staying within boundaries of image?

Question

So I am to loop through copyFrom.pixelData and copy it into pixelData.

I realize that I need to check the conditions of i and j, and have them not copy past the boundaries of pixelData[x][y],

I need another 2 loops for that? I tried this, but was getting segmentation fault.. Is this the right approach?

void Image::insert(int xoff, int yoff, const Image& copyFrom, Color notCopy)
{
    for (int x = xoff; x < xoff+copyFrom.width; x++) {
        for (int y = yoff; y < yoff+copyFrom.height; y++) {
            for (int i = 0; i<width; i++) {
                for (int j = 0; j<height; j++) {
                    if (copyFrom.pixelData[i][j].colorDistance(notCopy) > 20)
                        pixelData[x][y]=copyFrom.pixelData[i][j];
                    }
                }
            }
        }
    }
}

Answer 1

No, you don't need more loops for that.

Instead try:

int copywidth = std::min(width, copyFrom.width-xoff);
// likewise copyheight = ...
for( int x = 0; x < copywidth; x++ ) {
  // likewise for( int y ...
    pixelData[x][y] = copyFrom.pixelData[x+xoff][y+yoff];
}