Interactive Vector GUI

原文链接: https://www.nv5geospatialsoftware.com/Learn/Blogs/Blog-Details/interactive-vector-gui

7406 Rate this article:

4.0

Interactive Vector GUI

Anonym Thursday, December 15, 2016

With holidays rapidly approaching, I thought it might be nice to present a light hearted demonstration of capabilities; something that you can delight friends and family with during cold winter nights.  This week’s post shows how to use a simple widget_window to create an interactive vector animation.  The code is broken up into four pieces VectorBlog, VectorBlog_Event, VectorBlogMouseEvent, and VectorBlogVectorBuilder. The VectorBlog creates the widget itself and initially displays the vector information.  VectorBlog_Event runs the events for the base widget.  This is mainly the closing of the widget. VectorBlogMouseEvent is the mechanism by which the mouse locations are recoded by the widget window. Last but not least VectorBlogVectorBuilder builds the two matrices containing the horizontal and vertical components of the vector.  When the following code is run the cursor location is recorded, a distance weighted vector diagram is created, and the resulting image is then displayed in the widget window.  The only tricky bits in this code relate to the fact that there are two event handlers, one for the base widget and one for the mouse events in the widget window.  The object reference for the image displayed must also be maintained and manipulated each time the cursor is move.

Figure 1: Example Vector Plot

;+

; Build the vecort components

; This is distance weighting

;-

pro VectorBlogVectorBuilder, dims = dims, pt = pt, u = u, v = v

  compile_opt IDL2



  ; Get all the x locations

  xs = findgen(dims[0])

  xs = xs#replicate(1,dims[1])



  ; Get all the y locations

  ys = findgen(dims[1])

  ys = transpose(ys# replicate(1,dims[0]))



  ; Build the horizontal components

  u = pt[0] - xs



  ; Build the vertical components

  v =  pt[1] - ys

end





;+

; The event handler called when the mouse is moved.

;-

FUNCTION VectorBlogMouseEvent, win, x, y, keymods

  COMPILE_OPT idl2



  ; Set the window

  win.SetCurrent



  ; Set the scale factor

  sc = .05



  ; Get the size of the window

  dims = win.DIMENSIONS * sc



  ; Get the vecotr information

  VectorBlogVectorBuilder, dims = dims, pt = [x*sc,y*sc], $

    u = u , v = v



  ; Build the vecotr image

  vector = vector(u,v,xrange=[0,dims[0]], yrange=[0,dims[1]], /current, AUTO_COLOR=1,  $

    RGB_TABLE=73, AXIS_STYLE = 0, LENGTH_SCALE=1.5, ARROW_THICK =3)



  ; Delete the old image

  win.uvalue.delete



  ; Display the new image

  win.uvalue = vector







END





;+

; The event handler for the widget

;-

pro VectorBlog_Event, ev

  compile_opt IDL2





end





pro VectorBlog

  compile_opt IDL2



  ; Setup the widget

  tlb = widget_base()

  wwindow = widget_window(tlb, MOUSE_MOTION_HANDLER='VectorBlogMouseEvent', $

    XSIZE=500, YSIZE=500)

  widget_control, tlb, /REALIZE



  ; Set the scale factor

  sc = .05



  ; Get infomation about the widget window

  WIDGET_CONTROL, wwindow, GET_VALUE=w

  dims = w.DIMENSIONS * sc



  ; Build the vecotr infomation

  VectorBlogVectorBuilder, dims = dims, pt = [(dims[0])/2.,(dims[1])/2.], $

    u = u , v = v



  ; Display the vectors

  vector = vector(u,v,xrange=[0,dims[0]], yrange=[0,dims[1]], /current, AUTO_COLOR=1,  $

    RGB_TABLE=73, AXIS_STYLE = 0, LENGTH_SCALE=1.5, ARROW_THICK =3)



  ; Record the vector object

  w.uvalue = vector

  WIDGET_CONTROL, tlb, SET_UVALUE=w



  ; Start the task manager

  XMANAGER, 'VectorBlog', tlb



end

Maintaining Backward Compatibility in IDL 8.6 - Keep Calm And Read Your Release Notes New in IDL 8.6: IDLTasks