I want to use triangle type buttons on image but i am unable to do this...
How to do this?
This project can help you. you can customize the shape of the UIButton.
All UIViews - all of them - are rectangles. You cannot make a UIView that is a triangle, but you can make one that contains and presents a triangular shape and responds only to touches within that shape. You must understand of course that underneath it all, it's a rectangle, and you'll have to handle the case wherein the user touches outside of the triangle but inside of the rectangle, probably by passing such events through to views below. Indeed, you might have to handle all touch event combinations (touch down inside, touch up outside, touch move outside, etc) in this way.
Maybe the project referenced above will handle all this, I didn't look too deeply.
Related
I am trying to make an arrow shape. I understand that it will be done with CGRect method but can you give a complete example of how it will be done in SWIFT?
This can be done programmatically by first subclassing UIButton and overriding drawRect within it to form the shape of an arrow via bezier paths. Then simply set the title of the button to be whatever you want your text to be and position it accordingly within the shape you have drawn.
The benefit of doing it this way is that you can easily change the color of, scale and dimensions of the arrow since you control how the object is actually being drawn.
A good tool for drawing complex bezier paths is paintCode. I'm using the trial version and can pretty easily make shapes like this now.
I need to show a view on which I need to animate a polygon using its vertices. The polygon should be touchable, thus fire an event once touched, and I need to be able to move its vertices using some animation procedure, once it has fired that event.
I need to have three polygons like that to form a 3D Cube.
The darkened area is the view (actually an image) on which I have the cube.
There are two steps in the process: drawing and event handling.
Drawing can be done with Quartz2D, by implementing a drawRect in a view, calculating the coordinates of the cube on screen, followed by creating and drawing the path, which works fine for solidly filled shapes. The alternative method uses an OpenGL view where you specify triangles.
At the event handling end, you can implement onTouchesBegan: and friends to get the location of the interaction, and possibly hitTest: to allow other views below it to handle subsequent events. The next thing you will need to decide is how accurate you want to be - you can define a box that roughly matches the cube and test that for touches. Most people will want to touch it somewhere in the middle anyway. For accurate testing, you need the screen coordinates, and test each triangle in each polygon to see if it contains the location. Google turned up a nice explanation on the maths needed for that. In the OpenGL case, you'll have to manually repeat the calculations performed by OpenGL to find out where on screen your polygons have ended up.
I have this image:
What I want to do is to add a UITapGestureRecognizer to this image (or I can split the image in the different parts it consists of and add for each part a UITapGestureRecognizer) in order to have different actions according to the leaf tapped. If I split the image in different images each for each leaf the UIImageViews will probably overlap and tapping on one will be recognized as a tap on another one. Having just one image implies knowing the points of the screen that belongs to a leaf rather than to another one.
Any clues on how to do it would be really appreciated.
Thanks
Change your behavior by examining the gesture recognizer's locationInView:.
If you handle the image as one unit, implement this in your gesture recognizer call back to decide which "leaf" (if any) was tapped.
If you handle the image as multiple images, you could also implement it in your callback, or you could also implement in, e.g., your delegate's gestureRecognizerShouldBegin: to suppress events for touches outside the leaf as drawn.
EDIT: I didn't realize that you might also be looking for assistance on figuring out whether a point lies within a leaf. #PhillipMills is correct on this point: we need to know how you are drawing the image.
FOLLOW-UP: This is somewhat outside my area of expertise.
The easiest approach (from a hit-testing standpoint) is to do what #PhillipMills suggested, using Quartz drawing and CGPathContainsPoint(). If you have detailed graphics that you need rendered as a PNG, you could certainly construct a simple path that would be (virtually) overlayed to allow hit testing.
Your other options, AFAIK, are to do hit testing mathematically, but you would basically be reimplementing CGPathContainsPoint() but without a path, or to employ various tricks that look at the color of the pixels at your touch point to do hit testing. Googling will turn up some useful results if you go this route, but honestly for a shape as simple as what you've drawn, just use some UIBezierPath code to recreate in code.
