Complete hit test in text layout.

3 files changed, 44 insertions, 4 deletions

diff --git a/include/cru/platform/graph/text_layout.hpp b/include/cru/platform/graph/text_layout.hpp
index 4f6e81e1..d1cfb44b 100644
--- a/include/cru/platform/graph/text_layout.hpp
+++ b/include/cru/platform/graph/text_layout.hpp
@@ -8,6 +8,12 @@
 namespace cru::platform::graph {
 struct IFont;
 
+struct TextHitTestResult {
+  int position;
+  bool trailing;
+  bool insideText;
+};
+
 struct ITextLayout : virtual IGraphResource {
   virtual std::string GetText() = 0;
   virtual void SetText(std::string new_text) = 0;
@@ -20,5 +26,7 @@ struct ITextLayout : virtual IGraphResource {
 
   virtual Rect GetTextBounds() = 0;
   virtual std::vector<Rect> TextRangeRect(const TextRange& text_range) = 0;
+  virtual Point TextSingleRect(int position, bool trailing) = 0;
+  virtual TextHitTestResult HitTest(const Point& point) = 0;
 };
 }  // namespace cru::platform::graph
diff --git a/include/cru/win/graph/direct/text_layout.hpp b/include/cru/win/graph/direct/text_layout.hpp
index 5a8f3f9c..5f7be9f3 100644
--- a/include/cru/win/graph/direct/text_layout.hpp
+++ b/include/cru/win/graph/direct/text_layout.hpp
@@ -38,6 +38,8 @@ class DWriteTextLayout : public DirectGraphResource,
 
   Rect GetTextBounds() override;
   std::vector<Rect> TextRangeRect(const TextRange& text_range) override;
+  Point TextSingleRect(int position, bool trailing) override;
+  TextHitTestResult HitTest(const Point& point) override;
 
  private:
   std::string text_;
diff --git a/src/win/graph/direct/text_layout.cpp b/src/win/graph/direct/text_layout.cpp
index a070d288..ecee1727 100644
--- a/src/win/graph/direct/text_layout.cpp
+++ b/src/win/graph/direct/text_layout.cpp
@@ -80,10 +80,10 @@ std::vector<Rect> DWriteTextLayout::TextRangeRect(const TextRange& text_range) {
 
   std::vector<DWRITE_HIT_TEST_METRICS> hit_test_metrics(metrics_count);
   UINT32 actual_count;
-  text_layout_->HitTestTextRange(static_cast<UINT32>(start_index),
-                                 static_cast<UINT32>(end_index - start_index),
-                                 0, 0, hit_test_metrics.data(), metrics_count,
-                                 &actual_count);
+  ThrowIfFailed(text_layout_->HitTestTextRange(
+      static_cast<UINT32>(start_index),
+      static_cast<UINT32>(end_index - start_index), 0, 0,
+      hit_test_metrics.data(), metrics_count, &actual_count));
 
   hit_test_metrics.erase(hit_test_metrics.cbegin() + actual_count,
                          hit_test_metrics.cend());
@@ -99,4 +99,34 @@ std::vector<Rect> DWriteTextLayout::TextRangeRect(const TextRange& text_range) {
 
   return result;
 }
+
+Point DWriteTextLayout::TextSingleRect(int position, bool trailing) {
+  const auto index =
+      IndexUtf8ToUtf16(text_, static_cast<int>(position), w_text_);
+
+  DWRITE_HIT_TEST_METRICS metrics;
+  FLOAT left;
+  FLOAT top;
+  ThrowIfFailed(text_layout_->HitTestTextPosition(static_cast<UINT32>(index),
+                                                  static_cast<BOOL>(trailing),
+                                                  &left, &top, &metrics));
+  return Point{left, top};
+}
+
+TextHitTestResult DWriteTextLayout::HitTest(const Point& point) {
+  BOOL trailing;
+  BOOL inside;
+  DWRITE_HIT_TEST_METRICS metrics;
+
+  ThrowIfFailed(text_layout_->HitTestPoint(point.x, point.y, &trailing, &inside,
+                                           &metrics));
+
+  const auto index =
+      IndexUtf16ToUtf8(w_text_, static_cast<int>(metrics.textPosition), text_);
+  TextHitTestResult result;
+  result.position = index;
+  result.trailing = trailing != 0;
+  result.insideText = inside != 0;
+  return result;
+}
 }  // namespace cru::platform::graph::win::direct