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-- Multi-lingual version of the first page of example 4.
-- Copyright (C) 2008 - 2011 Jerry Bauck
-- This file is part of PLplot.
-- Thanks to the following for providing translated strings for this example:
-- Valery Pipin (Russian)
-- PLplot is free software; you can redistribute it and/or modify
-- it under the terms of the GNU Library General Public License as published
-- by the Free Software Foundation; either version 2 of the License, or
-- (at your option) any later version.
-- PLplot is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU Library General Public License for more details.
-- You should have received a copy of the GNU Library General Public License
-- along with PLplot; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
-- This example designed just for devices (e.g., psttfc and the
-- cairo-related devices) that use the pango and fontconfig libraries. The
-- best choice of glyph is selected by fontconfig and automatically rendered
-- by pango in way that is sensitive to complex text layout (CTL) language
-- issues for each unicode character in this example. Of course, you must
-- have the appropriate TrueType fonts installed to have access to all the
-- required glyphs.
-- Translation instructions: The strings to be translated are given by
-- x_label, y_label, alty_label, title_label, and line_label below.-- The
-- encoding used must be UTF-8.
-- The following strings to be translated involve some scientific/mathematical
-- jargon which is now discussed further to help translators.
-- (1) dB is a decibel unit, see http://en.wikipedia.org/wiki/Decibel .
-- (2) degrees is an angular measure, see
-- http://en.wikipedia.org/wiki/Degree_(angle) .
-- (3) low-pass filter is one that transmits (passes) low frequencies.
-- (4) pole is in the mathematical sense, see
-- http://en.wikipedia.org/wiki/Pole_(complex_analysis) .-- "Single Pole"
-- means a particular mathematical transformation of the filter function has
-- a single pole, see
-- http://ccrma.stanford.edu/~jos/filters/Pole_Zero_Analysis_I.html .--
-- Furthermore, a single-pole filter must have an inverse square decline
-- (or -20 db/decade). Since the filter plotted here does have that
-- characteristic, it must by definition be a single-pole filter, see also
-- http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/1p.htm
-- (5) decade represents a factor of 10, see
-- http://en.wikipedia.org/wiki/Decade_(log_scale) .
with
Ada.Strings.Unbounded,
Ada.Numerics,
Ada.Numerics.Long_Elementary_Functions,
PLplot_Auxiliary,
PLplot_Traditional;
use
Ada.Strings.Unbounded,
Ada.Numerics,
Ada.Numerics.Long_Elementary_Functions,
PLplot_Auxiliary,
PLplot_Traditional;
procedure x26a is
-- Here we show two ways of passing strings for plot1...
-- ...a function...
--function x_label(which : Integer) return String is
--begin
-- if which = 0 then return "Frequency"; end if;
-- if which = 1 then return "Частота"; end if;
-- return "oops";
--end x_label;
-- ...or an array of unbounded strings.
-- (TUB renames Ada.Strings.Unbounded.To_Unbounded_String in plplot_traditional.ads.)
x_label : array(0 .. 1) of Unbounded_String := (TUB("Frequency"), TUB("Частота"));
function y_label(which : Integer) return String is
begin
if which = 0 then return "Amplitude (dB)"; end if;
if which = 1 then return "Амплитуда (dB)"; end if;
return "oops";
end y_label;
function alty_label(which : Integer) return String is
begin
if which = 0 then return "Phase shift (degrees)"; end if;
if which = 1 then return "Фазовый сдвиг (градусы)"; end if;
return "oops";
end alty_label;
-- Short rearranged versions of y_label and alty_label.
-- (TUB renames Ada.Strings.Unbounded.To_Unbounded_String in plplot_traditional.ads.)
