Add SVG import and rendering features

include/tgfx/svg/SVGAttribute.h

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+/////////////////////////////////////////////////////////////////////////////////////////////////
+//
+//  Tencent is pleased to support the open source community by making tgfx available.
+//
+//  Copyright (C) 2024 THL A29 Limited, a Tencent company. All rights reserved.
+//
+//  Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+//  in compliance with the License. You may obtain a copy of the License at
+//
+//      https://opensource.org/licenses/BSD-3-Clause
+//
+//  unless required by applicable law or agreed to in writing, software distributed under the
+//  license is distributed on an "as is" basis, without warranties or conditions of any kind,
+//  either express or implied. see the license for the specific language governing permissions
+//  and limitations under the license.
+//
+/////////////////////////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include "tgfx/svg/SVGTypes.h"
+
+namespace tgfx {
+enum class SVGAttribute {
+  ClipRule,
+  Color,
+  ColorInterpolation,
+  ColorInterpolationFilters,
+  Cx,  // <circle>, <ellipse>, <radialGradient>: center x position
+  Cy,  // <circle>, <ellipse>, <radialGradient>: center y position
+  Fill,
+  FillOpacity,
+  FillRule,
+  Filter,
+  FilterUnits,
+  FontFamily,
+  FontSize,
+  FontStyle,
+  FontWeight,
+  Fx,  // <radialGradient>: focal point x position
+  Fy,  // <radialGradient>: focal point y position
+  GradientUnits,
+  GradientTransform,
+  Height,
+  Href,
+  Opacity,
+  Points,
+  PreserveAspectRatio,
+  R,   // <circle>, <radialGradient>: radius
+  Rx,  // <ellipse>,<rect>: horizontal (corner) radius
+  Ry,  // <ellipse>,<rect>: vertical (corner) radius
+  SpreadMethod,
+  Stroke,
+  StrokeDashArray,
+  StrokeDashOffset,
+  StrokeOpacity,
+  StrokeLineCap,
+  StrokeLineJoin,
+  StrokeMiterLimit,
+  StrokeWidth,
+  Transform,
+  Text,
+  TextAnchor,
+  ViewBox,
+  Visibility,
+  Width,
+  X,
+  X1,  // <line>: first endpoint x
+  X2,  // <line>: second endpoint x
+  Y,
+  Y1,  // <line>: first endpoint y
+  Y2,  // <line>: second endpoint y
+
+  Unknown,
+};
+
+struct SVGPresentationAttributes {
+  static SVGPresentationAttributes MakeInitial();
+
+  SVGProperty<SVGPaint, true> Fill;
+  SVGProperty<SVGNumberType, true> FillOpacity;
+  SVGProperty<SVGFillRule, true> FillRule;
+  SVGProperty<SVGFillRule, true> ClipRule;
+
+  SVGProperty<SVGPaint, true> Stroke;
+  SVGProperty<SVGDashArray, true> StrokeDashArray;
+  SVGProperty<SVGLength, true> StrokeDashOffset;
+  SVGProperty<SVGLineCap, true> StrokeLineCap;
+  SVGProperty<SVGLineJoin, true> StrokeLineJoin;
+  SVGProperty<SVGNumberType, true> StrokeMiterLimit;
+  SVGProperty<SVGNumberType, true> StrokeOpacity;
+  SVGProperty<SVGLength, true> StrokeWidth;
+
+  SVGProperty<SVGVisibility, true> Visibility;
+
+  SVGProperty<SVGColorType, true> Color;
+  SVGProperty<SVGColorspace, true> ColorInterpolation;
+  SVGProperty<SVGColorspace, true> ColorInterpolationFilters;
+
+  SVGProperty<SVGFontFamily, true> FontFamily;
+  SVGProperty<SVGFontStyle, true> FontStyle;
+  SVGProperty<SVGFontSize, true> FontSize;
+  SVGProperty<SVGFontWeight, true> FontWeight;
+  SVGProperty<SVGTextAnchor, true> TextAnchor;
+
+  // uninherited
+  SVGProperty<SVGNumberType, false> Opacity;
+  SVGProperty<SVGFuncIRI, false> ClipPath;
+  SVGProperty<SVGDisplay, false> Display;
+  SVGProperty<SVGFuncIRI, false> Mask;
+  SVGProperty<SVGFuncIRI, false> Filter;
+  SVGProperty<SVGColor, false> StopColor;
+  SVGProperty<SVGNumberType, false> StopOpacity;
+  SVGProperty<SVGColor, false> FloodColor;
+  SVGProperty<SVGNumberType, false> FloodOpacity;
+  SVGProperty<SVGColor, false> LightingColor;
+};
+}  // namespace tgfx

