Consider the following line drawing code:

int Image[20][20]; void draw_line(int x1, int y1, int x2, int y2, int value) {

// Calculate step size double dx = x2 - x1; double dy = y2 - y1;

// Draw points on line double x = x1 + 0.5; for (int y = y1; y <= y2; y++) {

Image[y][(int)x] = value;

x += dx/dy; }

}

a) What pixels in the image will be filled in when drawing a line from (10,5) to (15,15)?

b) What will happen if we try to draw a line with dx < 0?

c) What will happen if we try to draw a line with dy < 0?

d) What will happen if we try to draw a line with dy = 0?