Add NanoImage::update()

Signed-off-by: falkTX <falktx@falktx.com>

dgl/NanoVG.hpp

@@ -112,6 +112,11 @@ public:
     */
     GLuint getTextureHandle() const;
 
+   /**
+      Update the image data in-place.
+    */
+    void update(const uchar* data);
+
 private:
     Handle fHandle;
     Size<uint> fSize;

dgl/src/NanoVG.cpp

@@ -279,6 +279,14 @@ GLuint NanoImage::getTextureHandle() const
     return nvglImageHandle(fHandle.context, fHandle.imageId);
 }
 
+void NanoImage::update(const uchar* const data)
+{
+    DISTRHO_SAFE_ASSERT_RETURN(fHandle.context != nullptr && fHandle.imageId != 0,);
+    DISTRHO_SAFE_ASSERT_RETURN(data != nullptr,);
+
+    nvgUpdateImage(fHandle.context, fHandle.imageId, data);
+}
+
 void NanoImage::_updateSize()
 {
     int w=0, h=0;