add QAD::VirtualKeyboard library, vkbd for widgets with JSON-based description

libs/virtual_keyboard/virtual_keyboard.cpp

@@ -0,0 +1,166 @@
+#include "virtual_keyboard.h"
+
+#include "ui_virtual_keyboard.h"
+#include "virtual_keyboard_layout.h"
+#include "virtual_keyboard_layout_page.h"
+
+#include <QFile>
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QStyle>
+#include <QStyleFactory>
+#include <pibase.h>
+#include <picout.h>
+#include <piliterals_time.h>
+
+
+VirtualKeyboard::VirtualKeyboard(QWidget * parent): QWidget(parent) {
+	ui = new Ui::VirtualKeyboard();
+	ui->setupUi(this);
+	ui->stackedPages->setStyle(QStyleFactory::create("Fusion"));
+	connect(qApp, &QApplication::focusChanged, this, [this](QWidget * old, QWidget * now) {
+		if (watched) {
+			watched->removeEventFilter(this);
+			watched = nullptr;
+		}
+		if (!now || !layout) {
+			setKeyboardVisible(false);
+			return;
+		}
+		if (!now->inputMethodQuery(Qt::ImCursorPosition).isValid()) {
+			setKeyboardVisible(false);
+			return;
+		}
+		watched  = now;
+		auto imh = Qt::InputMethodHints(watched->inputMethodQuery(Qt::ImHints).toInt());
+		layout->setDefaultPage();
+		setKeyboardVisible(true);
+		layout->applyHints(imh);
+		watched->installEventFilter(this);
+	});
+}
+
+
+VirtualKeyboard::~VirtualKeyboard() {
+	if (watched) {
+		watched->removeEventFilter(this);
+		watched = nullptr;
+	}
+	destroy();
+	delete ui;
+}
+
+
+void VirtualKeyboard::init(QString layout_path) {
+	destroy();
+	QFile f(layout_path);
+	if (!f.open(QIODevice::ReadOnly)) return;
+	QJsonDocument doc = QJsonDocument::fromJson(f.readAll());
+	layout            = new VirtualKeyboardLayout(doc.object());
+	auto pages        = layout->getPages();
+	for (auto p: pages)
+		ui->stackedPages->addWidget(p);
+	connect(layout, &VirtualKeyboardLayout::gotoPageRequest, this, [this](QString pagename) {
+		auto page = layout->getPageByName(pagename);
+		if (!page) return;
+		ui->stackedPages->setCurrentWidget(page);
+		layout->setCurrentPage(page);
+	});
+	connect(layout, &VirtualKeyboardLayout::hideRequest, this, [this]() { setKeyboardVisible(false); });
+	layout->setDefaultPage();
+	// piCout << pages.size();
+	adjust();
+}
+
+
+bool VirtualKeyboard::eventFilter(QObject * o, QEvent * e) {
+	if (e->type() == QEvent::MouseButtonPress) setKeyboardVisible(true);
+	return QWidget::eventFilter(o, e);
+}
+
+
+void VirtualKeyboard::changeEvent(QEvent * e) {
+	QWidget::changeEvent(e);
+	switch (e->type()) {
+	case QEvent::LanguageChange: ui->retranslateUi(this); break;
+	case QEvent::Show: ui->retranslateUi(this); break;
+	default: break;
+	}
+}
+
+
+void VirtualKeyboard::resizeEvent(QResizeEvent * e) {
+	if (prev_width == width()) return;
+	prev_width = width();
+	adjust();
+}
+
+
+void VirtualKeyboard::showEvent(QShowEvent * e) {
+	if (first_show) {
+		first_show = false;
+		if (layout_path_.isEmpty()) init(":/virtual_keyboard/default.json");
+	}
+	QWidget::showEvent(e);
+}
+
+
+void VirtualKeyboard::destroy() {
+	piDeleteSafety(layout);
+	while (ui->stackedPages->count() > 0)
+		delete ui->stackedPages->widget(0);
+}
+
+
+void VirtualKeyboard::adjust() {
+	if (!layout) return;
+	auto pages = layout->getPages();
+	int cols   = 0;
+	for (auto p: pages)
+		cols = piMaxi(cols, p->buttonColumns());
+	if (cols < 1) return;
+	int spacing     = style()->pixelMetric(QStyle::PM_LayoutHorizontalSpacing, nullptr, this);
+	int pixel_width = width() - spacing * (cols - 1) - ui->verticalLayout->margin() * 2;
+	int bw          = piMaxi(2, pixel_width / cols);
+	ui->stackedPages->setStyleSheet(QString("font:%1px").arg(bw / 2));
+	for (auto p: pages)
+		p->setButtonsSize(bw);
+	// piCout << cols << spacing << bw;
+}
+
+
+void VirtualKeyboard::setKeyboardVisible(bool yes) {
+	if (always_visible || !isEnabled()) return;
+	if (yes) {
+		stopIndexedTimer(0);
+		setVisible(true);
+	} else startIndexedTimer(0, 10_Hz, [this]{
+		if (QApplication::mouseButtons() != 0) return;
+		stopIndexedTimer(0);
+		setVisible(false);
+	});
+}
+
+
+void VirtualKeyboard::setLayoutPath(const QString & path) {
+	layout_path_ = path;
+	init(layout_path_);
+}
+
+
+void VirtualKeyboard::setAlwaysVisible(bool yes) {
+	always_visible = yes;
+	if (yes) show();
+}
+
+
+void VirtualKeyboard::setEnabled(bool yes) {
+	if (!yes) hide();
+	QWidget::setEnabled(yes);
+}
+
+
+void VirtualKeyboard::setDisabled(bool yes) {
+	if (yes) hide();
+	QWidget::setDisabled(yes);
+}