From 4bcd13eabd73346b6df63ca3b88c80cc74e2385a Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Tue, 14 Jul 2015 07:57:54 -0600
Subject: [PATCH] Add RGB blending logic needed to support anti-aliasing
---
configs | 2 +-
include/fixedmath.h | 2 ++
include/nuttx/nx/nxglib.h | 33 +++++++++++++++++++++++++++++++++
libnx/nxglib/Make.defs | 8 ++++----
4 files changed, 40 insertions(+), 5 deletions(-)
diff --git a/configs b/configs
index 6ef8051be6..9b001f72c9 160000
--- a/configs
+++ b/configs
@@ -1 +1 @@
-Subproject commit 6ef8051be6870845a0cbbe769fcf9a3205285123
+Subproject commit 9b001f72c97902ceb979fe44c5564c17d3f19be3
diff --git a/include/fixedmath.h b/include/fixedmath.h
index 7ff6ef262b..38a991136b 100644
--- a/include/fixedmath.h
+++ b/include/fixedmath.h
@@ -121,6 +121,7 @@
/* Conversions */
#define b8toi(a) ((a) >> 8) /* Conversion to integer */
+#define ub8toi(a) ((a) >> 8) /* Conversion to unsigned integer */
#define itob8(i) (((b8_t)(i)) << 8) /* Conversion from integer */
#define uitoub8(i) (((ub8_t)(i)) << 8) /* Conversion from unsigned integer */
#define b8tof(b) (((float)b)/256.0) /* Conversion to float */
@@ -152,6 +153,7 @@
/* Conversions */
#define b16toi(a) ((a) >> 16) /* Conversion to integer */
+#define ub16toi(a) ((a) >> 16) /* Conversion to unsgined integer */
#define itob16(i) (((b16_t)(i)) << 16) /* Conversion from integer */
#define uitoub16(i) (((ub16_t)(i)) << 16) /* Conversion from unsigned integer */
#define b16tof(b) (((float)b)/65536.0) /* Conversion to float */
diff --git a/include/nuttx/nx/nxglib.h b/include/nuttx/nx/nxglib.h
index 6e2d1a53d5..d29d261f8f 100644
--- a/include/nuttx/nx/nxglib.h
+++ b/include/nuttx/nx/nxglib.h
@@ -745,6 +745,39 @@ void nxgl_circletraps(FAR const struct nxgl_point_s *center,
nxgl_coord_t radius,
FAR struct nxgl_trapezoid_s *circle);
+/****************************************************************************
+ * Name: nxglib_rgb24_blend and nxglib_rgb565_blend
+ *
+ * Description:
+ * Blend a foreground color onto a background color. This is *not* alpha
+ * blending: color2 is assumed to be opaque and "under" a semi-
+ * transparent color1.
+ *
+ * The frac1 value could be though as related to the 1/alpha value for
+ * color1. However, the background, color2, is always treated as though
+ * alpha == 1.
+ *
+ * This algorithm is used to handle endpoints as part of the
+ * implementation of anti-aliasing without transparency.
+ *
+ * Input Parameters:
+ * color1 - The semi-transparent, forground color
+ * color2 - The opaque, background color
+ * frac1 - The fractional amount of color1 to blend into color2
+ *
+ * Returned Value:
+ * The blended color, encoded just was the input color1 and color2
+ *
+ ****************************************************************************/
+
+#if !defined(CONFIG_NX_DISABLE_24BPP) || !defined(CONFIG_NX_DISABLE_32BPP)
+uint32_t nxglib_rgb24_blend(uint32_t color1, uint32_t color2, ub16_t frac1);
+#endif
+
+#ifndef CONFIG_NX_DISABLE_16BPP
+uint16_t nxglib_rgb565_blend(uint16_t color1, uint16_t color2, ub16_t frac1);
+#endif
+
#undef EXTERN
#if defined(__cplusplus)
}
diff --git a/libnx/nxglib/Make.defs b/libnx/nxglib/Make.defs
index 8593c91aca..2f972ab2f8 100644
--- a/libnx/nxglib/Make.defs
+++ b/libnx/nxglib/Make.defs
@@ -41,10 +41,10 @@ CSRCS += nxglib_circlepts.c nxglib_circletraps.c nxglib_intersecting.c
CSRCS += nxglib_nonintersecting.c nxglib_nullrect.c nxglib_rectadd.c
CSRCS += nxglib_rectcopy.c nxglib_rectinside.c nxglib_rectintersect.c
CSRCS += nxglib_rectoffset.c nxglib_rectoverlap.c nxglib_rectsize.c
-CSRCS += nxglib_rectunion.c nxglib_rgb2yuv.c nxglib_runcopy.c
-CSRCS += nxglib_runoffset.c nxglib_splitline.c nxglib_trapcopy.c
-CSRCS += nxglib_trapoffset.c nxglib_vectoradd.c nxglib_vectsubtract.c
-CSRCS += nxglib_yuv2rgb.c
+CSRCS += nxglib_rectunion.c nxglib_rgb2yuv.c nxglib_rgbblend.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
ifneq ($(CONFIG_NX_NPLANES),1)
CSRCS += nxglib_colorcmp.c nxglib_colorcopy.c