I have an NXT robot.
I want to map a room without any obstacles, and "give" this map to the robot.
I have this sample code:
// Create a rudimentary map:
Line[] lines = new Line[3];
lines[0] = new Line(75f, 100f, 100f, 100f);
lines[1] = new Line(100, 100, 87, 75);
lines[2] = new Line(87, 75, 75, 100);
lejos.geom.Rectangle bounds = new Rectangle(-50, -50, 250, 250); //(x,y,height,width)
LineMap myMap = new LineMap(lines, bounds); //create map
In this code, the lines create a triangle, that suppose to be an obstacle, and the bounds is the room walls.
The problem is that LineMap get lines and bounds, but the bounds is rectangle.
My type of room is without obstacles(so I don't need lines, or I can build a fake obstacle), and with 5 walls (Pentagon).
Does anyone know if there is any method that takes bounds of any kind and not just Rectangles?
If I can give the robot the lines as walls and not as obstacles it would be great.
Related
I'm trying to fill a round circle (transparent other than the outline of the circle) in an ImageView.
I have the code working:
public void setPercentage(int p) {
if (this.percentage != p ) {
this.percentage = p;
this.invalidate();
}
}
#Override public void onDraw(Canvas canvas) {
Canvas tempCanvas;
Paint paint;
Bitmap bmCircle = null;
if (this.getWidth() == 0 || this.getHeight() == 0 )
return ; // nothing to do
mergedLayersBitmap = Bitmap.createBitmap(this.getWidth(), this.getHeight(), Bitmap.Config.ARGB_8888);
tempCanvas = new Canvas(mergedLayersBitmap);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.FILL_AND_STROKE);
paint.setFilterBitmap(false);
bmCircle = drawCircle(this.getWidth(), this.getHeight());
tempCanvas.drawBitmap(bmCircle, 0, 0, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
tempCanvas.clipRect(0,0, this.getWidth(), (int) FloatMath.floor(this.getHeight() - this.getHeight() * ( percentage/100)));
tempCanvas.drawColor(0xFF660000, PorterDuff.Mode.CLEAR);
canvas.drawBitmap(mergedLayersBitmap, null, new RectF(0,0, this.getWidth(), this.getHeight()), new Paint());
canvas.drawBitmap(mergedLayersBitmap, 0, 0, new Paint());
}
static Bitmap drawCircle(int w, int h) {
Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bm);
Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
p.setColor(drawColor);
c.drawOval(new RectF(0, 0, w, h), p);
return bm;
}
It kind of works. However, I have two issues: I run out of memory quickly and the GC goes crazy. How can I utilize the least amount of memory for this operation?
I know I Shouldn't be instantiating objects in onDraw, however I'm not sure where to draw then. Thank you.
pseudo would look something like this.
for each pixel inside CircleBitmap {
if (pixel.y is < Yboundary && pixelIsInCircle(pixel.x, pixel.y)) {
CircleBitmap .setPixel(x, y, Color.rgb(45, 127, 0));
}
}
that may be slow, but it would work, and the smaller the circle the faster it would go.
just know the basics, bitmap width and height, for example 256x256, the circles radius, and to make things easy make the circle centered at 128,128. then as you go pixel by pixel, check the pixels X and Y to see if it falls inside the circle, and below the Y limit line.
then just use:
CircleBitmap .setPixel(x, y, Color.rgb(45, 127, 0));
edit: to speed things up, don't even bother looking at the pixels above the Y limit.
in case if you want to see another solution (perhaps cleaner), look at this link, filling a circle gradually from bottom to top android
I am trying to rotate the camera around to X-axis of the scene.
At this point my code is like this:
rotation += 0.05;
camera.position.y = Math.sin(rotation) * 500;
camera.position.z = Math.cos(rotation) * 500;
This makes the camera move around but during the rotation something weird happens and either the camera flips, or it skips some part of the imaginary circle it's following.
You have only provided a snippet of code, so I have to make some assumptions about what you are doing.
This code:
rotation += 0.05;
camera.position.x = 0;
camera.position.y = Math.sin(rotation) * 500;
camera.position.z = Math.cos(rotation) * 500;
camera.lookAt( scene.position ); // the origin
will cause the "flipping" you refer to because the camera is trying to remain "right side up", and it will quickly change orientation as it passes over the "north pole."
If you offset the camera's x-coordinate like so,
camera.position.x = 200;
the camera behavior will appear more natural to you.
Three.js tries to keep the camera facing up. When you pass 0 along the z-axis, it'll "fix" the camera's rotation. You can just check and reset the camera's angle manually.
camera.lookAt( scene.position ); // the origin
if (camera.position.z < 0) {
camera.rotation.z = 0;
}
I'm sure this is not the best solution, but if anyone else runs across this question while playing with three.js (like I just did), it'll give one step further.
This works for me, I hope it helps.
