[Impeller] A text layout and shaping API for the standalone library.

impeller/toolkit/interop/BUILD.gn

@@ -4,6 +4,14 @@
 
 import("//flutter/impeller/tools/impeller.gni")
 
+embed_blob("embedded_icu_data") {
+  symbol_name = "embedded_icu_data"
+  blob = "//flutter/third_party/icu/flutter/icudtl.dat"
+  hdr = "$target_gen_dir/embedded_icu_data.h"
+  cc = "$target_gen_dir/embedded_icu_data.cc"
+  deps = []
+}
+
 impeller_component("interop") {
   sources = [
     "color_filter.cc",
@@ -29,6 +37,12 @@ impeller_component("interop") {
     "object.h",
     "paint.cc",
     "paint.h",
+    "paragraph.cc",
+    "paragraph.h",
+    "paragraph_builder.cc",
+    "paragraph_builder.h",
+    "paragraph_style.cc",
+    "paragraph_style.h",
     "path.cc",
     "path.h",
     "path_builder.cc",
@@ -37,16 +51,21 @@ impeller_component("interop") {
     "surface.h",
     "texture.cc",
     "texture.h",
+    "typography_context.cc",
+    "typography_context.h",
   ]
 
-  deps = [
+  public_deps = [
     "../../base",
     "../../display_list",
     "../../entity",
     "../../renderer/backend",
     "//flutter/display_list",
     "//flutter/fml",
+    "//flutter/third_party/txt",
   ]
+
+  deps = [ ":embedded_icu_data" ]
 }
 
 impeller_component("library") {

impeller/toolkit/interop/dl_builder.cc

@@ -176,4 +176,13 @@ void DisplayListBuilder::DrawTextureRect(const Texture& texture,
   );
 }
 
+void DisplayListBuilder::DrawParagraph(const Paragraph& paragraph,
+                                       Point point) {
+  const auto& handle = paragraph.GetHandle();
+  if (!handle) {
+    return;
+  }
+  handle->Paint(&builder_, point.x, point.y);
+}
+
 }  // namespace impeller::interop

impeller/toolkit/interop/dl_builder.h

@@ -15,6 +15,7 @@
 #include "impeller/toolkit/interop/impeller.h"
 #include "impeller/toolkit/interop/object.h"
 #include "impeller/toolkit/interop/paint.h"
+#include "impeller/toolkit/interop/paragraph.h"
 #include "impeller/toolkit/interop/path.h"
 #include "impeller/toolkit/interop/texture.h"
 
@@ -106,6 +107,8 @@ class DisplayListBuilder final
 
   void DrawDisplayList(const DisplayList& dl, Scalar opacity);
 
+  void DrawParagraph(const Paragraph& paragraph, Point point);
+
   ScopedObject<DisplayList> Build();
 
  private:

impeller/toolkit/interop/formats.h

@@ -9,6 +9,9 @@
 
 #include "flutter/display_list/dl_builder.h"
 #include "flutter/display_list/dl_color.h"
+#include "flutter/third_party/txt/src/txt/font_style.h"
+#include "flutter/third_party/txt/src/txt/font_weight.h"
+#include "flutter/third_party/txt/src/txt/paragraph_style.h"
 #include "impeller/entity/entity.h"
 #include "impeller/geometry/color.h"
 #include "impeller/geometry/matrix.h"
@@ -418,6 +421,68 @@ constexpr flutter::DlColor ToDisplayListType(ImpellerColor color) {
   );
 }
 
+constexpr txt::FontWeight ToTxtType(ImpellerFontWeight weight) {
+  switch (weight) {
+    case ImpellerFontWeight100:
+      return txt::FontWeight::w100;
+    case ImpellerFontWeight200:
+      return txt::FontWeight::w200;
+    case ImpellerFontWeight300:
+      return txt::FontWeight::w300;
+    case ImpellerFontWeight400:
+      return txt::FontWeight::w400;
+    case ImpellerFontWeight500:
+      return txt::FontWeight::w500;
+    case ImpellerFontWeight600:
+      return txt::FontWeight::w600;
+    case ImpellerFontWeight700:
+      return txt::FontWeight::w700;
+    case ImpellerFontWeight800:
+      return txt::FontWeight::w800;
+    case ImpellerFontWeight900:
+      return txt::FontWeight::w900;
+  }
+  return txt::FontWeight::w400;
+}
+
+constexpr txt::FontStyle ToTxtType(ImpellerFontStyle style) {
+  switch (style) {
+    case ImpellerFontStyleNormal:
+      return txt::FontStyle::normal;
+    case ImpellerFontStyleItalic:
+      return txt::FontStyle::italic;
+  }
+  return txt::FontStyle::normal;
+}
+
+constexpr txt::TextAlign ToTxtType(ImpellerTextAlignment align) {
+  switch (align) {
+    case ImpellerTextAlignmentLeft:
+      return txt::TextAlign::left;
+    case ImpellerTextAlignmentRight:
+      return txt::TextAlign::right;
+    case ImpellerTextAlignmentCenter:
+      return txt::TextAlign::center;
+    case ImpellerTextAlignmentJustify:
+      return txt::TextAlign::justify;
+    case ImpellerTextAlignmentStart:
+      return txt::TextAlign::start;
+    case ImpellerTextAlignmentEnd:
+      return txt::TextAlign::end;
+  }
+  return txt::TextAlign::left;
+}
+
+constexpr txt::TextDirection ToTxtType(ImpellerTextDirection direction) {
+  switch (direction) {
+    case ImpellerTextDirectionRTL:
+      return txt::TextDirection::rtl;
+    case ImpellerTextDirectionLTR:
+      return txt::TextDirection::ltr;
+  }
+  return txt::TextDirection::ltr;
+}
+
 }  // namespace impeller::interop
 
 #endif  // FLUTTER_IMPELLER_TOOLKIT_INTEROP_FORMATS_H_