inputfieldsandbuttons.C

/*
** Copyright 2017-2021 Double Precision, Inc.
** See COPYING for distribution information.
*/

#include "config.h"
#include "close_flag.H"

#include <x/exception.H>
#include <x/destroy_callback.H>
#include <x/appid.H>
#include <x/w/main_window.H>
#include <x/w/gridlayoutmanager.H>
#include <x/w/gridfactory.H>
#include <x/w/label.H>
#include <x/w/text_param_literals.H>
#include <x/w/font_literals.H>
#include <x/w/input_field.H>
#include <x/w/container.H>
#include <x/w/canvas.H>
#include <x/w/button.H>
#include <x/w/shortcut.H>

#include <string>
#include <iostream>

std::string x::appid() noexcept
{
	return "inputfieldsandbuttons.examples.w.libcxx.com";
}

// inputfields.inc.H is autogenerated from inputfields.xml

#include <x/refptr_traits.H>
#include "inputfields.inc.H"

// inputfields gets installed in main_window->appdata, below.

class appdataObj : virtual public x::obj,
		   public inputfields {
public:

	using inputfields::inputfields;
};

typedef x::ref<appdataObj> appdata_t;

// This is the creator lambda, that gets passed to create_mainwindow() below,
// factored out for readability.

void create_mainwindow(const x::w::main_window &main_window,
		       const close_flag_ref &close_flag)
{
	// Each display element contains an optional 'appdata', a
	// generic LibCXX object, an x::ptr<x::obj>, that the library ignores,
	// and is for application to use.
	//
	// This can be a convenient place to store all display elements that
	// get created in the main application window.
	//
	// As discussed in the library's documentation, parent display
	// elements own references to their child display element, and
	// this main_window is the topmost display elements, so it's a
	// logical place to store all display elements for the application
	// to quickly reference.
	//
	// Using some innermost display element to store references to parent
	// display elements creates a circular reference, which will interfere
	// with LibCXX's object model anyway.
	//
	// We're going to use some framework templates and classes from the
	// LibCXX base class library.
	//
	// inputfields.inc.H gets generated from inputfields.xml by the
	// Makefile, and included above, and declares an inputfieldsptr class
	// containing ptrs to our input_fields, which we can install at our
	// leisure.

	inputfieldsptr new_inputfields;

	auto layout=main_window->gridlayout();

	// The main window's grid will have two columns. The first column
	// in each row will have a label, the second column will have a
	// text input field.

	// The labels will be aligned against the right margin of the
	// first column, to make them flush to the input field.

	// First row in the main window contains a label and an input field.

	x::w::gridfactory factory=layout->append_row();

	// Besides the right alignment, set the vertical alignment of the
	// label to middle, it looks better.

	factory->halign(x::w::halign::right)
		.valign(x::w::valign::middle)
		.create_label({"Subject:"});

	// And just in case we have some weird theme where the input field
	// is shorter in height than the label, align it vertically also.

	// The input fields initial contents are empty, and it is size to
	// be 30 columns.
	auto subject_field=factory->valign(x::w::valign::middle)
		.create_input_field("", {30});

	// Give the subject field a tooltip.

	subject_field->create_tooltip("A brief title");

	// Save it in new_inputfields

	new_inputfields.subject=subject_field;

	// Second row in the main window

	factory=layout->append_row();

	// It doesn't look like we need to vertically align either the label
	// or the column.
	factory->halign(x::w::halign::right).create_label({"Text:"});

	// That's because the second row's input field will have 30 columns
	// and four rows.
	//
	// Also, let's make the input field use a non-default, proportional
	// font, and set its initial contents to "Hello".
	//
	// The first parameter to create_input_field() is an x::w::text_param
	// that can specify the input field's font.

	auto text_field=factory->create_input_field({"arial"_font,
				"Hello,\n\n"},
		{30, 4});

	// The tooltip for the text field. Slightly longer tooltip, word
	// wrap it to 30 mm width.

	x::w::label_config tooltip_label_config;

	tooltip_label_config.widthmm=30;

	text_field->create_tooltip("A brief message, a few lines long.",
				   tooltip_label_config);

	// Save it in new_inputfields

	new_inputfields.text=text_field;

	// The third row of the main window will have all the buttons.
	//
	// First, create a nested container, which will span both columns,
	// and also use the grid layout manager.

	factory=layout->append_row();

	// Give the container some extra padding on the top.
	factory->top_padding(3.0)
		// Span it across both columns
		.colspan(2)
		.create_container
		([&]
		 (const auto &container)
		 {
			 // Get the grid layout manager for the container.

			 auto layout=container->gridlayout();
			 auto factory=layout->append_row();

			 // Cancel button, on the beginning of the row.

			 auto cancel=factory->create_button
				 ({"Cancel"},

				  // Button options:
				  //
				  // Esc key for a shortcut
				  x::w::shortcut{'\e'});

			 // Next to it is a "Reset" button, with an
			 // underlined "R", with an "Alt"-R shortcut.
			 // "R" can be specified in upper or lowercase.

			 auto reset=factory->create_button
				 ({"underline"_decoration,
				   "R",
				   "no"_decoration,
				   "eset"},

					 // Button options, keyboard shortcut.

					 x::w::shortcut{"Alt",'R'});

			 // Add empty space here, between the buttons.
			 // By default, create_canvas() creates a canvas
			 // that specifies 0 for its minimum and preferred
			 // size, with the maximum size unspecified (effectively
			 // infinite.
			 //
			 // This allows the grid layout manager to
			 // size the canvas spacer to fill the entire width
			 // of the edit button row.
			 //
			 // There's also a create_canvas() that takes a
			 // creator lambda, and explicit metrics specifications
			 // as parameters, for implementing more nuanced
			 // spacing.

			 factory->create_canvas();

			 // The "Ok" button at the end of the row.

