WindML双缓冲（Double Buffering）总结

双缓冲的目的是为了不闪烁，下面是从C:\Tornado2.2\target\src\ugl\example\dbuf\wexdbuf.c改造而来的，顺便把键盘鼠标输入和JPEG操作整理了

在： http://www.pudn.com/downloads526/sourcecode/embedded/detail2180188.html 下载

① 双缓冲：

//// JPEG初始化//int ret = 0;ret = JpegInit();if(ret < 0){uglBackgroundColorSet(gc, colorTable[BLACK].uglColor);uglForegroundColorSet(gc, colorTable[LIGHTGREEN].uglColor);uglTextDraw(gc, m0TextCoordinates.x, m0TextCoordinates.y, -1, "JpegInit Error\n");return ;}//// 装载第一幅JPEG图片//ret = JpegFrom("testimg1.jpg", &jpegDdbId1);if(ret < 0){uglTextDraw(gc, m0TextCoordinates.x, m0TextCoordinates.y, -1, "JpegFrom Error\n");return;}//// 装载第二幅JPEG图片//ret = JpegFrom("testimg2.jpg", &jpegDdbId2);if(ret < 0){uglTextDraw(gc, m0TextCoordinates.x, m0TextCoordinates.y, -1, "JpegFrom Error\n");return;}//// 创建两个要翻的页，并准备开始第二个页面上“画”——“活动页”//page[0] = UGL_PAGE_ZERO_ID;page[1] = uglPageCreate(devId);uglPageDrawSet(devId, page[1]);//// 死循环，里面不断画操作、“翻页”//while (1){//将将加载的第一幅JPEG位图，画到“活动页”uglBitmapSizeGet(jpegDdbId1, &jpegWidth, &jpegHeight);uglBitmapBlt(gc, jpegDdbId1, 0, 0, jpegWidth - 1, jpegHeight - 1,  UGL_DEFAULT_ID, 0, 0);//将将加载的第二幅JPEG位图，画到“活动页”uglBitmapSizeGet(jpegDdbId2, &jpegWidth, &jpegHeight);uglBitmapBlt(gc, jpegDdbId2, 0, 100, jpegWidth - 1, jpegHeight - 1,  UGL_DEFAULT_ID, 100, 100);//画一个大绿色的矩形框到“活动页”uglBackgroundColorSet(gc, colorTable[GREEN].uglColor);uglForegroundColorSet(gc, colorTable[GREEN].uglColor);uglRectangle(gc, rect.left, rect.top,  rect.right, rect.bottom);//画一个小一点的黑色的矩形框到“活动页”uglBackgroundColorSet(gc, colorTable[BLACK].uglColor);uglForegroundColorSet(gc, colorTable[BLACK].uglColor);uglRectangle(gc, rect.left + 15, rect.top + 15, rect.right - 15,  rect.bottom - 15);//画黄边蓝底的小球到“活动页”uglBackgroundColorSet(gc, colorTable[BLUE].uglColor);uglForegroundColorSet(gc, colorTable[YELLOW].uglColor);uglEllipse(gc, x, y, x + 32, y + 32, 0, 0, 0, 0);//// 文字显示“活动页”当前鼠标位置和键盘的状态//uglBackgroundColorSet(gc, colorTable[BLACK].uglColor);uglForegroundColorSet(gc, colorTable[LIGHTGREEN].uglColor);static char buf[100] = {0};static int  k = 0;sprintf(buf, "k= %d, mx= %d, my= %d, key= %d\n", k++, mouse_x, mouse_y, key);uglTextDraw(gc, 100, 100, -1, buf);//// 在循环中不断更新小球的位置，这一段不应该放在画线程中！！// if (x + 32 >= rect.right - 15)xinc = -1;else if (x <= rect.left + 15)xinc = 1;if (y + 32 >= rect.bottom - 15)yinc = -1;else if (y <= rect.top + 15)yinc = 1;x += xinc;y += yinc;//// 开始“翻页”，套用这个框架即可//if (pageIndex == 0){uglPageVisibleSet(devId, page[1]);//显示当前“活动页”uglPageDrawSet(devId, page[0]);//切换到另一个页面为“活动页”pageIndex = 1;}else{uglPageVisibleSet(devId, page[0]);uglPageDrawSet(devId, page[1]);pageIndex = 0;}}//while 结束

② JPEG：

//// 初始化JPEG//int JpegInit(){    UGL_JPEG_MODE jpegMode;    int jpegVersion;    jpegId = uglJpegInit(devId, &jpegVersion);    if (jpegId == UGL_NULL) {return -1;}    jpegMode.quality = 75;    jpegMode.smooth = 0;    jpegMode.scale = 1;    uglJpegModeSet(jpegId, &jpegMode);return 1;}//// 从文件中加载JPEG，到一副位图中//int JpegFrom(const char *filename, UGL_DDB_ID *pDdbId){    FILE *fp = fopen(filename, "rb");    if (fp == NULL){return -1;}    else{        uglJpegToDDBFromFile (jpegId, fp, pDdbId, UGL_NULL, 0, 0);        fclose (fp);}return 1;}

③ 键盘和鼠标输入线程：

//// 键盘和鼠标输入作为一个线程来处理//UGL_LOCAL int getInput(void){    UGL_MSG msg;    UGL_STATUS status;    int retVal = 0;static int kk = 0;printf("--%d\n", kk++);while(1){status = uglInputMsgGet (inputServiceId, &msg, UGL_NO_WAIT);printf("--%d\n", kk++);if (status != UGL_STATUS_Q_EMPTY){switch(msg.type){case MSG_POINTER://logMsg("Mouse: %d, %d\n", msg.data.pointer.position.x, msg.data.pointer.position.y, 0, 0, 0, 0);mouse_x = msg.data.pointer.position.x;mouse_y = msg.data.pointer.position.y;break;case MSG_KEYBOARD://logMsg("Keyborad: %04x\n", msg.data.keyboard.key, 0, 0, 0, 0, 0);key = msg.data.keyboard.key;break;}}uglOSTaskDelay (2);//一定要有个延时，否则该线程优先级高于界面画线程时，界面画线程将得不到执行！！}    return(retVal);}

④ 最后为启动：（因为在cpp文件中，声明时一定要：extern "C" void wexdbuf(); ）

void wexdbuf (void){    stopWex = UGL_FALSE;//创建画线程    uglOSTaskCreate("tWindMLDBuf", (UGL_FPTR)windMLExampleDBuf, 110,     0, 10240, 0,0,0,0,0);//等待输入设备创建完毕！！taskDelay(sysClkRateGet());//延时1s//创建输入多线程——该线程优先级高于“画线程”，因为“画线程”为死循环且循环中无延时    taskSpawn("tInput", 105, 0, 10000, (FUNCPTR)getInput,     0, 1, 2, 3, 4, 5, 6, 7, 8, 9);}