ruby--ruby/ext/tk/sample/demos-en/ruler.rb

# ruler.rb
#
# This demonstration script creates a canvas widget that displays a ruler
# with tab stops that can be set, moved, and deleted.
#
# ruler widget demo (called by 'widget')
#

# rulerMkTab --
# This method creates a new triangular polygon in a canvas to
# represent a tab stop.
#
# Arguments:
# c -           The canvas window.
# x, y -        Coordinates at which to create the tab stop.

def rulerMkTab(c,x,y)
  v = $demo_rulerInfo
  TkcPolygon.new(c, x, y, x+v.size, y+v.size, x-v.size, y+v.size)
end

# toplevel widget
if defined?($ruler_demo) && $ruler_demo
  $ruler_demo.destroy 
  $ruler_demo = nil
end

# demo toplevel widget
$ruler_demo = TkToplevel.new {|w|
  title("Ruler Demonstration")
  iconname("ruler")
  positionWindow(w)
}

# label
TkLabel.new($ruler_demo, 'font'=>$font, 'wraplength'=>'5i', 'justify'=>'left', 
            'text'=>"This canvas widget shows a mock-up of a ruler.  You can create tab stops by dragging them out of the well to the right of the ruler.  You can also drag existing tab stops.  If you drag a tab stop far enough up or down so that it turns dim, it will be deleted when you release the mouse button."){
  pack('side'=>'top')
}

# frame
$ruler_buttons = TkFrame.new($ruler_demo) {|frame|
  TkButton.new(frame) {
    text 'Dismiss'
    command proc{
      tmppath = $ruler_demo
      $ruler_demo = nil
      tmppath.destroy
    }
  }.pack('side'=>'left', 'expand'=>'yes')

  TkButton.new(frame) {
    text 'Show Code'
    command proc{showCode 'ruler'}
  }.pack('side'=>'left', 'expand'=>'yes')
}
$ruler_buttons.pack('side'=>'bottom', 'fill'=>'x', 'pady'=>'2m')

# canvas 
$ruler_canvas = TkCanvas.new($ruler_demo, 'width'=>'14.8c', 'height'=>'2.5c')
$ruler_canvas.pack('side'=>'top', 'fill'=>'x')

# 
unless Struct.const_defined?("RulerInfo")
  $demo_rulerInfo = Struct.new("RulerInfo", :grid, :left, :right, :x, :y, 
                               :top, :bottom, :size, :normalStyle, 
                               :activeStyle, :deleteStyle).new
end
$demo_rulerInfo.grid = '.25c'
$demo_rulerInfo.left = TkWinfo.fpixels($ruler_canvas, '1c')
$demo_rulerInfo.right = TkWinfo.fpixels($ruler_canvas, '13c')
$demo_rulerInfo.top = TkWinfo.fpixels($ruler_canvas, '1c')
$demo_rulerInfo.bottom = TkWinfo.fpixels($ruler_canvas, '1.5c')
$demo_rulerInfo.size = TkWinfo.fpixels($ruler_canvas, '.2c')
$demo_rulerInfo.normalStyle = {'fill'=>'black'}
if TkWinfo.depth($ruler_canvas) > 1
  $demo_rulerInfo.activeStyle = {'fill'=>'red', 'stipple'=>''}
  $demo_rulerInfo.deleteStyle = {'fill'=>'red', 
    'stipple'=>'@'+[$demo_dir, '..', 
                     'images', 'gray25.xbm'].join(File::Separator)}
else
  $demo_rulerInfo.activeStyle = {'fill'=>'black', 'stipple'=>''}
  $demo_rulerInfo.deleteStyle = {'fill'=>'black', 
    'stipple'=>'@'+[$demo_dir, '..', 
                     'images', 'gray25.xbm'].join(File::Separator)}
end

