Pass gestures to children - xamarin

I have an app with a game board and can pick up and move tiles around with panning using mr.gestures, that's working well.
My game board is a MR.Gestures.AbsoluteLayout and that's where I capture the panning gesture.
If I add that game board as a child to another MR.Gestures.AbsoluteLayout then it seems the gestures are blocked by the parent and it no longer works.
Is there a way to pass gestures though to children or ignore gestures on a parent in some way?

Is there a way to pass gestures though to children or ignore gestures
on a parent in some way?
For me this problem appeared only on Android.. The answer is Yes:
When parent receives gesture event it must check if finger x,y is within specific childs views. If yes, parent just ignores the gesture.
Regarding the code, ill just past one event handler to get the idea. In my case i have 2 childs (like and bookmark) over a parent frame:
//-------------------------------------------------------------------
private void OnTapped_MainFrame(object sender, TapEventArgs e)
//-------------------------------------------------------------------
{
//Get parent screen abs pos in pixels
//We are using native code get absolute screen position
var ptFrame = DependencyService.Get<INiftyHelpers>().GetViewAbsolutePosition((View)sender);
//Gets childs (hotspots) screen abs position in pixels
var ptFav = DependencyService.Get<INiftyHelpers>().GetViewAbsolutePosition((View)hsFav);
var ptLike = DependencyService.Get<INiftyHelpers>().GetViewAbsolutePosition((View)hsLike);
//Gets childs (hotspots) rectangles, everything in pixels using screen density
var rectFav = new Rectangle(ptFav, new Size(hsFav.Width * AppHelper.DisplayDensity, hsFav.Height * AppHelper.DisplayDensity));
var rectLike = new Rectangle(ptLike, new Size(hsLike.Width * AppHelper.DisplayDensity, hsLike.Height * AppHelper.DisplayDensity));
//Convert the finger XY to screen pos in pixels
var ptTouch = new Point(ptFrame.X + e.Center.X * AppHelper.DisplayDensity, ptFrame.Y + e.Center.Y * AppHelper.DisplayDensity); //absolute relative to screen
//check if withing childs
if (rectFav.Contains(ptTouch) || rectLike.Contains(ptTouch))
return; //Ignore input and let childs process their gestures!
//Process input
//..
}

Related

How to create dynamic stopping Scroll Rect in unity?

I have an gameobject1(added Scroll Rect component)and inside of it another gameobject2(The Scroll rect component's content).In gameobject2 has images.The number of images can be 10 or 20..(Any numbers).The Movement Type is Elastic.As you know it will stop scrolling only until gameobject2 height's length. How to stop on dynamic number's of length.In gameobject2 the number of images can be different. It depends on search results. The results can be 5,8, or 200. So I need to scroll until last of search result.So how to stop scrolling on exactly length in Scroll rect component?
You can use ContentSizeFitter component. GameObject with name "Content", is a content for scrollRect component of "ScrollView"-gameObject.
RectTransform#SetSizeWithCurrentAnchors
I use this a lot when building dynamic scrolling lists. After adding all the items I want (and each having a known size, and all positioned using that size) I update the content's RectTransform with the new size (total number of objects added * size of the object).
For example, I have this code:
int i = 0;
//for each item in a list of skills...
IEnumerator<Skill> list = SkillList.getSkillList();
Transform skillListParent = GuiManager.instance.skillPanel.transform;
while(list.MoveNext()) {
Skill sk = list.Current;
//create a prefab clone...
GameObject go = Main.Instantiate(PrefabManager.instance.SKILL_LISTITEM, skillListParent) as GameObject;
//set its position...
go.transform.localPosition = new Vector3(5, i * -110 -5, 5);
//add a button event or other data (some lines omitted)...
Transform t1 = go.transform.FindChild("BuyOne");
t1.GetComponent<Button>().onClick.AddListener(delegate {
doBuySkill(sk);
});
t1.GetChild(0).GetComponent<Text>().text = Main.AsCurrency(sk.getCost(1)) + " pts";
//track how many...
i++;
}
//update rect transform
((RectTransform)skillListParent).SetSizeWithCurrentAnchors(RectTransform.Axis.Vertical, (i * 110 + 10));

