infra: add the partial rendering build option

allow users to set partial rendering as option to use,
enabled by deault.

-Dextra="partial_render, ..."

meson.build

@@ -126,6 +126,12 @@ endif
 
 
 #Extra
+partial_render = get_option('extra').contains('partial_render')
+
+if partial_render
+    config_h.set10('THORVG_PARTIAL_RENDER_SUPPORT', true)
+endif
+
 lottie_expressions = lottie_loader and get_option('extra').contains('lottie_expressions')
 
 if lottie_expressions
@@ -230,6 +236,7 @@ summary(
 
 summary(
   {
+    'Partial Rendering': partial_render,
     'Lottie Expressions': lottie_expressions,
     'OpenGL Variant': gl_variant,
   },

meson_options.txt

@@ -65,6 +65,6 @@ option('file',
 
 option('extra',
    type: 'array',
-   choices: ['', 'opengl_es', 'lottie_expressions'],
+   choices: ['', 'partial_render', 'opengl_es', 'lottie_expressions'],
-   value: ['lottie_expressions'],
+   value: ['partial_render', 'lottie_expressions'],
    description: '"Enable support for extra options')

src/renderer/tvgRender.cpp

@@ -20,7 +20,6 @@
  * SOFTWARE.
  */
 
-#include <algorithm>
 #include "tvgMath.h"
 #include "tvgRender.h"
 
@@ -131,6 +130,9 @@ void RenderRegion::intersect(const RenderRegion& rhs)
     if (max.y < min.y) max.y = min.y;
 }
 
+#ifdef THORVG_PARTIAL_RENDER_SUPPORT
+
+#include <algorithm>
 
 void RenderDirtyRegion::init(uint32_t w, uint32_t h)
 {
@@ -311,6 +313,8 @@ void RenderDirtyRegion::commit()
     }
 }
 
+#endif
+
 /************************************************************************/
 /* RenderTrimPath Class Implementation                                  */
 /************************************************************************/

src/renderer/tvgRender.h

@@ -155,9 +155,11 @@ struct RenderRegion
     uint32_t h() const { return (uint32_t) sh(); }
 };
 
-struct RenderDirtyRegion
+
-{
+#ifdef THORVG_PARTIAL_RENDER_SUPPORT
-public:
+    struct RenderDirtyRegion
+    {
+    public:
         static constexpr const int PARTITIONING = 16;   //must be N*N
 
         void init(uint32_t w, uint32_t h);
@@ -186,7 +188,7 @@ public:
             return partitions[idx].list[partitions[idx].current];
         }
 
-private:
+    private:
         void subdivide(Array<RenderRegion>& targets, uint32_t idx, RenderRegion& lhs, RenderRegion& rhs);
 
         struct Partition
@@ -199,7 +201,23 @@ private:
         Key key;
         Partition partitions[PARTITIONING];
         bool disabled = false;
-};
+    };
+#else
+    struct RenderDirtyRegion
+    {
+        static constexpr const int PARTITIONING = 16;   //must be N*N
+
+        void init(uint32_t w, uint32_t h) {}
+        void commit() {}
+        void add(TVG_UNUSED const RenderRegion* prv, TVG_UNUSED const RenderRegion* cur) {}
+        void clear() {}
+        bool deactivate(TVG_UNUSED bool on) { return true; }
+        bool deactivated() { return true; }
+        const RenderRegion& partition(TVG_UNUSED int idx) { static RenderRegion tmp{}; return tmp; }
+        const Array<RenderRegion>& get(TVG_UNUSED int idx) { static Array<RenderRegion> tmp; return tmp; }
+    };
+#endif
+
 
 struct RenderPath
 {