Terminal: Rewrite rendering

The rendering has been rewritten to use cached GlyphRuns instead of text layouts. The VTerm specific code was moved into TerminalSurface. Change-Id: I10caa3db4ee932414987c9ddae2dcb777dc1f6e7 Reviewed-by: Cristian Adam <cristian.adam@qt.io> Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
2023-03-03 17:18:56 +01:00
parent bb4d9c92e7
commit 098c76832a
18 changed files with 1592 additions and 800 deletions
--- a/src/libs/3rdparty/libvterm/include/vterm.h
+++ b/src/libs/3rdparty/libvterm/include/vterm.h
@@ -496,7 +496,7 @@ void vterm_state_send_selection(VTermState *state, VTermSelectionMask mask, VTer

 typedef struct {
    unsigned int bold      : 1;
-    unsigned int underline : 2;
+    unsigned int underline : 3;
    unsigned int italic    : 1;
    unsigned int blink     : 1;
    unsigned int reverse   : 1;
@@ -514,6 +514,8 @@ enum {
  VTERM_UNDERLINE_SINGLE,
  VTERM_UNDERLINE_DOUBLE,
  VTERM_UNDERLINE_CURLY,
+  VTERM_UNDERLINE_DOTTED,
+  VTERM_UNDERLINE_DASHED
 };

 enum {
--- a/src/libs/3rdparty/libvterm/src/pen.c
+++ b/src/libs/3rdparty/libvterm/src/pen.c
@@ -323,6 +323,12 @@ INTERNAL void vterm_state_setpen(VTermState *state, const long args[], int argco
          case 3:
            state->pen.underline = VTERM_UNDERLINE_CURLY;
            break;
+          case 4:
+            state->pen.underline = VTERM_UNDERLINE_DOTTED;
+            break;
+          case 5:
+            state->pen.underline = VTERM_UNDERLINE_DASHED;
+            break;
        }
      }
      setpenattr_int(state, VTERM_ATTR_UNDERLINE, state->pen.underline);
--- a/src/libs/3rdparty/libvterm/src/screen.c
+++ b/src/libs/3rdparty/libvterm/src/screen.c
@@ -18,7 +18,7 @@ typedef struct
  VTermColor   fg, bg;

