moved from Mate-Extra

1 files changed, 162 insertions, 0 deletions

diff --git a/src/egg-discrete.c b/src/egg-discrete.c
new file mode 100644
index 0000000..a051282
--- /dev/null
+++ b/src/egg-discrete.c
@@ -0,0 +1,162 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2007-2008 Richard Hughes <[email protected]>
+ *
+ * Licensed under the GNU General Public License Version 2
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <glib.h>
+
+#include "egg-debug.h"
+#include "egg-discrete.h"
+
+/**
+ * egg_discrete_from_percent:
+ * @percentage: The percentage to convert
+ * @levels: The number of discrete levels
+ *
+ * We have to be carefull when converting from %->discrete as precision is very
+ * important if we want the highest value.
+ *
+ * Return value: The discrete value for this percentage.
+ **/
+guint
+egg_discrete_from_percent (guint percentage, guint levels)
+{
+	/* check we are in range */
+	if (percentage > 100)
+		return levels;
+	if (levels == 0) {
+		egg_warning ("levels is 0!");
+		return 0;
+	}
+	return ((gfloat) percentage * (gfloat) (levels - 1)) / 100.0f;
+}
+
+/**
+ * egg_discrete_to_percent:
+ * @hw: The discrete level
+ * @levels: The number of discrete levels
+ *
+ * We have to be carefull when converting from discrete->%.
+ *
+ * Return value: The percentage for this discrete value.
+ **/
+guint
+egg_discrete_to_percent (guint discrete, guint levels)
+{
+	/* check we are in range */
+	if (discrete > levels)
+		return 100;
+	if (levels == 0) {
+		egg_warning ("levels is 0!");
+		return 0;
+	}
+	return (guint) ((gfloat) discrete * (100.0f / (gfloat) (levels - 1)));
+}
+
+/**
+ * egg_discrete_to_fraction:
+ * @hw: The discrete level
+ * @levels: The number of discrete levels
+ *
+ * We have to be careful when converting from discrete->fractions.
+ *
+ * Return value: The floating point fraction (0..1) for this discrete value.
+ **/
+gfloat
+egg_discrete_to_fraction (guint discrete, guint levels)
+{
+	/* check we are in range */
+	if (discrete > levels)
+		return 1.0;
+	if (levels == 0) {
+		egg_warning ("levels is 0!");
+		return 0.0;
+	}
+	return (guint) ((gfloat) discrete / ((gfloat) (levels - 1)));
+}
+
+/***************************************************************************
+ ***                          MAKE CHECK TESTS                           ***
+ ***************************************************************************/
+#ifdef EGG_TEST
+#include "egg-test.h"
+
+void
+egg_discrete_test (gpointer data)
+{
+	guint value;
+	gfloat fvalue;
+	EggTest *test = (EggTest *) data;
+
+	if (!egg_test_start (test, "EggDiscrete"))
+		return;
+
+	/************************************************************/
+	egg_test_title (test, "convert discrete 0/10 levels");
+	value = egg_discrete_to_percent (0, 10);
+	if (value == 0) {
+		egg_test_success (test, "got %i", value);
+	} else {
+		egg_test_failed (test, "conversion incorrect (%i)", value);
+	}
+
+	/************************************************************/
+	egg_test_title (test, "convert discrete 9/10 levels");
+	value = egg_discrete_to_percent (9, 10);
+	if (value == 100) {
+		egg_test_success (test, "got %i", value);
+	} else {
+		egg_test_failed (test, "conversion incorrect (%i)", value);
+	}
+
+	/************************************************************/
+	egg_test_title (test, "convert discrete 20/10 levels");
+	value = egg_discrete_to_percent (20, 10);
+	if (value == 100) {
+		egg_test_success (test, "got %i", value);
+	} else {
+		egg_test_failed (test, "conversion incorrect (%i)", value);
+	}
+
+	/************************************************************/
+	egg_test_title (test, "convert discrete 0/10 levels");
+	fvalue = egg_discrete_to_fraction (0, 10);
+	if (fvalue > -0.01 && fvalue < 0.01) {
+		egg_test_success (test, "got %f", fvalue);
+	} else {
+		egg_test_failed (test, "conversion incorrect (%f)", fvalue);
+	}
+
+	/************************************************************/
+	egg_test_title (test, "convert discrete 9/10 levels");
+	fvalue = egg_discrete_to_fraction (9, 10);
+	if (fvalue > -1.01 && fvalue < 1.01) {
+		egg_test_success (test, "got %f", fvalue);
+	} else {
+		egg_test_failed (test, "conversion incorrect (%f)", fvalue);
+	}
+
+	egg_test_end (test);
+}
+
+#endif
+