Revived Fonts Viewer as an External app (in Utilities menu) (#1484)

* Add files via upload
* Moved Font Viewer to external app

firmware/application/external/font_viewer/ui_font_viewer.cpp

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2023 Mark Thompson
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "ui_font_viewer.hpp"
+
+#include "ui_font_fixed_8x16.hpp"
+#include "ui_styles.hpp"
+#include "ui_painter.hpp"
+
+#include "portapack.hpp"
+using namespace portapack;
+using namespace ui;
+
+namespace ui::external_app::font_viewer {
+
+/* DebugFontsView *******************************************************/
+
+uint16_t DebugFontsView::display_font(Painter& painter, uint16_t y_offset, const Style* font_style, std::string_view font_name) {
+    auto char_width{font_style->font.char_width()};
+    auto char_height{font_style->font.line_height()};
+    auto cpl{((screen_width / char_width) - 6) & 0xF8};  // Display a multiple of 8 characters per line
+    uint16_t line_pos{y_offset};
+
+    painter.draw_string({0, y_offset}, *font_style, font_name);
+
+    // Displaying ASCII+extended characters from 0x20 to 0xFF
+    for (uint8_t c = 0; c <= 0xDF; c++) {
+        line_pos = y_offset + ((c / cpl) + 2) * char_height;
+
+        if ((c % cpl) == 0)
+            painter.draw_string({0, line_pos}, *font_style, "Ox" + to_string_hex(c + 0x20, 2));
+
+        painter.draw_char({((c % cpl) + 5) * char_width, line_pos}, *font_style, (char)(c + 0x20));
+    }
+
+    return line_pos + char_height;
+}
+
+void DebugFontsView::paint(Painter& painter) {
+    int16_t line_pos;
+
+    line_pos = display_font(painter, 32, &Styles::white, "Fixed 8x16");
+    display_font(painter, line_pos + 16, &Styles::white_small, "Fixed 5x8");
+}
+
+DebugFontsView::DebugFontsView(NavigationView& nav)
+    : nav_{nav} {
+    set_focusable(true);
+}
+
+} /* namespace ui::external_app::font_viewer */