【DFB】IDirectFBInputDevice 方式处理事件 --键盘移动一个图片显示

#include <stdio.h>

#include <unistd.h>

#include <directfb/directfb.h>

static IDirectFB *dfb = NULL;

static IDirectFBSurface *primary = NULL;

static IDirectFBSurface *tux = NULL;

static int screen_width = 0;

static int screen_height = 0;

//全局变量

static IDirectFBInputDevice *keyboard = NULL;

int main (int argc, char **argv)

{

DFBSurfaceDescription dsc;

IDirectFBImageProvider *provider;

DFBInputDeviceKeyState escape = DIKS_UP;//先声明一个DFBInputDeviceKeyState枚举变量，

//并将其值定为DIKS_UP,即默认没有按下

int sprite_x, sprite_y, max_x, max_y;//定义四个整形值，其中max_x, max_y用于记录前面坐标允许的最大值，

//sprite_x, sprite_y用于记录图片左上角的坐标值，

//sprite_x在[0, max_x]，sprite_y在[0, max_y]范围内

DirectFBInit (&argc, &argv);

DirectFBCreate (&dfb);

dfb->SetCooperativeLevel (dfb, DFSCL_FULLSCREEN);

dsc.flags = DSDESC_CAPS;

dsc.caps = DSCAPS_PRIMARY | DSCAPS_FLIPPING;

dfb->CreateSurface( dfb, &dsc, &primary );

primary->GetSize (primary, &screen_width, &screen_height);

dfb->GetInputDevice (dfb, DIDID_KEYBOARD, &keyboard);

dfb->CreateImageProvider (dfb, "./my.jpg", &provider);

provider->GetSurfaceDescription (provider, &dsc);

dfb->CreateSurface (dfb, &dsc, &tux);//创建一个平面tux，此平面的大小即为图片的大小，信息记录在dsc中

provider->RenderTo (provider, tux, NULL);//将图片Render到tux上，而图片与tux大小一致，则即便使用了NULL，也不会有缩放发生

provider->Release (provider);

//设定4个int变量的值，以保证图片显示在屏幕正中心

max_x = screen_width - dsc.width;

max_y = screen_height - dsc.height;

sprite_x = (screen_width - dsc.width) / 2;

sprite_y = (screen_height - dsc.height) / 2;

DFBInputDeviceKeyState state;

//primary->SetColor(primary, 0x0, 0x0, 0x0, 0xff);

//primary->FillRectangle(primary, 0, 0, screen_width, screen_height);

while (escape == DIKS_UP){

//将tux显示在primary上面

primary->FillRectangle (primary, 0, 0, screen_width, screen_height);

primary->Blit (primary, tux, NULL, sprite_x, sprite_y);

primary->Flip (primary, NULL, DSFLIP_WAITFORSYNC);

//开始图片移动策略，如果想改变移动速度，可调整步进值

keyboard->GetKeyState (keyboard, DIKI_LEFT, &state);

if (state == DIKS_DOWN){

printf("DIKI_LEFT-----------------/n");

sprite_x--;

}

keyboard->GetKeyState (keyboard, DIKI_RIGHT, &state);

if (state == DIKS_DOWN){

printf("DIKI_RIGHT-----------------/n");

sprite_x++;

}

keyboard->GetKeyState (keyboard, DIKI_UP, &state);

if (state == DIKS_DOWN){

printf("DIKI_UP-----------------/n");

sprite_y--;

}

keyboard->GetKeyState (keyboard, DIKI_DOWN, &state);

if (state == DIKS_DOWN){

printf("DIKI_DOWN-----------------/n");

sprite_y++;

}

//开始定义策略使图片始终在屏幕范围内

if (sprite_x < 0)

sprite_x = 0;

else if (sprite_x > max_x)

sprite_x = max_x;

if (sprite_y < 0)

sprite_y = 0;

else if (sprite_y > max_y)

sprite_y = max_y;

keyboard->GetKeyState (keyboard, DIKI_ESCAPE, &escape);//检查DIKI_ESCAPE状态，为下一次循环做准备

//sleep(1);

}

//由小到大的释放资源

keyboard->Release (keyboard);

tux->Release (tux);

primary->Release (primary);

dfb->Release (dfb);

return 0;

}