  unsigned int bold      : 1;
-  unsigned int underline : 2;
+  unsigned int underline : 3;
  unsigned int italic    : 1;
  unsigned int blink     : 1;
  unsigned int reverse   : 1;
--- a/src/libs/3rdparty/libvterm/src/vterm_internal.h
+++ b/src/libs/3rdparty/libvterm/src/vterm_internal.h
@@ -41,7 +41,7 @@ struct VTermPen
  VTermColor fg;
  VTermColor bg;
  unsigned int bold:1;
-  unsigned int underline:2;
+  unsigned int underline:3;
  unsigned int italic:1;
  unsigned int blink:1;
  unsigned int reverse:1;
--- a/src/plugins/terminal/CMakeLists.txt
+++ b/src/plugins/terminal/CMakeLists.txt
@@ -3,16 +3,18 @@ add_qtc_plugin(Terminal
  PLUGIN_DEPENDS Core
  DEPENDS libvterm
  SOURCES
-    celllayout.cpp celllayout.h
+    celliterator.cpp celliterator.h
+    glyphcache.cpp glyphcache.h
+    keys.cpp keys.h
+    scrollback.cpp scrollback.h
+    shellmodel.cpp shellmodel.h
    terminal.qrc
-    terminalplugin.cpp terminalplugin.h
-    terminaltr.h
    terminalpane.cpp terminalpane.h
-    terminalwidget.cpp terminalwidget.h
+    terminalplugin.cpp terminalplugin.h
    terminalprocessinterface.cpp terminalprocessinterface.h
    terminalsettings.cpp terminalsettings.h
    terminalsettingspage.cpp terminalsettingspage.h
-    scrollback.h scrollback.cpp
-    shellmodel.cpp shellmodel.h
-    keys.cpp keys.h
+    terminalsurface.cpp terminalsurface.h
+    terminaltr.h
+    terminalwidget.cpp terminalwidget.h
 )
--- a/src/plugins/terminal/celliterator.cpp
+++ b/src/plugins/terminal/celliterator.cpp
@@ -0,0 +1,89 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#include "celliterator.h"
+
+#include "terminalsurface.h"
+
+#include <stdexcept>
+
+namespace Terminal::Internal {
+
+CellIterator::CellIterator(const TerminalSurface *surface, QPoint pos)
+    : m_state(State::INSIDE)
+    , m_surface(surface)
+{
+    m_pos = (pos.x()) + (pos.y() * surface->liveSize().width());
+    m_maxpos = surface->fullSize().width() * (surface->fullSize().height()) - 1;
+    updateChar();
+}
+
+CellIterator::CellIterator(const TerminalSurface *surface, int pos)
+    : m_state(State::INSIDE)
+    , m_surface(surface)
+{
+    m_pos = pos;
+    m_maxpos = surface->fullSize().width() * (surface->fullSize().height()) - 1;
+    updateChar();
+}
+
+CellIterator::CellIterator(const TerminalSurface *surface, State state)
+    : m_state(state)
+    , m_surface(surface)
+    , m_pos()
+{
+    m_maxpos = surface->fullSize().width() * (surface->fullSize().height()) - 1;
+    if (state == State::END) {
+        m_pos = m_maxpos + 1;
+    }
+}
+
+QPoint CellIterator::gridPos() const
+{
+    return m_surface->posToGrid(m_pos);
+}
+
+void CellIterator::updateChar()
+{
+    QPoint cell = m_surface->posToGrid(m_pos);
+    m_char = m_surface->fetchCharAt(cell.x(), cell.y());
+    if (m_char == 0)
+        m_char = U' ';
+}
+
+CellIterator &CellIterator::operator-=(int n)
+{
+    if (n == 0)
+        return *this;
+
+    if (m_pos - n < 0)
+        throw new std::runtime_error("-= n too big!");
+
+    m_pos -= n;
+    updateChar();
+
+    m_state = State::INSIDE;
+
+    if (m_pos == 0) {
+        m_state = State::BEGIN;
+    }
+
+    return *this;
+}
+
+CellIterator &CellIterator::operator+=(int n)
+{
+    if (n == 0)
+        return *this;
+
+    if (m_pos + n < m_maxpos) {
+        m_state = State::INSIDE;
+        m_pos += n;
+        updateChar();
+    } else {
+        *this = m_surface->end();
+    }
+    return *this;
+}
+
+} // namespace Terminal::Internal
--- a/src/plugins/terminal/celliterator.h
+++ b/src/plugins/terminal/celliterator.h
@@ -0,0 +1,95 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include <string>
+
+#include <QPoint>
+
+namespace Terminal::Internal {
+
+class TerminalSurface;
+
+class CellIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using difference_type = std::ptrdiff_t;
+    using value_type = std::u32string::value_type;
+    using pointer = std::u32string::value_type *;
+    // We need to return copies for std::reverse_iterator to work
+    using reference = std::u32string::value_type;
+
+    enum class State { BEGIN, INSIDE, END } m_state{};
+
+public:
+    CellIterator(const TerminalSurface *surface, QPoint pos);
+    CellIterator(const TerminalSurface *surface, int pos);
+    CellIterator(const TerminalSurface *surface, State state);
+
+public:
+    QPoint gridPos() const;
+
+public:
+    CellIterator &operator-=(int n);
+    CellIterator &operator+=(int n);
+
+    reference operator*() const { return m_char; }
+    pointer operator->() { return &m_char; }
+
+    CellIterator &operator++() { return *this += 1; }
+    CellIterator operator++(int)
+    {
+        CellIterator tmp = *this;
+        ++(*this);
+        return tmp;
+    }
+
+    CellIterator &operator--() { return *this -= 1; }
+    CellIterator operator--(int)
+    {
+        CellIterator tmp = *this;
+        --(*this);
+        return tmp;
+    }
+
+    bool operator!=(const CellIterator &other) const
+    {
+        if (other.m_state != m_state)
+            return true;
+
+        if (other.m_pos != m_pos)
+            return true;
+
+        return false;
+    }
+
+    bool operator==(const CellIterator &other) const { return !operator!=(other); }
+
+    CellIterator operator-(int n) const
+    {
+        CellIterator result = *this;
+        result -= n;
+        return result;
+    }
+
+    CellIterator operator+(int n) const
+    {
+        CellIterator result = *this;
+        result += n;
+        return result;
+    }
+
+    int position() const { return m_pos; }
+
+private:
+    void updateChar();
+
+    const TerminalSurface *m_surface{nullptr};
+    int m_pos{-1};
+    int m_maxpos{-1};
+    mutable std::u32string::value_type m_char;
+};
+
+} // namespace Terminal::Internal
--- a/src/plugins/terminal/celllayout.cpp
+++ b/src/plugins/terminal/celllayout.cpp
@@ -1,146 +0,0 @@
-// Copyright (C) 2022 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
-
-#include "celllayout.h"
-
-#include <QFontMetrics>
-
-namespace Terminal::Internal {
-
-QColor toQColor(const VTermColor &c)
-{
-    return QColor(qRgb(c.rgb.red, c.rgb.green, c.rgb.blue));
-};
-
-std::u32string cellToString(const VTermScreenCell &cell)
-{
-    if (cell.chars[0] != 0xFFFFFFFF) {
-        QString ch = QString::fromUcs4(cell.chars);
-        if (ch.size() > 1)
-            ch = ch.normalized(QString::NormalizationForm_C);
-        QList<uint> asUcs4 = ch.toUcs4();
-
-        std::u32string chUcs = std::u32string(asUcs4.begin(), asUcs4.end());
-        if (chUcs.size() > 0) {
-            if (chUcs[0] == 0)
-                chUcs[0] = 0x00a0;
-
-            return chUcs;
-        }
-    }
-    return std::u32string(1, (char32_t) 0x00a0);
-}
-
-void createTextLayout(QTextLayout &textLayout,
-                      std::u32string *resultText,
-                      VTermColor defaultBg,
-                      QRect cellRect,
-                      qreal lineSpacing,
-                      std::function<const VTermScreenCell *(int x, int y)> fetchCell)
-{
-    QList<QTextLayout::FormatRange> formats;
-
-    QTextCharFormat currentFormat;
-    int currentFormatStart = 0;
-    currentFormat.setForeground(QColor(0xff, 0xff, 0xff));
-    currentFormat.clearBackground();
-
-    QString layoutText;
-    if (resultText)
-        resultText->clear();
-
-    for (int y = cellRect.y(); y < cellRect.bottom() + 1; y++) {
-        QTextCharFormat format;
-
-        const auto setNewFormat = [&formats, &currentFormatStart, &layoutText, &currentFormat](
-                                      const QTextCharFormat &format) {
-            if (layoutText.size() != currentFormatStart) {
-                QTextLayout::FormatRange fr;
-                fr.start = currentFormatStart;
-                fr.length = layoutText.size() - currentFormatStart;
-                fr.format = currentFormat;
-                formats.append(fr);
-
-                currentFormat = format;
-                currentFormatStart = layoutText.size();
-            } else {
-                currentFormat = format;
-            }
-        };
-
-        for (int x = cellRect.x(); x < cellRect.right() + 1; x++) {
-            const VTermScreenCell *cell = fetchCell(x, y);
-
-            const VTermColor *bg = &cell->bg;
-            const VTermColor *fg = &cell->fg;
-
-            if (static_cast<bool>(cell->attrs.reverse)) {
-                bg = &cell->fg;
-                fg = &cell->bg;
-            }
-
-            format = QTextCharFormat();
-            format.setForeground(toQColor(*fg));
-
-            if (!vterm_color_is_equal(bg, &defaultBg))
-                format.setBackground(toQColor(*bg));
-            else
-                format.clearBackground();
-
-            if (cell->attrs.bold)
-                format.setFontWeight(QFont::Bold);
-            if (cell->attrs.underline)
-                format.setFontUnderline(true);
-            if (cell->attrs.italic)
-                format.setFontItalic(true);
-            if (cell->attrs.strike)
-                format.setFontStrikeOut(true);
-
-            if (format != currentFormat)
-                setNewFormat(format);
-
-            if (cell->chars[0] != 0xFFFFFFFF) {
-                QString ch = QString::fromUcs4(cell->chars);
-                if (ch == ' ')
-                    ch = QChar::Nbsp;
-                if (ch.size() > 0) {
-                    layoutText += ch;
-                } else {
-                    layoutText += QChar::Nbsp;
-                }
-            }
-
-            if (resultText)
-                *resultText += cellToString(*cell);
-        } // for x
-        setNewFormat(format);
-        if (y != cellRect.bottom())
-            layoutText.append(QChar::LineSeparator);
-    } // for y
-
-    QTextLayout::FormatRange fr;
-    fr.start = currentFormatStart;
-    fr.length = (layoutText.size() - 1) - currentFormatStart;
-    fr.format = currentFormat;
-    formats.append(fr);
-
-    textLayout.setText(layoutText);
-    textLayout.setFormats(formats);
-
-    qreal height = 0;
-    textLayout.beginLayout();
-    while (1) {
-        QTextLine line = textLayout.createLine();
-        if (!line.isValid())
-            break;
-
-        // Just give it a number that is definitely larger than
-        // the number of columns in a line.
-        line.setNumColumns(std::numeric_limits<int>::max());
-        line.setPosition(QPointF(0, height));
-        height += lineSpacing;
-    }
-    textLayout.endLayout();
-}
-
-} // namespace Terminal::Internal
--- a/src/plugins/terminal/celllayout.h
+++ b/src/plugins/terminal/celllayout.h
@@ -1,29 +0,0 @@
-// Copyright (C) 2022 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
-
-#pragma once
-
-#include <vterm.h>
-
-#include <QColor>
-#include <QFont>
-#include <QRect>
-#include <QString>
-#include <QTextLayout>
-
-#include <functional>
-
-namespace Terminal::Internal {
-
-QColor toQColor(const VTermColor &c);
-
-void createTextLayout(QTextLayout &textLayout,
-                      std::u32string *resultText,
-                      VTermColor defaultBg,
-                      QRect cellRect,
-                      qreal lineSpacing,
-                      std::function<const VTermScreenCell *(int x, int y)> fetchCell);
-
-std::u32string cellToString(const VTermScreenCell &cell);
-
-} // namespace Terminal::Internal
--- a/src/plugins/terminal/glyphcache.cpp
+++ b/src/plugins/terminal/glyphcache.cpp
@@ -0,0 +1,44 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#include "glyphcache.h"
+
+#include <QTextLayout>
+
+namespace Terminal::Internal {
+
+size_t qHash(const GlyphCacheKey &key, size_t seed = 0)
+{
+    return qHash(key.font, seed) ^ qHash(key.text, seed);
+}
+
+GlyphCache &GlyphCache::instance()
+{
+    static GlyphCache cache(5000);
+    return cache;
+}
+
+const QGlyphRun *GlyphCache::get(const QFont &font, const QString &text)
+{
+    GlyphCacheKey key{font, text};
+    if (auto *run = object(key))
+        return run;
+
+    QTextLayout layout;
+
+    layout.setText(text);
+    layout.setFont(font);
+
+    layout.beginLayout();
+    layout.createLine().setNumColumns(std::numeric_limits<int>::max());
+    layout.endLayout();
+
+    if (layout.lineCount() > 0) {
+        QGlyphRun *run = new QGlyphRun(layout.lineAt(0).glyphRuns().first());
+        insert(key, run);
+        return run;
+    }
+    return nullptr;
+}
+
+} // namespace Terminal::Internal
--- a/src/plugins/terminal/glyphcache.h
+++ b/src/plugins/terminal/glyphcache.h
@@ -0,0 +1,34 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include <QCache>
+#include <QFont>
+#include <QGlyphRun>
+#include <QString>
+
+namespace Terminal::Internal {
+
+struct GlyphCacheKey
+{
+    QFont font;
+    QString text;
+
+    bool operator==(const GlyphCacheKey &other) const
+    {
+        return font == other.font && text == other.text;
+    }
+};
+
+class GlyphCache : public QCache<GlyphCacheKey, QGlyphRun>
+{
+public:
+    using QCache::QCache;
+
+    static GlyphCache &instance();
+
+    const QGlyphRun *get(const QFont &font, const QString &text);
+};
+
+} // namespace Terminal::Internal
--- a/src/plugins/terminal/scrollback.cpp
+++ b/src/plugins/terminal/scrollback.cpp
@@ -3,7 +3,6 @@
 // SPDX-License-Identifier: BSD-3-Clause

