Improved svg support

[kunitoki]

This pull request introduces a range of improvements and fixes to the SVG parsing and rendering code, with a focus on more accurate style inheritance, improved handling of SVG attributes (such as preserveAspectRatio, stroke-dasharray, and stroke-miterlimit), and a significant refactor of SVG filter primitive support. The changes also include bug fixes in XML entity handling and bounds calculation, as well as enhancements to code clarity and maintainability.

The most important changes are:

SVG Style and Attribute Handling Improvements

• Improved inheritance of fill and stroke attributes in SVGParser::parseElement, ensuring child elements correctly inherit all relevant style properties from their parents unless explicitly overridden. This includes fill, stroke, opacity, dash array, join/cap, miter limit, and marker/clip attributes.
• Enhanced stroke-dasharray and stroke-dashoffset parsing in both CSS and attribute styles, with correct handling of the "none" value and negative dash values being ignored. Added a strokeDashArrayNone flag to SVGElement to track explicit disabling of dashes. [1] [2] [3]
• Changed stroke-miterlimit in SVGElement from a default value to std::optional, so it is only set if specified, and added support for inheriting it from parent elements. [1] [2]
• Added support for parsing and storing preserveAspectRatio on the root SVG element, including fitting and justification, and storing these in SVGData. [1] [2]

SVG Filter Refactor

• Refactored SVG filter support by introducing a base SVGFilterPrimitive class and specific primitives such as SVGFEBlend and SVGFEGaussianBlur, allowing for more extensible and accurate representation of SVG filter chains. The SVGFilter struct now contains a list of filter primitives instead of a single blur parameter.

SVG Parsing and Calculation Fixes

• Improved bounds calculation in SVGDocument::calculateBounds to recursively visit all elements and apply transforms, ensuring accurate document bounds.
• Fixed parsing of points attributes for polyline and polygon elements by removing empty strings from coordinate arrays. [1] [2]
• Set the SVG viewBox to the computed bounds if no viewBox is specified but bounds are available, improving rendering of SVGs without explicit viewBox.

XML Entity Handling Bug Fixes

• Fixed bugs in XML entity expansion and reading, ensuring correct substring indices are used when resolving entities, preventing parsing errors. [1] [2]

Code Quality and Maintenance

• Added and clarified log messages, improved function signatures for clarity, and made minor code cleanups throughout the codebase. [1] [2] [3] [4]

These changes collectively improve SVG rendering fidelity, code extensibility, and robustness.

[codecov]

Codecov Report

❌ Patch coverage is 81.56780% with 87 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.91%. Comparing base (27cf12f) to head (adfb4b4).

Files with missing lines	Patch %	Lines
modules/yup_graphics/drawables/yup_Drawable.cpp	79.82%	46 Missing ⚠️
modules/yup_graphics/svg/yup_SVGParser.cpp	80.93%	41 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #118      +/-   ##
==========================================
+ Coverage   78.79%   78.91%   +0.11%     
==========================================
  Files         627      628       +1     
  Lines       61533    61870     +337     
==========================================
+ Hits        48487    48823     +336     
- Misses      13046    13047       +1     

Files with missing lines	Coverage Δ
modules/yup_core/xml/yup_XmlDocument.cpp	84.28% <100.00%> (+1.94%)	⬆️
modules/yup_graphics/drawables/yup_Drawable.h	100.00% <100.00%> (ø)
modules/yup_graphics/svg/yup_SVGCssParser.cpp	99.63% <100.00%> (+<0.01%)	⬆️
modules/yup_graphics/svg/yup_SVGDocument.cpp	94.28% <100.00%> (+1.69%)	⬆️
modules/yup_graphics/svg/yup_SVGParser.cpp	81.71% <80.93%> (+1.36%)	⬆️
modules/yup_graphics/drawables/yup_Drawable.cpp	69.84% <79.82%> (+4.04%)	⬆️

... and 10 files with indirect coverage changes

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