I have drawn few concentric circles and added a gesture listener too on the same view. I have drawn a point where i am placing the marker and tapping the button below. Once i tap the button, i will be getting the (x,y) co ordinates of the position where i place the maker and clicked the button. now i have to find out the distance between the center(x,y) of the view and marking that i have made earlier. I tried with distance calculation form ula, but still i am not sure i am getting the right solution. This is because, for example , when i mark a point at the top portion of the circle and made a mark at the bottom portion of the circle, its giving a different value. Since all are circles, from which ever part of the circle i mark, it has to give me the same distance . am i right ?
I tried with lot of ideas, still nothing work out well.
I have attached the screen shot of that page too, Please take a look at it
Any help is Appreciable.
Thanks.
How are you using the distance formula?
It should just be something like this
Math.sqrt(Math.pow(clickX - centerX, 2) + Math.pow(clickY - centerY, 2));
You can use this formula,
double d = Math.sqrt( (x2-=x1)*x2 + (y2-=y1)*y2 );
Refer this question
Related
I'm trying to set the user location on the map such that it sits about 1/3 of the way up from the bottom of the screen, and when the map rotates, it will rotate around this point.
The closest I've got to achieving this is by using the setPadding() method, however, this causes the map to sort of shake when rotated, as the center point sort of 'floats' around where it actually should be. It looks quite ugly
int mapHeight = mapView.getHeight();
googleMap.setPadding(0, mapHeight / 5, 0, 0);
Is there a better way to do this?
Edit: Explained in picture below
You don't need paddings
Change mappoint X and Y values as you need you can call this where you want! may be inside your onLocationChanged like changeOffsetCenter(location.getLatitude(),location.getLongitude());
public void changeOffsetCenter(double latitude,double longitude) {
Point mappoint = mGoogleMap.getProjection().toScreenLocation(new LatLng(latitude, longitude));
mappoint.set(mappoint.x, mappoint.y-100); // change these values as you need , just hard coded a value if you want you can give it based on a ratio like using DisplayMetrics as well
mGoogleMap.animateCamera(CameraUpdateFactory.newLatLng(mGoogleMap.getProjection().fromScreenLocation(mappoint)));
}
output :
Google map v3 beta seems to fix it, using padding now properly move pivotX/pivotY for rotation
https://developers.google.com/maps/documentation/android-sdk/v3-client-migration
Accepted answer might be work of "animateCamera". Its makes "shaking of rotations" almost invisible. So more easy will be using
mMap.setPadding(leftPx, topPx, rightPx, bottomPx)
with mMap.animateCamera
or twice mMap.moveCamera(in case of changing bearing
1nd moveCamera rotate with center of device, 2nd moveCamera make correct center using padding)
Its kind of hack, while google do not fix rotation considering setPadding
I am using CCTMXTiledMap on cocos2dx-2.2, I created and added the tiled map like this:
// TileMap
CCTMXTiledMap *m_pTileMap = CCTMXTiledMap::create("tilesets/my-isometric-small.tmx");
float fPosX = m_pTileMap->getPositionX();
float fPosY = m_pTileMap->getPositionY();
CCLOG( "TileMapPos: %f, %f", fPosX, fPosY );
this->addChild(m_pTileMap);
The tiled map are created and rendered successfully, but out of position. I use CCTMXTiledMap::getPosition, CCTMXLayer::positionAt, and also examine the CCSprite that I get from CCTMXLayer::tileAt... all of them are returning the correct value based on cocos2d screen coordinate { (0, 0) from bottom left and increasing upward and rightward } However, when viewed on the screen, there is always a slight offset and I can't get where it come from. All the m_obOffsetPosition are confirmed to be zero...
By correct value, I mean the tiles are positioned in the pink area (I getPosition from each of the tile, create CCSprite for each, setPosition of each tile and add it to the screen... They show up in the pink area)
Image supposed to be positioned at shady pink boxes, but instead positioned in the blue area (the entire blue sea is the whole map)
Any ideas are highly appreciated... Thanks!!
After wasting days trying to dissect tilemap_parallax_nodes in cocos2d-x, finally I figured out the culprit... it is the Layer Property cc_vertexz that cause it to be rendered off position. I haven't got the time to figure out how and why it works that way and since I'm not going to use it anyway (I just need flat, single layer, thus no need z order etc), so I just remove that property from all of my Layers and the problem is gone..
