Add palette object. Optimise matching colour in case where we chose the palette. In other cases, we still have to seach all the colours, but that doesn't ever seem to be used.

8 files changed, 228 insertions, 66 deletions

diff --git a/include/libnsfb.h b/include/libnsfb.h
index 739617e..da8e5f6 100644
--- a/include/libnsfb.h
+++ b/include/libnsfb.h
@@ -13,6 +13,7 @@
 
 #include <stdint.h>
 
+typedef struct nsfb_palette_s nsfb_palette_t;
 typedef struct nsfb_cursor_s nsfb_cursor_t;
 typedef struct nsfb_s nsfb_t;
 typedef struct nsfb_event_s nsfb_event_t;
diff --git a/include/nsfb.h b/include/nsfb.h
index 5caff9b..9a61775 100644
--- a/include/nsfb.h
+++ b/include/nsfb.h
@@ -28,7 +28,7 @@ struct nsfb_s {
     uint8_t *ptr; /**< Base of video memory. */
     int linelen; /**< length of a video line. */
 
-    nsfb_colour_t palette[256]; /**< palette for index modes */
+    struct nsfb_palette_s *palette; /**< palette for index modes */
     nsfb_cursor_t *cursor; /**< cursor */
 
     struct nsfb_surface_rtns_s *surface_rtns; /**< surface routines. */
diff --git a/include/palette.h b/include/palette.h
new file mode 100644
index 0000000..845c1bc
--- /dev/null
+++ b/include/palette.h
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2012 Michael Drake <tlsa@netsurf-browser.org>
+ *
+ * This file is part of libnsfb, http://www.netsurf-browser.org/
+ * Licenced under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ *
+ * This is the *internal* interface for the cursor. 
+ */
+
+#ifndef PALETTE_H
+#define PALETTE_H 1
+
+#include <stdint.h>
+#include <limits.h>
+
+#include "libnsfb.h"
+#include "libnsfb_plot.h"
+
+enum nsfb_palette_type_e {
+	NSFB_PALETTE_EMPTY,     /**< empty palette object */
+	NSFB_PALETTE_NSFB_8BPP, /**< libnsfb's own 8bpp palette */
+	NSFB_PALETTE_OTHER      /**< any other palette  */
+};
+
+struct nsfb_palette_s {
+	enum nsfb_palette_type_e type; /**< Palette type */
+	uint8_t last; /**< Last used palette index */
+	nsfb_colour_t data[256]; /**< Palette for index modes */
+};
+
+/** Create an empty palette object. */
+bool nsfb_palette_new(struct nsfb_palette_s **palette);
+
+/** Free a palette object. */
+void nsfb_palette_free(struct nsfb_palette_s *palette);
+
+/** Generate libnsfb 8bpp default palette. */
+void nsfb_palette_generate_nsfb_8bpp(struct nsfb_palette_s *palette);
+
+
+static inline uint8_t nsfb_palette_best_match(
+		const struct nsfb_palette_s *palette,
+		nsfb_colour_t c)
+{
+	uint8_t best_col = 0;
+
+	nsfb_colour_t palent;
+	int col;
+	int dr, dg, db; /* delta red, green blue values */
+
+	int cur_distance;
+	int best_distance = INT_MAX;
+
+	switch (palette->type) {
+	case NSFB_PALETTE_NSFB_8BPP:
+		/* Index into colour cube part */
+		dr = ((( c        & 0xFF) * 5) + 128) / 256;
+		dg = ((((c >>  8) & 0xFF) * 7) + 128) / 256;
+		db = ((((c >> 16) & 0xFF) * 4) + 128) / 256;
+		col = 40 * dr + 5 * dg + db;
+
+		palent = palette->data[col];
+		dr = ( c        & 0xFF) - ( palent        & 0xFF);
+		dg = ((c >>  8) & 0xFF) - ((palent >> 8 ) & 0xFF);
+		db = ((c >> 16) & 0xFF) - ((palent >> 16) & 0xFF);
+		cur_distance = (dr * dr) + (dg * dg) + (db * db);
+
+		best_col = col;
+		best_distance = cur_distance;
+
+		/* Index into grayscale part */
+		col = (( c        & 0xFF) +
+		       ((c >>  8) & 0xFF) +
+		       ((c >> 16) & 0xFF) + (45 / 2)) / (15 * 3) - 1 + 240;
+		palent = palette->data[col];
+
+		dr = ( c        & 0xFF) - ( palent        & 0xFF);
+		dg = ((c >>  8) & 0xFF) - ((palent >>  8) & 0xFF);
+		db = ((c >> 16) & 0xFF) - ((palent >> 16) & 0xFF);
+		cur_distance = (dr * dr) + (dg * dg) + (db * db);
+		if (cur_distance < best_distance) {
+			best_distance = cur_distance;
+			best_col = col;
+		}
+		break;
+
+	case NSFB_PALETTE_OTHER:
+		/* Try all colours in palette */
+		for (col = 0; col <= palette->last; col++) {
+			palent = palette->data[col];
+
+			dr = ( c        & 0xFF) - ( palent        & 0xFF);
+			dg = ((c >>  8) & 0xFF) - ((palent >>  8) & 0xFF);
+			db = ((c >> 16) & 0xFF) - ((palent >> 16) & 0xFF);
+			cur_distance = (dr * dr) + (dg * dg) + (db * db);
+			if (cur_distance < best_distance) {
+				best_distance = cur_distance;
+				best_col = col;
+			}
+		}
+		break;
+
+	default:
+		break;
+	}
+
+        return best_col;
+}
+
+#endif /* PALETTE_H */
diff --git a/src/Makefile b/src/Makefile
index 283a99f..3c6e2f0 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,4 +1,4 @@
 # Sources
-DIR_SOURCES := libnsfb.c dump.c cursor.c
+DIR_SOURCES := libnsfb.c dump.c cursor.c palette.c
 
