data/attach/1907/fjoc0btieiuzbbimo7dix150ms8eemnt.jpg        在基于linux的嵌入式仿真平台开发中，终端的美观和可定制是一个重要的问题。单调的“白纸黑字”型表现方式可谓大煞风景。改造linux控制台使之美观可定制地展示开机信息和logo成为基于嵌入式linux应用的一项重要工作。
在本节主要讲解如何使用DirectFB来实现开机动画

架构

详细设计

DFB资源初始化

主要使用 DirectFB、Layer、Window、Surface这四种资源，其关系见资料“DirectFB、Layer、Window、Surface之间关系” DirectFBInit(&argc, &argv); DirectFBCreate(&dfb); /* Get the display layer.*/ dfb->GetDisplayLayer(dfb, 0, &layer); layer->GetConfiguration(layer, &config); /* Create the window. */ layer->CreateWindow(layer, &desc, &window); window->SetOpacity(window, 0xFF); /* Get the window's surface. */ window->GetSurface(window, surface);

DFB资源释放

/* Release the window's surface. */ surface->Release(surface); /* Release the window. */ window->Release(window); /* Release the layer. */ layer->Release(layer); dfb->Release(dfb);

图片资源初始化

DFBSurfaceDescription img_dsc; IDirectFBImageProvider *provider = NULL; /* 将要显示的图片及其相关信息保存在一个imageprovider中 */ ret = dfb->CreateImageProvider(dfb, filename, &provider); /* 将保存在provider中的图片信息提取出来，存于surface description中 */ ret = provider->GetSurfaceDescription(provider, &img_dsc); /* 根据surface description创建surface，尺寸与图片大小完全一致 */ ret = dfb->CreateSurface(dfb, &img_dsc, surface); /* 将图片呈递给刚才建立的logo平面，如果大小不一致，则进行缩放 */ ret = provider->RenderTo(provider, *surface, NULL); /* release provider */ provider->Release(provider);

图片资源初始化

imgSfc->Release(imgSfc);

动画渲染

static void fillDFBSurface( IDirectFBSurface *primary_sfc, IDirectFBSurface *img_sfc, int x, int y) { primary_sfc->Clear(primary_sfc, 0, 0, 0, 255); /* * blit即将两张位图（即thiz和source）按拉操作的方法组合成一张图片。 * 在DirectFB中，其定义的动作也是合理的：将img_sfc blit到primary_sfc上去， * 两个平面上的内容会产生叠加 */ primary_sfc->Blit(primary_sfc, img_sfc, NULL, x, y); /* 变换、更新surface buffer */ primary_sfc->Flip(primary_sfc, NULL, DSFLIP_WAITFORSYNC); return ; }

