java - propiedad - que significa alt en una imagen

Imagen/gráfico en una forma

Question

Me preguntaba si hay alguna forma de convertir una imagen / gráfico en una Shape . Por ejemplo, ¿puedo convertir el contorno de la forma de una motocicleta en una Shape para poder usarlo en Java? Sé que puedes hacerlo con cuadrados normales o con esquinas redondeadas, polígonos, etc. Pero, ¿hay alguna manera de hacer una forma personalizada?

Answer 1

la función getArea_FastHack se basa en el trabajo de Andrew Thompson, que fue muy útil. Sin embargo, el mío debería ser más rápido: (// Edit: y sloppier, también)

import java.awt.*;
import java.awt.geom.Area;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.File;
import java.io.IOException;
/**
 * CustomShape
 * based on a Class from Andrew Thompson * 
 * Source: http://stackoverflow.com/questions/7052422/image-graphic-into-a-shape-in-java/7059497#7059497
 * @author Samuel Schneider, Andrew Thompson
 * 
 *
 */
class CustomShape {

    private BufferedImage image=null;

    /**
     * Creates an Area with PixelPerfect precision
     * @param color The color that is draws the Custom Shape
     * @param tolerance The color tolerance
     * @return Area
     */
    public Area getArea(Color color, int tolerance) {
        if(image==null) return null;
        Area area = new Area();
        for (int x=0; x<image.getWidth(); x++) {
            for (int y=0; y<image.getHeight(); y++) {
                Color pixel = new Color(image.getRGB(x,y));
                if (isIncluded(color, pixel, tolerance)) {
                    Rectangle r = new Rectangle(x,y,1,1);
                    area.add(new Area(r));
                }
            }
        }

        return area;
    }

    public Area getArea_FastHack() {
        //Assumes Black as Shape Color
        if(image==null) return null;

        Area area = new Area();
        Rectangle r;
        int y1,y2;

        for (int x=0; x<image.getWidth(); x++) {
            y1=99;
            y2=-1;
            for (int y=0; y<image.getHeight(); y++) {
                Color pixel = new Color(image.getRGB(x,y));
                //-16777216 entspricht RGB(0,0,0)
                if (pixel.getRGB()==-16777216) {
                    if(y1==99) {y1=y;y2=y;}
                    if(y>(y2+1)) {
                        r = new Rectangle(x,y1,1,y2-y1);
                        area.add(new Area(r)); 
                        y1=y;y2=y;
                    }
                    y2=y;
                }               
            }
            if((y2-y1)>=0) {
                r = new Rectangle(x,y1,1,y2-y1);
                area.add(new Area(r)); 
            }
        }

        return area;
    }

    public static boolean isIncluded(Color target, Color pixel, int tolerance) {
        int rT = target.getRed();
        int gT = target.getGreen();
        int bT = target.getBlue();
        int rP = pixel.getRed();
        int gP = pixel.getGreen();
        int bP = pixel.getBlue();
        return(
            (rP-tolerance<=rT) && (rT<=rP+tolerance) &&
            (gP-tolerance<=gT) && (gT<=gP+tolerance) &&
            (bP-tolerance<=bT) && (bT<=bP+tolerance) );
    }

    public CustomShape(String path) {
        try {
            BufferedImage image = ImageIO.read(new File(path));
            this.image = image;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 2

motorcycle.jpg

motocicleta-03.png

ImageOutline.java

Este código requiere algo de paciencia (cuando se ejecuta).

import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.geom.Area;
import javax.imageio.ImageIO;
import java.io.File;
import java.util.Date;
import javax.swing.*;

/* Motorcycle image courtesy of ShutterStock
http://www.shutterstock.com/pic-13585165/stock-vector-travel-motorcycle-silhouette.html */
class ImageOutline {

    public static Area getOutline(BufferedImage image, Color color, boolean include, int tolerance) {
        Area area = new Area();
        for (int x=0; x<image.getWidth(); x++) {
            for (int y=0; y<image.getHeight(); y++) {
                Color pixel = new Color(image.getRGB(x,y));
                if (include) {
                    if (isIncluded(color, pixel, tolerance)) {
                        Rectangle r = new Rectangle(x,y,1,1);
                        area.add(new Area(r));
                    }
                } else {
                    if (!isIncluded(color, pixel, tolerance)) {
                        Rectangle r = new Rectangle(x,y,1,1);
                        area.add(new Area(r));
                    }
                }
            }
        }
        return area;
    }

    public static boolean isIncluded(Color target, Color pixel, int tolerance) {
        int rT = target.getRed();
        int gT = target.getGreen();
        int bT = target.getBlue();
        int rP = pixel.getRed();
        int gP = pixel.getGreen();
        int bP = pixel.getBlue();
        return(
            (rP-tolerance<=rT) && (rT<=rP+tolerance) &&
            (gP-tolerance<=gT) && (gT<=gP+tolerance) &&
            (bP-tolerance<=bT) && (bT<=bP+tolerance) );
    }

    public static BufferedImage drawOutline(int w, int h, Area area) {
        final BufferedImage result = new BufferedImage(
            w,
            h,
            BufferedImage.TYPE_INT_RGB);
        Graphics2D g = result.createGraphics();

        g.setColor(Color.white);
        g.fillRect(0,0,w,h);

        g.setClip(area);
        g.setColor(Color.red);
        g.fillRect(0,0,w,h);

        g.setClip(null);
        g.setStroke(new BasicStroke(1));
        g.setColor(Color.blue);
        g.draw(area);

        return result;
    }

    public static BufferedImage createAndWrite(
        BufferedImage image,
        Color color,
        boolean include,
        int tolerance,
        String name)
        throws Exception {
        int w = image.getWidth();
        int h = image.getHeight();