Hope it helps someone... Thanks!
Ohh.. damm Math !! once again stuck. It seems to be easy but i think its not that easy,
Problem Statement: I want to rotate the 3 fixed points which lies on a fixed circle.
1.when 1 point is selected remaining 2 points should be static mode and only selected point should move/rotate on circumference of circle.
2.And all 3 points are connected via 3 lines as shown in images..when we select a point and rotate it,connected lines also increase and decrease..
I already tried to solve this problem finding angle at each instant after touch.but its not quite working as per my need..
something like this
I hope the following explanation enable you to put the steps into your coding language.
Presumption is that the vertex to be moved has already selected and so the calculation of (xcnd,ycnd) as defined below is used to set the selected vertex of the triangle.
Let the constraining circle have centre at (cx,cy) and radius r.
Let the coordinates of where the screen is touched be (xtch,ytch)
Let the coordinates of where the screen is touched relative to the centre be (xrel,yrel)
then xrel = xtch - cx and yrel = ytch - cy
Let the coordinates of the point on the constraining circle when the screen is touched at (xtch,ytch) be (xcnd,ycnd).
xcndrel = xcnd - cx, and ycndrel = ycnd - cy give the coordinates on the constraining circle relative to its centre,
Note that
xrel and xcndrel will have the same signs (ie both positive or both negative)
and yrel and ycndrel will also have the same signs.
the function abs(x) = x if x>=0 and -x if x<0 should be available in whatever language you are using
the function sign(x) may or may not be available, sign(x) =1 if x>0 and -1 if x<0 and undefined for x=0
If not available then sign(x)=x/abs(x)
Check if xrel=0
if xrel=0 xcndrel=0, ycndrel=r*sign(yrel)
Otherwise work in first quadrant ie where x>0 and y>0 using abs(xrel) and abs(yrel)
find angle where screen is touched relative to centre of circle using
theta=arctan(abs(yrel)/abs(xrel))
find the coordinates (xcndrel, ycndrel) by using theta in the first quadrant and then placing in the correct quadrant using the signs of xrel and yrel
xcndrel = sign(xrel)*r*COS(theta)
ycndrel = sign(yrel)*r*SIN(theta)
Screen coordinates can now be found
xcnd = xcndrel +cx
ycnd = ycndrel + cy
I have a custom drawn rectangle which i want to move in a circular path based on touch events.
It follows the direction of the touch for clockwise or anticlockwise movement but basically move in circular motion, as if moving on the edge of the circle.
My current thought process is as follows:
Based on the users current and previous x,y i shall find the angle in degrees and then move this rectangle by the same angle by re-drawing in the new position, just making sure that it moves on the edge of a circle.
But this leads to some confusion on the following:
1. how do i decide whether angle movement is clockwise or anti-clockwise.
2. I am not being able to figure out the math for this properly.
Would this be the best approach or is there a better idea for doing this?
Also, if this is the best approach, could someone please tell me the formula for calculating the angle by which i should move it while taking care of the clocking and anticlockwise ?
could someone please help?
please let me know if any more details are required.
Thanks
Steps
Here are a few steps in order to move your rectangle along a circle's rim when the user taps and holds to the side of the circle:
1. Obtain direction desired.
2. Obtain angle from current x and y coordinates.
3. Add direction (+1 if counterclockwise, -1 if clockwise) to angle.
4. Calculate new x and y coordinates.
5. Update/display rectangle.
Details
1. In pseudocode, direction = sign(Rectangle1.x - UsersFingerPosition.x). Here sign is a function returning -1 if the number was negative, 0 if it is 0, and 1 if it is positive. Note that sign(0) will only result when the user is on the exact x and y of your rectangle's location. In that case, the rectangle would not move (which should be good). In Java, the sign function is Math.signum().
2. To obtain the current angle use the following java code:
double angle = Math.toDegrees(Math.atan2(Circle.y-Rectangle1.y, Rectangle1.x-Circle.x));
Note the order of Circle.y-Rectangle.y and Rectangle.x...Circle.x. This is a result of the coordinate (0, 0) being in the top left corner instead of the center of the screen.
