关于位图方面的（这个就是从四铮图里，分别取其相对的平均值，完后组合成一副完整的位图数据，之后，把它处理，但是其中有些地方不懂，可以较详细的解释下吗？）有错误

void CSCOMMDlg::Bilinear_interpolation()
{
if (m_vecImageData.size() <= 0)
{
return;
}
m_vecBilinearImageData.clear();
m_vecBilinearImageData.resize(m_vecImageData.size() * 4);

std::vector<int> vectemp0;
std::vector<int> vectemp1;
std::vector<int> vectemp2;

vectemp0.resize(m_vecImageData.size());
vectemp1.resize(m_vecImageData.size());
vectemp2.resize(m_vecImageData.size());

//step0
for (int i = 0;i < vectemp0.size();i++)
{
int a0,a1,a2,a3;
int sum;

if (i < IMAGE_HEIGHT) //第一排
{
if (i % (IMAGE_HEIGHT - 1) == 0 && i != 0)//最末端
{
sum = m_vecImageData[i];
}
else
{
a0 = m_vecImageData[i];
a1 = m_vecImageData[i + 1];

sum = (a0 + a1)/2;
}
}
else
{
int nCol = i / IMAGE_HEIGHT;

if (i % ((nCol + 1) * IMAGE_HEIGHT - 1) == 0)//最末端
{
a0 = m_vecImageData[i - IMAGE_HEIGHT];
a1 = m_vecImageData[i];

sum = (a0 + a1)/2;
}
else
{
a0 = m_vecImageData[i - IMAGE_HEIGHT];
a1 = m_vecImageData[i - IMAGE_HEIGHT + 1];
a2 = m_vecImageData[i];
a3 = m_vecImageData[i + 1];

sum = (a0 + a1 + a2 + a3)/4;
}
}
vectemp0[i] = sum;
}

//step1
for (int i = 0;i < vectemp1.size();i++)
{
int a0,a1,a2,a3;
int sum;

if (i < IMAGE_HEIGHT) //第一排
{
if (i == 0)//最前端
{
sum = (m_vecImageData[0] + vectemp0[0]) / 2;
}
else
{
a0 = vectemp0[i - 1];
a1 = vectemp0[i];
a2 = m_vecImageData[i];
sum = (a0 + a1 + a2)/3;
}
}
else
{
int nCol = i / IMAGE_HEIGHT;

if (i % IMAGE_HEIGHT == 0)//最前端
{
a0 = m_vecImageData[i - IMAGE_HEIGHT];
a1 = m_vecImageData[i];
a2 = vectemp0[i];

sum = (a0 + a1 + a2)/3;
}
else
{
a0 = m_vecImageData[i - IMAGE_HEIGHT];
a1 = m_vecImageData[i];
a2 = vectemp0[i - 1];
a3 = vectemp0[i];

sum = (a0 + a1 + a2 + a3)/4;
}
}
vectemp1[i] = sum;
}
//step2
for (int i = 0;i < vectemp2.size();i++)
{
int a0,a1,a2,a3;
int sum;

if (i >= (IMAGE_WIDTH - 1) * IMAGE_HEIGHT)//最后排
{
if (i == IMAGE_WIDTH * IMAGE_HEIGHT - 1)//最后排末端
{
sum = vectemp1[i];
}
else
{
a0 = vectemp1[i];
a1 = vectemp1[i + 1];

sum = (a0 + a1) / 2;
}
}
else
{
int nCol = i / IMAGE_HEIGHT;

if (i % ((nCol + 1) * IMAGE_HEIGHT - 1) == 0)//最末端
{
a0 = vectemp1[i];
a1 = vectemp1[i + IMAGE_HEIGHT];

sum = (a0 + a1)/2;
}
else
{
a0 = vectemp1[i];
a1 = vectemp1[i + 1];
a2 = vectemp1[i + IMAGE_HEIGHT];
a3 = vectemp1[i + IMAGE_HEIGHT + 1];
sum = (a0 + a1 + a2 + a3)/4;
}
}
vectemp2[i] = sum;
}

for (int i = 0 ;i < vectemp0.size();i++)
{
m_vecBilinearImageData[i * 4 + 0] = vectemp1[i];
m_vecBilinearImageData[i * 4 + 1] = vectemp0[i];
m_vecBilinearImageData[i * 4 + 2] = m_vecImageData[i];
m_vecBilinearImageData[i * 4 + 3] = vectemp2[i];
}
}