include/tgfx/svg/SVGDOM.h

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+/////////////////////////////////////////////////////////////////////////////////////////////////
+//
+//  Tencent is pleased to support the open source community by making tgfx available.
+//
+//  Copyright (C) 2024 THL A29 Limited, a Tencent company. All rights reserved.
+//
+//  Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+//  in compliance with the License. You may obtain a copy of the License at
+//
+//      https://opensource.org/licenses/BSD-3-Clause
+//
+//  unless required by applicable law or agreed to in writing, software distributed under the
+//  license is distributed on an "as is" basis, without warranties or conditions of any kind,
+//  either express or implied. see the license for the specific language governing permissions
+//  and limitations under the license.
+//
+/////////////////////////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include <memory>
+#include "tgfx/core/Canvas.h"
+#include "tgfx/core/Data.h"
+#include "tgfx/core/Picture.h"
+#include "tgfx/core/Size.h"
+#include "tgfx/svg/SVGFontManager.h"
+#include "tgfx/svg/node/SVGSVG.h"
+
+namespace tgfx {
+
+class SVGNode;
+using SVGIDMapper = std::unordered_map<std::string, std::shared_ptr<SVGNode>>;
+
+/**
+ * The SVGDOM class represents an SVG Document Object Model (DOM). It provides functionality to 
+ * traverse the SVG DOM tree and render the SVG.
+ * 
+ * Usage:
+ * 
+ * 1. Traversing the SVG DOM tree:
+ *    - Use getRoot() to obtain the root node. From the root node, you can access its attributes 
+ *      and child nodes, and then visit the child nodes.
+ *
+ * 2. Rendering the SVG:
+ *    - The simplest way to render is by calling render(canvas,nullptr). If you need to render text
+ *      with specific fonts or set the size of the SVG, you can use the following methods.
+ *    - If text rendering is required, use collectRenderFonts() to gather the necessary typefaces. 
+ *      Traverse the typefaces collected by the fontManager and set the typeface objects.
+ *    - Render the SVG using the render() method. If text rendering is needed, pass in the 
+ *      fontManager object. Otherwise, you can pass in nullptr.
+ *    - To set the size of the SVG, use setContainerSize(). If not set, the size of the root SVG
+ *      node will be used.
+ */
+class SVGDOM {
+ public:
+  /**
+   * Creates an SVGDOM object from the provided data.
+   */
+  static std::shared_ptr<SVGDOM> Make(const std::shared_ptr<Data>& data);
+
+  /**
+   * Returns the root SVG node.
+   */
+  const std::shared_ptr<SVGSVG>& getRoot() const;
+
+  /**
+   * Collects the font families and styles used for rendering and saves them in the font manager.
+   */
+  void collectRenderFonts(const std::shared_ptr<SVGFontManager>& fontManager);
+
+  /**
+   * Renders the SVG to the provided canvas.
+   * @param canvas The canvas to render to.
+   * @param fontManager The font manager for rendering SVG text. If no text rendering is needed, 
+   * this can be nullptr, and text will not be rendered. If no specific font is set, the default 
+   * font will be used for rendering.
+   */
+  void render(Canvas* canvas, const std::shared_ptr<SVGFontManager>& fontManager = nullptr);
+
+  /**
+   * Sets the size of the container that the SVG will be rendered into.
+   */
+  void setContainerSize(const Size& size);
+
+  /**
+   * Returns the size of the container that the SVG will be rendered into.
+   */
+  const Size& getContainerSize() const;
+
+ private:
+  /**
+   * Construct a new SVGDOM object
+   */
+  SVGDOM(std::shared_ptr<SVGSVG> root, SVGIDMapper&& mapper);
+
+  const std::shared_ptr<SVGSVG> root = nullptr;
+  const SVGIDMapper nodeIDMapper = {};
+  Size containerSize = {};
+};
+}  // namespace tgfx

