The documentation shows you the Java interface that your drag handler must satisfy. You can create a drag handler like so:

I'm still having trouble with peasycam syntax; when I try to use

1. cam.setLeftDragHandler(new DragHandler() {
2.    public void handleDrag(double dx, double dy) {
3.       println("Left-dragged " + dx + ", " + dy);
4.    }
5. });

I get "Cannot find a class or type named "DragHanler".

All I need to do is remap pan from default of mousewheel pressed drag to leftmousedrag, set rotation to null, and reassign zoom from mousewheel to mouse right.  This is what I have so far:

1. import peasy.*;
2. PeasyCam cam;
3. PeasyDragHandler DragHandler;
4. 
   
5. void setup() {
6.   cam = new PeasyCam(this, 100);
7.   cam.setMinimumDistance(50);
8.   cam.setMaximumDistance(500);
9.   cam.setRightDragHandler(null);
10.   cam.setLeftDragHandler(new DragHandler() {
11.     public void handleDrag(double dx, double dy) {
12.       println("Left-dragged " + dx + "," + dy);
13.     }
14.   });
15. //  cam.setLeftDragHandler(PeasyDragHandler());
16.  
17. //    if (!GlobeOn) {
18. //     cam.setLeftDragHandler(PeasyDragHandler handler);
19. //
20. //  camera.setRightDragHandler(PeasyDragHandler handler);
21. //
22. //  }
23. }
24. }
25. //public interface PeasyDragHandler {
26. //    public void handleDrag(final double dx, final double dy);
27. //}

If it is easy to remap panning to the left mouse, can you show me how to do that?  I've been looking all over the net for any samples where the handlers are reassigned and can't seem to find any examples, only references that it can be done.  It sounds like you've done it, but, I can't tell what components from the original post you are incorporating and what not.  Could you please post the entire Peasy commands to accomplish panning with the left mouse and zooming with the right mouse?

Ok I got it. So I don't really understand the value of creating your own interfaces aside from getting values about dragging like  MrFeinberg's example. However getting Peasy's drag handlers gives you access to methods which would otherwise not be visible and is a good way for remapping panning/zooming/rotating.

Ok, the following code does what I want; maps pan to left mouse and zoom to right mouse.  I am a little concerned that I don't explicitly set anything for right mouse yet, right mouse zooms as it I want it to.  The next thing I am trying to do is constrain the panning so that you can never pan beyond the borders of your world.  I am attempting to use PeasyCam in an image viewer application that allows you to zoom close up on the images and I want to stop users from viewing beyond the borders of the image.

1. import peasy.*;
2. PeasyCam cam;
3. PeasyDragHandler PanDragHandler;
4. PeasyDragHandler ZoomDragHandler;
5. public void setup(){
6.   size(100,100,P3D);
7.   cam = new PeasyCam(this, 100);
8.   cam.setMinimumDistance(50);
9.   cam.setMaximumDistance(500);
10.   PanDragHandler = cam.getPanDragHandler();
11.   ZoomDragHandler = cam.getZoomDragHandler();
12.   cam.setLeftDragHandler(PanDragHandler);
13.   cam.setWheelHandler(null);
14. }
15. public void draw(){
16.   background(0);
17. ellipse(0,0,200,200);
18. // it would be better to format the xyz's as strings
19. println(str(cam.getPosition()));
20. cam.beginHUD();
21.   rect(0,0,15,15);
22.   // it would be useful to print the camera position and look at to a generic peasy cam example sketch
23.   //String pos = cam.getPosition();
24.   //text(pos,0,6);
25. cam.endHUD();
26. }

So thats pretty complicated, and perhaps peasycam is not the best thing to use for what you are trying to do. I imagine you would do it by constraining both the camera location and the camera look at location, but changing the position of one i imagine will involve changing the necessary constraints for the other, i would look more into how cameras in 3d graphics work, starting here.

well, I'm going to continue with it ... I'm going to put it into a class where I can pass (or internally create) paths for the camera to follow and from what I have so far, that's pretty easy.  The only thing hanging me up is with the camera constraints as far as methods are concerned.  From the random motion, I think it will work for my purposes if I just use the lookAt and scale for constraining.  My program is for displaying images that are larger than the sketch window.  I set the cam default look to frame the entire image.  When the entire image is displayed, you can't pan because I need to constrain the image to fill the entire sketch window with no borders of the image showing, so, at 0 zoom, there's 0 constraint.  At different zooming levels, you can pan more because the image is so much larger than the sketch window.  So, there's a proportional relationship between the zoom level and how much panning can be done before the edge of the image is reached.

