Drawingarea drag&drop

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#1 (In Topic #503)
bill-lancaster
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bill-lancaster is in the usergroup ‘Regular’
 I wish to drag an item from a gridview to a picturebox.  At the position of the 'drop' in the picturebox a circle is to be drawn at that point.
My problem is that with the drop event in the  picturebox I can't get the x & y position in the picturebox..
It seems that when the mouse drag enters the picturebox the normal values of mouse.x & .y aren't available.
Any help would be appreciated.
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#2
BruceSteers
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Did you set Picturebox1.Tracking to true?
I think that how you activate mouse data on controls.  i could be wrong though :)
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#3
bill-lancaster
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bill-lancaster is in the usergroup ‘Regular’
 Thanks, yes, tracking and drop set to true.
I'm making a small project to better show the problem.
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#4
bill-lancaster
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bill-lancaster is in the usergroup ‘Regular’
This code shows the problem.
An item selected from the gridview and dropped in the drawingarea draws the circle in the wrong place

Code

' Gambas class file v3.15.2

Private Const MIME_TYPE As String = "text/x-gambas-dragndrop-example"
Private iMouseX As Integer
Private iMouseY As Integer

Public Sub Form_Open()
Dim i As Integer
  gdvTemp.Columns.Count = 1
  gdvTemp.Rows.Count = 4
  For i = 0 To 3
    gdvTemp[i, 0].Text = "item " & i
  Next
End

Public Sub gdvTemp_MouseDrag()
Dim hImage As Image
Dim sText As String
  sText = gdvTemp[gdvTemp.RowAt(Mouse.Y), gdvTemp.ColumnAt(Mouse.X)].Text
  hImage = New Image(32 + 8 + gdvTemp.Font.TextWidth(sText), 32, Color.Transparent)
  Paint.Begin(hImage)
  Paint.Font = gdvTemp.Font
  Paint.Text(sText, 34, 0, hImage.Width, 32, Align.Left)
  Paint.Fill
  Paint.End  
  Drag.Icon = hImage.Picture
  gdvTemp.Drag(sText, MIME_TYPE)
End

Public Sub DrawingArea1_Drop()
  DrawingArea1.Refresh
End

Public Sub DrawingArea1_Draw()
  Draw.Circle(iMouseX, iMouseY, 10)
End

Public Sub DrawingArea1_MouseMove()
  iMouseX = Mouse.X
  iMouseY = Mouse.Y
End
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#5
BruceSteers
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BruceSteers is in the usergroup ‘Guru’
 hmm , sorry i don't have time to test it but an initial look shows to me you may not want the gdvTemp_MouseDrag() event as this will constantly change. and i'd think possibly become null when you move off the gdvTemp object?

Perhaps try grabbing the info on MouseDown() and set picture on MouseUp() ?

Just a thought.
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#6
cogier
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Hi Bill,

I am a little confused here. You say 'I wish to drag an item from a gridview to a picturebox' but your example uses a DrawingArea :? ?

Do you want to drag the text from a GridView Cell to the DrawingArea/PictureBox and put a circle around it?

Can you provide a little more explanation.
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#7
vuott
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Cogier's doubts are legitimate.  :)

However, regarding the identification of the mouse coordinates (drop point), you have modify, as follows, this routine:

Code (gambas)

  1. Public Sub DrawingArea1_Drop()
  2.  
  3.   iMouseX = Drag.X
  4.   iMouseY = Drag.Y
  5.   DrawingArea1.Refresh
  6.  

It is understood that you have to set the "DrawingArea1.Drop" Property to "<COLOR color="#800000">True</COLOR>".
Europaeus sum !

<COLOR color="#FF8000">Amare memorentes atque deflentes ad mortem silenter labimur.</COLOR>
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#8
bill-lancaster
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bill-lancaster is in the usergroup ‘Regular’
 The full project is a horticultural/gardening database.  The drawingarea represents a bed and the gridview a list of plant/shrub names.  In fact there's more than one gridview with names.  When the item is dropped, the database gets the coordinates for that item so we know what each circle represents.
Perhaps the idea of drawing of a circle confuses the issue so how about dropping an icon in the drawing area instead but it must be at the drop point.
Thanks for all your thoughts on this.
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#9
bill-lancaster
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bill-lancaster is in the usergroup ‘Regular’
 And thanks for the thought Bruce, that's roughly what I was doing, I just had this foolish notion of making it more 'fancy' with a drag&drop effect!
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#10
cogier
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I have had a look at this and come up with a place to start. Run this code in a new 'Graphical application'. The next step would be to create a Class (called Plant?) containing text and/or a picture so that you can add this to the DrawingArea. This would give you the option to move the 'Plant' around, delete it etc. Have a look at ScreenShot which uses this principle in the 'Edit' feature. There is a short video that shows this here.

<IMG src="https://www.cogier.com/gambas/Garden.png"> </IMG>

Code (gambas)

  1. sDragText As String
  2. DrawingAreaGarden As DrawingArea
  3. GridViewData As GridView
  4.  
  5. Public Sub Form_Open()
  6.  
  7.   Dim iLoop As Integer
  8.   Dim sText As String[] = ["Bindweed", "Quackgrass", "Japanese Knotweed", "Canada Thistle", "Nutsedge", "Buckhorn Plantain", "Purslane", "Crabgrass", "Wild Violet", "Ground Ivy"]
  9.  
  10.   With Me
  11.     .Width = 500
  12.     .Height = 500
  13.     .Text = "Bill's garden"
  14.     .Arrangement = Arrange.Vertical
  15.     .Padding = 5
  17.  
  18.   With GridViewData = New GridView(Me) As "GridViewData"
  19.     .Expand = True
  20.     .Rows.Count = 0
  21.     .Columns.Count = 1
  23.  
  24.   For iLoop = 0 To sText.Max
  25.     Inc GridViewData.Rows.Count
  26.     GridViewData[iLoop, 0].Text = sText[iLoop]
  27.   Next
  28.  
  29.   With DrawingAreaGarden = New DrawingArea(Me) As "DrawingAreaGarden"
  30.     .Background = Color.Green
  31.     .Expand = True
  32.     .Cached = True
  33.     .Drop = True
  35.  
  37.  
  38. Public Sub GridViewData_Click()
  39.  
  40.   sDragText = GridViewData[Last.Row, Last.Column].Text
  41.  
  43.  
  44. Public Sub GridViewData_MouseDrag()
  45.  
  46.   GridViewData.Drag(sDragText)
  47.  
  49.  
  50. Public Sub DrawingAreaGarden_Drop()
  51.  
  52.   Paint.Begin(DrawingAreaGarden)
  53.   Paint.Text(sDragText, Mouse.ScreenX - DrawingAreaGarden.ScreenX, Mouse.ScreenY - DrawingAreaGarden.ScreenY)
  54.   Paint.Fill
  55.   Paint.Stroke
  56.   Paint.End
  57.  
  59.  
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#11
bill-lancaster
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bill-lancaster is in the usergroup ‘Regular’
Thanks Cogier, Ill have a look at this, trouble is there is too much japanese knot weed!
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#12
BruceSteers
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With Cogiers help you'll soon crack this Bill , he's an expert on this sort of thing , you should see his "Snapshot" app.
waaay beyond my capabilities lol.

no notions are foolish, it's all just part of the game we play :)
Best of luck :)
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#13
bill-lancaster
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bill-lancaster is in the usergroup ‘Regular’
 Thank you so much cogier, drawingarea1.screenx-mouse.screenx etc does the trick.
Don't know why I didn't think of it.
Now I need to find a way of getting rid of those pesky japanese knotweeds!
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