Add the character map example

Task-number: PYSIDE-841
Change-Id: I1aa30657b904d3814c21f16c2404e057e754a960
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

6 files changed, 376 insertions, 0 deletions

diff --git a/examples/widgets/widgets/charactermap/charactermap.pyproject b/examples/widgets/widgets/charactermap/charactermap.pyproject
new file mode 100644
index 000000000..c2b2c2068
--- /dev/null
+++ b/examples/widgets/widgets/charactermap/charactermap.pyproject
@@ -0,0 +1,4 @@
+{
+    "files": ["main.py", "characterwidget.py", "fontinfodialog.py",
+              "mainwindow.py"]
+}
diff --git a/examples/widgets/widgets/charactermap/characterwidget.py b/examples/widgets/widgets/charactermap/characterwidget.py
new file mode 100644
index 000000000..1df2a3b74
--- /dev/null
+++ b/examples/widgets/widgets/charactermap/characterwidget.py
@@ -0,0 +1,133 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from textwrap import dedent
+
+from PySide6.QtCore import QSize, Qt, Slot, Signal
+from PySide6.QtGui import (QBrush, QFont, QFontDatabase, QFontMetrics,
+                           QPainter, QPen)
+from PySide6.QtWidgets import QToolTip, QWidget
+
+COLUMNS = 16
+
+
+class CharacterWidget(QWidget):
+
+    character_selected = Signal(str)
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+
+        self._display_font = QFont()
+        self._last_key = -1
+        self._square_size = int(0)
+
+        self.calculate_square_size()
+        self.setMouseTracking(True)
+
+    @Slot(QFont)
+    def update_font(self, font):
+        self._display_font.setFamily(font.family())
+        self.calculate_square_size()
+        self.adjustSize()
+        self.update()
+
+    @Slot(str)
+    def update_size(self, fontSize):
+        self._display_font.setPointSize(int(fontSize))
+        self.calculate_square_size()
+        self.adjustSize()
+        self.update()
+
+    @Slot(str)
+    def update_style(self, fontStyle):
+        old_strategy = self._display_font.styleStrategy()
+        self._display_font = QFontDatabase.font(self._display_font.family(),
+                                                fontStyle,
+                                                self._display_font.pointSize())
+        self._display_font.setStyleStrategy(old_strategy)
+        self.calculate_square_size()
+        self.adjustSize()
+        self.update()
+
+    @Slot(bool)
+    def update_font_merging(self, enable):
+        if enable:
+            self._display_font.setStyleStrategy(QFont.PreferDefault)
+        else:
+            self._display_font.setStyleStrategy(QFont.NoFontMerging)
+        self.adjustSize()
+        self.update()
+
+    def calculate_square_size(self):
+        h = QFontMetrics(self._display_font, self).height()
+        self._square_size = max(16, 4 + h)
+
+    def sizeHint(self):
+        return QSize(COLUMNS * self._square_size,
+                     (65536 / COLUMNS) * self._square_size)
+
+    def _unicode_from_pos(self, point):
+        row = int(point.y() / self._square_size)
+        return row * COLUMNS + int(point.x() / self._square_size)
+
+    def mouseMoveEvent(self, event):
+        widget_position = self.mapFromGlobal(event.globalPosition().toPoint())
+        key = self._unicode_from_pos(widget_position)
+        c = chr(key)
+        family = self._display_font.family()
+        text = dedent(f'''
+                       <p>Character: <span style="font-size: 24pt; font-family: {family}">
+                       {c}</span><p>Value: 0x{key:x}
+                       ''')
+        QToolTip.showText(event.globalPosition().toPoint(), text, self)
+
+    def mousePressEvent(self, event):
+        if event.button() == Qt.LeftButton:
+            self._last_key = self._unicode_from_pos(event.position().toPoint())
+            if self._last_key != -1:
+                c = chr(self._last_key)
+                self.character_selected.emit(f"{c}")
+            self.update()
+        else:
+            super().mousePressEvent(event)
+
+    def paintEvent(self, event):
+        with QPainter(self) as painter:
+            self.render(event, painter)
+
+    def render(self, event, painter):
+        painter = QPainter(self)