			 // An alternative overload of create_button()
			 // takes a generic callable object as the first
			 // parameter instead of a label.

			 auto ok=factory->create_button
				 ([]
				  (const x::w::factory &f)
				  {
					  // The callable object uses the
					  // factory parameter that it
					  // receives as its own parameter
					  // (and not the factory that's
					  // creating the button itself).
					  //
					  // The callable object uses this
					  // factory to create the display
					  // element that becomes the button's
					  // contents. This can be a container
					  // with many display elements.
					  //
					  // Using create_label() is equivalent
					  // to using create_button() directly
					  // with a text string:

					  auto l=f->create_label("Ok");

					  // As with any other display element,
					  // it must be show()n to be visible.
					  l->show();
				  },
				  // Two options for this button. The second
				  // parameter to create_button() is an
				  // variadic template for all needed options,
				  // that must be passed in as a single
				  // parameter, in the listed order, see the
				  // documentation.
				  //
				  // Uniform initialization syntax is the
				  // easiest way to go:
				  {
					  // Thicker border, visual indication
					  // of a default button.
					  x::w::default_button(),
					  // Enter key for a shortcut
					  x::w::shortcut{'\n'}
				  });

			 // Specify what happens when the buttons get
			 // activated.

			 cancel->on_activate([close_flag]
					     (ONLY IN_THREAD,
					      const x::w::callback_trigger_t &trigger,
					      const x::w::busy &ignore)
					     {
						     std::cout << "Cancel"
							       << std::endl;

						     close_flag->close();
					     });

			 // Note that the Reset button's callback captures
			 // the input field object by value. This is ok,
			 // the input fields are not parent display elements
			 // of the Reset button. When the main window gets
			 // destroyed, the main window object drops its
			 // references to its display elements, including
			 // the Reset button, which then drops its reference
			 // on the input field elements, which allows them
			 // to be destroyed.

			 reset->on_activate([text_field, subject_field]
					    (ONLY IN_THREAD,
					     const x::w::callback_trigger_t &trigger,
					     const x::w::busy &ignore)
					    {
						    text_field->set("");
						    subject_field->set("");
					    });

			 ok->on_activate([close_flag]
					 (ONLY IN_THREAD,
					  const x::w::callback_trigger_t &trigger,
					  const x::w::busy &ignore)
					 {
						 std::cout << "Ok"
							   << std::endl;

						 close_flag->close();
					 });
		 },
		 x::w::new_gridlayoutmanager());

	// Now that our fields have been saved in new_inputfields, we can
	// construct an ref<obj> out of them, and attach them to main_window's
	// appdata.
	//
	// This create_mainwindow() is, after all, main_window's creator, so
	// this is a part of our mission statement.

	main_window->appdata=appdata_t::create(new_inputfields);
}

void inputfieldsandbuttons()
{
	x::destroy_callback::base::guard guard;

	auto close_flag=close_flag_ref::create();

	auto main_window=
		x::w::main_window::create([&]
					  (const auto &main_window)
					  {
						  create_mainwindow(main_window,
								    close_flag);
					  });

	main_window->on_disconnect([]
				   {
					   _exit(1);
				   });

	guard(main_window->connection_mcguffin());

	main_window->set_window_title("Enter a message");
	main_window->on_delete
		([close_flag]
		 (ONLY IN_THREAD,
		  const x::w::busy &ignore)
		 {
			 close_flag->close();
		 });

	main_window->show_all();

	close_flag->wait();

	// Retrieve the appdata_t, with our fields, that the creator attached
	// to the main_window.

	appdata_t appdata=main_window->appdata;

	// Retrieve each input_field, and get() its contents.

	// Each input_field must be locked, first:

	x::w::input_lock subject_lock{appdata->subject};
	x::w::input_lock text_lock{appdata->text};

	std::cout << "Subject ("
		  << subject_lock.size()
		  << " character): " << subject_lock.get() << std::endl
		  << std::endl << text_lock.get();

	// Normally it's possible that a character gets typed after
	// size() returns, and before get() gets called, hence the
	// get() would return a shorter or a smaller string (let's ignore
	// for the moment that size() returns unicode character count,
	// and get() returns UTF-8).
	//
	// However, the input_lock blocks the internal library execution
	// thread from accessing the contents of the field, so that can't
	// happen.
}

int main(int argc, char **argv)
{
	try {
		inputfieldsandbuttons();
	} catch (const x::exception &e)
	{
		e->caught();
		exit(1);
	}
	return 0;
}