 #include "scrollback.h"
-#include "celllayout.h"

 #include <cassert>
 #include <cstring>
@@ -15,15 +14,6 @@ Scrollback::Line::Line(int cols, const VTermScreenCell *cells, VTermState *vts)
    : m_cols(cols)
    , m_cells(std::make_unique<VTermScreenCell[]>(cols))
 {
-    m_textFuture = std::async(std::launch::async, [this, cols] {
-        std::u32string text;
-        text.reserve(cols);
-        for (int i = 0; i < cols; ++i) {
-            text += cellToString(m_cells[i]);
-        }
-        return text;
-    });
-
    memcpy(m_cells.get(), cells, cols * sizeof(cells[0]));
    for (int i = 0; i < cols; ++i) {
        vterm_state_convert_color_to_rgb(vts, &m_cells[i].fg);
@@ -37,34 +27,6 @@ const VTermScreenCell *Scrollback::Line::cell(int i) const
    return &m_cells[i];
 }

-const QTextLayout &Scrollback::Line::layout(int version, const QFont &font, qreal lineSpacing) const
-{
-    if (!m_layout)
-        m_layout = std::make_unique<QTextLayout>();
-
-    if (m_layoutVersion != version) {
-        VTermColor defaultBg;
-        defaultBg.type = VTERM_COLOR_DEFAULT_BG;
-        m_layout->clearLayout();
-        m_layout->setFont(font);
-        createTextLayout(*m_layout,
-                         nullptr,
-                         defaultBg,
-                         QRect(0, 0, m_cols, 1),
-                         lineSpacing,
-                         [this](int x, int) { return &m_cells[x]; });
-        m_layoutVersion = version;
-    }
-    return *m_layout;
-}
-
-const std::u32string &Scrollback::Line::text() const
-{
-    if (!m_text)
-        m_text = m_textFuture.get();
-    return *m_text;
-}
-
 Scrollback::Scrollback(size_t capacity)
    : m_capacity(capacity)
 {}
@@ -95,26 +57,9 @@ void Scrollback::popto(int cols, VTermScreenCell *cells)
    m_deque.pop_front();
 }

-size_t Scrollback::scroll(int delta)
-{
-    m_offset = std::min(std::max(0, static_cast<int>(m_offset) + delta),
-                        static_cast<int>(m_deque.size()));
-    return m_offset;
-}
-
 void Scrollback::clear()
 {
-    m_offset = 0;
    m_deque.clear();
 }

-std::u32string Scrollback::currentText()
-{
-    std::u32string currentText;
-    for (auto it = m_deque.rbegin(); it != m_deque.rend(); ++it) {
-        currentText += it->text();
-    }
-    return currentText;
-}
-
 } // namespace Terminal::Internal
--- a/src/plugins/terminal/scrollback.h
+++ b/src/plugins/terminal/scrollback.h
@@ -29,25 +29,17 @@ public:
        const VTermScreenCell *cell(int i) const;
        const VTermScreenCell *cells() const { return &m_cells[0]; };

