Reland "Initial integration of libtxt with Flutter alongside Blink." (f…

…lutter#3793)

* Transition to Hybrid lib/txt and blink text system.

BUILD.gn

@@ -8,6 +8,7 @@ group("flutter") {
   deps = [
     "//flutter/lib/snapshot:generate_snapshot_bin",
     "//flutter/sky",
+    "//lib/txt",
   ]
 
   if (is_fuchsia) {
@@ -30,6 +31,8 @@ group("flutter") {
       "//flutter/sky/engine/wtf:wtf_unittests",
       "//flutter/synchronization:synchronization_unittests",
       "//lib/ftl:ftl_unittests",
+      "//lib/txt/examples:txt_example($host_toolchain)",
+      "//lib/txt/tests($host_toolchain)",  # txt_unittests
     ]
   }
 }

DEPS

@@ -71,6 +71,9 @@ deps = {
   'src/lib/zip':
    Var('fuchsia_git') + '/zip' + '@' + '92dc87ca645fe8e9f5151ef6dac86d8311a7222f',
 
+  'src/lib/txt':
+   Var('fuchsia_git') + '/txt' + '@' + 'b44e28c2fd75d7d4b9dcc862bb2c01a090bb53e1',
+
   'src/third_party/gtest':
    Var('fuchsia_git') + '/third_party/gtest' + '@' + 'c00f82917331efbbd27124b537e4ccc915a02b72',
 

common/settings.h

@@ -27,6 +27,7 @@ struct Settings {
   bool use_test_fonts = false;
   bool dart_non_checked_mode = false;
   bool enable_software_rendering = false;
+  bool using_blink = true;
   std::string aot_snapshot_path;
   std::string aot_vm_snapshot_data_filename;
   std::string aot_vm_snapshot_instr_filename;

lib/ui/BUILD.gn

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 source_set("ui") {
+
   sources = [
     "compositing/scene.cc",
     "compositing/scene.h",
@@ -55,6 +56,12 @@ source_set("ui") {
     "text/paragraph.h",
     "text/paragraph_builder.cc",
     "text/paragraph_builder.h",
+    "text/paragraph_impl.cc",
+    "text/paragraph_impl.h",
+    "text/paragraph_impl_blink.cc",
+    "text/paragraph_impl_blink.h",
+    "text/paragraph_impl_txt.cc",
+    "text/paragraph_impl_txt.h",
     "text/text_box.cc",
     "text/text_box.h",
     "ui_dart_state.cc",
@@ -83,5 +90,6 @@ source_set("ui") {
     "//lib/tonic",
     "//third_party/skia",
     "//third_party/skia:gpu",
+    "//lib/txt",
   ]
 }

lib/ui/text/paragraph.cc

@@ -4,14 +4,16 @@
 
 #include "flutter/lib/ui/text/paragraph.h"
 
+#include "flutter/common/settings.h"
 #include "flutter/common/threads.h"
 #include "flutter/sky/engine/core/rendering/PaintInfo.h"
-#include "flutter/sky/engine/core/rendering/RenderText.h"
 #include "flutter/sky/engine/core/rendering/RenderParagraph.h"
+#include "flutter/sky/engine/core/rendering/RenderText.h"
 #include "flutter/sky/engine/core/rendering/style/RenderStyle.h"
 #include "flutter/sky/engine/platform/fonts/FontCache.h"
 #include "flutter/sky/engine/platform/graphics/GraphicsContext.h"
 #include "flutter/sky/engine/platform/text/TextBoundaries.h"
+#include "flutter/sky/engine/wtf/PassOwnPtr.h"
 #include "lib/ftl/tasks/task_runner.h"
 #include "lib/tonic/converter/dart_converter.h"
 #include "lib/tonic/dart_args.h"
@@ -31,7 +33,7 @@ IMPLEMENT_WRAPPERTYPEINFO(ui, Paragraph);
   V(Paragraph, maxIntrinsicWidth)   \
   V(Paragraph, alphabeticBaseline)  \
   V(Paragraph, ideographicBaseline) \
-  V(Paragraph, didExceedMaxLines) \
+  V(Paragraph, didExceedMaxLines)   \
   V(Paragraph, layout)              \
   V(Paragraph, paint)               \
   V(Paragraph, getWordBoundary)     \
@@ -41,155 +43,65 @@ IMPLEMENT_WRAPPERTYPEINFO(ui, Paragraph);
 DART_BIND_ALL(Paragraph, FOR_EACH_BINDING)
 
