Solved

GDI

Posted on 2007-03-29
4
226 Views
Last Modified: 2010-03-31
Hi Experts ..

Assume that I draw a polygon in a panel (swing app), How can  I change the color of the polygon when it is clicked??  I have image/map in a panel, the user draw polygon or rectangle to surround an area in the map!! I want to allow  the user to be able to move this polygon or rectangle!! so when he clicks on it, its color changed showing that it is selected!! and he can move it!!
At the first stage I want to know how can I change its color??  
0
Comment
Question by:DrAske
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
4 Comments
 
LVL 3

Expert Comment

by:cavey_79
ID: 18817328
This is a bit more difficult than it seems. First you would need some custom code to figure out which polygon was selected - that involves basically checking if the click point is very close to any of the polygon's edges.


Then, you would need to remember which polygon was clicked and inside the method you do the drawing, change the color before drawing and then change it back to black (or whatever you're using)

for (Polygon p : polygons){
if (p.isSelected()){
graphics.setColor(Color.RED);
}
//your usual polygon drawing stuff code here
if(p.isSelected()){
graphics.setColor(Color.BLACK);
}
}
0
 
LVL 9

Author Comment

by:DrAske
ID: 18831258
>>that involves basically checking if the click point is very close to any of the polygon's edges.
I think this can be done, but what about circle?? how can I determine If I click inside it?? it doesn't have edges??
0
 
LVL 3

Accepted Solution

by:
cavey_79 earned 500 total points
ID: 18833822
You will only want clicks on the edge of the circle, that means distance to center = circle radius.
for (Circle c: circles){
  if distanceTo(clickPoint, c.getCenter())==c.getRadius){
  c.setSelected(true);
}
}

You can replace this:
  if distanceTo(clickPoint, c.getCenter())==c.getRadius){
to
   if Math.abs(distanceTo(clickPoint, c.getCenter())-c.getRadius))<1{

Play with different values of the last number (1) to see which make sense.
0
 
LVL 9

Author Comment

by:DrAske
ID: 18834602
Thank you *covey* :o)

Really appreciate your help ..
regards,
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
map related example 6 59
Why my table column Id is not passed to java object? 4 45
spring jars download 1 52
Java Eclipse Loop 3 29
This was posted to the Netbeans forum a Feb, 2010 and I also sent it to Verisign. Who didn't help much in my struggles to get my application signed. ------------------------- Start The idea here is to target your cell phones with the correct…
Introduction Java can be integrated with native programs using an interface called JNI(Java Native Interface). Native programs are programs which can directly run on the processor. JNI is simply a naming and calling convention so that the JVM (Java…
This video teaches viewers about errors in exception handling.
This tutorial will introduce the viewer to VisualVM for the Java platform application. This video explains an example program and covers the Overview, Monitor, and Heap Dump tabs.

735 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question