I am making a map editor for my games. I had already managed to add an object to the map when the user clicks on the map. It would be handy for me to add objects in a path the user clicks mouse and drags (like the pencil in mspaint). What events do I need to register to give that effect?
Thanks for any ideas.
Here is the main idea :
use MouseUp() MouseDown() and MouseMove() .
Set some bool to 0 - tell you if you are Dragging.
When (mouse Down) and (flag==0) then START_DRAGGING.
Then mouse move knows if you are dragging by flag==1.
When (mouse UP) and (flag == 1) you know youv'e just stopped dragging, so set flag to 0 again.
Related
I am developing a WPF application, where I need to allow user to rearrange objects by drag-drop. It is basically dragging objects within a canvas area and moving them to another area of the canvas. The mouse cursor would change to a drag cursor while dragging is happening.
The requirement is like the mouse pointer cannot leave the canvas area while the dragging is in progress. For that I am using the Win32 ClipCursor api to restrict the cursor to a certain boundary of the screen.
This is working fine when mouse is used. However, if touch is used, i.e. if the pointer is moved through touch, it is possible to take the cursor out of the bounding rectangle. Can anyone please help to understand why it is happening? I am handling the PreviewMouseMove and MouseLeftButtonUp events for starting and ending the drag. Do I need to handle the Touch and the Stylus events as well?
Thanks!
I wanna build a card game in Unity.
I want to player swipe cards left or right but I wanna show some tricks about what's gonna happen if they swipe left or right so if they grab the card (2D Image) and go a bit left or right a text will appear on image depends on side.
I tried to use swipe and use X axis change but It's not working properly.
Here is a basic pictured information about what i wanna build:
I would advise using the drag handlers system in unity to track where the card started, and trigger different effects at different distances / directions from its origin.
You can detect the drag of the card by implementing IBeginDragHandler, IDragHandler, IEndDragHandler on a script on your card object.
Begin is called when the object starts dragging, Drag is called during each frame its moving, and End is called when the object is dropped.
When a drag begins, you can cache the position where the card started. Then in Drag handler each frame you can check the distance of your card from where it started. Once it has moved more than a certain distance, you can trigger whatever tricks or effects you want to show.
Depending on how your coordinate space is set up, you could for example know left from right during drag updates such as:
// Inside of your on drag method, check each frame for where the card is
// If it has moved far enough, trigger an effect
if (Vector3.Distance(dragStartPosition, transfom.position) > yourTriggerDistance) {
// if X is greater, the card moved right
if (transform.position.x > dragStartPosition.x) {
// Trigger Right swipe text
ShowSomeRightSwipeText();
}
// otherwise, X is smaller, so the card has moved left by the required distance
else {
// Trigger left swipe text
ShowSomeLeftSwipeText();
}
}
Also please remember that:
In order for these interfaces to work, you need to have a Physics 2D Raycaster attached to your camera in the scene.
You need to make sure you have an Event System in the scene as well.
The above two things are often asked issues here regarding detecting object dragging.
I have a Drag() method on form_MouseDown event. I also have a click event on the form. The problem is that if I click on the form, MouseDown event gets triggered and it never gets the chance to trigger click event.
What is the best way to solve this issue? I was thinking counting pixels if the form is actually dragged, but there has to be a better way. Any suggestions?
I was thinking counting pixels if the form is actually dragged, but there has to be a better way.
Nope, that's exactly how you have to do it.
This isn't just a software limitation; it's very much a practical one as well. If you think through the problem from a user's perspective, you'll immediately see the problem as well as the solution. Ask yourself, what is the difference between a click and a drag?
Both of them start with the mouse button going down over the object, but one of them ends with the mouse button going back up over the object in the same position and the other one ends with the mouse button going back up in a completely different position.
Since time machines haven't been perfected yet, you have no way of knowing this in advance.
So yes, you need to maintain some kind of a distance threshold, and if the pointer moves outside of that distance threshold while it is down over the object, then you consider it a drag. Otherwise, you consider it a click.