 Paragraph::Paragraph(PassOwnPtr<RenderView> renderView)
-    : m_renderView(renderView) {}
+    : m_paragraphImpl(std::make_unique<ParagraphImplBlink>(renderView)) {}
+
+Paragraph::Paragraph(std::unique_ptr<txt::Paragraph> paragraph)
+    : m_paragraphImpl(
+          std::make_unique<ParagraphImplTxt>(std::move(paragraph))) {}
 
 Paragraph::~Paragraph() {
   if (m_renderView) {
     RenderView* renderView = m_renderView.leakPtr();
-    Threads::UI()->PostTask(
-        [renderView]() { renderView->destroy(); });
+    Threads::UI()->PostTask([renderView]() { renderView->destroy(); });
   }
 }
 
 double Paragraph::width() {
-  return firstChildBox()->width();
+  return m_paragraphImpl->width();
 }
 
 double Paragraph::height() {
-  return firstChildBox()->height();
+  return m_paragraphImpl->height();
 }
 
 double Paragraph::minIntrinsicWidth() {
-  return firstChildBox()->minPreferredLogicalWidth();
+  return m_paragraphImpl->minIntrinsicWidth();
 }
 
 double Paragraph::maxIntrinsicWidth() {
-  return firstChildBox()->maxPreferredLogicalWidth();
+  return m_paragraphImpl->maxIntrinsicWidth();
 }
 
 double Paragraph::alphabeticBaseline() {
-  return firstChildBox()->firstLineBoxBaseline(
-      FontBaselineOrAuto(AlphabeticBaseline));
+  return m_paragraphImpl->alphabeticBaseline();
 }
 
 double Paragraph::ideographicBaseline() {
-  return firstChildBox()->firstLineBoxBaseline(
-      FontBaselineOrAuto(IdeographicBaseline));
+  return m_paragraphImpl->ideographicBaseline();
 }
 
 bool Paragraph::didExceedMaxLines() {
-  RenderBox* box = firstChildBox();
-  ASSERT(box->isRenderParagraph());
-  RenderParagraph* paragraph = static_cast<RenderParagraph*>(box);
-  return paragraph->didExceedMaxLines();
+  return m_paragraphImpl->didExceedMaxLines();
 }
 
 void Paragraph::layout(double width) {
-  FontCachePurgePreventer fontCachePurgePreventer;
-
-  int maxWidth = LayoutUnit(width);  // Handles infinity properly.
-  m_renderView->setFrameViewSize(IntSize(maxWidth, intMaxForLayoutUnit));
-  m_renderView->layout();
+  m_paragraphImpl->layout(width);
 }
 
 void Paragraph::paint(Canvas* canvas, double x, double y) {
-  SkCanvas* skCanvas = canvas->canvas();
-  if (!skCanvas)
-    return;
-
-  FontCachePurgePreventer fontCachePurgePreventer;
-
-  // Very simplified painting to allow painting an arbitrary (layer-less)
-  // subtree.
-  RenderBox* box = firstChildBox();
-  skCanvas->translate(x, y);
-
-  GraphicsContext context(skCanvas);
-  Vector<RenderBox*> layers;
-  LayoutRect bounds = box->absoluteBoundingBoxRect();
-  FTL_DCHECK(bounds.x() == 0 && bounds.y() == 0);
-  PaintInfo paintInfo(&context, enclosingIntRect(bounds), box);
-  box->paint(paintInfo, LayoutPoint(), layers);
-  // Note we're ignoring any layers encountered.
-  // TODO(abarth): Remove the concept of RenderLayers.
-
-  skCanvas->translate(-x, -y);
+  m_paragraphImpl->paint(canvas, x, y);
 }
 
 std::vector<TextBox> Paragraph::getRectsForRange(unsigned start, unsigned end) {
-  if (end <= start || start == end)
-    return std::vector<TextBox>();
-
-  unsigned offset = 0;
-  std::vector<TextBox> boxes;
-  for (RenderObject* object = m_renderView.get(); object;
-       object = object->nextInPreOrder()) {
-    if (!object->isText())
-      continue;
-    RenderText* text = toRenderText(object);
-    unsigned length = text->textLength();
-    if (offset + length > start) {
-      unsigned startOffset = offset > start ? 0 : start - offset;
-      unsigned endOffset = end - offset;
-      text->appendAbsoluteTextBoxesForRange(boxes, startOffset, endOffset);
-    }
-    offset += length;
-    if (offset >= end)
-      break;
-  }
-
-  return boxes;
-}
-
-int Paragraph::absoluteOffsetForPosition(const PositionWithAffinity& position) {
-  FTL_DCHECK(position.renderer());
-  unsigned offset = 0;
-  for (RenderObject* object = m_renderView.get(); object;
-       object = object->nextInPreOrder()) {
-    if (object == position.renderer())
-      return offset + position.offset();
-    if (object->isText()) {
-      RenderText* text = toRenderText(object);
-      offset += text->textLength();
-    }
-  }
-  FTL_DCHECK(false);
-  return 0;
+  return m_paragraphImpl->getRectsForRange(start, end);
 }
 
