1 files changed, 89 insertions, 0 deletions
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;
+}