Refreshing a ruby tk window/scrollbox

Ruby
1

I have a TkScrollBox object that displays a list of records. I want to
sort the list and filter it in various ways, but the only way I’ve
figured out how to do this is to get rid of the old window and create a
new window with the sorting option. My question is, is there a way to
refresh a TkScrollBox or the window itself so I don’t have to create a
new window each time?

Thanks in advance,
DBH

2

On Apr 22, 2007, at 6:51 PM, DBH wrote:

I have a TkScrollBox object that displays a list of records. I
want to
sort the list and filter it in various ways, but the only way I’ve
figured out how to do this is to get rid of the old window and
create a
new window with the sorting option. My question is, is there a way to
refresh a TkScrollBox or the window itself so I don’t have to create a
new window each time?

What I do in situations similar to what you describe is to delete the
contents of the list box and repopulate it with new contents. The
following is a rather long example demonstrating this technique. I’m
sorry I don’t have a shorter one. The technique is coded into
X11ColorBrowser#category_selected_action.

Hope this helps.

Regards, Morton

#! /usr/bin/ruby -w # Author: Morton G. # Date: August 26, 2006 # X11 color browser

require ‘tk’

class X11ColorCategory

# Full path name of the X11 colors file.
RGB_TXT = "/usr/X11R6/lib/X11/rgb.txt"

#Dictionary of rgb values keyed by color name.
COLORS = {}

def X11ColorCategory.read_rgb_table
   # read and parse the X11 colors file.
   File.foreach(RGB_TXT) do |rgb|
      next if rgb =~ /^!/ # skip header line
      rgb = rgb.lstrip.split(/\s+/)
      r = rgb.shift
      g = rgb.shift
      b = rgb.shift
      key = rgb.join(' ')
      COLORS[key] = "r:#{r} g:#{g} b:#{b}"
   end
   COLORS
end

def X11ColorCategory.all
   ALL_CATEGORIES
end

def X11ColorCategory.rgb(color_name)
   COLORS[color_name]
end

def extract(pattern)
   @members, OTHER.members =
      OTHER.members.partition { |m| m =~ pattern }
   self
end

def initialize(name)
   @name = name
   @members = []
end

attr_accessor :name, :members

ALL = X11ColorCategory.new('ALL')
X11ColorCategory.read_rgb_table.each {|key,| ALL.members << key}
ALL.members.sort!
OTHER = X11ColorCategory.new('OTHER')
ALL.members.each {|m| OTHER.members << m}
REDS = X11ColorCategory.new('REDS').
   extract(/red|rose|pink|salmon|fire/i)
GREENS = X11ColorCategory.new('GREENS').
   extract(/green|chartreuse|olive|honeydew/i)
BLUES = X11ColorCategory.new('BLUES').
   extract(/blue|navy/i)
CYANS = X11ColorCategory.new('CYANS').
   extract(/cyan|aqua|azure|turquoise/i)
MAGENTAS = X11ColorCategory.new('MAGENTAS').
   extract(/magenta|maroon|violet|plum|purple|orchid|thistle/i)
YELLOWS = X11ColorCategory.new('YELLOWS').
   extract(/yellow|gold|lemon|corn/i)
ORANGES = X11ColorCategory.new('ORANGES').
   extract(/orange|tomato|peach|coral/i)
BROWNS = X11ColorCategory.new('BROWNS').
   extract(/brown|tan|wood|choc|sienna|wheat|peru/i)
WHITES = X11ColorCategory.new('WHITES').
   extract(/white|ivory|snow|lace/i)
GRAYS = X11ColorCategory.new('GRAYS').
   extract(/gr[ae]y|gainsboro/i)

ALL_CATEGORIES = [
   REDS,
   ORANGES,
   YELLOWS,
   GREENS,
   CYANS,
   BLUES,
   MAGENTAS,
   BROWNS,
   WHITES,
   GRAYS,
   OTHER
]

end

class X11ColorBrowser

# Action performed when category selection is made.
def category_selected_action
   @category_names.focus
   @selected_category =
      X11ColorCategory.all[@category_names.curselection[0]]
   @color_names.delete(0, 'end')
   @selected_category.members.each { |m| @color_names.insert

