svgio visitor, add draw commands and create the from svg

Adds a visitor for svgio for visiting svg nodes and create something
useful from them.

Basic draw commands - a tree of draw commands (with sub-pixel
precision support) just to store a simple definition for drawing.

Adds a svg draw visitor and create draw commands from the svg
structure and expose the commands through UNO API.

Change-Id: I073e891a2cffdd76d4e3b838590e3a19c998e9bf
Reviewed-on: https://gerrit.libreoffice.org/68770
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
(cherry picked from commit 7894fd2b442eff45ecf14088ebd17ee9f8678752)

1 files changed, 12 insertions, 0 deletions

diff --git a/svgio/inc/svgnode.hxx b/svgio/inc/svgnode.hxx
index 22df883b22b3..c10179bf236a 100644
--- a/svgio/inc/svgnode.hxx
+++ b/svgio/inc/svgnode.hxx
@@ -80,6 +80,8 @@ namespace svgio
         // which members should be initialized
         Display getDisplayFromContent(const OUString& aContent);
 
+      class Visitor;
+
         class SvgNode : public InfoProvider
         {
         private:
@@ -137,6 +139,8 @@ namespace svgio
             SvgNode(const SvgNode&) = delete;
             SvgNode& operator=(const SvgNode&) = delete;
 
+            void accept(Visitor& rVisitor);
+
             /// scan helper to read and interpret a local CssStyle to mpLocalCssStyle
             void readLocalCssStyle(const OUString& aContent);
 
@@ -182,6 +186,14 @@ namespace svgio
             /// alternative parent
             void setAlternativeParent(const SvgNode* pAlternativeParent = nullptr) { mpAlternativeParent = pAlternativeParent; }
         };
+
+      class Visitor
+      {
+      public:
+            virtual ~Visitor() = default;
+            virtual void visit(SvgNode const & pNode) = 0;
+      };
+
     } // end of namespace svgreader
 } // end of namespace svgio