Changeset 32066f2 in mainline for uspace/lib/gfx/src/coord.c

Timestamp:

2020-08-27T11:24:39Z (4 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

e2776ff

Parents:

20d0098

git-author:

Jiri Svoboda <jiri@…> (2020-08-26 18:34:29)

git-committer:

Jiri Svoboda <jiri@…> (2020-08-27 11:24:39)

Message:

Need to be able to paint in the negative quadrants

File:

• uspace/lib/gfx/src/coord.c (modified) (1 diff)

uspace/lib/gfx/src/coord.c

@@ -39 +39 @@
 #include <stddef.h>
 
+/** Divide @a a by @a b and round towards negative numbers.
+ *
+ * Regular integer division always rounds towards zero. This is not useful
+ * e.g. for scaling down, where we always need to round towards negative
+ * numbers.
+ *
+ * @param a Dividend
+ * @param b Divisor
+ * @return Quotient
+ */
+gfx_coord_t gfx_coord_div_rneg(gfx_coord_t a, gfx_coord_t b)
+{
+        if ((a > 0 && b > 0) || (a < 0 && b < 0)) {
+                /* Result is non-negative, round towards zero */
+                return a / b;
+        } else {
+                /* Result is negative, round away from zero */
+                return (a - b + 1) / b;
+        }
+}
+
 /** Add two vectors.
  *