NX: Don't change the background if the color has not really changed

libnx/nxglib/Make.defs

@@ -1,7 +1,7 @@
 ############################################################################
 # libnx/nxglib/Make.defs
 #
-#   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -37,14 +37,14 @@
 
 ifeq ($(CONFIG_NX),y)
 
-CSRCS += nxglib_circlepts.c nxglib_circletraps.c nxglib_colorcopy.c
-CSRCS += nxglib_intersecting.c nxglib_nonintersecting.c nxglib_nullrect.c
-CSRCS += nxglib_rectadd.c nxglib_rectcopy.c nxglib_rectinside.c
-CSRCS += nxglib_rectintersect.c nxglib_rectoffset.c nxglib_rectoverlap.c
-CSRCS += nxglib_rectsize.c nxglib_rectunion.c nxglib_rgb2yuv.c
-CSRCS += nxglib_runcopy.c nxglib_runoffset.c nxglib_splitline.c
-CSRCS += nxglib_trapcopy.c nxglib_trapoffset.c nxglib_vectoradd.c
-CSRCS += nxglib_vectsubtract.c nxglib_yuv2rgb.c
+CSRCS += nxglib_circlepts.c nxglib_circletraps.c nxglib_colorcmp.c
+CSRCS += nxglib_colorcopy.c nxglib_intersecting.c nxglib_nonintersecting.c
+CSRCS += nxglib_nullrect.c nxglib_rectadd.c nxglib_rectcopy.c
+CSRCS += nxglib_rectinside.c nxglib_rectintersect.c nxglib_rectoffset.c
+CSRCS += nxglib_rectoverlap.c nxglib_rectsize.c nxglib_rectunion.c
+CSRCS += nxglib_rgb2yuv.c nxglib_runcopy.c nxglib_runoffset.c
+CSRCS += nxglib_splitline.c nxglib_trapcopy.c nxglib_trapoffset.c
+CSRCS += nxglib_vectoradd.c nxglib_vectsubtract.c nxglib_yuv2rgb.c
 
 # Add the nxglib/ directory to the build
 

libnx/nxglib/nxglib_colorcmp.c

@@ -0,0 +1,92 @@
+/****************************************************************************
+ * libnx/nxglib/nxglib_colorcmp.c
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <nuttx/nx/nxglib.h>
+
+/****************************************************************************
+ * Pre-Processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nxgl_colorcmp
+ *
+ * Description:
+ *   This is essentially memcmp for colors.  This does very little for us
+ *   other than hide all of the conditional compilation for planar colors
+ *   in one place.
+ *
+ ****************************************************************************/
+
+bool nxgl_colorcmp(const nxgl_mxpixel_t color1[CONFIG_NX_NPLANES],
+                   const nxgl_mxpixel_t color2[CONFIG_NX_NPLANES])
+{
+  int i;
+
+  for (i = 0; i < CONFIG_NX_NPLANES; i++)
+    {
+      if (color1[i] != color2[i])
+        {
+          return false;
+        }
+    }
+
+  return true;
+}