 Dart_Handle Paragraph::getPositionForOffset(double dx, double dy) {
-  LayoutPoint point(dx, dy);
-  PositionWithAffinity position = m_renderView->positionForPoint(point);
-  Dart_Handle result = Dart_NewList(2);
-  Dart_ListSetAt(result, 0, ToDart(absoluteOffsetForPosition(position)));
-  Dart_ListSetAt(result, 1, ToDart(static_cast<int>(position.affinity())));
-  return result;
+  return m_paragraphImpl->getPositionForOffset(dx, dy);
 }
 
 Dart_Handle Paragraph::getWordBoundary(unsigned offset) {
-  String text;
-  int start = 0, end = 0;
-
-  for (RenderObject* object = m_renderView.get(); object;
-       object = object->nextInPreOrder()) {
-    if (!object->isText())
-      continue;
-    RenderText* renderText = toRenderText(object);
-    text.append(renderText->text());
-  }
-
-  TextBreakIterator* it = wordBreakIterator(text, 0, text.length());
-  if (it) {
-    end = it->following(offset);
-    if (end < 0)
-      end = it->last();
-    start = it->previous();
-  }
-
-  Dart_Handle result = Dart_NewList(2);
-  Dart_ListSetAt(result, 0, ToDart(start));
-  Dart_ListSetAt(result, 1, ToDart(end));
-  return result;
+  return m_paragraphImpl->getWordBoundary(offset);
 }
 
 }  // namespace blink

lib/ui/text/paragraph.h

@@ -6,9 +6,14 @@
 #define FLUTTER_LIB_UI_TEXT_PARAGRAPH_H_
 
 #include "flutter/lib/ui/painting/canvas.h"
+#include "flutter/lib/ui/text/paragraph_impl.h"
+#include "flutter/lib/ui/text/paragraph_impl_blink.h"
+#include "flutter/lib/ui/text/paragraph_impl_txt.h"
 #include "flutter/lib/ui/text/text_box.h"
 #include "flutter/sky/engine/core/rendering/RenderView.h"
+#include "flutter/sky/engine/wtf/PassOwnPtr.h"
 #include "lib/tonic/dart_wrappable.h"
+#include "lib/txt/src/paragraph.h"
 
 namespace tonic {
 class DartLibraryNatives;
@@ -22,10 +27,15 @@ class Paragraph : public ftl::RefCountedThreadSafe<Paragraph>,
   FRIEND_MAKE_REF_COUNTED(Paragraph);
 
  public:
-  static ftl::RefPtr<Paragraph> create(PassOwnPtr<RenderView> renderView) {
+  static ftl::RefPtr<Paragraph> Create(PassOwnPtr<RenderView> renderView) {
     return ftl::MakeRefCounted<Paragraph>(renderView);
   }
 
+  static ftl::RefPtr<Paragraph> Create(
+      std::unique_ptr<txt::Paragraph> paragraph) {
+    return ftl::MakeRefCounted<Paragraph>(std::move(paragraph));
+  }
+
   ~Paragraph() override;
 
   double width();
@@ -48,12 +58,14 @@ class Paragraph : public ftl::RefCountedThreadSafe<Paragraph>,
   static void RegisterNatives(tonic::DartLibraryNatives* natives);
 
  private:
-  RenderBox* firstChildBox() const { return m_renderView->firstChildBox(); }
+  std::unique_ptr<ParagraphImpl> m_paragraphImpl;
 
-  int absoluteOffsetForPosition(const PositionWithAffinity& position);
+  RenderBox* firstChildBox() const { return m_renderView->firstChildBox(); }
 
   explicit Paragraph(PassOwnPtr<RenderView> renderView);
 
+  explicit Paragraph(std::unique_ptr<txt::Paragraph> paragraph);
+
   OwnPtr<RenderView> m_renderView;
 };