[DFB] 显示字符串 走马灯效果

//字体显示 #include <stdio.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <directfb/directfb.h> static IDirectFB            *dfb = NULL; static IDirectFBSurface        *primary = NULL; static IDirectFBFont        *font = NULL;//IDerectFBFont为测量字符的接口，用于计量字符串或单个字符，查询/选择编码等 static char *text = "DirectFB Chinsung !";//此为需要显示的字符 static int screen_width        = 0; static int screen_height    = 0; int main() {     int i, width;     DFBFontDescription        font_dsc;     DFBSurfaceDescription    dsc;     DirectFBInit(0, 0);     DirectFBCreate(&dfb);     dfb->SetCooperativeLevel(dfb, DFSCL_FULLSCREEN);     dsc.flags = DSDESC_CAPS;                        //建立用于创建primary的描述     dsc.caps  = DSCAPS_PRIMARY | DSCAPS_FLIPPING;     dfb->CreateSurface(dfb, &dsc, &primary);//利用先前的dsc描述创建一个IDirectFBSurface     primary->GetSize(primary, &screen_width, &screen_height);//将primary刚才获取到的屏幕长宽赋给screen_width和screen_height         font_dsc.flags = DFDESC_HEIGHT;     font_dsc.height = 48;    //设置DFBFontDescription相应属性，这里将字高设为 48     dfb->CreateFont(dfb, "./simkai.ttf", &font_dsc, &font);//利用刚刚设置好的DFBFontDescription创建字体对象     primary->SetFont(primary, font);    //设置primary要使用的字体对象，这里为font     font->GetStringWidth(font, text, -1, &width);//设置要使用的字体的宽度，并将其结果赋给width     //走马灯效果     for(i = screen_width; i > -width; --i){         //清空屏幕         primary->SetColor(primary, 0x0, 0x0, 0x0, 0xff);                        primary->FillRectangle(primary, 0, 0, screen_width, screen_height);         //显示字符串         primary->SetColor (primary, 0x80, 0x0, 0x20, 0x80);         primary->DrawString (primary, text, -1, i, screen_height/2, DSTF_LEFT);         primary->Flip (primary, NULL, DSFLIP_WAITFORSYNC); //最后Flip一下使前面的操作在屏幕上可见     }     font->Release(font);     primary->Release(primary);     dfb->Release(dfb);     return 0; }