Legend_0 : Legend_String_Array_Type(0..1) := (TUB("Amplitude"), TUB("Phase shift"));
Legend_1 : Legend_String_Array_Type(0..1) := (TUB("Амплитуда"), TUB("Фазовый сдвиг"));
Legend_text : array(0 .. 1) of Legend_String_Array_Type(0..1) := (Legend_0, Legend_1);
function title_label(which : Integer) return String is
begin
if which = 0 then return "Single Pole Low-Pass Filter"; end if;
if which = 1 then return "Однополюсный Низко-Частотный Фильтр"; end if;
return "oops";
end title_label;
function line_label(which : Integer) return String is
begin
if which = 0 then return "-20 dB/decade"; end if;
if which = 1 then return "-20 dB/десяток"; end if;
return "oops";
end line_label;
procedure plot1
(x_label, y_label, alty_label : String;
L_Text : Legend_String_Array_Type;
title_label, line_label : String)
is
freql, ampl, phase : Real_Vector(0 .. 100);
f0, freq : Long_Float;
opt_array : Integer_Array_1D(0 .. 1);
text_colors, line_colors, line_styles : Integer_Array_1D(0..1);
symbol_numbers, symbol_colors : Integer_Array_1D(0 .. 1);
line_widths, symbol_scales : Real_Vector(0 .. 1);
symbols : Legend_String_Array_Type(0 .. 1);
legend_width, legend_height : Long_Float;
-- Dummy arrays for unused entities. C uses null arguments but we can't.
Box_Colors, Box_Patterns : Integer_Array_1D(0 .. 1):= (others => 0);
Box_Scales, Box_Line_Widths : Real_Vector(0 .. 1):= (others => 1.0);
begin
pladv(0);
f0 := 1.0;
for i in freql'range loop
freql(i) := -2.0 + Long_Float(i) / 20.0;
freq := 10.0 ** freql(i);
ampl(i) := 20.0 * log(1.0 / sqrt(1.0 + (freq / f0) ** 2.0), 10.0);
phase(i) := -(180.0 / pi) * arctan(freq / f0);
end loop;
plvpor(0.15, 0.85, 0.1, 0.9);
plwind(-2.0, 3.0, -80.0, 0.0);
-- Try different axis and labelling styles.
plcol0(1);
plbox("bclnst", 0.0, 0, "bnstv", 0.0, 0);
-- Plot ampl vs freq
plcol0(2);
plline(freql, ampl);
plcol0(2);
plptex(1.6, -30.0, 1.0, -20.0, 0.5, line_label);
-- Put labels on
plcol0(1);
plmtex("b", 3.2, 0.5, 0.5, x_label);
plmtex("t", 2.0, 0.5, 0.5, title_label);
plcol0(2);
plmtex("l", 5.0, 0.5, 0.5, y_label);
-- For the gridless case, put phase vs freq on same plot
plcol0(1);
plwind(-2.0, 3.0, -100.0, 0.0);
plbox("", 0.0, 0, "cmstv", 30.0, 3);
plcol0(3);
plline(freql, phase);
plstring(freql, phase, "*");
plcol0(3);
plmtex("r", 5.0, 0.5, 0.5, alty_label);
-- Draw a legend
-- First legend entry.
opt_array(0) := Legend_Line;
text_colors(0) := 2;
line_colors(0) := 2;
line_styles(0) := 1;
line_widths(0) := 1.0;
symbol_colors(0) := 3; -- Don't care; not used.
symbol_scales(0) := 1.0; -- Don't care; not used.
symbol_numbers(0) := 4; -- Don't care; not used.
symbols(0) := To_Unbounded_String("*"); -- Don't care; not used.
-- Second legend entry.
opt_array(1) := Legend_Line + Legend_Symbol;
text_colors(1) := 3;
line_colors(1) := 3;
line_styles(1) := 1;
line_widths(1) := 1.0;
symbol_colors(1) := 3;
symbol_scales(1) := 1.0;
symbol_numbers(1) := 4;
symbols(1) := To_Unbounded_String("*");
plscol0a(15, 32, 32, 32, 0.70);
pllegend(legend_width, legend_height,
Legend_Background + Legend_Bounding_Box, 0,
0.0, 0.0, 0.1, 15,
1, 1, 0, 0,
opt_array,
1.0, 1.0, 2.0,
1.0, text_colors, L_Text,
Box_Colors, Box_Patterns,
Box_Scales, Box_Line_Widths,
line_colors, line_styles, line_widths,
symbol_colors, symbol_scales, symbol_numbers, symbols);
end plot1;
begin
-- Parse and process command line arguments */
plparseopts(PL_PARSE_FULL);
-- Initialize plplot
plinit;
plfont(2);
-- Make log plots using two different styles.
for i in 0 .. 1 loop
plot1(To_String(x_label(i)), y_label(i), alty_label(i), legend_text(i),
title_label(i), line_label(i));
end loop;
plend;
end x26a;
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