Stretches the view according to the aspect of a user set screen rectangle.

StretchView.py

import Rhino
import scriptcontext as sc
import rhinoscriptsyntax as rs


def GetBaseMode():
    """
    Making new display modes via RC seems to be broken
    When that is fixed, this will help create the StretchView mode
    if it does not exist.
    """
    display_modes = Rhino.Display.DisplayModeDescription.GetDisplayModes()
    if not display_modes: return Rhino.Commands.Result.Failure

    go = Rhino.Input.Custom.GetOption()
    go.SetCommandPrompt("Set a display mode to copy as a stretched mode.")
    opt_list = []
    for i, mode in enumerate(display_modes):
        english_name = mode.EnglishName
        english_name = english_name.translate(None, "_ -,.")
        opt_list.append( go.AddOption(english_name) )

    # Get the command option
    go.Get()
    if go.CommandResult()!=Rhino.Commands.Result.Success:
      return None

    selected_index = go.Option().Index
    selected_description = None
    for i,option in enumerate(opt_list):
        if option==selected_index:
            return  display_modes[i]
            

def StretchView():
    modeName = "StretchView"
    display_modes = Rhino.Display.DisplayModeDescription.GetDisplayModes()
    if not display_modes: return Rhino.Commands.Result.Failure
    
    mode_list = []
    
    for i, mode in enumerate(display_modes):
        english_name = mode.EnglishName
        english_name = english_name.translate(None, "_ -,.")
        mode_list.append( english_name)
        
    if modeName in(mode_list):
        mode = display_modes[mode_list.index(modeName)]
    else:
        msg = ("Rhino could not find a display mode named " + modeName + ". \n" 
        + "Please create a display mode named " + modeName +" and try again.\n \n"
        + "The name " + chr(34) + modeName + chr(34) + " has been copied to the clipboard for convenience.")
        
        print msg
        Rhino.UI.Dialogs.ShowMessageBox(msg, modeName)
        rs.ClipboardText(modeName)
        return
        
    rc, rectangle, view = Rhino.Input.RhinoGet.Get2dRectangle(True)
    if rc != Rhino.Commands.Result.Success:
        return
    pass
    vp = view.ActiveViewport
    if vp.IsPerspectiveProjection:
        vp.ChangeToParallelProjection(True)
        print "The viewport has been set to parallel projection."
        #return
    
    vp.DisplayMode = mode
    ratio = rectangle.Width/rectangle.Height

    mode.DisplayAttributes.ViewSpecificAttributes.HorizontalViewportScale = ratio
    Rhino.Display.DisplayModeDescription.UpdateDisplayMode(mode)

    sc.doc.Views.Redraw()
    return Rhino.Commands.Result.Success

if __name__=="__main__":
    StretchView()