+        painter.fillRect(event.rect(), QBrush(Qt.white))
+        painter.setFont(self._display_font)
+        redraw_rect = event.rect()
+        begin_row = int(redraw_rect.top() / self._square_size)
+        end_row = int(redraw_rect.bottom() / self._square_size)
+        begin_column = int(redraw_rect.left() / self._square_size)
+        end_column = int(redraw_rect.right() / self._square_size)
+        painter.setPen(QPen(Qt.gray))
+        for row in range(begin_row, end_row + 1):
+            for column in range(begin_column, end_column + 1):
+                x = int(column * self._square_size)
+                y = int(row * self._square_size)
+                painter.drawRect(x, y, self._square_size, self._square_size)
+
+        font_metrics = QFontMetrics(self._display_font)
+        painter.setPen(QPen(Qt.black))
+        for row in range(begin_row, end_row + 1):
+            for column in range(begin_column, end_column + 1):
+                key = int(row * COLUMNS + column)
+                painter.setClipRect(column * self._square_size,
+                                    row * self._square_size,
+                                    self._square_size, self._square_size)
+
+                if key == self._last_key:
+                    painter.fillRect(column * self._square_size + 1,
+                                     row * self._square_size + 1,
+                                     self._square_size, self._square_size, QBrush(Qt.red))
+
+                text = chr(key)
+                painter.drawText(column * self._square_size + (self._square_size / 2) -
+                                 font_metrics.horizontalAdvance(text) / 2,
+                                 row * self._square_size + 4 + font_metrics.ascent(),
+                                 text)
diff --git a/examples/widgets/widgets/charactermap/doc/charactermap.rst b/examples/widgets/widgets/charactermap/doc/charactermap.rst
new file mode 100644
index 000000000..1a38615c4
--- /dev/null
+++ b/examples/widgets/widgets/charactermap/doc/charactermap.rst
@@ -0,0 +1,8 @@
+Character Map Example
+=====================
+
+The example displays an array of characters which the user can click on
+to enter text in a line edit. The contents of the line edit can then be
+copied into the clipboard, and pasted into other applications. The
+purpose behind this sort of tool is to allow users to enter characters
+that may be unavailable or difficult to locate on their keyboards.
diff --git a/examples/widgets/widgets/charactermap/fontinfodialog.py b/examples/widgets/widgets/charactermap/fontinfodialog.py
new file mode 100644
index 000000000..aa874884f
--- /dev/null
+++ b/examples/widgets/widgets/charactermap/fontinfodialog.py
@@ -0,0 +1,47 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from PySide6.QtCore import Qt, qVersion, qFuzzyCompare
+from PySide6.QtGui import QGuiApplication, QFontDatabase
+from PySide6.QtWidgets import (QDialog, QDialogButtonBox,
+                               QPlainTextEdit, QVBoxLayout)
+
+
+def _format_font(font):
+    family = font.family()
+    size = font.pointSizeF()
+    return f"{family}, {size}pt"
+
+
+class FontInfoDialog(QDialog):
+
+    def __init__(self, parent):
+        super().__init__(parent)
+        self.setWindowFlags(self.windowFlags() & ~Qt.WindowContextHelpButtonHint)
+        main_layout = QVBoxLayout(self)
+        text_edit = QPlainTextEdit(self.text(), self)
+        text_edit.setReadOnly(True)
+        text_edit.setFont(QFontDatabase.systemFont(QFontDatabase.FixedFont))
+        main_layout.addWidget(text_edit)
+        button_box = QDialogButtonBox(QDialogButtonBox.Close, self)
+        button_box.rejected.connect(self.reject)
+        main_layout.addWidget(button_box)
+
+    def text(self):
+        default_font = QFontDatabase.systemFont(QFontDatabase.GeneralFont)
+        fixed_font = QFontDatabase.systemFont(QFontDatabase.FixedFont)
+        title_font = QFontDatabase.systemFont(QFontDatabase.TitleFont)
+        smallest_readable_font = QFontDatabase.systemFont(QFontDatabase.SmallestReadableFont)
+
+        v = qVersion()
+        platform = QGuiApplication.platformName()
+        dpi = self.logicalDpiX()