That distance threshold should not be 0. The user should not be required to hold the mouse completely still in order to initiate a click. A lot of users are sub-par mousers. They are very likely to twitch slightly when trying to click. If the threshold is 0, they'll end up doing a lot of inadvertent dragging when they try to click.
Of course, you don't actually have to worry about any of this or compute the drag threshold yourself. Instead, use the Windows default values, obtainable by calling the GetSystemMetrics function and specifying either SM_CXDRAG or SM_CYDRAG. (These might be exposed somewhere by the WinForms framework, but I don't think so. It's just as easy to P/Invoke them yourself.)
const int SM_CXDRAG = 68;
const int SM_CYDRAG = 69;
[DllImport("user32.dll")]
static extern int GetSystemMetrics(int index);
Point GetDragThreshold()
{
return new Point(GetSystemMetrics(SM_CXDRAG), GetSystemMetrics(SM_CYDRAG));
}
In the field of UX/UI, this sort of thing is called hysteresis or debouncing, by analogy to the use of these terms in physics and electronics.
I found this solution, although it is for a double-click and a mouse down events:
void pictureBox_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left && e.Clicks ==1)
{
PictureBox pb = (PictureBox)sender;
DoDragDrop((ImageData)pb.Tag, DragDropEffects.Copy);
}
}
source: http://code.rawlinson.us/2007/04/c-dragdrop-and-doubleclick.html
Unfortunatelly, at the point of time when "button-is-pressed" you don't know yet if the desired action is just a click or a drag-drop. You will find it out it later.
For a click, the determinant is "no movement" and "button up".
For a drag, the determinant is "movement" and "button up".
Hence, to disambiguate those interactions, you have to track not only the buttons, but also the movement. You do not need to track the overall movement, only the movement between button-down and button-up is interesting.
Those events are therefore a good place to start/stop the Mouse.Capture mechanisms (to dynamically present drag adorners and drop location hints), or, in simplier form - to store the origin and target of movement vector and check if the distance is > D (even if movement occurred, there should be some safe minimal distance within which the DRAG is canceleed. The mouse is "jaggy" sometimes, and people would really don't like your app to start dragging when they double click at the end of fast mouse pointer movement :) )
I need help with mouse drag and drop. I would like to make something like mouse macro. You specify the XY coordinates of cursor and then drag something to another XY coordinates automatically. Is it possible?
I know how to simulate Mouse Click and Mouse Movement, but I am not sure with the Mouse Dragging.
WM_MOUSEDOWN, WM_MOUSEMOVE, WM_MOUSEUP -- use Spy++ to view windows messages
I'm working with a WPF app, more specifically a Canvas with draggable elements.
Once an item is being dragged, I'd like to limit the scope of cursor movement to inside the canvas where the items are being dragged about.
The event which can start a drag is shown below
private void WidgetCanvas_PreviewHeaderLeftMouseDown(object sender, MouseButtonEventArgs e)
{
e.Handled = true;
... logic to figure out if this is a valid drag, blah blah blah ...
this.IsDragging = true;
// TODO: clip the available cursor movement to actual width of Canvas
}
On the Preview-MouseUp, I'd like to simply "unclip" the cursor movement back to it's normal state.
I'll be monitoring the movement of the mouse once I start dragging (PreviewMouseMove), so worst case, I could manually check the position of the mouse and keep it constrained to the canvas, but that seems a little ugly.
Anyone have a better way to limit the cursor boundaries?
There's no clean way to do this and the not-so-clean ways will make your mouse cursor "jitter" at the border of the clipping area.
Moreover, I'd question if this is really a good idea. The user should really own the mouse and he or she generally gets frustrated when you try to artificially limit things that he or she owns.
If you want to provide feedback when the mouse leaves your canvas, maybe you could leave the item being dragged stuck along the border while the mouse button is still down? This would tell the user that he or she has left the target area without trying to impose limitations on where the mouse can go.
Good luck!
You should be able to do it using the ClipCursor native API.