Rotating around X-Axis:
var x_axis = new THREE.Vector3( 1, 0, 0 );
var quaternion = new THREE.Quaternion;
camera.position.applyQuaternion(quaternion.setFromAxisAngle(x_axis, rotation_speed));
camera.up.applyQuaternion(quaternion.setFromAxisAngle(x_axis, rotation_speed));
Rotating around Y-Axis:
var y_axis = new THREE.Vector3( 0, 1, 0 );
camera.position.applyQuaternion(quaternion.setFromAxisAngle(y_axis, angle));
Rotating around Z-Axis:
var z_axis = new THREE.Vector3( 0, 0, 1 );
camera.up.applyQuaternion(quaternion.setFromAxisAngle(z_axis, angle));
I wanted to move my camera to a new location while having the camera look at a particular object, and this is what I came up with [make sure to load tween.js]:
/**
* Helper to move camera
* #param loc Vec3 - where to move the camera; has x, y, z attrs
* #param lookAt Vec3 - where the camera should look; has x, y, z attrs
* #param duration int - duration of transition in ms
**/
function flyTo(loc, lookAt, duration) {
// Use initial camera quaternion as the slerp starting point
var startQuaternion = camera.quaternion.clone();
// Use dummy camera focused on target as the slerp ending point
var dummyCamera = camera.clone();
dummyCamera.position.set(loc.x, loc.y, loc.z);
// set the dummy camera quaternion
var rotObjectMatrix = new THREE.Matrix4();
rotObjectMatrix.makeRotationFromQuaternion(startQuaternion);
dummyCamera.quaternion.setFromRotationMatrix(rotObjectMatrix);
dummyCamera.up.set(camera)
console.log(camera.quaternion, dummyCamera.quaternion);
// create dummy controls to avoid mutating main controls
var dummyControls = new THREE.TrackballControls(dummyCamera);
dummyControls.target.set(loc.x, loc.y, loc.z);
dummyControls.update();
// Animate between the start and end quaternions
new TWEEN.Tween(camera.position)
.to(loc, duration)
.onUpdate(function(timestamp) {
// Slerp the camera quaternion for smooth transition.
// `timestamp` is the eased time value from the tween.
THREE.Quaternion.slerp(startQuaternion, dummyCamera.quaternion, camera.quaternion, timestamp);
camera.lookAt(lookAt);
})
.onComplete(function() {
controls.target = new THREE.Vector3(scene.children[1].position-0.001);
camera.lookAt(lookAt);
}).start();
}
Example usage:
var pos = {
x: -4.3,
y: 1.7,
z: 7.3,
};
var lookAt = scene.children[1].position;
flyTo(pos, lookAt, 60000);
Then in your update()/render() function, call TWEEN.update();
Full example
I want to change the paper(objects base) size of Raphael to fit the window resizing. [ using Firefox_13.0, Raphael_2.1.0, WindowsXP ]
If it is available, I would like to fit full-screen-mode.
==================================================
(steps)
I created the paper : paper = Raphael(0, 50, 800, 600); // initial width and height are 800 and 600.
I placed objects on the paper.
The window size of browser is checked by windowW = window.innerWidth and winnowH = window.innerHeight (on Firefox).
Scaling value is calculated by sv = windowW/800;
And scaling the paper by paper.scale(sv, sv);
==================================================
(the script)
window.onload = function () {
paper = Raphael(0, 50, 800, 600);
var background = paper.rect(0, 0, 800, 600).attr({fill:'#669999'});
// placing the objects
var circle = ...;
var rect = ...;
var ellipse = ...;
winowW = window.innerWidth;
winowH = window.innerHeight;
sv = winowW/800.
paper.scale(sv, sv);
}
==================================================
(result)
Though circle.scale(sv), rect.scale(sv, sv) and ellipse.scale(sv, sv) are valid, paper.scale(sv, sv) and background.scale(sv, sv) are not.
Why this case is happen ? I can get the window size by window.onresize = function() {...} on real-time. If there are better methods, please tell me.
Thanks,
I've succeeded by following two points:
1) "paper" itself is not manipulative object. I think we should look it as billboard.
2) use st = paper.set() and put the objects(circle, rect, ...) in it. And use st.scale(sv, sv, 0, 0);
* third and fourth parameter (0, 0) are very impotent.
(caution)
Serial resizing operation is not good for the function "scale()". Because each of resizing coefficient is piled as the
power of a number. So when one have done 1.1 times resizing operation 5 times, the scale will be 1.1^5.
Use setViewBox()
It should do the work
http://raphaeljs.com/reference.html#Paper.setViewBox
I have a collection of latitudes and longitudes and I'll be grabbing sets of these and want to draw a polygon based on them.
The datasets won't be the outline so will need an algorithm to establish which ones make up the outline of a polygon containing all the latitudes and longitudes supplied. This polygon needs to be flexible so the polygon can be concave if the points dictate that.
Any help would be appreciated.
** UPDATE **
Sorry, should have put more detail.
My code below produces a horrible looking polygon. As explain in my first post I want to create a nice concave or convex polygon based on the latlng's provided.
Just need a way of plotting the outer latlngs.