3. Simple enough, just add direction to angle. If desired, do something like
angle += direction*2; //So it will move more quickly
4. To get the new x and y coordinates of your rectangle, use the trigonometric functions sine and cosine:
Rectangle1.x = Math.cos(Math.toRadians(angle))*Circle.radius + Circle.x - Rectangle1.width;
Rectangle1.y = Math.sin(Math.toRadians(angle))*Circle.radius + Circle.y - Rectangle1.height;
(where Circle.x and Circle.y are the coordinates of the center of your circle and Circle.radius is naturally it's radius).
5. This one you'll have to take care of (or have already) :)!
Hope this helps you!
Steps
Here are a few steps in order to move your rectangle along a circle's rim:
1. Obtain finger position/Check that it's still dragging the rectangle.
2. Obtain angle from current x and y coordinates.
3. Calculate new x and y coordinates.
4. Update/display rectangle.
Details
1. This one is probably specific to your code, however, make sure that when the user starts dragging the rectangle, you set a variable like rectangleDragging to true. Before you run the next steps (in the code), check that rectangleDragging == true. Set it to false once the user lets go.
2. To obtain the current angle use the following java code:
double angle = Math.toDegrees(Math.atan2(Circle.y-Finger.y, Finger.x-Circle.x));
Note the order of Circle.y-Finger.y and Finger.x...Circle.x. This is a result of the coordinate (0, 0) being in the top left corner instead of the center of the screen.
3. To get the new x and y coordinates of your rectangle, use the trigonometric functions sine and cosine:
Rectangle1.x = Math.cos(Math.toRadians(angle))*Circle.radius + Circle.x - Rectangle1.width;
Rectangle1.y = Math.sin(Math.toRadians(angle))*Circle.radius + Circle.y - Rectangle1.height;
(where Circle.x and Circle.y are the coordinates of the center of your circle and Circle.radius is naturally it's radius). Subtracting the width and height of the rectangle should center it on the circle's border instead of placing the left, upper corner on the circle.
4. This one you'll have to take care of (or have already) :)!
Hope this helps you!
I need to apply click/touch events for only visible part of the View. Say for example a image of size 200X200. Apart from center 50X50, remaining part is transparent. I want to get touch events only for that 50X50 visible part Not on remaining transparent part.
In above image (its single image), only inner Diamond has got visible part. Apart from that Diamond is transparent area. So, if I touch Diamond then only I want to do something else ignore.
Edit :
Rachita's link helped me. I gone through that link and got idea how can I implement. But I could not understand some constants like 320, 240 etc while creating Points. In my case, I know the Diamond (in above image) x and y Ponits (hard coded values asctually). So, using those how can I determine, whether I touched inside Diamond or outside?
my Diamond points are as below
pointA = new Point(0, 183);
pointB = new Point(183, 0);
pointC = new Point(366, 183);
pointD = new Point(183, 366);
Edit :
Finally got solution from Luksprog. Its based on checking touched point pixel color. If color is 0 means, you touched transparent layer else you touched some colored part of the image. Simple, but very effective. Have a look at it here.
AFAIK you can not implement this with onclick listener or my any other direct way .You will have to use onTouchListener .
Firstly set your view dynamically at a specific (x,y) position using this How can I dynamically set the position of view in Android?
Calculate the region your diamond will occupy (you should khow the size of image inorder to calculate area of diamond)
3.Trigger a action in onTouchListener only when x, y fall in the required region. Use How to get the Touch position in android?
check this link to calculate if a given point lies in the required square
EDIT
To understand the coordinate system of android refer to this link How do android screen coordinates work?
Display mdisp = getWindowManager().getDefaultDisplay();
int maxX= mdisp.getWidth();
int maxY= mdisp.getHeight();
(x,y) :-
1) (0,0) is top left corner.
2) (maxX,0) is top right corner
3) (0,maxY) is bottom left corner
4) (maxX,maxY) is bottom right corner
here maxX and maxY are screen maximum height and width in pixels, which we have retrieved in above given code.
Remember if you want to support multiple devices with different screen sizes,make sure you use a relative value for x,y ie some ratio of screen height or width ,as different devices have different ppi
Check if touched point lies in the required polygon
I thinks these link might help you determining if the point touched (you can get x,y from onTouch event eg.event.getX()) lies in the required polygon whose points you have mentioned in the question . determine if a given point is inside the polygon and How can I determine whether a 2D Point is within a Polygon?