 include $(NSBUILD)/Makefile.subdir
diff --git a/src/libnsfb.c b/src/libnsfb.c
index 6f14c99..a341088 100644
--- a/src/libnsfb.c
+++ b/src/libnsfb.c
@@ -15,6 +15,7 @@
 #include "libnsfb_plot.h"
 #include "libnsfb_event.h"
 #include "nsfb.h"
+#include "palette.h"
 #include "surface.h"
 
 /* exported interface documented in libnsfb.h */
@@ -50,6 +51,10 @@ int
 nsfb_free(nsfb_t *nsfb)
 {
     int ret;
+
+    if (nsfb->palette != NULL)
+        nsfb_palette_free(nsfb->palette);
+
     ret = nsfb->surface_rtns->finalise(nsfb);
     free(nsfb);
     return ret;
diff --git a/src/palette.c b/src/palette.c
new file mode 100644
index 0000000..eba95cd
--- /dev/null
+++ b/src/palette.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2012 Michael Drake <tlsa@netsurf-browser.org>
+ *
+ * This file is part of libnsfb, http://www.netsurf-browser.org/
+ * Licenced under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ */
+
+/** \file
+ * Palette (implementation).
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "palette.h"
+
+
+/** Create an empty palette object. */
+bool nsfb_palette_new(struct nsfb_palette_s **palette)
+{
+	*palette = malloc(sizeof(struct nsfb_palette_s));
+	if (*palette == NULL) {
+		return false;
+	}
+
+	(*palette)->type = NSFB_PALETTE_EMPTY;
+	(*palette)->last = 0;
+
+	return true;
+}
+
+/** Free a palette object. */
+void nsfb_palette_free(struct nsfb_palette_s *palette)
+{
+	if (palette != NULL)
+		free(palette);
+}
+
+/** Generate libnsfb 8bpp default palette. */
+void nsfb_palette_generate_nsfb_8bpp(struct nsfb_palette_s *palette)
+{
+	int rloop, gloop, bloop;
+	int loop = 0;
+	uint8_t r, g, b;
+
+	/* Build a linear 6-8-5 levels RGB colour cube palette.
+	 * This accounts for 240 colours */
+#define RLIM 6
+#define GLIM 8
+#define BLIM 5
+	for (rloop = 0; rloop < RLIM; rloop++) {
+		for (gloop = 0; gloop < GLIM; gloop++) {
+			for (bloop = 0; bloop < BLIM; bloop++) {
+				r = ((rloop * 255 * 2) + RLIM - 1) /
+						(2 * (RLIM - 1));
+				g = ((gloop * 255 * 2) + GLIM - 1) /
+						(2 * (GLIM - 1));
+				b = ((bloop * 255 * 2) + BLIM - 1) /
+						(2 * (BLIM - 1));
+
+				palette->data[loop] = r | g << 8 | b << 16;
+				loop++;
+			}
+		}
+	}
+#undef RLIM
+#undef GLIM
+#undef BLIM
+
+	/* Should have 240 colours set */
+	assert(loop == 240);
+
+	/* Fill index 240 to index 255 with grayscales */
+	/* Note: already have full black and full white from RGB cube */
+	for (; loop < 256; loop++) {
+		int ngray = loop - 240 + 1;
+		r = ngray * 15; /* 17*15 = 255 */
+
+		g = b = r;
+
+		palette->data[loop] = r | g << 8 | b << 16;
+	}
+
+	/* Set palette details */
+	palette->type = NSFB_PALETTE_NSFB_8BPP;
+	palette->last = 255;
+}
diff --git a/src/plot/8bpp.c b/src/plot/8bpp.c
index b72303d..05574d8 100644
--- a/src/plot/8bpp.c
+++ b/src/plot/8bpp.c
@@ -10,7 +10,6 @@
 #include <stdbool.h>
 #include <endian.h>
 #include <stdlib.h>
-#include <limits.h>
 #include <string.h>
 
 #include "libnsfb.h"
@@ -18,6 +17,7 @@
 #include "libnsfb_plot_util.h"
 