I think I need to just find this proportion and calculate the x and y constraints from the given zoom window, image size, and sketch size.

It may take weeks for me to figure out, but, Im sure it's just two lines of pretty simple code.

I'm too lazy to create a PGraphics background to use for demonstration purposes; you'll have to substitute your own image that's larger than the 640 x 420 or d/l and use the one I'm using from http://www.deviantart.com/download/202365255/alien_mollusc_homeland_by_unafra3yd-d3che13.png

1. import peasy.*;
2. PeasyCam cam;
3. PeasyDragHandler PanDragHandler;
4. PeasyDragHandler ZoomDragHandler;
5. //PFont fontA;
6. PImage bgimg;
7. float cx,cy,cz;
8. long time;
9. int UpdateInterval;
10. int LastUpdate;
11.  
12. int steps;
13. void setup(){
14.  
15.   size(640,400,P3D);
16.   cz = 100;
17.  
18.   bgimg = loadImage("landscape-crop1.png");
19.  // fontA = loadFont("BlueHighway-24.vlw");
20.   cam = new PeasyCam(this,bgimg.width/2, bgimg.height/2, 0, 600);
21.   cam.setMinimumDistance(100);
22.   cam.setMaximumDistance(550);
23.   PanDragHandler = cam.getPanDragHandler();
24.   ZoomDragHandler = cam.getZoomDragHandler();
25.   cam.setLeftDragHandler(PanDragHandler);
26.   cam.setWheelHandler(null);
27.  
28.   //cam.lookAt(bgimg.width/2, bgimg.height/2, 0);
29.  
30.   LastUpdate = millis();
31.   UpdateInterval = 1000;
32.  
33.   cz = -300;
34.  
35.   //  width of image = 1280
36.   //  screen width = 640
37.   //  screen height = 420
38.   //  height of image = 790
39.   //  if cz zoom = 0, then we want to constrain cx and cy to a few pixeles.
40. }
41. void draw()  {
42.  background(0);
43.  //imageMode(CENTER);
44.  image(bgimg,0,0);
45.  
46.  //println(str(cam.getPosition()));
47.  cam.beginHUD();
48.  fill(255);
49.  rect(0,0,80,44);
50.  fill(#1419F2);
51.  text("camX " + str(round(cam.getPosition()[0])) + "\ncamY " + str(round(cam.getPosition()[1])) + "\ncamZ " + str(round(cam.getPosition()[2])) ,12,12);
52.  cam.endHUD();
53.  
54.  if (millis()-LastUpdate >= UpdateInterval) {
55.   //if (GameMode) { }
56.   //cam.lookAt(600, 200, 100, 6000);
57.  // {mvcamBasic();}
58.   mvcamRand();
59.   UpdateInterval = int(random(6,15)*1000);
60.   LastUpdate = millis();
61.  }
62.  
63. }
64. public void mvcamRand() {
65.  cam.lookAt(random(bgimg.width),random(bgimg.height),cz-100+random(200),UpdateInterval-500);
66. }
67. public void mvcamBasic(){
68.   cam.lookAt(215, 235, -450,1000);
69.   //println(str(cam.getPosition()));
70. }
71. public void mvcam2(){
72.   cam.lookAt(254, 522, cz,4000);
73.   //println(str(cam.getPosition()));
74. }
75. public void mvcam3(){
76.   cam.lookAt(857, 527, cz,15000);
77.   //println(str(cam.getPosition()));
78. }
79. public void keyPressed() {
80.   if (key == '1') {mvcamBasic();}
81.   if (key == '2') {mvcam2();}
82.   if (key == '3') {mvcam3();}
83.   if (key == 'x') {cam.reset(3000);}
84. }

Really sorry, but I'm a really newbie in Processing and I need help from the community.