+        dpr = self.devicePixelRatio()
+        text = f"Qt {v} on {platform}, {dpi}DPI"
+        if not qFuzzyCompare(dpr, float(1)):
+            text += f", device pixel ratio: {dpr}"
+        text += ("\n\nDefault font : " + _format_font(default_font)
+                 + "\nFixed font : " + _format_font(fixed_font)
+                 + "\nTitle font : " + _format_font(title_font)
+                 + "\nSmallest font: " + _format_font(smallest_readable_font))
+        return text
diff --git a/examples/widgets/widgets/charactermap/main.py b/examples/widgets/widgets/charactermap/main.py
new file mode 100644
index 000000000..e84a1d8af
--- /dev/null
+++ b/examples/widgets/widgets/charactermap/main.py
@@ -0,0 +1,17 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+import sys
+
+from PySide6.QtWidgets import QApplication
+
+from mainwindow import MainWindow
+
+"""PySide6 port of the widgets/widgets/ charactermap example from Qt6"""
+
+
+if __name__ == "__main__":
+    app = QApplication(sys.argv)
+    window = MainWindow()
+    window.show()
+    sys.exit(app.exec())
diff --git a/examples/widgets/widgets/charactermap/mainwindow.py b/examples/widgets/widgets/charactermap/mainwindow.py
new file mode 100644
index 000000000..5f0e2bce4
--- /dev/null
+++ b/examples/widgets/widgets/charactermap/mainwindow.py
@@ -0,0 +1,167 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from PySide6.QtCore import Qt, QSignalBlocker, Slot
+from PySide6.QtGui import QGuiApplication, QClipboard, QFont, QFontDatabase
+from PySide6.QtWidgets import (QCheckBox, QComboBox, QFontComboBox,
+                               QHBoxLayout, QLabel, QLineEdit, QMainWindow,
+                               QPushButton, QScrollArea,
+                               QVBoxLayout, QWidget)
+
+from characterwidget import CharacterWidget
+from fontinfodialog import FontInfoDialog
+
+
+class MainWindow(QMainWindow):
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+
+        self._character_widget = CharacterWidget()
+        self._filter_combo = QComboBox()
+        self._style_combo = QComboBox()
+        self._size_combo = QComboBox()
+        self._font_combo = QFontComboBox()
+        self._line_edit = QLineEdit()
+        self._scroll_area = QScrollArea()
+        self._font_merging = QCheckBox()
+
+        file_menu = self.menuBar().addMenu("File")
+        file_menu.addAction("Quit", self.close)
+        help_menu = self.menuBar().addMenu("Help")
+        help_menu.addAction("Show Font Info", self.show_info)
+        help_menu.addAction("About &Qt", qApp.aboutQt)
+
+        central_widget = QWidget()
+
+        self._filter_label = QLabel("Filter:")
+        self._filter_combo = QComboBox()
+        self._filter_combo.addItem("All", int(QFontComboBox.AllFonts.value))
+        self._filter_combo.addItem("Scalable", int(QFontComboBox.ScalableFonts.value))
+        self._filter_combo.addItem("Monospaced", int(QFontComboBox.MonospacedFonts.value))
+        self._filter_combo.addItem("Proportional", int(QFontComboBox.ProportionalFonts.value))
+        self._filter_combo.setCurrentIndex(0)
+        self._filter_combo.currentIndexChanged.connect(self.filter_changed)
+
+        self._font_label = QLabel("Font:")
+        self._font_combo = QFontComboBox()
+        self._size_label = QLabel("Size:")
+        self._size_combo = QComboBox()
+        self._style_label = QLabel("Style:")
+        self._style_combo = QComboBox()
+        self._font_merging_label = QLabel("Automatic Font Merging:")
+        self._font_merging = QCheckBox()
+        self._font_merging.setChecked(True)
+
+        self._scroll_area = QScrollArea()
+        self._character_widget = CharacterWidget()
+        self._scroll_area.setWidget(self._character_widget)
+        self.find_styles(self._font_combo.currentFont())
+        self.find_sizes(self._font_combo.currentFont())
+
+        self._line_edit = QLineEdit()
+        self._line_edit.setClearButtonEnabled(True)
+        self._clipboard_button = QPushButton("To clipboard")
+        self._font_combo.currentFontChanged.connect(self.find_styles)
+        self._font_combo.currentFontChanged.connect(self.find_sizes)
