From cec9583fe97a74a44625e63cfa22318db2699ee4 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ian@liberator.relativity.greenend.org.uk>
Date: Sat, 4 Jul 2009 01:23:53 +0100
Subject: [PATCH] New inline function ri_rgb; introduce typedef for rgb sample

---
 pctb/convert.h   | 9 +++++++++
 pctb/structure.h | 4 ++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/pctb/convert.h b/pctb/convert.h
index 83be1e8..b61563f 100644
--- a/pctb/convert.h
+++ b/pctb/convert.h
@@ -51,6 +51,8 @@ typedef struct RgbImage {
    */
 } RgbImage;
 
+typedef unsigned long Rgb;
+
 void identify_rgbimage(const RgbImage *base, Rect portion,
 		       char result[MAXIMGIDENT], const char *what);
 RgbImage *alloc_rgb_image(int w, int h);
@@ -58,6 +60,13 @@ void fwrite_ppmraw(FILE *f, const RgbImage *ri);
 
 #define RI_PIXEL(ri,x,y) ((ri)->data + ((y)*(ri)->w + (x)) * 3)
 
+static inline Rgb ri_rgb(const RgbImage *ri, int x, int y) {
+  const unsigned char *rip= RI_PIXEL(ri,x,y);
+  return (rip[0] << 16) |
+         (rip[1] <<  8) |
+         (rip[2]      );
+}
+
 /*----- from structure.c -----*/
 
 void find_structure(const CanonImage *im, int *max_relevant_y_r);
diff --git a/pctb/structure.h b/pctb/structure.h
index f3fbb72..beadfed 100644
--- a/pctb/structure.h
+++ b/pctb/structure.h
@@ -34,7 +34,7 @@
 
 
 typedef struct {
-  unsigned long rgb; /* on screen */
+  Rgb rgb; /* on screen */
   char c; /* canonical */
 } CanonColourInfo;
 
@@ -45,7 +45,7 @@ CanonImage *alloc_canon_image(int w, int h);
 #define CANONICALISE_IMAGE(im,w,h, COMPUTE_RGB) do{		\
     /* compute_rgb should be a number of statements, or		\
      * a block, which assigns to				\
-     *   unsigned long rgb;					\
+     *   Rgb rgb;						\
      * given the values of					\
      *   int x,y;						\
      * all of which are anamorphic.  Result is stored in im.	\
-- 
2.30.2