Get Composite() to befriend the screen's BitMap to ensure they are on the same graphics board. This should fix the slowness when multiple graphics cards are installed.

amiga/bitmap.c

@@ -453,7 +453,7 @@ static struct BitMap *ami_bitmap_get_truecolour(struct bitmap *bitmap,int width,
 						COMPTAG_DestHeight,height,
 						COMPTAG_OffsetX,0,
 						COMPTAG_OffsetY,0,
-						COMPTAG_FriendBitMap,friendbm,
+						COMPTAG_FriendBitMap, scrn->RastPort.BitMap,
 						TAG_DONE);
 #endif
 		}

amiga/plotters.c

@@ -711,6 +711,7 @@ static bool ami_bitmap(int x, int y, int width, int height, struct bitmap *bitma
 					COMPTAG_SrcHeight,height,
 					COMPTAG_OffsetX,x,
 					COMPTAG_OffsetY,y,
+					COMPTAG_FriendBitMap, scrn->RastPort.BitMap,
 					TAG_DONE);
 #endif
 	}
@@ -873,6 +874,7 @@ static void ami_bitmap_tile_hook(struct Hook *hook,struct RastPort *rp,struct Ba
 					COMPTAG_SrcHeight,bfbm->height,
 					COMPTAG_OffsetX,xf,
 					COMPTAG_OffsetY,yf,
+					COMPTAG_FriendBitMap, scrn->RastPort.BitMap,
 					TAG_DONE);
 #endif
 			}

amiga/thumbnail.c

@@ -84,6 +84,7 @@ bool thumbnail_create(hlcache_handle *content, struct bitmap *bitmap,
 					COMPTAG_DestHeight,bitmap->height,
 					COMPTAG_OffsetX,0,
 					COMPTAG_OffsetY,0,
+					COMPTAG_FriendBitMap, scrn->RastPort.BitMap,
 					TAG_DONE);
 	}
 	else