-        const QTextLayout &layout(int version, const QFont &font, qreal lineSpacing) const;
-        const std::u32string &text() const;
-
    private:
        int m_cols;
        std::unique_ptr<VTermScreenCell[]> m_cells;
-        mutable std::unique_ptr<QTextLayout> m_layout;
-        mutable int m_layoutVersion{-1};
-        mutable std::optional<std::u32string> m_text;
-        mutable std::future<std::u32string> m_textFuture;
    };

 public:
    Scrollback(size_t capacity);
    Scrollback() = delete;

-    size_t capacity() const { return m_capacity; };
-    size_t size() const { return m_deque.size(); };
-    size_t offset() const { return m_offset; };
+    int capacity() const { return m_capacity; };
+    int size() const { return static_cast<int>(m_deque.size()); };

    const Line &line(size_t index) const { return m_deque.at(index); };
    const std::deque<Line> &lines() const { return m_deque; };
@@ -56,16 +48,11 @@ public:
                 const VTermScreenCell *cells,
                 VTermState *vts);
    void popto(int cols, VTermScreenCell *cells);
-    size_t scroll(int delta);
-    void unscroll() { m_offset = 0; };

    void clear();

-    std::u32string currentText();
-
 private:
    size_t m_capacity;
-    size_t m_offset{0};
    std::deque<Line> m_deque;
 };

