Use a better image resize code

The box filter from irrlicht produces wrong brightness when using with
different size

android/Android.mk

@@ -150,6 +150,17 @@ LOCAL_CFLAGS       := -I../lib/bullet/src/
 include $(BUILD_STATIC_LIBRARY)
 include $(CLEAR_VARS)
 
+
+# Graphics utils
+LOCAL_MODULE       := graphics_utils
+LOCAL_PATH         := .
+LOCAL_CPP_FEATURES += rtti
+LOCAL_SRC_FILES    := $(wildcard ../lib/graphics_utils/mipmap/*.c)
+LOCAL_CFLAGS       := -I../lib/graphics_utils/mipmap
+include $(BUILD_STATIC_LIBRARY)
+include $(CLEAR_VARS)
+
+
 # Irrlicht
 LOCAL_MODULE       := irrlicht
 LOCAL_PATH         := .
@@ -184,6 +195,7 @@ LOCAL_CFLAGS       := -I../lib/angelscript/include      \
                       -I../lib/ifaddrs                  \
                       -I../lib/irrlicht/include         \
                       -I../lib/irrlicht/source/Irrlicht \
+                      -I../lib/graphics_utils           \
                       -I../src                          \
                       -Iobj/curl/include                \
                       -Iobj/fribidi/include             \
@@ -205,7 +217,7 @@ LOCAL_CPPFLAGS     := -std=gnu++0x
 
 LOCAL_STATIC_LIBRARIES := irrlicht bullet enet ifaddrs angelscript  \
                           vorbisfile vorbis ogg openal curl libssl libcrypto \
-                          gnustl_static raqm fribidi harfbuzz freetype
+                          gnustl_static raqm fribidi harfbuzz freetype graphics_utils
 
 include $(BUILD_SHARED_LIBRARY)
 include $(CLEAR_VARS)

lib/irrlicht/source/Irrlicht/CImage.cpp

@@ -368,11 +368,6 @@ void CImage::copyToScalingBoxFilter(IImage* target, s32 bias, bool blend)
 	s32 fy = core::ceil32( sourceYStep );
 	f32 sx;
 	f32 sy;
-	// Color emoji scaled wrongly with overbright color if larger than 4
-	if (fx > 4)
-		fx = 4;
-	if (fy > 4)
-		fy = 4;
 
 	sy = 0.f;
 	for ( u32 y = 0; y != destSize.Height; ++y )

src/font/font_with_face.cpp

@@ -36,6 +36,14 @@
 #include "GlyphLayout.h"
 #include <array>
 
+#ifndef SERVER_ONLY
+extern "C"
+{
+    #include <mipmap/img.h>
+    #include <mipmap/imgresize.h>
+}
+#endif
+
 // ----------------------------------------------------------------------------
 /** Constructor. It will initialize the \ref m_spritebank and TTF files to use.
  *  \param name The name of face, used by irrlicht to distinguish spritebank.
@@ -280,7 +288,27 @@ void FontWithFace::insertGlyph(unsigned font_number, unsigned glyph_index)
                 ->getVideoDriver()->createImage(video::ECF_A8R8G8B8,
                 { cur_glyph_width , cur_glyph_height});
             assert(scaled);
-            unscaled->copyToScalingBoxFilter(scaled);
+            if (cur_glyph_width >= bits->width ||
+                cur_glyph_height >= bits->rows)
+            {
+                unscaled->copyToScaling(scaled);
+            }
+            else
+            {
+                imReduceOptions options;
+                imReduceSetOptions(&options, IM_REDUCE_FILTER_LINEAR/*filter*/,
+                    3/*hopcount*/, 16.0f/*alpha*/, 1.0f/*amplifynormal*/,
+                    0.0f/*normalsustainfactor*/);
+                int ret = imReduceImageKaiserData((unsigned char*)scaled->lock(),
+                    (unsigned char*)unscaled->lock(), bits->width, bits->rows, 4,
+                    bits->width * 4, cur_glyph_width , cur_glyph_height,
+                    &options);
+                if (ret != 1)
+                {
+                    Log::error("FontWithFace",
+                        "Error reduce bitmap font size.");
+                }
+            }
             uint8_t* scaled_data = (uint8_t*)scaled->lock();
             for (unsigned int i = 0; i < cur_glyph_width * cur_glyph_height;
                  i++)