C语言 cs50滤镜(模糊)分配(pset4)

Question

我正在做一个cs50分配过滤器(模糊)。我做得不是很好，但它起作用了。模糊除第一行(北)和最后一行(南)以外的所有像素。图片的角是模糊的，但角后的像素颜色真的很不寻常。我不知道是条件还是颜色的变化把它搞砸了。所以我可以用另一双眼睛来找问题，谢谢[点击这里查看详情]

void blur(int height, int width, RGBTRIPLE image[height][width])
{
RGBTRIPLE changed[height][width];
for(int i=0 ; i<=height-1 ;i++)
{
for(int j=0 ; j<=width-1 ; j++)
{
if(i==0) //main if  north corners
{
if (j==0)
{
changed[i][j].rgbtRed =round( (image[i][j].rgbtRed + image[i][j+1].rgbtRed + image[i+1][j+1].rgbtRed + image[i+1][j].rgbtRed) /4);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j+1].rgbtGreen + image[i+1][j+1].rgbtGreen + image[i+1][j].rgbtGreen) /4);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i][j+1].rgbtBlue + image[i+1][j+1].rgbtBlue + image[i+1][j].rgbtBlue) /4);

}
else if(j==width-1)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i][j-1].rgbtRed + image[i+1][j-1].rgbtRed + image[i+1][j].rgbtRed) /4);
changed[i][j].rgbtGreen = round( (image[i][j].rgbtGreen + image[i][j-1].rgbtGreen + image[i+1][j-1].rgbtGreen + image[i+1][j].rgbtGreen) /4);
changed[i][j].rgbtBlue = round( (image[i][j].rgbtBlue + image[i][j-1].rgbtBlue + image[i+1][j-1].rgbtBlue + image[i+1][j].rgbtBlue) /4);
}
}
else if(i==height-1) //main if south corners
{
if (j==0)
{
changed[i][j].rgbtRed = round( (image[i][j].rgbtRed + image[i-1][j].rgbtRed + image[i-1][j+1].rgbtRed + image[i][j+1].rgbtRed) /4);
changed[i][j].rgbtGreen = round( (image[i][j].rgbtGreen + image[i-1][j].rgbtGreen + image[i-1][j+1].rgbtGreen + image[i][j+1].rgbtGreen) /4);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i-1][j].rgbtBlue + image[i-1][j+1].rgbtBlue + image[i][j+1].rgbtBlue) /4);
}
else if(j==width-1)
{
changed[i][j].rgbtRed = round ((image[i][j].rgbtRed + image[i-1][j].rgbtRed + image[i-1][j-1].rgbtRed + image[i][j-1].rgbtRed) /4);
changed[i][j].rgbtGreen = round ((image[i][j].rgbtGreen + image[i-1][j].rgbtGreen + image[i-1][j-1].rgbtGreen + image[i][j-1].rgbtGreen) /4);
changed[i][j].rgbtBlue = round ((image[i][j].rgbtBlue + image[i-1][j].rgbtBlue + image[i-1][j-1].rgbtBlue + image[i][j-1].rgbtBlue) /4);
}
}
else if(i>0 && i<height-1 && j==0) //main if left side
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i-1][j].rgbtRed + image[i-1][j+1].rgbtRed + image[i][j+1].rgbtRed + image[i+1][j+1].rgbtRed + image[i+1][j].rgbtRed) /6);
changed[i][j].rgbtGreen = round( (image[i][j].rgbtGreen + image[i-1][j].rgbtGreen + image[i-1][j+1].rgbtGreen + image[i][j+1].rgbtGreen + image[i+1][j+1].rgbtGreen + image[i+1][j].rgbtGreen) /6);
changed[i][j].rgbtBlue = round ((image[i][j].rgbtBlue + image[i-1][j].rgbtBlue + image[i-1][j+1].rgbtBlue + image[i][j+1].rgbtBlue + image[i+1][j+1].rgbtBlue + image[i+1][j].rgbtBlue) /6);
}
else if(i>0 && i<height-1 && j==width-1) //main if right side 