--- a/src/plugins/terminal/terminalsurface.cpp
+++ b/src/plugins/terminal/terminalsurface.cpp
@@ -0,0 +1,504 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#include "terminalsurface.h"
+
+#include "keys.h"
+#include "scrollback.h"
+
+#include <utils/qtcassert.h>
+
+#include <vterm.h>
+
+#include <QLoggingCategory>
+
+Q_LOGGING_CATEGORY(log, "qtc.terminal.surface", QtWarningMsg);
+
+namespace Terminal::Internal {
+
+QColor toQColor(const VTermColor &c)
+{
+    return QColor(qRgb(c.rgb.red, c.rgb.green, c.rgb.blue));
+};
+
+struct TerminalSurfacePrivate
+{
+    TerminalSurfacePrivate(TerminalSurface *surface, const QSize &initialGridSize)
+        : m_vterm(vterm_new(initialGridSize.height(), initialGridSize.width()), vterm_free)
+        , m_vtermScreen(vterm_obtain_screen(m_vterm.get()))
+        , m_scrollback(std::make_unique<Internal::Scrollback>(5000))
+        , q(surface)
+    {
+        vterm_set_utf8(m_vterm.get(), true);
+
+        static auto writeToPty = [](const char *s, size_t len, void *user) {
+            auto p = static_cast<TerminalSurfacePrivate *>(user);
+            emit p->q->writeToPty(QByteArray(s, static_cast<int>(len)));
+        };
+
+        vterm_output_set_callback(m_vterm.get(), writeToPty, this);
+
+        memset(&m_vtermScreenCallbacks, 0, sizeof(m_vtermScreenCallbacks));
+
+        m_vtermScreenCallbacks.damage = [](VTermRect rect, void *user) {
+            auto p = static_cast<TerminalSurfacePrivate *>(user);
+            rect.start_row += p->m_scrollback->size();
+            rect.end_row += p->m_scrollback->size();
+            p->invalidate(rect);
+            return 1;
+        };
+        m_vtermScreenCallbacks.sb_pushline = [](int cols, const VTermScreenCell *cells, void *user) {
+            auto p = static_cast<TerminalSurfacePrivate *>(user);
+            return p->sb_pushline(cols, cells);
+        };
+        m_vtermScreenCallbacks.sb_popline = [](int cols, VTermScreenCell *cells, void *user) {
+            auto p = static_cast<TerminalSurfacePrivate *>(user);
+            return p->sb_popline(cols, cells);
+        };
+        m_vtermScreenCallbacks.settermprop = [](VTermProp prop, VTermValue *val, void *user) {
+            auto p = static_cast<TerminalSurfacePrivate *>(user);
+            return p->setTerminalProperties(prop, val);
+        };
+        m_vtermScreenCallbacks.movecursor =
+            [](VTermPos pos, VTermPos oldpos, int visible, void *user) {
+                auto p = static_cast<TerminalSurfacePrivate *>(user);
+                return p->movecursor(pos, oldpos, visible);
+            };
+
+        m_vtermScreenCallbacks.sb_clear = [](void *user) {
+            auto p = static_cast<TerminalSurfacePrivate *>(user);
+            return p->sb_clear();
+        };
+
+        vterm_screen_set_callbacks(m_vtermScreen, &m_vtermScreenCallbacks, this);
+        vterm_screen_set_damage_merge(m_vtermScreen, VTERM_DAMAGE_SCROLL);
+        vterm_screen_enable_altscreen(m_vtermScreen, true);
+
+        VTermState *vts = vterm_obtain_state(m_vterm.get());
+        vterm_state_set_bold_highbright(vts, true);
+
+        vterm_screen_reset(m_vtermScreen, 1);
+    }
+
+    QSize liveSize() const
+    {
+        int rows;
+        int cols;
+        vterm_get_size(m_vterm.get(), &rows, &cols);
+
+        return QSize(cols, rows);
+    }
+
+    TerminalCell toCell(const VTermScreenCell &cell)
+    {
+        TerminalCell result;
+        result.width = cell.width;
+        result.text = QString::fromUcs4(cell.chars);
+
+        const VTermColor *bg = &cell.bg;
+        const VTermColor *fg = &cell.fg;
+
+        if (static_cast<bool>(cell.attrs.reverse))
+            std::swap(fg, bg);
+
+        const QColor cellBgColor = toQColor(*bg);
+        const QColor cellFgColor = toQColor(*fg);
+
+        if (cellBgColor != m_defaultBgColor)
+            result.background = toQColor(*bg);
+
+        result.foreground = cellFgColor;
+
+        result.bold = cell.attrs.bold;
+        result.strikeOut = cell.attrs.strike;
+
+        if (cell.attrs.underline > 0) {
+            result.underlineStyle = QTextCharFormat::NoUnderline;
+            switch (cell.attrs.underline) {
+            case VTERM_UNDERLINE_SINGLE:
+                result.underlineStyle = QTextCharFormat::SingleUnderline;
+                break;
+            case VTERM_UNDERLINE_DOUBLE:
+                // TODO: Double underline
+                result.underlineStyle = QTextCharFormat::SingleUnderline;
+                break;
+            case VTERM_UNDERLINE_CURLY:
+                result.underlineStyle = QTextCharFormat::WaveUnderline;
+                break;
+            case VTERM_UNDERLINE_DASHED:
+                result.underlineStyle = QTextCharFormat::DashUnderline;
+                break;
+            case VTERM_UNDERLINE_DOTTED:
+                result.underlineStyle = QTextCharFormat::DotLine;
+                break;
+            }
+        }
+
+        result.strikeOut = cell.attrs.strike;
+
+        return result;
+    }
+
+    VTermColor defaultBgColor() const
+    {
+        VTermColor defaultBg;
+        if (!m_altscreen) {
+            VTermColor defaultFg;
+            vterm_state_get_default_colors(vterm_obtain_state(m_vterm.get()),
+                                           &defaultFg,
+                                           &defaultBg);
+            // We want to compare the cell bg against this later and cells don't
+            // set DEFAULT_BG
+            defaultBg.type = VTERM_COLOR_RGB;
+            return defaultBg;
+        } // This is a slightly better guess when in an altscreen
+
+        VTermPos vtp{0, 0};
+        static VTermScreenCell refCell{};
+        vterm_screen_get_cell(m_vtermScreen, vtp, &refCell);
+        return refCell.bg;
+    }
+
+    // Callbacks from vterm
+    void invalidate(VTermRect rect)
+    {
+        emit q->invalidated(
+            QRect{QPoint{rect.start_col, rect.start_row}, QPoint{rect.end_col, rect.end_row - 1}});
+    }
+
+    int sb_pushline(int cols, const VTermScreenCell *cells)
+    {
+        m_scrollback->emplace(cols, cells, vterm_obtain_state(m_vterm.get()));
+        emit q->fullSizeChanged(q->fullSize());
+        return 1;
+    }
+
+    int sb_popline(int cols, VTermScreenCell *cells)
+    {
+        if (m_scrollback->size() == 0)
+            return 0;
+
+        m_scrollback->popto(cols, cells);
+        emit q->fullSizeChanged(q->fullSize());
+        return 1;
+    }
+
+    int sb_clear()
+    {
+        m_scrollback->clear();
+        emit q->fullSizeChanged(q->fullSize());
+        return 1;
+    }
+
+    int setTerminalProperties(VTermProp prop, VTermValue *val)
+    {
+        switch (prop) {
+        case VTERM_PROP_CURSORVISIBLE:
+            m_cursor.visible = val->boolean;
+            break;
+        case VTERM_PROP_CURSORBLINK:
+            qCDebug(log) << "Ignoring VTERM_PROP_CURSORBLINK" << val->boolean;
+            break;
+        case VTERM_PROP_CURSORSHAPE:
+            qCDebug(log) << "Ignoring VTERM_PROP_CURSORSHAPE" << val->number;
+            break;
+        case VTERM_PROP_ICONNAME:
+            //emit iconTextChanged(val->string);
+            break;
+        case VTERM_PROP_TITLE:
+            break;
+        case VTERM_PROP_ALTSCREEN:
+            m_altscreen = val->boolean;
+            emit q->altscreenChanged(m_altscreen);
+            //setSelection(std::nullopt);
+            break;
+        case VTERM_PROP_MOUSE:
+            qCDebug(log) << "Ignoring VTERM_PROP_MOUSE" << val->number;
+            break;
+        case VTERM_PROP_REVERSE:
+            qCDebug(log) << "Ignoring VTERM_PROP_REVERSE" << val->boolean;
+            break;
+        case VTERM_N_PROPS:
+            break;
+        }
+        return 1;
+    }
+    int movecursor(VTermPos pos, VTermPos oldpos, int visible)
+    {
+        Q_UNUSED(oldpos);
+        Cursor oldCursor = q->cursor();
+        m_cursor = {{pos.col, pos.row}, visible > 0};
+        q->cursorChanged(oldCursor, q->cursor());
+        return 1;
+    }
+
+    const VTermScreenCell *cellAt(int x, int y)
+    {
+        QTC_ASSERT(y >= 0 && x >= 0, return nullptr);
+        QTC_ASSERT(y < liveSize().height() + m_scrollback->size() && x < liveSize().width(),
+                   return nullptr);
+        if (y < m_scrollback->size()) {
+            const auto &sbl = m_scrollback->line((m_scrollback->size() - 1) - y);
+            if (x < sbl.cols()) {
+                return sbl.cell(x);
+            }
+            return nullptr;
+        }
+
+        y -= m_scrollback->size();
+
+        static VTermScreenCell refCell{};
+        VTermPos vtp{y, x};
+        vterm_screen_get_cell(m_vtermScreen, vtp, &refCell);
+        vterm_screen_convert_color_to_rgb(m_vtermScreen, &refCell.fg);
+        vterm_screen_convert_color_to_rgb(m_vtermScreen, &refCell.bg);
+
+        return &refCell;
+    }
+
+    std::unique_ptr<VTerm, void (*)(VTerm *)> m_vterm;
+    VTermScreen *m_vtermScreen;
+    VTermScreenCallbacks m_vtermScreenCallbacks;
+
+    QColor m_defaultBgColor;
+    Cursor m_cursor;
+
+    bool m_altscreen{false};
+
+    std::unique_ptr<Internal::Scrollback> m_scrollback;
+
+    TerminalSurface *q;
+};
+
+TerminalSurface::TerminalSurface(QSize initialGridSize)
+    : d(std::make_unique<TerminalSurfacePrivate>(this, initialGridSize))
+{}
+
+TerminalSurface::~TerminalSurface() = default;