        System.out.println("Get Area: " + new Date() + " - " + name);
        Area area = getOutline(image, color, include, tolerance);
        System.out.println("Got Area: " + new Date() + " - " + name);

        final BufferedImage result = drawOutline(w,h,area);
        displayAndWriteImage(result, name);

        return result;
    }

    public static void displayAndWriteImage(BufferedImage image, String fileName) throws Exception {
        ImageIO.write(image, "png", new File(fileName));
        JOptionPane.showMessageDialog(null, new JLabel(new ImageIcon(image)));
    }

    public static void main(String[] args) throws Exception {
        final BufferedImage outline = ImageIO.read(new File("motorcycle.jpg"));
        BufferedImage crop = outline.getSubimage(17,35,420,270);
        displayAndWriteImage(crop, "motorcycle-01.png");

        BufferedImage crude = createAndWrite(crop, Color.white, false, 60, "motorcycle-02.png");

        BufferedImage combo = createAndWrite(crude, Color.red, true, 0, "motorcycle-03.png");
    }
}

Answer 3

Aquí hay algo más rápido pero menos preciso, útil para la verificación de colisiones o física 2D.

    Point[] MakePoly(BufferedImage spr,int d,int angle){

//creates an outline of a transparent image, points are stored in an array
//arg0 - BufferedImage source image 
//arg1 - Int detail (lower = better)
//arg2 - Int angle threshold in degrees (will remove points with angle differences below this level; 15 is a good value)
//      making this larger will make the body faster but less accurate;


    int w= spr.getWidth(null);  int h= spr.getHeight(null);

    // increase array size from 255 if needed
    int[] vertex_x=new int[255], vertex_y=new int[255], vertex_k=new int[255]; 

    int numPoints=0, tx=0,ty=0,fy=-1,lx=0,ly=0; vertex_x[0]=0; vertex_y[0]=0; vertex_k[0]=1; 
    for (tx=0;tx<w;tx+=d)  for (ty=0;ty<h;ty+=1)       if((spr.getRGB(tx,ty)>>24) != 0x00 ) 
        {vertex_x[numPoints]=tx; vertex_y[numPoints]=h-ty; vertex_k[numPoints]=1; numPoints++; if (fy<0) fy=ty; lx=tx; ly=ty; break;  }      
    for (ty=0;ty<h;ty+=d)  for (tx=w-1;tx>=0;tx-=1)    if((spr.getRGB(tx,ty)>>24)  != 0x00 && ty > ly)
        {vertex_x[numPoints]=tx; vertex_y[numPoints]=h-ty; vertex_k[numPoints]=1; numPoints++; lx=tx; ly=ty; break;  }     
    for (tx=w-1;tx>=0;tx-=d)  for (ty=h-1;ty>=0;ty-=1) if((spr.getRGB(tx,ty)>>24) != 0x00 && tx < lx)
        {vertex_x[numPoints]=tx; vertex_y[numPoints]=h-ty; vertex_k[numPoints]=1; numPoints ++; lx=tx; ly=ty; break; }     
    for (ty=h-1;ty>=0;ty-=d)  for (tx=0;tx<w;tx+=1)    if((spr.getRGB(tx,ty)>>24) != 0x00 && ty < ly && ty > fy)
        {vertex_x[numPoints]=tx; vertex_y[numPoints]=h-ty; vertex_k[numPoints]=1; numPoints ++; lx=tx; ly=ty; break; }      
    double ang1,ang2;       for (int i=0;i<numPoints-2;i++) {
        ang1 = PointDirection(vertex_x[i],vertex_y[i], vertex_x[i+1],vertex_y[i+1]);
        ang2 = PointDirection(vertex_x[i+1],vertex_y[i+1], vertex_x[i+2],vertex_y[i+2]);
         if (Math.abs(ang1-ang2) <= angle)   vertex_k[i+1] = 0;         }
    ang1 = PointDirection(vertex_x[numPoints-2],vertex_y[numPoints-2], vertex_x[numPoints-1],vertex_y[numPoints-1]);
    ang2 = PointDirection(vertex_x[numPoints-1],vertex_y[numPoints-1], vertex_x[0],vertex_y[0]);
     if (Math.abs(ang1-ang2) <= angle)      vertex_k[numPoints-1] = 0; 
    ang1 = PointDirection(vertex_x[numPoints-1],vertex_y[numPoints-1], vertex_x[0],vertex_y[0]);
    ang2 = PointDirection(vertex_x[0],vertex_y[0], vertex_x[1],vertex_y[1]);
     if (Math.abs(ang1-ang2) <= angle)      vertex_k[0] = 0;
     int n=0;for (int i=0;i<numPoints;i++)if(vertex_k[i]==1)n++;
    Point[] poly= new Point[n]; n=0; for (int i=0;i<numPoints;i++) if (vertex_k[i]==1)
    { poly[n]=new Point(); poly[n].x=vertex_x[i]; poly[n].y=h-vertex_y[i];n++;} return poly;
}

double PointDirection(double xfrom,double yfrom,double xto,double yto){
    return  Math.atan2(yto-yfrom,xto-xfrom)*180/Math.PI ;
}