class interface WINDOW_SCROLLBAR
feature(s) from SCROLLBAR
-- Type of scrollbar
is_horizontal: BOOLEAN
-- Is this scrollbar horizontal?
ensure
coherent: is_vertical = not is_horizontal
is_vertical: BOOLEAN
-- Is this scrollbar vertical?
ensure
coherent: is_vertical = not is_horizontal
feature(s) from SCROLLBAR
-- Range & conversion from/to ratios
Default_range: INTEGER
range: INTEGER
-- Slider position range.
set_range (rg: INTEGER)
-- Set slider position range.
ensure
ok: -- range = rg unless recursive size change
is_valid_range (r: INTEGER): BOOLEAN
-- Is the given range valid?
ensure
done: -- Result implies (r >= 1 and Result <= range)
units_to_ratio (unit: INTEGER): DOUBLE
-- Convert from 1-(INTEGER) to 0-1 (DOUBLE)
require
valid_range: is_valid_range(unit)
ensure
good_ratio: Result >= 0 and then Result <= 1
ratio_to_units (ratio: DOUBLE): INTEGER
-- Convert from 0-1 (DOUBLE) to 1-(INTEGER).
require
good_ratio: ratio >= 0 and then ratio <= 1
ensure
valid_range: is_valid_range(Result)
feature(s) from SCROLLBAR
-- Steppings
line_step: INTEGER
-- Step to go when line up/down.
page_step: INTEGER
-- Step to go when page up/down.
set_line_step (rg: INTEGER)
-- Set line_step.
require
positive: rg >= 0
set_page_step (rg: INTEGER)
-- Set page_step.
require
positive: rg >= 0
feature(s) from SCROLLBAR
-- Slider position and size
slider_size: INTEGER
-- Size of the slider.
set_slider_size (s: INTEGER)
-- Set the size of the slider.
require
correct_size: is_valid_range(s)
ensure
size_set: slider_size = s
slider_position: INTEGER
-- Slider position range.
ensure
is_valid_range(Result)
set_slider_position (pos: INTEGER)
-- Set slider position range.
require
correct_pos: is_valid_range(pos)
ensure
pos_set: pos = slider_position
feature(s) from SCROLLBAR
-- Event support
tracked: BOOLEAN
-- Is the mouse cursor currently moving slider
feature(s) from SCROLLBAR
-- Command
set_command (gc: GUI_COMMAND)
-- Set when_slider_moved command.
require
nothing: -- Void is no command
invariant
valid_dir: is_horizontal xor is_vertical;
end of WINDOW_SCROLLBAR