runtime: refactor text.buildRenderStyles

This PR does sth similar to https://github.com/rive-app/rive/pull/8988. This PR is written in preparation for text follow path, whose runtime version will be very similar to https://github.com/rive-app/rive/pull/8961/files.

There are golden tests covering text rendering in 8988.

Diffs=
63c22338aa runtime: refactor text.buildRenderStyles (#9009)

Co-authored-by: Susan Wang <[email protected]>

.rive_head

@@ -1 +1 @@
-8f9da9d694556c39397c96dbd24dde118220f0ed
+63c22338aa4ae1ff4dd872ed7ed9ee096baf6b48

include/rive/text/text.hpp

@@ -2,10 +2,12 @@
 #define _RIVE_TEXT_CORE_HPP_
 #include "rive/generated/text/text_base.hpp"
 #include "rive/math/aabb.hpp"
+#include "rive/math/rect.hpp"
 #include "rive/text/text_value_run.hpp"
 #include "rive/text_engine.hpp"
 #include "rive/shapes/shape_paint_path.hpp"
 #include "rive/simple_array.hpp"
+#include <unordered_map>
 #include <vector>
 #include "rive/text/glyph_lookup.hpp"
 namespace rive
@@ -178,6 +180,22 @@ class OrderedLine
     }
 };
 
+struct TextBoundsInfo
+{
+    float minY;
+    float maxWidth;
+    float totalHeight;
+    int ellipsisLine;
+    bool isEllipsisLineLast;
+};
+
+enum class LineIter : uint8_t
+{
+    drawLine,
+    skipThisLine,
+    yOutOfBounds
+};
+
 class TextStyle;
 class Text : public TextBase
 {
@@ -294,6 +312,12 @@ class Text : public TextBase
     StyledText m_modifierStyledText;
 
     GlyphLookup m_glyphLookup;
+
+    std::unordered_map<uint16_t, std::vector<Rect>> m_textValueRunToRects;
+    void clearRenderStyles();
+    TextBoundsInfo computeBoundsInfo();
+    LineIter shouldDrawLine(float y, float totalHeight, const GlyphLine& line);
+
 #endif
     float m_layoutWidth = NAN;
     float m_layoutHeight = NAN;