Scrollable drawing in Gtk::Layout

I'd like to use custom drawing within a Gtk::Layout. That is, I'm using the C++ bindings for Gtk3 (GTKmm 3.14.0), and I have embedded widgets placed on the "canvas", on top of my custom drawing. Basically this works just fine.
Now the problem is related to scrolling. Gtk::Layout can be placed into a Gtk::ScrolledWindow, and when the scrollable area is set to something larger than the visible allocation, scrollbars will show up. Unfortunately, those scrollbars influence only the placement of the embedded widgets, while my custom drawing remains at a fixed position within the window.
This means, both the Gtk::Allocation and the cairo context seem to be related to precisely the visible area, not to the extended virtual "canvas". I could work around that problem by accessing the adjustments from the scrollbars and then translate the cairo context accordingly...
My question is:
is this the proper way to handle such a scrollable drawing?
or is there some way to let the framework do this work for me?
Judging from the source code of gtk+3.0-3.14.5 (which is in Debian/Stable), the Gtk::Layout does nothing to adjust the drawing context. It just invokes the inherited draw() function from GtkWidget. On the other hand, Gtk::Layout is a full-blown container (it inherits from Gtk::Container), and it is scrollable, which together means that it handles gtk_layout_size_allocate() by passing a suitable allocation (screen area) to each of the embedded child widgets -- and in this respect it does handle the moving and clipping related to scrolling the virtual canvas (calls gdk_window_move_resize()).
Thus, if we want to combine the embedded child widgets with custom drawing, we need to bridge this discrepancy manually. This is quite easy actually: all we need to do is to look into the Gtk::Adjusments corresponding to the scrollbars. Because the value of these adjusments is precisely the upper left corner of the visible viewport. Now, if we want our custom drawing to use absolute canvas coordinates, we just have to translate() the given Cairo context. Beware: it is important to save() the state and to restore() it to pristine state when done, otherwise those translations will accumulate.
Here is some example code to demonstrate this custom drawing
we derive a custom container class called Canvas from Gtk::Layout
we override the on_draw() handler, because only there all size allocation to embedded child widgets have been processed
Layering: child widgets are always drawn in the order they have been added to the Gtk::Layout container. Any custom drawing done before invoking the inherited on_draw() function will be below those widgets; any drawing done afterwards will happen on top of them.
if necessary, we can use the foreach(callback) mechanism to visit all child widgets to find out their current position and extension
void
Canvas::determineExtension()
{
if (not recalcExtension_) return;
uint extH=20, extV=20;
Gtk::Container::ForeachSlot callback
= [&](Gtk::Widget& chld)
{
auto alloc = chld.get_allocation();
uint x = alloc.get_x();
uint y = alloc.get_y();
x += alloc.get_width();
y += alloc.get_height();
extH = max (extH, x);
extV = max (extV, y);
};
foreach(callback);
recalcExtension_ = false;
set_size (extH, extV); // define extension of the virtual canvas
}
bool
Canvas::on_draw(Cairo::RefPtr<Cairo::Context> const& cox)
{
if (shallDraw_)
{
uint extH, extV;
determineExtension();
get_size (extH, extV);
auto adjH = get_hadjustment();
auto adjV = get_vadjustment();
double offH = adjH->get_value();
double offV = adjV->get_value();
cox->save();
cox->translate(-offH, -offV);
// draw red diagonal line
cox->set_source_rgb(0.8, 0.0, 0.0);
cox->set_line_width (10.0);
cox->move_to(0, 0);
cox->line_to(extH, extV);
cox->stroke();
cox->restore();
// cause child widgets to be redrawn
bool event_is_handled = Gtk::Layout::on_draw(cox);
// any drawing which follows happens on top of child widgets...
cox->save();
cox->translate(-offH, -offV);
cox->set_source_rgb(0.2, 0.4, 0.9);
cox->set_line_width (2.0);
cox->rectangle(0,0, extH, extV);
cox->stroke();
cox->restore();
return event_is_handled;
}
else
return Gtk::Layout::on_draw(cox);
}

How can I click on coordinates on globe?

I am using chrome experiment's globe http://globe.chromeexperiments.com and I would like to click on any color coordinates to show popup but event listener is not being called. can somebody assist me how to do it?
You could try casting a ray from the camera into the scenery and then getting the intercepts. See the docs for rayCaster.
What you would do is create a new rayCaster object, then get the mouse coordinates of the user's screen. You would need to create some kind of "onclick" event on the parent element of the canvas.
Once the event occurs, the rayCaster object has a property which handles our situation, "setFromCamera". However, you need to provide it a list of all of the objects that you are interested in intersecting, that is all of the rectangles.
So you code would look something like this, note that I used jQuery for this:
var rayCaster = new THREE.Raycaster();
var onClickEventHandler = function(e) {
//Save the mouse data as a vector
//width and height pertain to the size of the canvas.
var mousePosition = new THREE.Vector3((e.offsetX / width) * 2 - 1,
-(e.offsetY / height) * 2 + 1,
0.5);
rayCaster.setFromCamera(mousePosition, camera);
//"objects" is the array of meshes that you care about the user intersecting
var intersects = rayCaster.intersectObjects(objects);
}
What is contained inside the "intersects" array is all of the items from the "objects" array which ere intersected by the ray in the order of intersection. You are likely interested in the first element of this array.
I don't know if that globe utility provides a better way of doing it, what I showed is the generic way of selecting an object in the scenery.