TkcLine.new($ruler_canvas, 
            '1c', '0.5c', '1c', '1c', '13c', '1c', '13c', '0.5c', 'width'=>1)
(0..11).each{|i|
  x = i+1
  TkcLine.new($ruler_canvas, "#{x}c", '1c', "#{x}c", '0.6c', 'width'=>1)
  TkcLine.new($ruler_canvas, "#{x}.25c", '1c', "#{x}.25c", '0.8c', 'width'=>1)
  TkcLine.new($ruler_canvas, "#{x}.5c", '1c', "#{x}.5c", '0.7c', 'width'=>1)
  TkcLine.new($ruler_canvas, "#{x}.75c", '1c', "#{x}.75c", '0.8c', 'width'=>1)
  TkcText.new($ruler_canvas, "#{x}.15c", '0.75c', 'text'=>i, 'anchor'=>'sw')
}

$rulerTag_well = TkcTag.new($ruler_canvas)
$ruler_canvas\
.addtag_withtag($rulerTag_well,
                TkcRectangle.new($ruler_canvas, 
                                 '13.2c', '1c', '13.8c', '0.5c', 
                                 'outline'=>'black', 
                                 'fill'=>($ruler_canvas\
                                          .configinfo('background'))[4]) )
$ruler_canvas\
.addtag_withtag($rulerTag_well,
                rulerMkTab($ruler_canvas, 
                           TkWinfo.pixels($ruler_canvas, '13.5c'), 
                           TkWinfo.pixels($ruler_canvas, '.65c') ) )

$rulerTag_well.bind('1', proc{|x,y| rulerNewTab($ruler_canvas,x,y)}, '%x %y')
$ruler_canvas.itembind('tab', '1', 
                       proc{|x,y| rulerSelectTab($ruler_canvas,x,y)}, '%x %y')
$ruler_canvas.bind('B1-Motion', 
                   proc{|x,y| rulerMoveTab($ruler_canvas,x,y)}, '%x %y')
$ruler_canvas.bind('Any-ButtonRelease-1', proc{rulerReleaseTab($ruler_canvas)})

# rulerNewTab --
# Does all the work of creating a tab stop, including creating the
# triangle object and adding tags to it to give it tab behavior.
#
# Arguments:
# c -           The canvas window.
# x, y -        The coordinates of the tab stop.

def rulerNewTab(c,x,y)
  v = $demo_rulerInfo
  c.addtag_withtag('active', rulerMkTab(c,x,y))
  c.addtag_withtag('tab', 'active')
  v.x = x
  v.y = y
  rulerMoveTab(c,x,y)
end

# rulerSelectTab --
# This method is invoked when mouse button 1 is pressed over
# a tab.  It remembers information about the tab so that it can
# be dragged interactively.
#
# Arguments:
# c -           The canvas widget.
# x, y -        The coordinates of the mouse (identifies the point by
#               which the tab was picked up for dragging).

def rulerSelectTab(c,x,y)
  v = $demo_rulerInfo
  v.x = c.canvasx(x, v.grid)
  v.y = v.top+2
  c.addtag_withtag('active', 'current')
  c.itemconfigure('active', v.activeStyle)
  c.raise('active')
end

# rulerMoveTab --
# This method is invoked during mouse motion events to drag a tab.
# It adjusts the position of the tab, and changes its appearance if
# it is about to be dragged out of the ruler.
#
# Arguments:
# c -           The canvas widget.
# x, y -        The coordinates of the mouse.

def rulerMoveTab(c,x,y)
  v = $demo_rulerInfo
  return if c.find_withtag('active') == []
  cx = c.canvasx(x,v.grid)
  cy = c.canvasy(y)
  cx = v.left if cx < v.left
  cx = v.right if cx > v.right
  if (cy >= v.top && cy <= v.bottom)
    cy = v.top+2
    c.itemconfigure('active', v.activeStyle)
  else
    cy = cy-v.size-2
    c.itemconfigure('active', v.deleteStyle)
  end
  c.move('active', cx-v.x, cy-v.y)
  v.x = cx
  v.y = cy
end

# rulerReleaseTab --
# This method is invoked during button release events that end
# a tab drag operation.  It deselects the tab and deletes the tab if
# it was dragged out of the ruler.
#
# Arguments:
# c -           The canvas widget.
# x, y -        The coordinates of the mouse.

def rulerReleaseTab(c)
  v = $demo_rulerInfo
  return if c.find_withtag('active') == []
  if v.y != v.top+2
    c.delete('active')
  else
    c.itemconfigure('active', v.normalStyle)
    c.dtag('active')
  end
end