From 922d7f6c96f81a33538900f8a8992a5b6f640874 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 23 Apr 2020 02:00:05 +0800
Subject: ...

---
 include/cru/platform/graph_base.hpp          | 9 +++++++++
 include/cru/ui/render/text_render_object.hpp | 2 +-
 include/cru/win/graph/direct/text_layout.hpp | 2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

(limited to 'include')

diff --git a/include/cru/platform/graph_base.hpp b/include/cru/platform/graph_base.hpp
index 0b997770..c880c7a2 100644
--- a/include/cru/platform/graph_base.hpp
+++ b/include/cru/platform/graph_base.hpp
@@ -229,6 +229,15 @@ struct TextRange final {
 
   gsl::index GetEnd() const { return position + count; }
 
+  TextRange Normalize() const {
+    auto result = *this;
+    if (result.count < 0) {
+      result.position += result.count;
+      result.count = -result.count;
+    }
+    return result;
+  }
+
   gsl::index position = 0;
   gsl::index count = 0;
 };
diff --git a/include/cru/ui/render/text_render_object.hpp b/include/cru/ui/render/text_render_object.hpp
index 1c472753..c062c9f0 100644
--- a/include/cru/ui/render/text_render_object.hpp
+++ b/include/cru/ui/render/text_render_object.hpp
@@ -27,7 +27,7 @@ class TextRenderObject : public RenderObject {
   void SetFont(std::shared_ptr<platform::graph::IFont> font);
 
   std::vector<Rect> TextRangeRect(const TextRange& text_range);
-  Point TextSingleRect(int position, bool trailing);
+  Point TextSingleRect(gsl::index position, bool trailing);
   platform::graph::TextHitTestResult TextHitTest(const Point& point);
 
   std::optional<TextRange> GetSelectionRange() const {
diff --git a/include/cru/win/graph/direct/text_layout.hpp b/include/cru/win/graph/direct/text_layout.hpp
index a9b89011..90faadf9 100644
--- a/include/cru/win/graph/direct/text_layout.hpp
+++ b/include/cru/win/graph/direct/text_layout.hpp
@@ -37,6 +37,8 @@ class DWriteTextLayout : public DirectGraphResource,
   void SetMaxHeight(float max_height) override;
 
   Rect GetTextBounds() override;
+  // Return empty vector if text_range.count is 0. Text range could be in
+  // reverse direction, it should be normalized first in implementation.
   std::vector<Rect> TextRangeRect(const TextRange& text_range) override;
   Point TextSingleRect(gsl::index position, bool trailing) override;
   TextHitTestResult HitTest(const Point& point) override;
-- 
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