apis: remove a beta api.

- const uint32_t* Picture::data(uint32_t* w, uint32_t* h) const

Returning pixel data is not guaranteed as the picture may contain vector resources.
Remove it unless it's absolutely necessary.

@Issue: https://github.com/thorvg/thorvg/issues/1372

inc/thorvg.h

@@ -1307,17 +1307,6 @@ public:
      */
     Result size(float* w, float* h) const noexcept;
 
-    /**
-     * @brief Gets the pixels information of the picture.
-     *
-     * @note The data must be pre-multiplied by the alpha channels.
-     *
-     * @warning Please do not use it, this API is not official one. It could be modified in the next version.
-     *
-     * @BETA_API
-     */
-    const uint32_t* data(uint32_t* w, uint32_t* h) const noexcept;
-
     /**
      * @brief Loads a raw data from a memory block with a given size.
      *

src/lib/tvgPicture.cpp

@@ -97,23 +97,6 @@ Result Picture::size(float* w, float* h) const noexcept
 }
 
 
-const uint32_t* Picture::data(uint32_t* w, uint32_t* h) const noexcept
-{
-    //Try it, If not loaded yet.
-    pImpl->load();
-
-    if (pImpl->loader) {
-        if (w) *w = static_cast<uint32_t>(pImpl->loader->w);
-        if (h) *h = static_cast<uint32_t>(pImpl->loader->h);
-    } else {
-        if (w) *w = 0;
-        if (h) *h = 0;
-    }
-    if (pImpl->surface) return pImpl->surface->buf32;
-    else return nullptr;
-}
-
-
 Result Picture::mesh(const Polygon* triangles, uint32_t triangleCnt) noexcept
 {
     if (!triangles && triangleCnt > 0) return Result::InvalidArguments;

src/lib/tvgPictureImpl.h

@@ -318,6 +318,22 @@ struct Picture::Impl
         load();
         return new PictureIterator(paint);
     }
+
+    uint32_t* data(uint32_t* w, uint32_t* h)
+    {
+        //Try it, If not loaded yet.
+        load();
+
+        if (loader) {
+            if (w) *w = static_cast<uint32_t>(loader->w);
+            if (h) *h = static_cast<uint32_t>(loader->h);
+        } else {
+            if (w) *w = 0;
+            if (h) *h = 0;
+        }
+        if (surface) return surface->buf32;
+        else return nullptr;
+    }
 };
 
 #endif //_TVG_PICTURE_IMPL_H_

src/savers/tvg/tvgTvgSaver.cpp

@@ -26,6 +26,7 @@
 #include "tvgTvgSaver.h"
 #include "tvgLzw.h"
 #include "tvgShapeImpl.h"
+#include "tvgPictureImpl.h"
 
 #ifdef _WIN32
     #include <malloc.h>
@@ -607,7 +608,7 @@ TvgBinCounter TvgSaver::serializePicture(const Picture* picture, const Matrix* p
 
     //Case - Bitmap Image:
     uint32_t w, h;
-    auto pixels = picture->data(&w, &h);
+    auto pixels = P(picture)->data(&w, &h);
     if (!pixels) return 0;
 
     writeTag(TVG_TAG_CLASS_PICTURE);