--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libmlk-ui/ui/align.h	Sat Nov 28 22:37:30 2020 +0100
@@ -0,0 +1,102 @@
+/*
+ * align.h -- user interface alignment
+ *
+ * Copyright (c) 2020 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef MOLKO_UI_ALIGN_H
+#define MOLKO_UI_ALIGN_H
+
+/**
+ * \file align.h
+ * \brief User interface alignment.
+ */
+
+/**
+ * \brief Label alignment in bounding box.
+ *
+ * The alignment is described as following:
+ *
+ * ```
+ * +---------------------+
+ * | 2        3        4 |
+ * |                     |
+ * | 9        1        5 |
+ * |                     |
+ * | 8        7        6 |
+ * +---------------------+
+ * ```
+ *
+ * The default value of 0 (LABEL_ALIGN_NONE) means the alignment isn't used.
+ */
+enum align {
+	ALIGN_NONE,             /*!< No alignment. */
+	ALIGN_CENTER,           /*!< Align to the center. */
+	ALIGN_TOP_LEFT,         /*!< Top left. */
+	ALIGN_TOP,              /*!< Top center (aligned horizontally). */
+	ALIGN_TOP_RIGHT,        /*!< Top right. */
+	ALIGN_RIGHT,            /*!< Right (aligned vertically). */
+	ALIGN_BOTTOM_RIGHT,     /*!< Bottom right. */
+	ALIGN_BOTTOM,           /*!< Bottom (aligned horizontally). */
+	ALIGN_BOTTOM_LEFT,      /*!< Bottom left. */
+	ALIGN_LEFT              /*!< Left (aligned vertically). */
+};
+
+/**
+ * Align the given object relative to its parent region.
+ *
+ * The arguments are described as following:
+ *
+ * ```
+ * Example of ALIGN_LEFT (centered vertically but placed on the left.)
+ *
+ *    px, py
+ *      +----------pw----------+
+ *      |                      |
+ *      | x, y                 |
+ *      | +---w---+            |
+ *     ph h       |            |
+ *      | +-------+            |
+ *      |                      |
+ *      |                      |
+ *      +----------------------+
+ * ```
+ *
+ * As a convenience, x and y are left untouched if align is ALIGN_NONE which
+ * means you can set the coordinates to default values and still call the align
+ * function without need to check.
+ *
+ * \param align the desired alignment
+ * \param x the pointer to x coordinate to modify (may be NULL)
+ * \param y the pointer yo y coordinate to modify (may be NULL)
+ * \param w the object width
+ * \param h the object height
+ * \param px the parent region start
+ * \param py the parent region start
+ * \param pw the parent region width
+ * \param ph the parent region height
+ */
+void
+align(enum align align,
+      int *x,
+      int *y,
+      unsigned int w,
+      unsigned int h,
+      int px,
+      int py,
+      unsigned int pw,
+      unsigned int ph);
+
+#endif /* !MOLKO_UI_ALIGN_H */