Android 中的 Floodfill 算法

Question

I am not able to find a floodfill algorithm implementation for Android.

Any idea if a floodfill API is available in Android, and if not, is there any other alternative?

Answer 1

FloodFill in android

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);
}
}
}

You should use a asynctask to use the floodfill algorithm. Using the same on the main thread caused out of memory error. Even if i use floofill algorithm sometime filling a huge area takes more time causing the application to become unresponsive at time.

Fill the complete canvas but keep the bound fill area as it is like circle, rectangle . This link could solve your problem

Answer 2

Do you have some definition of the shape?

If so, have a look at the Canvas docs . You can fill a region by defining a clip area and then calling canvas.drawColor.

Rough example:

    Rect r = new Rect(0,0,300,300);
    canvas.clipRect(r); // see also clipRegion
    canvas.drawColor(Color.RED);

There are several clip functions, so you should be able build whatever you're trying to fill.

On the other hand, if you want to floodfill a region in a loaded bitmap, then I don't know.