(“end”, m) }
@color_names.selection_set(0)
color_selected_action
end

# Action performed when color selection is made.
def color_selected_action
   color = @selected_category.members[@color_names.curselection[0]]
   @color_rect.background(color)
   @rgb_lbl.text(X11ColorCategory.rgb(color))
end

# Action performed when browser window is mapped.
def window_mapped_action
   return if @mapped
   @mapped = true
   X11ColorCategory.all.each do |category|
      @category_names.insert("end", category.name)
   end
   @category_names.selection_set(0)
   category_selected_action
end

def initialize
   # Flag indicating that window has been mapped at least once.
   @mapped = false
   # Holder for currently selected color category
   @selected_category = nil
   # Set up the browser window.
   root = TkRoot.new {title 'Color Browser'}
   # Panel at top of browser containing scrolling list of X11

colors and
# label displaying selected color.
top_pnl = TkFrame.new(root)
# List box displaying names of X11 color categories.
@category_names = TkListbox.new(top_pnl)
# Scroll bar for the color names list.
vbar1 = TkScrollbar.new(top_pnl)
@category_names.yscrollbar(vbar1)
# List box displaying names of X11 colors within selected
category.
@color_names = TkListbox.new(top_pnl)
# Scroll bar for the color names list.
vbar2 = TkScrollbar.new(top_pnl)
@color_names.yscrollbar(vbar2)
# Label displaying selected color.
@color_rect = TkLabel.new(top_pnl, ‘width’=>25)
# Request layout of top panel.
@category_names.pack(“side”=>“left”, “fill”=>“both”,
“expand”=>true,
“padx”=>5)
vbar1.pack(“side”=>“left”, “after”=>@category_names, “fill”=>“y”)
@color_names.pack(“side”=>“left”, “after”=>vbar1, “fill”=>“both”,
“expand”=>true, “padx”=>5)
vbar2.pack(“side”=>“left”, “after”=>@color_names, “fill”=>“y”)
@color_rect.pack(“side”=>“right”, “fill”=>“both”, “expand”=>true,
“padx”=>5)
top_pnl.pack(“side”=>“top”, “fill”=>“both”, “expand”=>true,
“padx”=>5, “pady”=>8)
# Panel at bottom of browser containing exit button and label
# displaying RGB values of selected color.
btm_pnl = TkFrame.new(root)
# Label displaying rgb values of selected color.
@rgb_lbl = TkLabel.new(btm_pnl) {
text “r:xxx g:xxx b:xxx”
}
# Exit button.
@quit_btn = TkButton.new(btm_pnl) {
text “Exit”
command { Tk.root.destroy }
}
# Request layout of bottom panel.
@rgb_lbl.pack(“side”=>“left”, “anchor”=>“w”)
@quit_btn.pack(“side”=>“right”)
btm_pnl.pack(“side”=>“bottom”, “fill”=>“x”, “padx”=>10,
“pady”=>8)
# Set initial window geometry; i.e., size and placement.
win_w, win_h = 750, 300
root.minsize(win_w, win_h)
win_x = (root.winfo_screenwidth - win_w) / 2
root.geometry("#{win_w}x#{win_h}+#{win_x}+50")
# Make Cmnd+Q work as expected (for Mac OS X).
root.bind(‘Command-q’) { @quit_btn.invoke }
# Bind mouse button-1, space bar, window map event to their
actions.
@category_names.bind(‘Map’) { window_mapped_action }
ev = TkVirtualEvent.new(‘ButtonRelease-1’, ‘space’)
@category_names.bind(ev) { category_selected_action }
@color_names.bind(ev) { color_selected_action }
Tk.mainloop
end

end

X11ColorBrowser.new