Starling TouchEvent on Sprite

I have some images/sprites/buttons (i tried them all :)) scrolling/moving on the stage. The user has to tap them to remove them.
The problem is that the touchevent does not match the position of the image.
The faster the touchable sprites move, the further the distance between the touch and the actual image. i.e.:
a image is moving across the screen with 20px/frame:
Touching the image triggers nothing, touching 20 before it triggers a touch on the image.
when image is not moving, this doesn't happen. It seems that the image is already moved internally, but not yet drawn to the screen, but thats just a wild guess. The example below uses a button, but the same goes for an image. I"ll provide a short example of the code, but i guess its pretty straightforward what i'm trying to do.
private var _image:Button;
protected function init():void {
//create pickup image
_image = new Button(assets.getTexture("button"));
_image.scaleWhenDown = 1;
_image.addEventListener(Event.TRIGGERED, onClick_image);
addChild(_image);
//listen to touch event (not used, but example for touch on image instead of button
//touchable = true;
//addEventListener(TouchEvent.TOUCH, onTouch_image);
}
private function onEnter_frame(e:Event):void {
_image.x -= 20;
}

Get the Absolute Origin of an Object when DragStartedEvent fired

I've an app which like the image shown below (sorry I used an iPhone like mock-ups)
The app has an image as background (displayed using Canvas which takes the whole visual screen size), then another shape (the red rectangle in this case) will shown above the background which can be dragged and pinch zoomed.
Now the question is:
How can I get the coordinates (origins from top-left corner of the screen, i.e. top-left of the canvas) of the top-left corner of the rectangle?
UPDATE
According to #Will's suggestion, I currently move the rectangle in this case via DragDelta using TranslateTransform inside it, like:
rectTransform.X += e.HorizonalChange;
rectTransform.Y += e.VerticalChange;
The rectangle is defined within code, not in XAML:
rect.Stroke = new SolidColorBrush(Colors.Green);
rect.StrokeThickness = 10;
rect.Fill = new SolidColorBrush(Colors.Transparent);
rect.HorizontalAlignment = System.Windows.HorizontalAlignment.Center;
rect.VerticalAlignment = System.Windows.VerticalAlignment.Center;
rect.Width = 200;
rect.Height = 200;
canvas.Children.Add(rect);
and the canvas is defined within XAML.
What I've tried:
Initially I was trying to get the start point when the Drag event begins, but by using the DragStarted(object sender, DragStartedGestureEventArgs e), I am only able to output the coords of the point which was touched, but not the point of top-left corner of this rectangle.
And it's similar to the DragCompleted event which will return me the point the gesture ends.
So is there any chance I can get the origin coords of the red rectangle?
I spent nearly an afternoon on Google as well as MSDN and then finally come to find this on SO:
How to get the position of an element in a StackPanel?
which enlightened me using the similar method. In that case, they managed to get the absolute coordinates of an UI Element. Similarily, in my case, I intend to know the absolute origin(coordinates) of the red rectangle to the background canvas.
I use:
GeneralTransform gt = canvas.TransformToVisual(rect);
Point currentPos = gt.Transform(new Point(0, 0));
Then the currentPos is the current position of rectangle (its an absolute position, relative to the canvas).
And Here's the reference of TransformToVisual in MSDN
There's only one thing to pay attention to: the value of X and Y are negative.
Not 100% sure of the syntax here, but in WPF (which should be analogous) I'd handle it by
private double _startX, startY, _endX, _endY;
private void DragStarted(object sender, DragStartedGestureEventArgs e)
{
var rect = sender as UIElement; // I'm assuming the sender is your Rectangle
this._startX = Canvas.GetLeft(rect);
this._startY = Canvas.GetTop(rect);
}
private void DragCompleted(object sender, DragCompletedGestureOrWhateverLolEventArgs e)
{
var rect = sender as UIElement; // I'm assuming the sender is your Rectangle
this._endX = Canvas.GetLeft(rect);
this._endY = Canvas.GetTop(rect);
}
What you say? Not type safe? Yeah, well, okay. How about give your rectangle an x:Name and then use that in these methods?
<Rectangle x:Name="rect" SkipOtherPropertiesLol="true" />
and
this._startX = Canvas.GetLeft(rect); //etc
Attached properties are a little confusing at first, but they are very powerful and easy to use once you understand their fairy magic.

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