{
changed[i][j].rgbtRed = round ((image[i][j].rgbtRed + image[i-1][j].rgbtRed + image[i-1][j-1].rgbtRed + image[i][j-1].rgbtRed + image[i+1][j-1].rgbtRed + image[i+1][j].rgbtRed) /6);
changed[i][j].rgbtGreen = round ((image[i][j].rgbtGreen + image[i-1][j].rgbtGreen + image[i-1][j-1].rgbtGreen + image[i][j-1].rgbtGreen + image[i+1][j-1].rgbtGreen + image[i+1][j].rgbtGreen) /6);
changed[i][j].rgbtBlue = round ((image[i][j].rgbtBlue + image[i-1][j].rgbtBlue + image[i-1][j-1].rgbtBlue + image[i][j-1].rgbtBlue + image[i+1][j-1].rgbtBlue + image[i+1][j].rgbtBlue) /6);
}
else if(i==0 && j>0 && j<width-1) //main if north side
{
changed[i][j].rgbtRed = round ((image[i][j].rgbtRed + image[i][j-1].rgbtRed + image[i+1][j-1].rgbtRed + image[i+1][j].rgbtRed + image[i+1][j+1].rgbtRed + image[i][j+1].rgbtRed) /6);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j-1].rgbtGreen + image[i+1][j-1].rgbtGreen + image[i+1][j].rgbtGreen + image[i+1][j+1].rgbtGreen + image[i][j+1].rgbtGreen) /6);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i][j-1].rgbtBlue + image[i+1][j-1].rgbtBlue + image[i+1][j].rgbtBlue + image[i+1][j+1].rgbtBlue + image[i][j+1].rgbtBlue) /6);
}
else if(i==height-1 && j>0 && j>width-1) //main if south side
{
changed[i][j].rgbtRed = round( (image[i][j].rgbtRed + image[i][j-1].rgbtRed + image[i-1][j-1].rgbtRed + image[i-1][j].rgbtRed + image[i-1][j+1].rgbtRed + image[i][j+1].rgbtRed) /6);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j-1].rgbtGreen + image[i-1][j-1].rgbtGreen + image[i-1][j].rgbtGreen + image[i-1][j+1].rgbtGreen + image[i][j+1].rgbtGreen) /6);
changed[i][j].rgbtBlue = round( (image[i][j].rgbtBlue + image[i][j-1].rgbtBlue + image[i-1][j-1].rgbtBlue + image[i-1][j].rgbtBlue + image[i-1][j+1].rgbtBlue + image[i][j+1].rgbtBlue) /6);
}
else //other pixels in the middle
{
changed[i][j].rgbtRed = round ((image[i][j].rgbtRed + image[i][j-1].rgbtRed + image[i-1][j-1].rgbtRed + image[i-1][j].rgbtRed + image[i-1][j+1].rgbtRed + image[i][j+1].rgbtRed + image[i+1][j+1].rgbtRed + image[i+1][j].rgbtRed + image[i+1][j-1].rgbtRed) /9);
changed[i][j].rgbtGreen = round ((image[i][j].rgbtGreen + image[i][j-1].rgbtGreen + image[i-1][j-1].rgbtGreen + image[i-1][j].rgbtGreen + image[i-1][j+1].rgbtGreen + image[i][j+1].rgbtGreen + image[i+1][j+1].rgbtGreen + image[i+1][j].rgbtGreen + image[i+1][j-1].rgbtGreen) /9);
changed[i][j].rgbtBlue = round( (image[i][j].rgbtBlue + image[i][j-1].rgbtBlue + image[i-1][j-1].rgbtBlue + image[i-1][j].rgbtBlue + image[i-1][j+1].rgbtBlue + image[i][j+1].rgbtBlue + image[i+1][j+1].rgbtBlue + image[i+1][j].rgbtBlue + image[i+1][j-1].rgbtBlue) /9);
}
}
}
for (int i = 0 ;i<=height-1 ; i++)
{
for (int j = 0 ; j<=width-1 ; j++)
{
image[i][j]=changed[i][j];
}
}

return;