+
+int TerminalSurface::cellWidthAt(int x, int y) const
+{
+    const VTermScreenCell *cell = d->cellAt(x, y);
+    if (!cell)
+        return 0;
+    return cell->width;
+}
+
+QSize TerminalSurface::liveSize() const
+{
+    return d->liveSize();
+}
+
+QSize TerminalSurface::fullSize() const
+{
+    return QSize{d->liveSize().width(), d->liveSize().height() + d->m_scrollback->size()};
+}
+
+std::u32string::value_type TerminalSurface::fetchCharAt(int x, int y) const
+{
+    const VTermScreenCell *cell = d->cellAt(x, y);
+    if (!cell)
+        return 0;
+
+    if (cell->width == 0)
+        return 0;
+
+    QString s = QString::fromUcs4(cell->chars, 6).normalized(QString::NormalizationForm_C);
+    const QList<uint> ucs4 = s.toUcs4();
+    return std::u32string(ucs4.begin(), ucs4.end()).front();
+}
+
+TerminalCell TerminalSurface::fetchCell(int x, int y) const
+{
+    static TerminalCell emptyCell{1, {}, {}};
+
+    QTC_ASSERT(y >= 0, return emptyCell);
+    QTC_ASSERT(y < d->liveSize().height() + d->m_scrollback->size(), return emptyCell);
+
+    const VTermScreenCell *refCell = d->cellAt(x, y);
+    if (!refCell)
+        return emptyCell;
+
+    return d->toCell(*refCell);
+}
+
+void TerminalSurface::clearAll()
+{
+    // Fake a scrollback clearing
+    QByteArray data{"\x1b[3J"};
+    vterm_input_write(d->m_vterm.get(), data.constData(), data.size());
+
+    // Send Ctrl+L which will clear the screen
+    emit writeToPty(QByteArray("\f"));
+}
+
+void TerminalSurface::resize(QSize newSize)
+{
+    vterm_set_size(d->m_vterm.get(), newSize.height(), newSize.width());
+}
+
+QPoint TerminalSurface::posToGrid(int pos) const
+{
+    return {pos % d->liveSize().width(), pos / d->liveSize().width()};
+}
+int TerminalSurface::gridToPos(QPoint gridPos) const
+{
+    return gridPos.y() * d->liveSize().width() + gridPos.x();
+}
+
+void TerminalSurface::dataFromPty(const QByteArray &data)
+{
+    vterm_input_write(d->m_vterm.get(), data.constData(), data.size());
+    vterm_screen_flush_damage(d->m_vtermScreen);
+}
+
+void TerminalSurface::flush()
+{
+    vterm_screen_flush_damage(d->m_vtermScreen);
+}
+
+void TerminalSurface::setColors(QColor foreground, QColor background)
+{
+    VTermState *vts = vterm_obtain_state(d->m_vterm.get());
+
+    VTermColor fg;
+    VTermColor bg;
+
+    vterm_color_rgb(&fg, foreground.red(), foreground.green(), foreground.blue());
+    vterm_color_rgb(&bg, background.red(), background.green(), background.blue());
+
+    d->m_defaultBgColor = background;
+
+    vterm_state_set_default_colors(vts, &fg, &bg);
+    vterm_screen_reset(d->m_vtermScreen, 1);
+}
+
+void TerminalSurface::setAnsiColor(int index, QColor color)
+{
+    VTermState *vts = vterm_obtain_state(d->m_vterm.get());
+
+    VTermColor col;
+    vterm_color_rgb(&col, color.red(), color.green(), color.blue());
+    vterm_state_set_palette_color(vts, index, &col);
+
+    vterm_screen_reset(d->m_vtermScreen, 1);
+}
+
+void TerminalSurface::pasteFromClipboard(const QString &clipboardText)
+{
+    if (clipboardText.isEmpty())
+        return;
+
+    vterm_keyboard_start_paste(d->m_vterm.get());
+    for (unsigned int ch : clipboardText.toUcs4())
+        vterm_keyboard_unichar(d->m_vterm.get(), ch, VTERM_MOD_NONE);
+    vterm_keyboard_end_paste(d->m_vterm.get());
+
+    if (!d->m_altscreen) {
+        emit unscroll();
+    }
+}
+
+void TerminalSurface::sendKey(Qt::Key key)
+{
+    if (key == Qt::Key_Escape)
+        vterm_keyboard_key(d->m_vterm.get(), VTERM_KEY_ESCAPE, VTERM_MOD_NONE);
+}
+
+void TerminalSurface::sendKey(const QString &text)
+{
+    for (const unsigned int ch : text.toUcs4())
+        vterm_keyboard_unichar(d->m_vterm.get(), ch, VTERM_MOD_NONE);
+}
+
+void TerminalSurface::sendKey(QKeyEvent *event)
+{
+    bool keypad = event->modifiers() & Qt::KeypadModifier;
+    VTermModifier mod = Internal::qtModifierToVTerm(event->modifiers());
+    VTermKey key = Internal::qtKeyToVTerm(Qt::Key(event->key()), keypad);
+
+    if (key != VTERM_KEY_NONE) {
+        if (mod == VTERM_MOD_SHIFT && (key == VTERM_KEY_ESCAPE || key == VTERM_KEY_BACKSPACE))
+            mod = VTERM_MOD_NONE;
+
+        vterm_keyboard_key(d->m_vterm.get(), key, mod);
+    } else if (event->text().length() == 1) {
+        // This maps to delete word and is way to easy to mistakenly type
+        //        if (event->key() == Qt::Key_Space && mod == VTERM_MOD_SHIFT)
+        //            mod = VTERM_MOD_NONE;
+
+        // Per https://github.com/justinmk/neovim/commit/317d5ca7b0f92ef42de989b3556ca9503f0a3bf6
+        // libvterm prefers we send the full keycode rather than sending the
+        // ctrl modifier.  This helps with ncurses applications which otherwise
+        // do not recognize ctrl+<key> and in the shell for getting common control characters
+        // like ctrl+i for tab or ctrl+j for newline.
+
+        // Workaround for "ALT+SHIFT+/" (\ on german mac keyboards)
+        if (mod == (VTERM_MOD_SHIFT | VTERM_MOD_ALT) && event->key() == Qt::Key_Slash) {
+            mod = VTERM_MOD_NONE;
+        }
+
+        vterm_keyboard_unichar(d->m_vterm.get(), event->text().toUcs4()[0], VTERM_MOD_NONE);
+
+        // TODO: ??
+        //setSelection(std::nullopt);
+    } else if (mod == VTERM_MOD_CTRL && event->key() >= Qt::Key_A && event->key() < Qt::Key_Z) {
+        vterm_keyboard_unichar(d->m_vterm.get(), 'a' + (event->key() - Qt::Key_A), mod);
+    }
+}
+
+Cursor TerminalSurface::cursor() const
+{
+    Cursor cursor = d->m_cursor;
+    cursor.position.setY(cursor.position.y() + d->m_scrollback->size());
+
+    return cursor;
+}
+
+QColor TerminalSurface::defaultBgColor() const
+{
+    return toQColor(d->defaultBgColor());
+}
+
+CellIterator TerminalSurface::begin() const
+{
+    auto res = CellIterator(this, {0, 0});
+    res.m_state = CellIterator::State::BEGIN;
+    return res;
+}
+
+CellIterator TerminalSurface::end() const
+{
+    return CellIterator(this, CellIterator::State::END);
+}
+
+std::reverse_iterator<CellIterator> TerminalSurface::rbegin() const
+{
+    return std::make_reverse_iterator(end());
+}
+
+std::reverse_iterator<CellIterator> TerminalSurface::rend() const
+{
+    return std::make_reverse_iterator(begin());
+}
+
+CellIterator TerminalSurface::iteratorAt(QPoint pos) const
+{
+    return CellIterator(this, pos);
+}
+CellIterator TerminalSurface::iteratorAt(int pos) const
+{
+    return CellIterator(this, pos);
+}
+
+std::reverse_iterator<CellIterator> TerminalSurface::rIteratorAt(QPoint pos) const
+{
+    return std::make_reverse_iterator(iteratorAt(pos));
+}
+
+std::reverse_iterator<CellIterator> TerminalSurface::rIteratorAt(int pos) const
+{
+    return std::make_reverse_iterator(iteratorAt(pos));
+}
+
+} // namespace Terminal::Internal
--- a/src/plugins/terminal/terminalsurface.h
+++ b/src/plugins/terminal/terminalsurface.h
@@ -0,0 +1,103 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include "celliterator.h"
+
+#include <QKeyEvent>
+#include <QSize>
+#include <QTextCharFormat>
+
+#include <memory>
+
+namespace Terminal::Internal {
+
+class Scrollback;
+
+struct TerminalSurfacePrivate;
+
+struct TerminalCell
+{
+    int width;
+    QString text;
+    bool bold{false};
+    bool italic{false};
+    QColor foreground;
+    std::optional<QColor> background;
+    QTextCharFormat::UnderlineStyle underlineStyle{QTextCharFormat::NoUnderline};
+    bool strikeOut{false};
+};
+
+struct Cursor
+{
+    QPoint position;
+    bool visible;
+};
+
+class TerminalSurface : public QObject
+{
+    Q_OBJECT;
+
+public:
+    TerminalSurface(QSize initialGridSize);
+    ~TerminalSurface();
+
+public:
+    CellIterator begin() const;
+    CellIterator end() const;
+    std::reverse_iterator<CellIterator> rbegin() const;
+    std::reverse_iterator<CellIterator> rend() const;
+
+    CellIterator iteratorAt(QPoint pos) const;
+    CellIterator iteratorAt(int pos) const;
+
+    std::reverse_iterator<CellIterator> rIteratorAt(QPoint pos) const;
+    std::reverse_iterator<CellIterator> rIteratorAt(int pos) const;
+
+public:
+    void clearAll();
+
+    void resize(QSize newSize);
+
+    TerminalCell fetchCell(int x, int y) const;
+    std::u32string::value_type fetchCharAt(int x, int y) const;
+    int cellWidthAt(int x, int y) const;
+
+    QSize liveSize() const;
+    QSize fullSize() const;
+
+    QPoint posToGrid(int pos) const;
+    int gridToPos(QPoint gridPos) const;
+
+    void dataFromPty(const QByteArray &data);
+    void flush();
+
+    void setColors(QColor foreground, QColor background);
+    void setAnsiColor(int index, QColor color);
+
+    void pasteFromClipboard(const QString &text);
+
+    void sendKey(Qt::Key key);
+    void sendKey(QKeyEvent *event);
+    void sendKey(const QString &text);
+
+    int invertedScrollOffset() const;
+
+    Cursor cursor() const;
+
+    QColor defaultBgColor() const;
+
+signals:
+    void writeToPty(const QByteArray &data);
+    void invalidated(QRect grid);
+    void fullSizeChanged(QSize newSize);
+    void cursorChanged(Cursor oldCursor, Cursor newCursor);
+    void altscreenChanged(bool altScreen);
+    void unscroll();
+
+private:
+    std::unique_ptr<TerminalSurfacePrivate> d;
+};
+
+} // namespace Terminal::Internal
--- a/src/plugins/terminal/terminalwidget.cpp
+++ b/src/plugins/terminal/terminalwidget.cpp
--- a/src/plugins/terminal/terminalwidget.h
+++ b/src/plugins/terminal/terminalwidget.h
@@ -3,7 +3,7 @@