+        self._font_combo.currentFontChanged.connect(self._character_widget.update_font)
+        self._size_combo.currentTextChanged.connect(self._character_widget.update_size)
+        self._style_combo.currentTextChanged.connect(self._character_widget.update_style)
+        self._character_widget.character_selected.connect(self.insert_character)
+
+        self._clipboard_button.clicked.connect(self.update_clipboard)
+        self._font_merging.toggled.connect(self._character_widget.update_font_merging)
+
+        controls_layout = QHBoxLayout()
+        controls_layout.addWidget(self._filter_label)
+        controls_layout.addWidget(self._filter_combo, 1)
+        controls_layout.addWidget(self._font_label)
+        controls_layout.addWidget(self._font_combo, 1)
+        controls_layout.addWidget(self._size_label)
+        controls_layout.addWidget(self._size_combo, 1)
+        controls_layout.addWidget(self._style_label)
+        controls_layout.addWidget(self._style_combo, 1)
+        controls_layout.addWidget(self._font_merging_label)
+        controls_layout.addWidget(self._font_merging, 1)
+        controls_layout.addStretch(1)
+
+        line_layout = QHBoxLayout()
+        line_layout.addWidget(self._line_edit, 1)
+        line_layout.addSpacing(12)
+        line_layout.addWidget(self._clipboard_button)
+
+        central_layout = QVBoxLayout(central_widget)
+        central_layout.addLayout(controls_layout)
+        central_layout.addWidget(self._scroll_area, 1)
+        central_layout.addSpacing(4)
+        central_layout.addLayout(line_layout)
+
+        self.setCentralWidget(central_widget)
+        self.setWindowTitle("Character Map")
+
+    @Slot(QFont)
+    def find_styles(self, font):
+        current_item = self._style_combo.currentText()
+        self._style_combo.clear()
+        styles = QFontDatabase.styles(font.family())
+        for style in styles:
+            self._style_combo.addItem(style)
+
+        style_index = self._style_combo.findText(current_item)
+
+        if style_index == -1:
+            self._style_combo.setCurrentIndex(0)
+        else:
+            self._style_combo.setCurrentIndex(style_index)
+
+    @Slot(int)
+    def filter_changed(self, f):
+        filter = QFontComboBox.FontFilter(self._filter_combo.itemData(f))
+        self._font_combo.setFontFilters(filter)
+        count = self._font_combo.count()
+        self.statusBar().showMessage(f"{count} font(s) found")
+
+    @Slot(QFont)
+    def find_sizes(self, font):
+        current_size = self._size_combo.currentText()
+        with QSignalBlocker(self._size_combo):
+            # sizeCombo signals are now blocked until end of scope
+            self._size_combo.clear()
+
+            style = QFontDatabase.styleString(font)
+            if QFontDatabase.isSmoothlyScalable(font.family(), style):
+                sizes = QFontDatabase.standardSizes()
+                for size in sizes:
+                    self._size_combo.addItem(f"{size}")
+                    self._size_combo.setEditable(True)
+            else:
+                sizes = QFontDatabase.smoothSizes(font.family(), style)
+                for size in sizes:
+                    self._size_combo.addItem(f"{size}")
+                    self._size_combo.setEditable(False)
+
+        size_index = self._size_combo.findText(current_size)
+
+        if size_index == -1:
+            self._size_combo.setCurrentIndex(max(0, self._size_combo.count() / 3))
+        else:
+            self._size_combo.setCurrentIndex(size_index)
+
+    @Slot(str)
+    def insert_character(self, character):
+        self._line_edit.insert(character)
+
+    @Slot()
+    def update_clipboard(self):
+        clipboard = QGuiApplication.clipboard()
+        clipboard.setText(self._line_edit.text(), QClipboard.Clipboard)
+        clipboard.setText(self._line_edit.text(), QClipboard.Selection)
+
+    @Slot()
+    def show_info(self):
+        screen_geometry = self.screen().geometry()
+        dialog = FontInfoDialog(self)
+        dialog.setWindowTitle("Fonts")
+        dialog.setAttribute(Qt.WA_DeleteOnClose)
+        dialog.resize(screen_geometry.width() / 4, screen_geometry.height() / 4)
+        dialog.show()