 #include "nsfb.h"
+#include "palette.h"
 #include "plot.h"
 
 static inline uint8_t *get_xy_loc(nsfb_t *nsfb, int x, int y)
@@ -28,34 +28,18 @@ static inline uint8_t *get_xy_loc(nsfb_t *nsfb, int x, int y)
 
 static inline nsfb_colour_t pixel_to_colour(nsfb_t *nsfb, uint8_t pixel)
 {
-        return nsfb->palette[pixel];
+        if (nsfb->palette == NULL)
+                return 0;
+
+        return nsfb->palette->data[pixel];
 }
 
 static uint8_t colour_to_pixel(nsfb_t *nsfb, nsfb_colour_t c)
 {
-        nsfb_colour_t palent;
-        int col;
-
-        int dr, dg, db; /* delta red, green blue values */
-
-        int cur_distance;
-        int best_distance = INT_MAX;
-        uint8_t best_col = 0;
-
-        for (col = 0; col < 256; col++) {
-                palent = nsfb->palette[col];
-
-                dr = (c & 0xFF) - (palent & 0xFF);
-                dg = ((c >> 8) & 0xFF) - ((palent >> 8) & 0xFF);
-                db = ((c >> 16) & 0xFF) - ((palent >> 16) & 0xFF);
-                cur_distance = ((dr * dr) + (dg * dg) + (db *db));
-                if (cur_distance < best_distance) {
-                        best_distance = cur_distance;
-                        best_col = col;
-                }
-        }
+        if (nsfb->palette == NULL)
+                return 0;
 
-        return best_col;
+        return nsfb_palette_best_match(nsfb->palette, c);
 }
 
 #define PLOT_TYPE uint8_t
diff --git a/src/surface/sdl.c b/src/surface/sdl.c
index d598b8a..7a86dc1 100644
--- a/src/surface/sdl.c
+++ b/src/surface/sdl.c
@@ -6,7 +6,6 @@
  *                http://www.opensource.org/licenses/mit-license.php
  */
 
-#include <assert.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <SDL/SDL.h>
@@ -18,6 +17,7 @@
 
 #include "nsfb.h"
 #include "surface.h"
+#include "palette.h"
 #include "plot.h"
 #include "cursor.h"
 
@@ -353,49 +353,19 @@ set_palette(nsfb_t *nsfb)
 {
     SDL_Surface *sdl_screen = nsfb->surface_priv;
     SDL_Color palette[256];
-    int rloop, gloop, bloop;
     int loop = 0;
 
-    /* Build a linear 6-8-5 levels RGB colour cube palette.
-     * This accounts for 240 colours */
-#define RLIM 6
-#define GLIM 8
-#define BLIM 5
-    for (rloop = 0; rloop < RLIM; rloop++) {
-        for (gloop = 0; gloop < GLIM; gloop++) {
-            for (bloop = 0; bloop < BLIM; bloop++) {
-                palette[loop].r = ((rloop * 255 * 2) + RLIM - 1) / (2 * (RLIM - 1));
-                palette[loop].g = ((gloop * 255 * 2) + GLIM - 1) / (2 * (GLIM - 1));
-                palette[loop].b = ((bloop * 255 * 2) + BLIM - 1) / (2 * (BLIM - 1));
-
-                nsfb->palette[loop] = palette[loop].r |
-                        palette[loop].g << 8 |
-                        palette[loop].b << 16;
-                loop++;
-            }
-        }
-    }
-#undef RLIM
-#undef GLIM
-#undef BLIM
-
-    /* Should have 240 colours set */
-    assert(loop == 240);
+    /* Get libnsfb palette */
+    nsfb_palette_generate_nsfb_8bpp(nsfb->palette);
 
-    /* Fill index 240 to index 255 with grayscales */
-    /* Note: already have full black and full white from RGB cube */
-    for (; loop < 256; loop++) {
-        int ngray = loop - 240 + 1;
-        palette[loop].r = ngray * 15; /* 17*15 = 255 */
-
-        palette[loop].g = palette[loop].b = palette[loop].r;
-
-        nsfb->palette[loop] = palette[loop].r |
-                palette[loop].g << 8 |
-                palette[loop].b << 16;
+    /* Create SDL palette from nsfb palette */
+    for (loop = 0; loop < 256; loop++) {
+        palette[loop].r = (nsfb->palette->data[loop]      ) & 0xFF;
+        palette[loop].g = (nsfb->palette->data[loop] >>  8) & 0xFF;
+        palette[loop].b = (nsfb->palette->data[loop] >> 16) & 0xFF;
     }
 
-    /* Set palette */
+    /* Set SDL palette */
     SDL_SetColors(sdl_screen, palette, 0, 256);
 
 }
@@ -487,8 +457,10 @@ static int sdl_initialise(nsfb_t *nsfb)
 
     nsfb->surface_priv = sdl_screen;
 
-    if (nsfb->bpp == 8)
+    if (nsfb->bpp == 8) {
+        nsfb_palette_new(&nsfb->palette);
         set_palette(nsfb);
+    }
 
     nsfb->ptr = sdl_screen->pixels;
     nsfb->linelen = sdl_screen->pitch;