Flood fill explanation

Question

Im working with my project with paiting/coloring features.Can anyone explain this flood fill algorithm and how this works? Is this flood fill queue? and what does queue mean(in this algorithm)?

public class FloodFill {
    public void floodFill(Bitmap image, Point node, int targetColor,
                          int replacementColor) {
        int width = image.getWidth();
        int height = image.getHeight();
        int target = targetColor;
        int replacement = replacementColor;
        if (target != replacement) {
            Queue<Point> queue = new LinkedList<Point>();
            do {

                int x = node.x;
                int y = node.y;
                while (x > 0 && image.getPixel(x - 1, y) == target) {
                    x--;

                }
                boolean spanUp = false;
                boolean spanDown = false;
                while (x < width && image.getPixel(x, y) == target) {
                    image.setPixel(x, y, replacement);
                    if (!spanUp && y > 0
                            && image.getPixel(x, y - 1) == target) {
                        queue.add(new Point(x, y - 1));
                        spanUp = true;
                    } else if (spanUp && y > 0
                            && image.getPixel(x, y - 1) != target) {
                        spanUp = false;
                    }
                    if (!spanDown && y < height - 1
                            && image.getPixel(x, y + 1) == target) {
                        queue.add(new Point(x, y + 1));
                        spanDown = true;
                    } else if (spanDown && y < height - 1
                            && image.getPixel(x, y + 1) != target) {
                        spanDown = false;
                    }
                    x++;
                }
            } while ((node = queue.poll()) != null);
        }
    }
}

What would you like to know? Currently you are drawing to a bitmap based on position on the screen and color. — HB., Oct 14 '17 at 14:00
Ok, what exactly are your Westin can you please them in bullets separately — Aniruddha K.M, Oct 14 '17 at 14:02

score 0 · Answer 1 · answered Oct 14 '17 at 15:07

There is not a specific name for this algorithm, BUT when filling large areas, I would recommend QueueLinear Flood Fill Algorith which is way faster than the above.

Here is a link to implementation:

http://www.codeproject.com/Articles/16405/Queue-Linear-Flood-Fill-A-Fast-Flood-Fill-Algorith

Flood fill explanation

1 Answers1