How can I drag a world?
roronoa wrote ...
2012/10/22
How to drag a world?
I press the mouse button on a random point on the world and then move it with the mouse still pressed that the image, which is to big for the screen moves together with the mouse. Just like for example google maps. Catch and drag scrolling.
Just use a actor with big image, and think he is the "world"
When dragging, update the locations of the "world" and all things "in it" with your mouse.
do you want this to hapen if the run button is pressed or if it's not pressed?
if you want it when the button isn't pressed Upupzealot's way will work but if you want it to hapen while the szenario is executing it would be a bit tricky.
I came up with this code to drag an oversized image on the world background.
import greenfoot.*;
public class Pad extends World
{
GreenfootImage image = new GreenfootImage("fractal.png"); // the oversized image
int imgX, imgY; // holds current image offsets
int prsX, prsY; // holds where mouse button first pressed
boolean dragging; // flags dragging state
public Pad()
{
super(400, 400, 1);
setBackground(image);
}
public void act()
{
if (!dragging && Greenfoot.mousePressed(null))
{
MouseInfo mi = Greenfoot.getMouseInfo();
prsX = mi.getX();
prsY = mi.getY();
dragging = true;
}
if (dragging && Greenfoot.mouseDragged(null))
{
MouseInfo mi = Greenfoot.getMouseInfo();
updateBackground(imgX - (prsX - mi.getX()), imgY - (prsY - mi.getY()));
}
if (dragging && Greenfoot.mouseDragEnded(null))
{
MouseInfo mi = Greenfoot.getMouseInfo();
boolean bgChanged = updateBackground(imgX - (prsX - mi.getX()), imgY - (prsY - mi.getY()));
if (bgChanged)
{
imgX -= prsX - mi.getX();
imgY -= prsY - mi.getY();
}
dragging = false;
}
}
public boolean updateBackground(int x, int y)
{
if (x > 0 || x < getWidth() - image.getWidth() + 1 || y > 0 || y < getHeight() - image.getHeight() + 1)
{
updateBackground(imgX, imgY);
return false;
}
GreenfootImage bg = new GreenfootImage(getWidth(), getHeight());
bg.drawImage(image, x, y);
setBackground(bg);
return true;
}
}You need to login to post a reply.