include/tgfx/svg/SVGFontManager.h

@@ -0,0 +1,114 @@
+/////////////////////////////////////////////////////////////////////////////////////////////////
+//
+//  Tencent is pleased to support the open source community by making tgfx available.
+//
+//  Copyright (C) 2024 THL A29 Limited, a Tencent company. All rights reserved.
+//
+//  Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+//  in compliance with the License. You may obtain a copy of the License at
+//
+//      https://opensource.org/licenses/BSD-3-Clause
+//
+//  unless required by applicable law or agreed to in writing, software distributed under the
+//  license is distributed on an "as is" basis, without warranties or conditions of any kind,
+//  either express or implied. see the license for the specific language governing permissions
+//  and limitations under the license.
+//
+/////////////////////////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include <algorithm>
+#include <memory>
+#include <unordered_map>
+#include <vector>
+#include "tgfx/core/Typeface.h"
+#include "tgfx/svg/SVGTypes.h"
+#include "tgfx/svg/node/SVGNode.h"
+namespace tgfx {
+
+/**
+ * Information about SVG fonts, including weight and style (Oblique, Italic, Normal).
+ */
+class SVGFontInfo {
+ public:
+  struct Hash {
+    std::size_t operator()(const SVGFontInfo& info) const {
+      return std::hash<int>()(static_cast<int>(info._weight)) ^
+             std::hash<int>()(static_cast<int>(info._style));
+    }
+  };
+
+  SVGFontInfo(SVGFontWeight::Type weight, SVGFontStyle::Type style)
+      : _weight(weight), _style(style) {
+  }
+
+  bool operator==(const SVGFontInfo& other) const {
+    return _weight == other._weight && _style == other._style;
+  }
+
+  SVGFontWeight::Type weight() const {
+    return _weight;
+  }
+  SVGFontStyle::Type style() const {
+    return _style;
+  }
+
+ private:
+  SVGFontWeight::Type _weight;
+  SVGFontStyle::Type _style;
+};
+
+/**
+ * Manages fonts for SVG rendering, using fontFamily and SVGFontInfo as keys to store Typeface 
+ * objects.
+ */
+class SVGFontManager {
+ public:
+  /**
+   * Creates an SVGFontManager object with the default typeface. If the default typeface is nullptr,
+   * retrun nullptr.
+   */
+  static std::shared_ptr<SVGFontManager> Make(const std::shared_ptr<Typeface>& defaultTypeface);
+
+  /**
+   * Destructor.
+   */
+  ~SVGFontManager() = default;
+
+  /**
+   * Adds a font style to the font manager. If the font family and style already exist, this method
+   * does nothing and returns false.
+   */
+  bool setTypeface(const std::string& fontFamily, SVGFontInfo info,
+                   const std::shared_ptr<Typeface>& typeface);
+
+  /**
+   * Get the font families stored in the font manager.
+   */
+  std::vector<std::string> getFontFamilies() const;
+
+  /**
+   * Get the font styles stored in the font manager for the specified font family.
+   */
+  std::vector<SVGFontInfo> getFontInfos(const std::string& fontFamily) const;
+
+ protected:
+  void addFontStyle(const std::string& fontFamily, SVGFontInfo info);
+
+  std::shared_ptr<Typeface> getTypefaceForRendering(const std::string& fontFamily,
+                                                    SVGFontInfo info) const;
+
+ private:
+  explicit SVGFontManager(const std::shared_ptr<Typeface>& typeface);
+
+  std::unordered_map<std::string,
+                     std::unordered_map<SVGFontInfo, std::shared_ptr<Typeface>, SVGFontInfo::Hash>>
+      typefaceMap;
+  std::shared_ptr<Typeface> defaultTypeface;
+
+  friend class SVGRenderContext;
+  friend class SVGDOM;
+};
+
+}  // namespace tgfx