backport commit #a0ea6361 from git/master to frameworks branch

CCBUGS: 333540
CCBUGS: 319383
CCBUGS: 345168

libs/dimg/dimg.cpp

@@ -1204,7 +1204,7 @@ void DImg::prepareSubPixelAccess()
         }
         else
         {
-            float d = sqrt(((float)i) / LANCZOS_TABLE_RES);
+            float d          = sqrt(((float)i) / LANCZOS_TABLE_RES);
             lanczos_func [i] = (LANCZOS_DATA_TYPE)((LANCZOS_DATA_ONE * LANCZOS_SUPPORT *
                                                     sin(M_PI * d) * sin((M_PI / LANCZOS_SUPPORT) * d)) /
                                                    (M_PI * M_PI * d * d));
@@ -1264,7 +1264,7 @@ static inline int normalizeAndClamp(int norm, int sum, int max)
 
 DColor DImg::getSubPixelColor(float x, float y) const
 {
-    if (isNull() || x >= width() || y >= height())
+    if (isNull() || x < 0 || y < 0 || x >= width() || y >= height())
     {
         return DColor();
     }
@@ -1301,16 +1301,15 @@ DColor DImg::getSubPixelColor(float x, float y) const
             for (xc = xs; xc <= xe; xc += 1.0, dx -= 1.0)
             {
                 uchar* data = bits() + (int)(xs * bytesDepth()) + (int)(width() * ys * bytesDepth());
-                DColor src = DColor(data, sixteenBit());
-
-                float d = dx * dx + dy * dy;
+                DColor src  = DColor(data, sixteenBit());
+                float d     = dx * dx + dy * dy;
 
                 if (d >= LANCZOS_SUPPORT * LANCZOS_SUPPORT)
                 {
                     continue;
                 }
 
-                d    = lanczos_func [(int)(d * LANCZOS_TABLE_RES)];
+                d     = lanczos_func [(int)(d * LANCZOS_TABLE_RES)];
                 norm += d;
                 sumR += d * src.red();
                 sumG += d * src.green();
@@ -1361,7 +1360,7 @@ DColor DImg::getSubPixelColor(float x, float y) const
                 continue;
             }
 
-            d    = lanczos_func [(d * LANCZOS_TABLE_RES) >> 12];
+            d     = lanczos_func [(d * LANCZOS_TABLE_RES) >> 12];
             norm += d;
             sumR += d * src.red();
             sumG += d * src.green();
@@ -1381,6 +1380,16 @@ DColor DImg::getSubPixelColor(float x, float y) const
 
 DColor DImg::getSubPixelColorFast(float x, float y) const
 {
+    if (x < 0)
+    {
+        x = 0;
+    }
+
+    if (y < 0)
+    {
+        y = 0;
+    }
+
     int xx    = (int)x;
     int yy    = (int)y;
     float d_x = x - (int)x;