java - JLabel goes out of alignment (aka funky) when overlaying a rectangle on it -

i have gui making popular software imagemagick in java swing.
now, implementing crop feature , trying implement drawable box denote region cropped.
issue although have gotten rectangle draw on jlabel, jlabel starts move around once finish painting graphics on it.
example, here screenshot of app before , after selection made.

here code mousereleased() event listener

private void input_showermousereleased(java.awt.event.mouseevent evt) {                                                end_x = evt.getx();     end_y = evt.gety();     paint(input_shower.getgraphics());     input_shower.revalidate(); }             

here code paint() method

public void paint(graphics g) {     super.paintcomponents(g);     graphics2d g2 = (graphics2d) g;     g2.setcolor(color.red);     g2.setstroke(new basicstroke(5));     rectangle2d.double rectangle = new rectangle2d.double(start_x, start_y, (end_x - start_x), (end_y - start_y));     g2.draw(rectangle); } 

are there ideas why happening , possible solutions?

this dangerous code:

private void input_showermousereleased(java.awt.event.mouseevent evt) {                                                end_x = evt.getx();     end_y = evt.gety();     paint(input_shower.getgraphics());     input_shower.revalidate(); } 

since you're painting directly component graphics object not given jvm. don't this, , instead paint passively.

instead use end_x , end_y in listened jcomponent's paintcomponent method , draw that.

e.g.,

import java.awt.color; import java.awt.dimension; import java.awt.graphics; import java.awt.event.mouseadapter; import java.awt.event.mouseevent; import java.awt.image.bufferedimage; import java.io.ioexception; import java.net.url;  import javax.imageio.imageio; import javax.swing.*;  @suppresswarnings("serial") public class paintcomponentcorrect extends jpanel {    public static final string bull_fight = "https://duke.kenai.com/misc/bullfight.jpg";    private static final color rect_color = new color(150, 150, 255);    private int startx;    private int starty;    private int endx;    private int endy;    private bufferedimage img;     public paintcomponentcorrect() throws ioexception {       url url = new url(bull_fight);       img = imageio.read(url);        mymouseadapt mymouseadapt = new mymouseadapt();       addmouselistener(mymouseadapt);       addmousemotionlistener(mymouseadapt);    }     @override    protected void paintcomponent(graphics g) {       super.paintcomponent(g);       if (img != null) {          g.drawimage(img, 0, 0, null);       }       g.setcolor(rect_color);       int x = math.min(startx, endx);       int y = math.min(starty, endy);       int width = math.abs(startx - endx);       int height = math.abs(starty - endy);       g.drawrect(x, y, width, height);    }     @override    public dimension getpreferredsize() {       if (ispreferredsizeset() || img == null) {          return super.getpreferredsize();       }       return new dimension(img.getwidth(), img.getheight());    }     private class mymouseadapt extends mouseadapter {       private bufferedimage subimg;        @override       public void mousepressed(mouseevent e) {          if (e.getbutton() != mouseevent.button1) {             return;          }          startx = e.getx();          starty = e.gety();          endx = startx;          endy = starty;          repaint();       }        @override       public void mousereleased(mouseevent e) {          if (e.getbutton() != mouseevent.button1) {             return;          }          endx = e.getx();          endy = e.gety();          repaint();          int x = math.min(startx, endx);          int y = math.min(starty, endy);          int w = math.abs(startx - endx);          int h = math.abs(starty - endy);            subimg = img.getsubimage(x, y, w, h);          imageicon icon = new imageicon(subimg);          joptionpane.showmessagedialog(paintcomponentcorrect.this, icon);       }        @override       public void mousedragged(mouseevent e) {          endx = e.getx();          endy = e.gety();          repaint();       }    }     private static void createandshowgui() {       paintcomponentcorrect mainpanel = null;       try {          mainpanel = new paintcomponentcorrect();       } catch (ioexception e) {          e.printstacktrace();          system.exit(-1);       }        jframe frame = new jframe("paintcomponent correct");       frame.setdefaultcloseoperation(jframe.dispose_on_close);       frame.getcontentpane().add(mainpanel);       frame.pack();       frame.setlocationbyplatform(true);       frame.setvisible(true);    }     public static void main(string[] args) {       swingutilities.invokelater(new runnable() {          public void run() {             createandshowgui();          }       });    } }