向Surface写位图数据的方法
Surface的Buffer准备好后，就可以向Buffer写位图数据，
Surface的Buffer跟普通的图像数据一样，也是按一定格式组织的一根根的扫描线数据。
下面的例子假设源和目的格式都是32位，并且大小不超标
uint8_t *sbits;
sbits = (uint8_t *)bitmap->getPixels();
int sstride;
sstride = bitmap->rowBytes();
int sbpp; // bytes per pixel
sbpp = bitmap->bytesPerPixel();
uint8_t *sline;
sline = sbits + (int)src->fTop * sstride + (int)src->fLeft *
sbpp;
uint8_t *dbits;
dbits = static_cast(mBufferHeap.heap->base());
//memcpy(dbits, sbits, 800 * 480 * 4);
//need check format
int dstride;
dstride = 800 * 4;; // color : abgr
int dbpp; // bytes per pixel
dbpp = 4;
uint8_t *dline;
dline = dbits + (int)dst.fTop * dstride + (int)dst.fLeft *
dbpp;
int width;
int height;
width = (int)(dst.fRight - dst.fLeft);
height = (int)(dst.fBottom - dst.fTop);
while (height--)
{
memcpy(dline, sline, width * sbpp);
dline += dstride;
sline += sstride;
}