全文代码示例

/********************************************** * Author: younger.liucn@hotmail.com * File name: animation.c * Description: animation * Version, Desc * 1.1 Created **********************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "animation.h" /* config information */ #define ANIM_IMAGES_COUNT 12 /* support png, jpg */ #define ANIM_IMAGE_FORMAT "png" #define ANIM_FILE_NAME_MAX_SIZE 255 #define ANIM_IMG_DEFAULT_WIDTH 960 #define ANIM_IMG_DEFAULT_HEIGHT 540 #define ANIM_IMG_DEFAULT_FPS 10 #define ANIM_MAX_RUNNING_MTIME (20000) #define ANIM_BLACK_IMAGE "/home/younger/DFB/animApp/images/black.png" #define ANIM_DEFAULT_LOGO_NAME "/home/younger/DFB/animApp/images/welcome.jpg" #define ANIM_DEFAULT_LOGO_PATH "/home/younger/DFB/animApp/images/default" /********************************************************* * log flags and func of debug and error infor.[Begin] ********************************************************/ //#define ANIM_SYS_LAYER //#define _ANIM_DEBUG_ #ifdef _ANIM_DEBUG_ #define ANIM_DEBUG(format, ...) do { printf("[BootAnimation:%4dL]DEBUG: "format, __LINE__, ##__VA_ARGS__); } while (0) #else #define ANIM_DEBUG(format, ...) do {} while (0) #endif #define ANIM_NOTICE(format, ...) do { printf("[BootAnimation:%4dL]INFO: "format, __LINE__, ##__VA_ARGS__); } while (0) #define ANIM_ERROR(format, ...) do { printf("[BootAnimation:%4dL]ERROR: "format, __LINE__, ##__VA_ARGS__); } while (0) #define DFBCHECK(x...) do { DFBResult err = x; if (err != (DFBResult)DFB_OK) { fprintf(stderr, "[%s:%s() L:%u] DFB Error:", __FILE__, __FUNCTION__, __LINE__); DirectFBErrorFatal(#x, err); } } while(0) /********************************************************* * log flags and func of debug and error infor.[End] ********************************************************/ /********************************************************* * Data structure and Global variants [Begin] ********************************************************/ /* 使用directFB画图所需的四个DFB资源 */ struct bootanimation_dsc { IDirectFB *dfb; IDirectFBDisplayLayer *layer; IDirectFBWindow *window; IDirectFBSurface *surface; }; static struct bootanimation_dsc badsc; /* 定义图片Surface */ static IDirectFBSurface *imgSfc[ANIM_IMAGES_COUNT]; /********************************************************* * Data structure and Global variants [End] ********************************************************/ /********************************************************* * Some functions help animation [Begin] ********************************************************/ /* if exist, return 1; otherwise, return 0. */ static inline int checkFileExist(const char *filename) { if((access(filename, R_OK)) != -1) return 1; return 0; } /********************************************************* * Some functions help animation [End] ********************************************************/ void freeResources() { /* Release the window's surface. */ if(badsc.surface) badsc.surface->Release(badsc.surface); /* Release the window. */ if (badsc.window) badsc.window->Release(badsc.window); /* Release the layer. */ if (badsc.layer) badsc.layer->Release(badsc.layer); badsc.dfb->Release(badsc.dfb); return ; } static void initResources(int argc, char **argv) { DFBResult ret; badsc.window = NULL; badsc.surface = NULL; badsc.dfb = NULL; IDirectFB *dfb = NULL; DFBWindowDescription desc; DFBDisplayLayerConfig config; /* 初始化DirectFB */ DirectFBInit(&argc, &argv); DirectFBCreate(&dfb); if (!dfb) { ANIM_ERROR("directfb interface is NULL "); return ; } badsc.dfb = dfb; /* 初始化 display layer：其中ANIM_LAYERID_USING设置为0.*/ ret = badsc.dfb->GetDisplayLayer(badsc.dfb, ANIM_LAYERID_USING, &(badsc.layer)); if(ret != (DFBResult)DFB_OK) { ANIM_ERROR("Get layer(%d) failed! ", ANIM_LAYERID_USING); goto fail; } else { ANIM_DEBUG("Get layer(%d) independently. ", ANIM_LAYERID_USING); } /* 获取display layer的配置，. */ badsc.layer->GetConfiguration(badsc.layer, &config); /* 设置window参数，并创建Window */ desc.flags = (DFBWindowDescriptionFlags)(DWDESC_POSX | DWDESC_POSY | DWDESC_WIDTH | DWDESC_HEIGHT | DWDESC_CAPS | DWDESC_OPTIONS); desc.posx = 0; desc.posy = 0; desc.width = config.width; desc.height = config.height; desc.caps = (DFBWindowCapabilities)(DWCAPS_NODECORATION); desc.options = (DFBWindowOptions) (DWOP_GHOST); ret = badsc.layer->CreateWindow(badsc.layer, &desc, &(badsc.window)); if(ret != (DFBResult)DFB_OK) { ANIM_ERROR("Create window failed! "); goto fail; } /* 设置透明度 */ ret = badsc.window->SetOpacity(badsc.window, 0xFF); if(ret != (DFBResult)DFB_OK) { ANIM_ERROR("SetOpacity failed! "); goto fail; } /* 获取window的surface. */ ret = badsc.window->GetSurface(badsc.window, &(badsc.surface)); if(ret != (DFBResult)DFB_OK) { ANIM_ERROR("SetOpacity failed! "); goto fail; } return ; fail: freeResources(); return ; } /* free images */ static void deinitImages() { int i = 0; for (i = 0; i <= ANIM_IMAGES_COUNT; i++) { if (imgSfc[i]) { imgSfc[i]->Release(imgSfc[i]); } else { break; } } return ; } static int doLoadImg(const char *filename, IDirectFBSurface **surface, unsigned int *width, unsigned int *height) { int ret; IDirectFB *dfb = badsc.dfb; DFBSurfaceDescription img_dsc; IDirectFBImageProvider *provider = NULL; if(NULL == surface || NULL == filename) { ANIM_ERROR("doLoadImg() failed for %d. ", -EINVAL); return -EINVAL; } ANIM_DEBUG("doLoadImg() entry:%s . ", filename); if(!checkFileExist(filename)) { ANIM_ERROR("file %s does not exist. ", filename); return -EINVAL; } /* 将要显示的图片及其相关信息保存在一个image provider中 */ ret = dfb->CreateImageProvider(dfb, filename, &provider); if(ret) { ANIM_ERROR("CreateImageProvider() for %s failed %d. ", filename, ret); return ret; } /* 将保存在provider中的图片信息提取出来，存于surface description中 */ ret = provider->GetSurfaceDescription(provider, &img_dsc); if(ret) { ANIM_ERROR("GetSurfaceDescription() for %s failed %d. ", filename, ret); provider->Release(provider); return ret; } /* 根据surface description创建surface，尺寸与图片大小完全一致 */ ret = dfb->CreateSurface(dfb, &img_dsc, surface); if(ret) { ANIM_ERROR("CreateSurface() for %s failed %d. ", filename, ret); provider->Release(provider); return ret; } /* 将图片呈递给刚才建立的logo平面，如果大小不一致，则进行缩放 */ ret = provider->RenderTo(provider, *surface, NULL); if(ret) { ANIM_ERROR("RenderTo() for %s failed %d. ", filename, ret); (*surface)->Release(*surface); provider->Release(provider); return ret; } /* Return width / height? */ if(width) { *width = img_dsc.width; } if(height){ *height = img_dsc.height; } /* release provider */ provider->Release(provider); ANIM_DEBUG("doLoadImg() exit. "); return ret; } static int initImages() { int ret = 0, i = 0; char filename[ANIM_FILE_NAME_MAX_SIZE]; IDirectFBSurface *tmp_sfc = NULL; for (i = 0; i < ANIM_IMAGES_COUNT; i++) { imgSfc[i] = NULL; } for (i = 0; i < ANIM_IMAGES_COUNT; i++) { tmp_sfc = NULL; memset(filename, 0x0, sizeof(filename)); snprintf(filename, ANIM_FILE_NAME_MAX_SIZE, "%s/%d.%s", ANIM_DEFAULT_LOGO_PATH, i, ANIM_IMAGE_FORMAT); ret = doLoadImg(filename, &tmp_sfc, NULL, NULL); if (ret != 0) { goto bail; } imgSfc[i] = tmp_sfc; } return 0; bail: deinitImages(); return -1; } static void fillDFBSurface( IDirectFBSurface *primary_sfc, IDirectFBSurface *img_sfc, int x, int y) { primary_sfc->Clear(primary_sfc, 0, 0, 0, 255); /* * blit即将两张位图（即thiz和source）按拉操作的方法组合成一张图片。 * 在DirectFB中，其定义的动作也是合理的：将img_sfc blit到primary_sfc上去， * 两个平面上的内容会产生叠加 */ primary_sfc->Blit(primary_sfc, img_sfc, NULL, x, y); /* 变换、更新surface buffer */ primary_sfc->Flip(primary_sfc, NULL, DSFLIP_WAITFORSYNC); return ; } /* 计算两个时刻的时间差(b-a),单位毫秒 (From kernel) */ static unsigned long deltaMsecs(struct timespec *a, struct timespec *b) { long delta_secs = 0, delta_msecs = 0; if(a->tv_sec < b->tv_sec || (a->tv_sec == b->tv_sec && a->tv_nsec < b->tv_nsec)) { return 0; } delta_secs = a->tv_sec - b->tv_sec; delta_msecs = (a->tv_nsec - b->tv_nsec) / 1000000; while(delta_msecs < 0) { delta_secs--; delta_msecs += 1000; } return delta_secs * 1000 + delta_msecs; } static void doMovie() { int ret, i; int width = 0, height = 0; struct timespec before_draw, after_draw; unsigned long elapsed_msec, total_msec; IDirectFBSurface *primary = badsc.surface; IDirectFBSurface *bg_sfc = NULL; unsigned long interval = (1000 / ANIM_IMG_DEFAULT_FPS); primary->GetSize(primary, &width, &height); primary->SetColor(primary, 0, 0, 0, 255); primary->Clear(primary, 0, 0, 0, 255); primary->Flip(primary, NULL, DSFLIP_WAITFORSYNC); ANIM_NOTICE("Animation start ... "); total_msec = 0; i = 0; do { if(i >= ANIM_IMAGES_COUNT) { i = 0; } clock_gettime(CLOCK_MONOTONIC, &before_draw); fillDFBSurface(primary, imgSfc[i], (width - ANIM_IMG_DEFAULT_WIDTH) / 2, (height - ANIM_IMG_DEFAULT_HEIGHT) / 2); clock_gettime(CLOCK_MONOTONIC, &after_draw); elapsed_msec = deltaMsecs(&after_draw, &before_draw); if(elapsed_msec < interval) { usleep((interval - elapsed_msec) * 1000); total_msec += interval; } else { total_msec += elapsed_msec; } ANIM_DEBUG("elapsed %lu ms ", elapsed_msec < interval ? interval : elapsed_msec); if(total_msec >= ANIM_MAX_RUNNING_MTIME) { ANIM_NOTICE("Stopped by Timeout(%lu). ", total_msec); break; } i++; } while(1); out: primary->SetColor(primary, 0, 0, 0, 0); primary->Clear(primary, 0, 0, 0, 0); primary->Flip(primary, NULL, DSFLIP_WAITFORSYNC); ANIM_NOTICE("Animation exit with black screen... "); return ; } static void doAnimation() { sem_t *sem_closed = NULL; if (initImages()) { ANIM_ERROR("Init images failed! "); return ; } doMovie(); deinitImages(); return ; } int main(int argc, char **argv) { ANIM_NOTICE("Animation entry. "); initResources(argc, argv); doAnimation(); freeResources(); ANIM_NOTICE("Animation exit. "); return 0; }
注意： /home/younger/DFB/animApp/images/default目录下需要存放0.png~11.png等12张图片
Ok！