 #pragma once

-#include "scrollback.h"
+#include "terminalsurface.h"

 #include <utils/qtcprocess.h>
 #include <utils/terminalhooks.h>
@@ -13,8 +13,6 @@
 #include <QTextLayout>
 #include <QTimer>

-#include <vterm.h>
-
 #include <chrono>
 #include <memory>

@@ -22,6 +20,7 @@ namespace Terminal {

 class TerminalWidget : public QAbstractScrollArea
 {
+    friend class CellIterator;
    Q_OBJECT
 public:
    TerminalWidget(QWidget *parent = nullptr,
@@ -49,8 +48,23 @@ public:

    struct Selection
    {
-        QPoint start;
-        QPoint end;
+        int start;
+        int end;
+
+        bool operator!=(const Selection &other) const
+        {
+            return start != other.start || end != other.end;
+        }
+    };
+
+    struct LinkSelection : public Selection
+    {
+        Utils::FilePath filePath;
+
+        bool operator!=(const LinkSelection &other) const
+        {
+            return filePath != other.filePath || Selection::operator!=(other);
+        }
    };

    QString shellName() const;
@@ -80,7 +94,7 @@ protected:

 protected:
    void onReadyRead(bool forceFlush);
-    void setupVTerm();
+    void setupSurface();
    void setupFont();
    void setupPty();
    void setupColors();
@@ -88,23 +102,27 @@ protected:

    void writeToPty(const QByteArray &data);

-    void createTextLayout();
-
-    // Callbacks from vterm
-    void invalidate(VTermRect rect);
-    int sb_pushline(int cols, const VTermScreenCell *cells);
-    int sb_popline(int cols, VTermScreenCell *cells);
-    int sb_clear();
-    int setTerminalProperties(VTermProp prop, VTermValue *val);
-    int movecursor(VTermPos pos, VTermPos oldpos, int visible);
-
-    const VTermScreenCell *fetchCell(int x, int y) const;
+    int paintCell(QPainter &p,
+                  const QRectF &cellRect,
+                  QPoint gridPos,
+                  const Internal::TerminalCell &cell,
+                  QFont &f) const;
+    void paintCells(QPainter &painter, QPaintEvent *event) const;
+    void paintCursor(QPainter &painter) const;
+    void paintPreedit(QPainter &painter) const;
+    void paintSelection(QPainter &painter) const;
+    void paintDebugSelection(QPainter &painter, const Selection &selection) const;

    qreal topMargin() const;

