B4J Question Scroll mouse event ?

hookshy

Well-Known Member
Licensed User
Longtime User
I did not found any scroll mouse event ?

I post recently a simple example on how to move a pane , using the midle scroll button it defines the pan action over a pane .
How will I do the zoom ?

I did thought I could do zoom as in layout designer but it would have been nice to use mouse as in all other graphics software !
 
Sort by date Sort by votes

Erel

B4X founder
Staff member
Licensed User
Longtime User
You can add an OnScroll event to a node with JavaObject:
B4X: 
Sub Process_Globals
   Private fx As JFX
   Private MainForm As Form
End Sub

Sub AppStart (Form1 As Form, Args() As String)
   MainForm = Form1
   MainForm.Show
   Dim jo As JavaObject = MainForm.RootPane
   Dim e As Object = jo.CreateEventFromUI("javafx.event.EventHandler", "scroll", Null)
   jo.RunMethod("setOnScroll", Array(e))
End Sub

Sub Scroll_Event (MethodName As String, Args() As Object) As Object
   Dim scrollevent As JavaObject = args(0)
   Log(scrollevent.RunMethod("getDeltaY", Null))
   Return Null
End Sub
 
Upvote 0

hookshy

Well-Known Member
Licensed User
Longtime User
thanks Erel I will try it ...

Regarding the zoom over pane that contain different objects ...I did manage scale image and parent dimensions in order to get the zoom
but yet i try to imagine a way to zoom over text ... for now I leave the text in original font size

Q: How could I scale the text size according to reference objects ? knowing that I have to restore original text size on 100% zoom
any hints ?
 
Upvote 0

hookshy

Well-Known Member
Licensed User
Longtime User
I am trying to figure out how to maintain the aspect ration of objects while zooming ... like abstract designer zoom to 50%

I do find difficult to put the question !
Do I have to make a grid snap in order to make the proper scaling ?
How do I increment the imageviews sizes relative to panel size ... actually I do not know how to scale the parent to mantain aspect ratio and distances between objects
Quite a hard task ..

Any hints will be apreciated


I must ajust left,top dimensions relative to zoom level ..easy said than done
 
Last edited:
Upvote 0

hookshy

Well-Known Member
Licensed User
Longtime User
I did think about it ...I can resize all objects with zoom factor as well as the parent window ...then
I must reposition all object on the new modified parent to fit the old left,top dimensions ..in this way I will maintain the real distance between objects
if an image view was on 20dip left and 20dip top then ... on a zoom level of 200% the new position must be 40dip left 40dip top ...

I did have some problems because I used a scale factor like
imgx.width=imgx.wdth*1.1
imgx.width=imgx.wdth/1.1
this was in my opinion a mistake then I made a scale adding dimensions like:
imgx.width=imgx.wdth+10
imgx.width=imgx.wdth-10
parent.width=parent.width+10
parent.height=parent.height +10

I do not now if I will make it work till the end but I like thing about how stuff works ... I guess all other features of my project will be great also ..
I am building a hmi for industrial wwtp that will connect to various plc
 
Upvote 0
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…