Not sure if this will be helpful but if you get stuck on figuring out which leaf was clicked, you could use an old image map trick we used to use in CD-ROM projects for pixel accurate click tracking on images.
You have your full size image. Make a 25% (or less) scaled version of it. Fill each of the leaf regions you want to track clicks on with a different color; anything you want to ignore make black. When the full size image is clicked, get the x/y coordinates and scale them by the percentage of your scaled image. Then get the pixel color of the scaled image at the scaled x/y coordinate. By determining the pixel color you will know which leaf was clicked.
Sounds clunky but it works really well and is fast.
(all that said, I don't think alpha areas of images trigger the gesture recognizer - so breaking the image up would be less complicated/code intensive.)
If you can break the shape apart into the constituent elements, then you can put each into it's own layer and use the method discussed in this stackoverflow discussion to determine which was touched: Hit Testing with CALayer using the alpha properties of the CALayer contents
There are three layers added to UIView. One layer draws a rectangle. One draws a circle. One draws a polygon. The layer's opacity is no. When I touched the polygon, I want to get the correct layer which draws the polygon. And the three layers are full filled to the view. I have implemented this. But I don't know if we have better solution to solve it .My way is like this:
1.Drawing the content using -drawLayer:inContext. store the CGPath that you used.
2.In the UIView's -touchedEnded:withEvent method. using CGPathContainsPoint() to detect if the touch point is contained by the CGPath.
Maybe this is the stupid way to solve this. Anyone who can tell me how to solve it better?
If you need an accurate hit test for path's I'm afraid you have to check/iterate the layer hierarchy yourself if the point is inside your path using CGPathContainsPoint as you suggested.
While iterating you could optimize it by skipping layers where the point is outside their frame.
For less fine grained control you can get the touched layer by using CALayers
- (CALayer *)hitTest:(CGPoint)thePoint
method.
If you have a layer hierarchy with a nesting level < 1000 (which is almost always true) I would not worry too much.
I am interested in adding an option to my GIS Map application, the ability to draw Polygon, circle, polyroutes overlays for the user to search data within.The problem is that I've read and tested codes of how to draw an overlay, but they are always static.I want it to be dynamic, with dynamic center and points (or radius) set by the user on click.A mystery for me.(I'm a beginner in iPhone programming, this is my first app.)And I'm not using and don't want to use things like ArcGIS API for iPhone.I would appreciate any help.
To let the user "draw" an arbitrary polygon on the map, one approach is to use draggable annotations that represent the corners of the polygon. Provide an "Add Corner" button and some kind of Remove Corner button on each annotation.
See my answer to User creating a box on MKMapView for some more details. On that question though, the OP actually ended up using another solution described in the comments which would work well if the polygons are always rectangles.
For implementing a button in an annotation view (if you want a "Remove Corner" button on the annotations), see my answer to How to get click event from a button added over MKAnnotationView.
Once you a have a polygon or other overlay on the map, dragging it by direct touches may only be possible by adding a gesture recognizer to the map (with its own scrolling turned off) and using a custom MKOverlay and MKOverlayView that allow coordinate changes. Adding a gesture recognizer directly to an MKOverlayView doesn't seem to work and the built-in overlay classes don't allow changes to coordinates.
An alternative to moving by direct touches is putting some controls on the side (Up/Down/Left/Right/etc buttons) that modify the custom overlay.
The Apple sample app Breadcrumb gives an example of a custom overlay/view for a path. In WWDC 2010, the sample app LocationReminders gives an example of a custom overlay/view for a circle that can move and resize.
Finally, when you do a search for businesses, you could use the overlay's boundingMapRect (which is always a rectangle regardless of the overlay's shape) as the bounding box for the initial search and then check if the coordinate of each business found is in the overlay's actual shape using the answer to How to determine if an annotation is inside of MKPolygonView (iOS).