}

Answer 1

模糊图片中除第一行(北)和最后一行(南)以外的所有像素

如果对所有的ifs和elses进行大小写区分，会发现拐角之间应该处理北和南边的代码块没有在前面的if(i==0)和if(i==height-1)之后输入;确实，对于许多很容易忽略的情况，您可以移动代码块，或者您可以使整个操作更简洁，例如:

for (int i = 0; i < height; ++i)
for (int j = 0; j < width; ++j)
{
int r = 0, g = 0, b = 0, c = 0;   // surrounding pixel color sums and count
for (int y = i-1; y <= i+1; ++y) if (0 <= y && y < height)
for (int x = j-1; x <= j+1; ++x) if (0 <= x && x < width)
r += image[y][x].rgbtRed,
g += image[y][x].rgbtGreen,
b += image[y][x].rgbtBlue,
++c;
// now compute the rounded averages
changed[i][j].rgbtRed   = (r+c/2)/c;
changed[i][j].rgbtGreen = (g+c/2)/c;
changed[i][j].rgbtBlue  = (b+c/2)/c;
}

Answer 2

这是修改后的代码

RGBTRIPLE changed[height][width];
for (int i = 0 ; i <= height - 1 ;i++)
{
for (int j = 0 ; j <= width - 1 ; j++)
{
//main if north side
if (i == 0 && j > 0 && j < width - 1 )
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i][j - 1].rgbtRed + image[i + 1][j - 1].rgbtRed + image[i + 1][j].rgbtRed + image[i + 1][j + 1].rgbtRed + image[i][j + 1].rgbtRed) / (6.0));
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j - 1].rgbtGreen + image[i + 1][j - 1].rgbtGreen + image[i + 1][j].rgbtGreen + image[i + 1][j + 1].rgbtGreen + image[i][j + 1].rgbtGreen) / (6.0));
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i][j - 1].rgbtBlue + image[i + 1][j - 1].rgbtBlue + image[i + 1][j].rgbtBlue + image[i + 1][j + 1].rgbtBlue + image[i][j + 1].rgbtBlue) / (6.0));
}
//main if south side
else if (i==height - 1  && j > 0 && j > width - 1)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i][j - 1].rgbtRed + image[i - 1][j - 1].rgbtRed + image[i - 1][j].rgbtRed + image[i - 1][j + 1].rgbtRed + image[i][j + 1].rgbtRed) / (6.0));
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j - 1].rgbtGreen + image[i - 1][j - 1].rgbtGreen + image[i - 1][j].rgbtGreen + image[i - 1][j + 1].rgbtGreen + image[i][j + 1].rgbtGreen) / (6.0));
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i][j - 1].rgbtBlue + image[i - 1][j - 1].rgbtBlue + image[i - 1][j].rgbtBlue + image[i - 1][j + 1].rgbtBlue + image[i][j + 1].rgbtBlue) / (6.0));
}