    QPoint viewportToGlobal(QPoint p) const;
    QPoint globalToViewport(QPoint p) const;
-    QPoint globalToGrid(QPoint p) const;
+    QPoint globalToGrid(QPointF p) const;
+    QPointF gridToGlobal(QPoint p, bool bottom = false, bool right = false) const;
+    QRect gridToViewport(QRect rect) const;
+
+    void updateViewport();
+    void updateViewport(const QRect &rect);

    int textLineFromPixel(int y) const;
    std::optional<int> textPosFromPoint(const QTextLayout &textLayout, QPoint p) const;
@@ -112,6 +130,17 @@ protected:
    std::optional<QTextLayout::FormatRange> selectionToFormatRange(
        TerminalWidget::Selection selection, const QTextLayout &layout, int rowOffset) const;

+    void checkLinkAt(const QPoint &pos);
+
+    struct TextAndOffsets
+    {
+        int start;
+        int end;
+        std::u32string text;
+    };
+
+    TextAndOffsets textAt(const QPoint &pos) const;
+
    void applySizeChange();

    void updateScrollBars();
@@ -122,38 +151,25 @@ protected:

 private:
    std::unique_ptr<Utils::QtcProcess> m_process;
+    std::unique_ptr<Internal::TerminalSurface> m_surface;

    QString m_shellName;

-    std::unique_ptr<VTerm, void (*)(VTerm *)> m_vterm;
-    VTermScreen *m_vtermScreen;
-    QSize m_vtermSize;
-
    QFont m_font;
    QSizeF m_cellSize;
-    qreal m_cellBaseline;
-    qreal m_lineSpacing;

-    bool m_altscreen{false};
    bool m_ignoreScroll{false};

    QString m_preEditString;

    std::optional<Selection> m_selection;
-    QPoint m_selectionStartPos;
-
-    std::unique_ptr<Internal::Scrollback> m_scrollback;
-
-    QTextLayout m_textLayout;
+    std::optional<LinkSelection> m_linkSelection;

    struct
    {
-        int row{0};
-        int col{0};
-        bool visible{false};
-    } m_cursor;
-
-    VTermScreenCallbacks m_vtermScreenCallbacks;
+        QPoint start;
+        QPoint end;
+    } m_activeMouseSelect;

    QAction m_copyAction;
    QAction m_pasteAction;
@@ -165,8 +181,6 @@ private:

    QTimer m_flushDelayTimer;

-    int m_layoutVersion{0};
-
    std::array<QColor, 18> m_currentColors;

    Utils::Terminal::OpenTerminalParameters m_openParameters;
@@ -174,8 +188,6 @@ private:
    std::chrono::system_clock::time_point m_lastFlush;
    std::chrono::system_clock::time_point m_lastDoubleClick;
    bool m_selectLineMode{false};
-
-    std::u32string m_currentLiveText;
 };

 } // namespace Terminal
--- a/src/plugins/terminal/tests/colors
+++ b/src/plugins/terminal/tests/colors
@@ -0,0 +1,112 @@
+#!/usr/bin/python3
+# Source: https://gist.github.com/lilydjwg/fdeaf79e921c2f413f44b6f613f6ad53
+
+from functools import partial
+
+
+def colors16():
+  for bold in [0, 1]:
+    for i in range(30, 38):
+      for j in range(40, 48):
+        print(f'\x1b[{bold};{i};{j}m {bold};{i};{j} |\x1b[0m', end='')
+      print()
+    print()
+
+  for bold in [0, 1]:
+    for i in range(90, 98):
+      for j in range(100, 108):
+        print(f'\x1b[{bold};{i};{j}m {bold};{i};{j} |\x1b[0m', end='')
+      print()
+    print()
+
+
+def color1(c, n=0):
+  print(f'\x1b[{n};38;5;{c}m{c:4}\x1b[0m', end='')
+
+
+def color1_sep(c):
+  if (c - 15) % 18 == 0:
+    print()
+
+
+def color2(c):
+  print(f'\x1b[48;5;{c}m  \x1b[0m', end='')
+
+
+def color2_sep(c):
+  if (c - 15) % 36 == 0:
+    print()
+  elif (c - 15) % 6 == 0:
+    print(' ', end='')
+
+
+def colors256(color, sepfunc):
+  for i in range(0, 8):
+    color(i)
+  print()
+  for i in range(8, 16):
+    color(i)
+  print('\n')
+
+  for i in range(16, 232):
+    color(i)
+    sepfunc(i)
+  print()
+
+  for i in range(232, 256):
+    color(i)
+  print('\n')
+
+
+def colors_gradient():
+  s = '/\\' * 40
+  for col in range(0, 77):
+    r = 255 - col * 255 // 76
+    g = col * 510 // 76
+    b = col * 255 // 76
+    if g > 255:
+      g = 510 - g
+    print(
+        f'\x1b[48;2;{r};{g};{b}m\x1b[38;2;{255-r};{255-g};{255-b}m{s[col]}\x1b[0m', end='')
+  print()
+
+
+def other_attributes():
+  for i in range(0, 10):
+    print(f' \x1b[{i}mSGR {i:2}\x1b[m', end=' ')
+  print(' \x1b[53mSGR 53\x1b[m', end=' ')  # overline
+  print('\n')
+  # https://askubuntu.com/a/985386/235132
+  for i in range(1, 6):
+    print(f' \x1b[4:{i}mSGR 4:{i}\x1b[m', end=' ')
+  print(' \x1b[21mSGR 21\x1b[m', end=' ')
+
+  print(
+      ' \x1b[4:3m\x1b[58;2;135;0;255mtruecolor underline\x1b[59m\x1b[4:0m', end=' ')
+  print(' \x1b]8;;https://askubuntu.com/a/985386/235132\x1b\\hyperlink\x1b]8;;\x1b\\')
+
+
+if __name__ == '__main__':
+  print('basic 16 colors, foreground & background:\n')
+  colors16()
+
+  print('256 colors:\n')
+  colors256(color1, color1_sep)
+
+  print('256 colors, bold:\n')
+  colors256(partial(color1, n=1), color1_sep)
+
+  print('256 colors, dim:\n')
+  colors256(partial(color1, n=2), color1_sep)
+
+  print('256 colors, bold dim:\n')
+  colors256(partial(color1, n='1;2'), color1_sep)
+
+  print('256 colors, solid background:\n')
+  colors256(color2, color2_sep)
+
+  print('true colors gradient:\n')
+  colors_gradient()
+
+  print('other attributes:\n')
+  other_attributes()