Greyscale bars/Display: Difference between revisions

=={{header|Eiffel}}==

[https://github.com/ljr1981/rosettacode_answers/blob/main/testing/rc_greyscale_bars/rc_greyscale_bars_test_set.e Full Example Code]

[https://github.com/ljr1981/rosettacode_answers/blob/main/testing/rc_greyscale_bars/eifgreyscale.png PNG Output]

<lang>

feature -- Test routines

rc_greyscale_bars_test

-- Greyscale bars/Display

note

testing:

"execution/isolated",

"execution/serial"

local

y: INTEGER

do

y := 0

paint_row (black, y, r1_div_count, r1_width)

y := y + row_height

paint_row (white, y, r2_div_count, r2_width)

y := y + row_height

paint_row (black, y, r3_div_count, r3_width)

y := y + row_height

paint_row (white, y, r4_div_count, r4_width)

pic.save_to_named_file (create {EV_PNG_FORMAT}, ".\testing\rc_greyscale_bars\eifgreyscale.png")

end

feature {NONE} -- Test Support

paint_row (a_init_color: REAL; a_y, r_div, r_width: INTEGER)

-- `paint_row' with rectangles from `black' to `white' or reverse.

require

valid_color: a_init_color = white or else a_init_color = black

valid_y: (<<0,row_height * 1, row_height * 2, row_height * 3>>).has (a_y)

valid_div: (<<r1_div_count, r2_div_count, r3_div_count, r4_div_count>>).has (r_div)

valid_width: (<<r1_width, r2_width, r3_width, r4_width>>).has (r_width)

local

color: REAL

x, dir: INTEGER

do

color := a_init_color

if color = white then dir := down else dir := up end

⟳ i:1 |..| r_div ¦

pic.set_foreground_color (create {EV_COLOR}.make_with_rgb (color, color, color))

pic.fill_rectangle (x, a_y, r_width, row_height)

color := color + ((1/r_div).truncated_to_real * dir)

x := x + r_width

⟲

end

feature -- Constants

pic: EV_PIXMAP

once

create Result.make_with_size (width, height)

end

width: INTEGER = 1024

height: INTEGER = 768

row_height: INTEGER once Result := (height / 4).truncated_to_integer end

r1_width: INTEGER = 128; r1_div_count: INTEGER = 8

r2_width: INTEGER = 64; r2_div_count: INTEGER = 16

r3_width: INTEGER = 32; r3_div_count: INTEGER = 32

r4_width: INTEGER = 16; r4_div_count: INTEGER = 64

black: REAL = 0.0

white: REAL = 1.0

down: INTEGER = -1

up: INTEGER = 1

</lang>