Added Unicode Boxes unittest and README-unittests.txt

This test helps check for issues with multiline widgets
drawing text properly.

The README-unittests.txt was added to help developers
add new unit tests easily.

1 files changed, 106 insertions, 0 deletions

diff --git a/test/unittest_unicode.cxx b/test/unittest_unicode.cxx
new file mode 100644
index 000000000..65cec32e5
--- /dev/null
+++ b/test/unittest_unicode.cxx
@@ -0,0 +1,106 @@
+//
+// Unit tests for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 1998-2022 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please see the following page on how to report bugs and issues:
+//
+//     https://www.fltk.org/bugs.php
+//
+
+#include "unittests.h"
+
+#include <FL/Fl.H>
+#include <FL/Fl_Group.H>
+#include <FL/Fl_Text_Display.H>
+#include <FL/Fl_Multiline_Input.H>
+#include <FL/Fl_Choice.H>
+#include <FL/Fl_Hor_Value_Slider.H>
+#include <FL/fl_draw.H>
+
+#include "unittest_unicode_utf8.h"      // defines utf8_box_test[]
+static const char *helptext =
+  "In this test, ideally the box's lines should all be touching "
+  "without white space between. Underbar and overbars should both "
+  "be visible and not touching. All the above should be unaffected "
+  "by different font sizes and font settings.";
+
+
+class UnicodeBoxTest : public Fl_Group {
+  Fl_Text_Buffer      *textbuffer;
+  Fl_Text_Display     *textdisplay;
+  Fl_Multiline_Input  *multilineinput;
+  Fl_Choice           *font_choice;
+  Fl_Hor_Value_Slider *fontsize_slider;
+
+  // Font choice callback
+  void FontChoice_CB2() {
+    switch ( font_choice->value() ) {
+      case 0: textdisplay->textfont(FL_COURIER); break;
+      case 1: textdisplay->textfont(FL_SCREEN); break;
+    }
+    parent()->redraw();
+  }
+  static void FontChoice_CB(Fl_Widget*, void *userdata) {
+    UnicodeBoxTest *o = (UnicodeBoxTest*)userdata;
+    o->FontChoice_CB2();
+  }
+
+  // Slider callback - apply new font size to widgets
+  void FontSizeSlider_CB2() {
+    // Get font size from slider value, apply to widgets
+    int fontsize = (int)fontsize_slider->value();
+    textdisplay->textsize(fontsize);
+    multilineinput->textsize(fontsize);
+    multilineinput->position(0);                // keep scrolled to top
+    parent()->redraw();
+  }
+  static void FontSizeSlider_CB(Fl_Widget*, void *userdata) {
+    UnicodeBoxTest *o = (UnicodeBoxTest*)userdata;
+    o->FontSizeSlider_CB2();
+  }
+
+public:
+  static Fl_Widget *create() {
+    return new UnicodeBoxTest(TESTAREA_X, TESTAREA_Y, TESTAREA_W, TESTAREA_H);
+  }
+
+  UnicodeBoxTest(int x, int y, int w, int h) : Fl_Group(x, y, w, h) {
+    // Fl_Text_Display
+    textbuffer = new Fl_Text_Buffer();
+    textbuffer->text(utf8_box_test);
+    textdisplay = new Fl_Text_Display(x+5, y+20, 250, 250, "Fl_Text_Display");
+    textdisplay->textfont(FL_COURIER);
+    textdisplay->buffer(textbuffer);
+    textdisplay->tooltip(helptext);
+    // Fl_Multiline_Input
+    multilineinput = new Fl_Multiline_Input(x+250+15, y+20, 250, 250, "Fl_Multiline_Input");
+    multilineinput->align(FL_ALIGN_CENTER|FL_ALIGN_TOP);
+    multilineinput->textfont(FL_COURIER);
+    multilineinput->value(utf8_box_test);
+    multilineinput->tooltip(helptext);
+    // Font choice
+    //    Fonts must be fixed width to work correctly..
+    font_choice = new Fl_Choice(x+150, y+h-80, 200, 25, "Font face");
+    font_choice->add("FL_COURIER");
+    font_choice->add("FL_SCREEN");
+    font_choice->value(0);
+    font_choice->callback(FontChoice_CB, (Fl_Widget*)this);
+    // Font size slider
+    fontsize_slider = new Fl_Hor_Value_Slider(x+150, y+h-50, 200, 25, "Font size");
+    fontsize_slider->align(FL_ALIGN_LEFT);
+    fontsize_slider->range(1.0, 50.0);
+    fontsize_slider->step(1.0);
+    fontsize_slider->value(14.0);
+    fontsize_slider->callback(FontSizeSlider_CB, (Fl_Widget*)this);
+    end();
+  }
+};
+
+UnitTest unicode_font_test(kUnicodeBoxTest, "Unicode Boxes", UnicodeBoxTest::create);