//main if left side
else if (i > 0 && i < height - 1 && j == 0)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i - 1][j].rgbtRed + image[i - 1][j + 1].rgbtRed + image[i][j + 1].rgbtRed + image[i + 1][j + 1].rgbtRed + image[i + 1][j].rgbtRed) / 6.0);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i - 1][j + 1].rgbtGreen + image[i][j + 1].rgbtGreen + image[i + 1][j + 1].rgbtGreen + image[i + 1][j].rgbtGreen) / 6.0);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i - 1][j + 1].rgbtBlue + image[i][j + 1].rgbtBlue + image[i + 1][j + 1].rgbtBlue + image[i + 1][j].rgbtBlue) / 6.0);
}
//main if right side
else if (i > 0 && i < height - 1 && j == width - 1)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i - 1][j].rgbtRed + image[i - 1][j - 1].rgbtRed + image[i][j - 1].rgbtRed + image[i + 1][j - 1].rgbtRed + image[i + 1][j].rgbtRed) / 6.0);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i - 1][j - 1].rgbtGreen + image[i][j - 1].rgbtGreen + image[i + 1][j - 1].rgbtGreen + image[i + 1][j].rgbtGreen) / 6.0);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i - 1][j - 1].rgbtBlue + image[i][j - 1].rgbtBlue + image[i + 1][j - 1].rgbtBlue + image[i + 1][j].rgbtBlue) / 6.0);
}
//main if  north corners
if (i == 0)
{
//north left corner
if (j == 0)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i][j + 1].rgbtRed + image[i + 1][j + 1].rgbtRed + image[i + 1][j].rgbtRed) / 4.0);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j + 1].rgbtGreen + image[i + 1][j + 1].rgbtGreen + image[i + 1][j].rgbtGreen) / 4.0);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i][j + 1].rgbtBlue + image[i + 1][j + 1].rgbtBlue + image[i + 1][j].rgbtBlue) / 4.0);

}
//north left corner
else if (j == width - 1)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i][j - 1].rgbtRed + image[i + 1][j - 1].rgbtRed + image[i + 1][j].rgbtRed) / 4.0);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j - 1].rgbtGreen + image[i + 1][j - 1].rgbtGreen + image[i + 1][j].rgbtGreen) / 4.0);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i][j - 1].rgbtBlue + image[i + 1][j - 1].rgbtBlue + image[i + 1][j].rgbtBlue) / 4.0);
}
}
//main if south corners
else if (i == height - 1)
{
//south right corner
if (j == 0)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i - 1][j].rgbtRed + image[i - 1][j + 1].rgbtRed + image[i][j + 1].rgbtRed) / 4.0);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i - 1][j + 1].rgbtGreen + image[i][j + 1].rgbtGreen) / 4.0);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i - 1][j + 1].rgbtBlue + image[i][j + 1].rgbtBlue) / 4.0);
}
//south left corner
else if (j == width - 1)
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i - 1][j].rgbtRed + image[i - 1][j - 1].rgbtRed + image[i][j - 1].rgbtRed) / 4.0);
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i - 1][j - 1].rgbtGreen + image[i][j - 1].rgbtGreen) / 4.0);
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i - 1][j - 1].rgbtBlue + image[i][j - 1].rgbtBlue) / 4.0);
}
}
else //other pixels in the middle
{
changed[i][j].rgbtRed = round((image[i][j].rgbtRed + image[i][j - 1].rgbtRed + image[i - 1][j - 1].rgbtRed + image[i - 1][j].rgbtRed + image[i - 1][j + 1].rgbtRed + image[i][j + 1].rgbtRed + image[i + 1][j + 1].rgbtRed + image[i + 1][j].rgbtRed + image[i + 1][j - 1].rgbtRed) / (9.0));
changed[i][j].rgbtGreen = round((image[i][j].rgbtGreen + image[i][j - 1].rgbtGreen + image[i - 1][j - 1].rgbtGreen + image[i - 1][j].rgbtGreen + image[i - 1][j + 1].rgbtGreen + image[i][j + 1].rgbtGreen + image[i + 1][j + 1].rgbtGreen + image[i + 1][j].rgbtGreen + image[i + 1][j - 1].rgbtGreen) / (9.0));
changed[i][j].rgbtBlue = round((image[i][j].rgbtBlue + image[i][j - 1].rgbtBlue + image[i - 1][j - 1].rgbtBlue + image[i - 1][j].rgbtBlue + image[i - 1][j + 1].rgbtBlue + image[i][j + 1].rgbtBlue + image[i + 1][j + 1].rgbtBlue + image[i + 1][j].rgbtBlue + image[i + 1][j - 1].rgbtBlue) / (9.0));
}
}
}
//putting the changed color value in original image(applying the blue filter)
for (int i = 0 ; i <= height - 1   ; i++)
{
for (int j = 0 ; j <= width - 1 ; j++)
{
image[i][j] = changed[i][j];
}
}

return;