Module: Tk::Scrollable

Included in:
Listbox, Text, Tile::Treeview
Defined in:
lib/ffi-tk/command/scrollable.rb

Instance Method Summary collapse

Instance Method Details

#xscrollbar(sbar) ⇒ Object 



131
132
133
134
135
136
137
138
 
# File 'lib/ffi-tk/command/scrollable.rb', line 131

def xscrollbar(sbar)
  @xscrollbar = sbar
  @xscrollbar.orient :horizontal

  xscrollcommand { |*arg| @xscrollbar.set(*arg); true }
  @xscrollbar.command { |_action, fraction| xview_moveto(fraction) }
  @xscrollbar
end

#xscrollcommand(&block) ⇒ Object 



140
141
142
 
# File 'lib/ffi-tk/command/scrollable.rb', line 140

def xscrollcommand(&block)
  configure(xscrollcommand: block) if block
end

#xview(index = None) ⇒ Object

Returns a list containing two elements. Each element is a real fraction between 0 and 1; together they describe the portion of the document’s horizontal span that is visible in the window. For example, if the first element is .2 and the second element is .6, 20% of the text is off-screen to the left, the middle 40% is visible in the window, and 40% of the text is off-screen to the right. The fractions refer only to the lines that are actually visible in the window: if the lines in the window are all very short, so that they are entirely visible, the returned fractions will be 0 and 1, even if there are other lines in the text that are much wider than the window. These are the same values passed to scrollbars via the -xscrollcommand option.



16
17
18
19
20
21
22
 
# File 'lib/ffi-tk/command/scrollable.rb', line 16

def xview(index = None)
  if None == index
    execute(:xview).to_a(&:to_f)
  else
    execute_only(:xview, index)
  end
end

#xview_moveto(fraction) ⇒ Object

Adjusts the view in the window so that fraction of the horizontal span of the text is off-screen to the left. Fraction is a fraction between 0 and 1.



27
28
29
 
# File 'lib/ffi-tk/command/scrollable.rb', line 27

def xview_moveto(fraction)
  execute_only(:xview, :moveto, fraction)
end

#xview_scroll(number, what) ⇒ Object

This command shifts the view in the window left or right according to number and what. What must be units, pages or pixels. If what is units or pages then number must be an integer, otherwise number may be specified in any of the forms acceptable to Tk_GetPixels, such as “2.0c” or “1i” (the result is rounded to the nearest integer value. If no units are given, pixels are assumed). If what is units, the view adjusts left or right by number average-width characters on the display; if it is pages then the view adjusts by number screenfuls; if it is pixels then the view adjusts by number pixels. If number is negative then characters farther to the left become visible; if it is positive then characters farther to the right become visible.



45
46
47
 
# File 'lib/ffi-tk/command/scrollable.rb', line 45

def xview_scroll(number, what)
  execute_only(:xview, :scroll, number, what)
end

#yscrollbar(sbar) ⇒ Object 



122
123
124
125
126
127
128
129
 
# File 'lib/ffi-tk/command/scrollable.rb', line 122

def yscrollbar(sbar)
  @yscrollbar = sbar
  @yscrollbar.orient :vertical

  yscrollcommand { |*arg| @yscrollbar.set(*arg); true }
  @yscrollbar.command { |_action, fraction| yview_moveto(fraction) }
  @yscrollbar
end

#yscrollcommand(&block) ⇒ Object 



144
145
146
 
# File 'lib/ffi-tk/command/scrollable.rb', line 144

def yscrollcommand(&block)
  configure(yscrollcommand: block) if block
end

#yview(index = None) ⇒ Object

Returns a list containing two elements, both of which are real fractions between 0 and 1. The first element gives the position of the first visible pixel of the first character (or image, etc) in the top line in the window, relative to the text as a whole (0.5 means it is halfway through the text, for example). The second element gives the position of the first pixel just after the last visible one in the bottom line of the window, relative to the text as a whole. These are the same values passed to scrollbars via the -yscrollcommand option.

This command makes the first character on the line after the one given by number visible at the top of the window. Number must be an integer. This command used to be used for scrolling, but now it is obsolete.



64
65
66
67
68
69
70
 
# File 'lib/ffi-tk/command/scrollable.rb', line 64

def yview(index = None)
  if None == index
    execute(:yview).to_a(&:to_f)
  else
    execute_only(:yview, index)
  end
end

#yview_moveto(fraction) ⇒ Object

Adjusts the view in the window so that the pixel given by fraction appears at the top of the top line of the window. Fraction is a fraction between 0 and 1; 0 indicates the first pixel of the first character in the text, 0.33 indicates the pixel that is one-third the way through the text; and so on. Values close to 1 will indicate values close to the last pixel in the text (1 actually refers to one pixel beyond the last pixel), but in such cases the widget will never scroll beyond the last pixel, and so a value of 1 will effectively be rounded back to whatever fraction ensures the last pixel is at the bottom of the window, and some other pixel is at the top.



83
84
85
 
# File 'lib/ffi-tk/command/scrollable.rb', line 83

def yview_moveto(fraction)
  execute_only(:yview, :moveto, fraction)
end

#yview_pickplace(index) ⇒ Object

Changes the view in the widget’s window to make index visible.

The widget chooses where index appears in the window:

1

If index is already visible somewhere in the window then the command does nothing.

2

If index is only a few lines off-screen above the window then it will be positioned at the top of the window.

3

If index is only a few lines off-screen below the window then it will be positioned at the bottom of the window.

4

Otherwise, index will be centered in the window.

The [yview_pickplace] method has been obsoleted by the [see] method.

see

handles both x- and y-motion to make a location visible, whereas the

yview_pickplace

mode only handles motion in y).



118
119
120
 
# File 'lib/ffi-tk/command/scrollable.rb', line 118

def yview_pickplace(index)
  execute(:yview, '-pickplace', index)
end

#yview_scroll(number, what) ⇒ Object

This command adjust the view in the window up or down according to number and what. What must be units, pages or pixels. If what is units or pages then number must be an integer, otherwise number may be specified in any of the forms acceptable to Tk_GetPixels, such as “2.0c” or “1i” (the result is rounded to the nearest integer value. If no units are given, pixels are assumed). If what is units, the view adjusts up or down by number lines on the display; if it is pages then the view adjusts by number screenfuls; if it is pixels then the view adjusts by number pixels. If number is negative then earlier positions in the text become visible; if it is positive then later positions in the text become visible.



100
101
102
 
# File 'lib/ffi-tk/command/scrollable.rb', line 100

def yview_scroll(number, what)
  execute_only(:yview, :scroll, number, what)
end