Apologies if this is still asking too much but thought it was worth one last try.
function initialize() {
var myLatLng = new google.maps.LatLng(51.407431, -0.727142);
var myOptions = {
zoom: 12,
center: myLatLng,
mapTypeId: google.maps.MapTypeId.TERRAIN
};
var map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
var bermudaTriangle;
var map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
var triangleCoords = [
new google.maps.LatLng(51.392692, -0.740358),
new google.maps.LatLng(51.400618, -0.742469),
new google.maps.LatLng(51.40072, -0.72418),
new google.maps.LatLng(51.400732, -0.743817),
new google.maps.LatLng(51.401258, -0.743386),
new google.maps.LatLng(51.401264, -0.741445),
new google.maps.LatLng(51.401443, -0.725555),
new google.maps.LatLng(51.401463, -0.744042),
new google.maps.LatLng(51.402281, -0.739059)
];
var minX = triangleCoords[0].lat();
var maxX = triangleCoords[0].lat();
var minY = triangleCoords[0].lng();
var maxY = triangleCoords[0].lng();
for (var i = 1; i < triangleCoords.length; i++) {
if (triangleCoords[i].lat() < minX) minX = triangleCoords[i].lat();
if (triangleCoords[i].lat() > maxX) maxX = triangleCoords[i].lat();
if (triangleCoords[i].lng() < minY) minY = triangleCoords[i].lng();
if (triangleCoords[i].lng() > maxY) maxY = triangleCoords[i].lng();
}
// Construct the polygon
bermudaTriangle = new google.maps.Polygon({
paths: triangleCoords,
strokeColor: "#FF0000",
strokeOpacity: 0.8,
strokeWeight: 2,
fillColor: "#FF0000",
fillOpacity: 0.35
});
bermudaTriangle.setMap(map);
}
Your problem is not enough defined : with a given set of points, you may end up with many different polygons if you do not add a constraint other than 'create a nice concave or convex polygon'.
And even a simple example shows that :
imagine a triangle ABC, and let D be the center of this triangle, what output will you expect for {A,B,C,D} set of points ?
ABC, since D is inside ?
or ADBCA polygon ?
or ABDCA polygon ?
or ABCDA polygon ?
now if you say 'well D is in the center, it's obvious we should discard D', let D be closer and closer from, say, the AB segment. When do you decide the best output is ABC or ADBCA ?
So you have to add constraints to be able to build an algorithm, since if you cannot not decide by yourself for the above {A,B,C,D} example, how could a computer do ? :-) For example if you call AvgD the average distance beetween points, you could add the constraint that no segment of your outer polygon should be longer than 1.2*AvgD (or, better, Alpha*AvgD, and you try your algorithm with different alpha).
To solve your issue, i would use first a classical hull algorithm to get the outer convex polygon (which is deterministic), then break down the segments that are 'too' long (with the constraint(s) you want) putting more and more inner points into the outlining until all constraints are ok. Something like 'digging holes' into the convex polygon.
'Breaking down' a too long segment is also a thing you can do in quite different maners. One may be to search for the nearest not-in-the-outline point from the middle point of the segment. Another would be to choose the point having lowest radius with current segment... Now that you have your new point, break the segment in two, update your list of too-loong segment, and do it again until you're done (or until you reach a 'satisfactory' average length for too long segments, or ...)
Good luck !
I have images of the following kind
I want that small lines which I have encircled using yellow, should be combined to form a single line., i.e. if distance between 2 lines is less than some threshold, they should be joined.
I tried using Dilate command of emgucv, but the unwanted lines also get bold.
Thanx in advance :-)
What your after is the Houghline function I provided a method bellow. By changing these settings you can join lines up and only display those with the strongest characteristics. However, this method may struggle since you have a very very noisy image you may want to look into a better edge detection method first before attempting to find those lines.
For every line:
private Image<Bgr, Byte> apply_Hough(Image<Bgr, Byte> Input_Image)
{
LineSegment2D[] lines = Input_Image.HoughLinesBinary(
1, //Distance resolution in pixel-related units
Math.PI / 45.0, //Angle resolution measured in radians.
50, //threshold
100, //min Line width
1 //gap between lines
)[0]; //Get the lines from the first channel
Image<Bgr, Byte> lineImage = img.Copy();
foreach (LineSegment2D line in lines)
Input_Image.Draw(line, new Bgr(Color.Red), 2);
return Input_Image;
}
Hough lines uses and very advanced voting method in which only the strongest lines will be shown and they should be listed accordingly. So also try using a for loop in replace of the foreach loop to only display the first 6 strongest lines such as this.
For the 6 strongest lines:
private Image<Bgr, Byte> apply_Hough(Image<Bgr, Byte> Input_Image)
{
LineSegment2D[] lines = Input_Image.HoughLinesBinary(
1, //Distance resolution in pixel-related units
Math.PI / 90.0, //Angle resolution measured in radians.
50, //threshold
100, //min Line width
1 //gap between lines
)[0]; //Get the lines from the first channel
Image<Bgr, Byte> lineImage = img.Copy();
for (int i = 0; i <= 6; i++)
{
Input_Image.Draw(lines[i], new Bgr(Color.Red), 2);
}
return Input_Image;
}
Hope this helps,
Cheers,
Chris