEO | C.SDL_INIT_TIMER)
	defer C.SDL_Quit()
	runtime.LockOSThread()
	window := C.SDL_CreateWindow(C.CString("play"), 0, 0, 1680, 1050,
		C.SDL_WINDOW_BORDERLESS|C.SDL_WINDOW_RESIZABLE|C.SDL_WINDOW_MAXIMIZED|C.SDL_WINDOW_OPENGL)
	if window == nil {
		fatalSDLError()
	}
	defer C.SDL_DestroyWindow(window)
	C.SDL_DisableScreenSaver()
	renderer := C.SDL_CreateRenderer(window, -1, C.SDL_RENDERER_ACCELERATED)
	if renderer == nil {
		fatalSDLError()
	}
	defer C.SDL_DestroyRenderer(renderer)
	var width, height C.int
	C.SDL_GetWindowSize(window, &width, &height)
	texture := C.SDL_CreateTexture(renderer,
		C.SDL_PIXELFORMAT_YV12,
		C.SDL_TEXTUREACCESS_STREAMING,
		width, height)
	if texture == nil {
		fatalSDLError()
	}
	defer C.SDL_DestroyTexture(texture)

	// sdl ttf
	if C.TTF_Init() == C.int(-1) {
		log.Fatal("sdl ttf init failed")
	}
	defer C.TTF_Quit()
	font := C.TTF_OpenFont(C.CString("/home/reus/font.ttf"), 32)
	if font == nil {
		fatalTTFError()
	}
	defer C.TTF_CloseFont(font)

	// open decoder
	decoder, err := NewDecoder(os.Args[1])
	if err != nil {
		log.Fatal(err)
	}
	if len(decoder.AudioStreams) == 0 || len(decoder.VideoStreams) == 0 {
		log.Fatal("no video or audio")
	}
	defer decoder.Close()

	// audio
	aCodecCtx := decoder.AudioStreams[0].codec
	audioStream := setupAudioOutput(int(aCodecCtx.sample_rate), int(aCodecCtx.channels), decoder)

	// call closure in sdl thread
	callEventCode := C.SDL_RegisterEvents(1)
	callbacks := make(chan func(Env), 1024)
	call := func(f func(env Env)) {
		var event C.SDL_Event
		var userevent C.SDL_UserEvent
		userevent._type = C.SDL_USEREVENT
		userevent.code = C.Sint32(callEventCode)
		C.set_userevent(&event, userevent)
		callbacks <- f
		C.SDL_PushEvent(&event)
	}

	// show fps
	nFrames := 0
	var fpsTexture *C.SDL_Texture
	var fpsColor C.SDL_Color
	var fpsSrc, fpsDst C.SDL_Rect
	fpsColor.r = 255
	fpsColor.g = 255
	fpsColor.b = 255
	fpsColor.a = 0
	go func() {
		for _ = range time.NewTicker(time.Second * 1).C {
			call(func(env Env) {
				cText := C.CString(fmt.Sprintf("%d", nFrames))
				sur := C.TTF_RenderUTF8_Blended(font, cText, fpsColor)
				fpsSrc.w = sur.w
				fpsSrc.h = sur.h
				fpsDst.w = sur.w
				fpsDst.h = sur.h
				C.SDL_DestroyTexture(fpsTexture)
				fpsTexture = C.SDL_CreateTextureFromSurface(env.renderer, sur)
				C.SDL_FreeSurface(sur)
				C.free(unsafe.Pointer(cText))
				nFrames = 0
			})
		}
	}()

	// render
	go func() {
		for {
			frame := <-decoder.timedFrames
			nFrames++
//.........這裏部分代碼省略.........

// Create a 32-bit ARGB surface and render the given text at high quality,
// using alpha blending to dither the font with the given color.
// This function returns the new surface, or NULL if there was an error.
func TTFRenderBlended(font *C.TTF_Font, text string,
	color C.SDL_Color) *C.SDL_Surface {
	ctext := cstr(text)
	defer ctext.free()
	return C.TTF_RenderUTF8_Blended(font, ctext, color)
}