LibWeb: Rename directory LibHTML => LibWeb

Let's rename this to LibWeb since it aims to provide more parts of the
web platform than just HTML. :^)

Libraries/LibWeb/Layout/LayoutText.cpp

@@ -0,0 +1,237 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/StringBuilder.h>
+#include <AK/Utf8View.h>
+#include <LibCore/DirIterator.h>
+#include <LibGfx/Font.h>
+#include <LibGUI/Painter.h>
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/Layout/LayoutBlock.h>
+#include <LibWeb/Layout/LayoutText.h>
+#include <ctype.h>
+
+namespace Web {
+
+LayoutText::LayoutText(const Text& text)
+    : LayoutNode(&text)
+{
+    set_inline(true);
+}
+
+LayoutText::~LayoutText()
+{
+}
+
+static bool is_all_whitespace(const String& string)
+{
+    for (size_t i = 0; i < string.length(); ++i) {
+        if (!isspace(string[i]))
+            return false;
+    }
+    return true;
+}
+
+const String& LayoutText::text_for_style(const StyleProperties& style) const
+{
+    static String one_space = " ";
+    if (is_all_whitespace(node().data())) {
+        if (style.string_or_fallback(CSS::PropertyID::WhiteSpace, "normal") == "normal")
+            return one_space;
+    }
+    return node().data();
+}
+
+void LayoutText::render_fragment(RenderingContext& context, const LineBoxFragment& fragment) const
+{
+    auto& painter = context.painter();
+    painter.set_font(style().font());
+
+    auto background_color = style().property(CSS::PropertyID::BackgroundColor);
+    if (background_color.has_value() && background_color.value()->is_color())
+        painter.fill_rect(enclosing_int_rect(fragment.rect()), background_color.value()->to_color(document()));
+
+    auto color = style().color_or_fallback(CSS::PropertyID::Color, document(), context.palette().base_text());
+    auto text_decoration = style().string_or_fallback(CSS::PropertyID::TextDecoration, "none");
+
+    if (document().inspected_node() == &node())
+        context.painter().draw_rect(enclosing_int_rect(fragment.rect()), Color::Magenta);
+
+    bool is_underline = text_decoration == "underline";
+    if (is_underline)
+        painter.draw_line(enclosing_int_rect(fragment.rect()).bottom_left().translated(0, 1), enclosing_int_rect(fragment.rect()).bottom_right().translated(0, 1), color);
+
+    painter.draw_text(enclosing_int_rect(fragment.rect()), m_text_for_rendering.substring_view(fragment.start(), fragment.length()), Gfx::TextAlignment::TopLeft, color);
+}
+
+template<typename Callback>
+void LayoutText::for_each_word(Callback callback) const
+{
+    Utf8View view(m_text_for_rendering);
+    if (view.is_empty())
+        return;
+
+    auto start_of_word = view.begin();
+
+    auto commit_word = [&](auto it) {
+        int start = view.byte_offset_of(start_of_word);
+        int length = view.byte_offset_of(it) - view.byte_offset_of(start_of_word);
+
+        if (length > 0) {
+            callback(view.substring_view(start, length), start, length);
+        }
+
+        start_of_word = it;
+    };
+
+    bool last_was_space = isspace(*view.begin());
+
+    for (auto it = view.begin(); it != view.end();) {
+        bool is_space = isspace(*it);
+        if (is_space == last_was_space) {
+            ++it;
+            continue;
+        }
+        last_was_space = is_space;
+        commit_word(it);
+        ++it;
+    }
+    if (start_of_word != view.end())
+        commit_word(view.end());
+}
+
+void LayoutText::split_preformatted_into_lines(LayoutBlock& container)
+{
+    auto& font = style().font();
+    auto& line_boxes = container.line_boxes();
+    m_text_for_rendering = node().data();
+
+    Utf8View view(m_text_for_rendering);
+    if (view.is_empty())
+        return;
+
+    auto start_of_line = view.begin();
+
+    auto commit_line = [&](auto it) {
+        int start = view.byte_offset_of(start_of_line);
+        int length = view.byte_offset_of(it) - view.byte_offset_of(start_of_line);
+        if (length > 0)
+            line_boxes.last().add_fragment(*this, start, length, font.width(view), font.glyph_height());
+    };
+
+    bool last_was_newline = false;
+    for (auto it = view.begin(); it != view.end();) {
+        bool did_commit = false;
+        if (*it == '\n') {
+            commit_line(it);
+            line_boxes.append(LineBox());
+            did_commit = true;
+            last_was_newline = true;
+        } else {
+            last_was_newline = false;
+        }
+        ++it;
+        if (did_commit)
+            start_of_line = it;
+    }
+    if (start_of_line != view.end() || last_was_newline)
+        commit_line(view.end());
+}
+
+void LayoutText::split_into_lines(LayoutBlock& container)
+{
+    auto& font = style().font();
+    float space_width = font.glyph_width(' ') + font.glyph_spacing();
+
+    auto& line_boxes = container.line_boxes();
+    if (line_boxes.is_empty())
+        line_boxes.append(LineBox());
+    float available_width = container.width() - line_boxes.last().width();
+
+    if (style().string_or_fallback(CSS::PropertyID::WhiteSpace, "normal") == "pre") {
+        split_preformatted_into_lines(container);
+        return;
+    }
+
+    // Collapse whitespace into single spaces
+    auto utf8_view = Utf8View(node().data());
+    StringBuilder builder(node().data().length());
+    for (auto it = utf8_view.begin(); it != utf8_view.end(); ++it) {
+        if (!isspace(*it)) {
+            builder.append(utf8_view.as_string().characters_without_null_termination() + utf8_view.byte_offset_of(it), it.codepoint_length_in_bytes());
+        } else {
+            builder.append(' ');
+            auto prev = it;
+            while (it != utf8_view.end() && isspace(*it)) {
+                prev = it;
+                ++it;
+            }
+            it = prev;
+        }
+    }
+    m_text_for_rendering = builder.to_string();
+
+    struct Word {
+        Utf8View view;
+        int start;
+        int length;
+    };
+    Vector<Word> words;
+
+    for_each_word([&](const Utf8View& view, int start, int length) {
+        words.append({ Utf8View(view), start, length });
+    });
+
+    for (size_t i = 0; i < words.size(); ++i) {
+        auto& word = words[i];
+
+        float word_width;
+        bool is_whitespace = isspace(*word.view.begin());
+
+        if (is_whitespace)
+            word_width = space_width;
+        else
+            word_width = font.width(word.view) + font.glyph_spacing();
+
+        if (line_boxes.last().width() > 0 && word_width > available_width) {
+            line_boxes.append(LineBox());
+            available_width = container.width();
+        }
+
+        if (is_whitespace && line_boxes.last().fragments().is_empty())
+            continue;
+
+        line_boxes.last().add_fragment(*this, word.start, is_whitespace ? 1 : word.length, word_width, font.glyph_height());
+        available_width -= word_width;
+
+        if (available_width < 0) {
+            line_boxes.append(LineBox());
+            available_width = container.width();
+        }
+    }
+}
+
+}