diff --git a/source/paint/graphics.cpp b/source/paint/graphics.cpp
index c622aa3f..20048291 100644
--- a/source/paint/graphics.cpp
+++ b/source/paint/graphics.cpp
@@ -1473,7 +1473,7 @@ namespace paint
 			{
 				if (vertical)
 				{
-					int x1 = good_rct.x, x2 = good_rct.right();
+					int x1 = good_rct.x, x2 = good_rct.right() - 1;
 					auto y = good_rct.y;
 					for (; y < endpos; ++y)
 					{
@@ -1489,7 +1489,7 @@ namespace paint
 				}
 				else
 				{
-					int y1 = good_rct.y, y2 = good_rct.bottom();
+					int y1 = good_rct.y, y2 = good_rct.bottom() - 1;
 					auto x = good_rct.x;
 					for (; x < endpos; ++x)
 					{
diff --git a/source/paint/pixel_buffer.cpp b/source/paint/pixel_buffer.cpp
index 81316842..304bbc33 100644
--- a/source/paint/pixel_buffer.cpp
+++ b/source/paint/pixel_buffer.cpp
@@ -238,10 +238,18 @@ namespace nana{	namespace paint
 				auto d = rawptr;
 				const unsigned char* s;
 
+				int src_line_bytes;
+
 				if (is_negative)
+				{
 					s = rawbits;
+					src_line_bytes = -static_cast<int>(bytes_per_line);
+				}
 				else
+				{
 					s = rawbits + bytes_per_line * (height - 1);
+					src_line_bytes = static_cast<int>(bytes_per_line);
+				}
 
 				for(std::size_t i = 0; i < height; ++i)
 				{
@@ -256,7 +264,7 @@ namespace nana{	namespace paint
 						s_p += 3;
 					}
 					d += pixel_size.width;
-					s -= bytes_per_line;
+					s -= src_line_bytes;
 				}
 			}
 			else if(16 == bits_per_pixel)