java - Finding AffineTransform origin on screen -

let's have affinetransform (transform) , call bunch of it's methods. lets rotate , translate it. transform graphics object (g2d) it:

g2d.transform(transform); 

i want find coordinate on my screen new (0, 0) is. if drew rectangle @ coordinates untransformed g2d , 1 transformed g2d overlap. how can point, have math, affinetransform or graphics2d have built in way (i couldn't find one)?

you could...

create copy of original graphics context (graphics#create) (which idea) apply transform copy (this leave original unaffected, don't forget dispose of copy when you're done)

import java.awt.dimension; import java.awt.eventqueue; import java.awt.fontmetrics; import java.awt.graphics; import java.awt.graphics2d; import java.awt.geom.affinetransform; import java.awt.image.bufferedimage; import java.io.file; import java.io.ioexception; import java.util.logging.level; import java.util.logging.logger; import javax.imageio.imageio; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.uimanager; import javax.swing.unsupportedlookandfeelexception;  public class test {      public static void main(string[] args) {         new test();     }      public test() {         eventqueue.invokelater(new runnable() {             @override             public void run() {                 try {                     uimanager.setlookandfeel(uimanager.getsystemlookandfeelclassname());                 } catch (classnotfoundexception | instantiationexception | illegalaccessexception | unsupportedlookandfeelexception ex) {                     ex.printstacktrace();                 }                  jframe frame = new jframe("testing");                 frame.setdefaultcloseoperation(jframe.exit_on_close);                 frame.add(new testpane());                 frame.pack();                 frame.setlocationrelativeto(null);                 frame.setvisible(true);             }         });     }      public class testpane extends jpanel {          private bufferedimage img;          public testpane() {             try {                 img = imageio.read(your source image here...);             } catch (ioexception ex) {                 ex.printstacktrace();             }         }          @override         public dimension getpreferredsize() {             return img == null ? new dimension(200, 200) : new dimension(img.getwidth(), img.getheight());         }          @override         protected void paintcomponent(graphics g) {             super.paintcomponent(g);             graphics2d g2d = (graphics2d) g.create();             int x = (getwidth() - img.getwidth()) / 2;             int y = (getheight() - img.getheight()) / 2;             affinetransform @ = affinetransform.gettranslateinstance(x, y);             at.rotate(math.toradians(180), img.getwidth() / 2, img.getheight() / 2);             g2d.settransform(at);             g2d.drawimage(img, 0, 0, this);             g2d.dispose();              // don't touching original ;)             g2d = (graphics2d) g.create();             fontmetrics fm = g2d.getfontmetrics();             g2d.drawstring("top left", 0, 0 + fm.getascent());              string txt = "bottom right";             g2d.drawstring(txt, getwidth() - fm.stringwidth(txt) - 1, ((getheight() - fm.getheight()) - 1) + fm.getascent());             g2d.dispose();         }      }  } 

you could...

reverse transformation, tricky if it's complex transformation...

you could...

get reference original transformation first, apply new transform, paint ever needed painted , reapply original transformation

you could...

use affinetransform#settoidentity "reset" transform it's original state...

    affinetransform @ = g2d.gettransform();     at.translate(x, y);     at.rotate(math.toradians(180), img.getwidth() / 2, img.getheight() / 2);     // drawing...      at.settoidentity();     g2d.settransform(at);     // basics