[media] v4l2-rect.h: new header with struct v4l2_rect helper functions

This makes it easier to share this code with any driver that needs to
manipulate the v4l2_rect datastructure.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

Documentation/DocBook/device-drivers.tmpl

@@ -233,6 +233,7 @@ X!Isound/sound_firmware.c
 !Iinclude/media/v4l2-mediabus.h
 !Iinclude/media/v4l2-mem2mem.h
 !Iinclude/media/v4l2-of.h
+!Iinclude/media/v4l2-rect.h
 !Iinclude/media/v4l2-subdev.h
 !Iinclude/media/videobuf2-core.h
 !Iinclude/media/videobuf2-v4l2.h

include/media/v4l2-rect.h

@@ -0,0 +1,173 @@
+/*
+ * v4l2-rect.h - v4l2_rect helper functions
+ *
+ * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _V4L2_RECT_H_
+#define _V4L2_RECT_H_
+
+#include <linux/videodev2.h>
+
+/**
+ * v4l2_rect_set_size_to() - copy the width/height values.
+ * @r: rect whose width and height fields will be set
+ * @size: rect containing the width and height fields you need.
+ */
+static inline void v4l2_rect_set_size_to(struct v4l2_rect *r,
+					 const struct v4l2_rect *size)
+{
+	r->width = size->width;
+	r->height = size->height;
+}
+
+/**
+ * v4l2_rect_set_min_size() - width and height of r should be >= min_size.
+ * @r: rect whose width and height will be modified
+ * @min_size: rect containing the minimal width and height
+ */
+static inline void v4l2_rect_set_min_size(struct v4l2_rect *r,
+					  const struct v4l2_rect *min_size)
+{
+	if (r->width < min_size->width)
+		r->width = min_size->width;
+	if (r->height < min_size->height)
+		r->height = min_size->height;
+}
+
+/**
+ * v4l2_rect_set_max_size() - width and height of r should be <= max_size
+ * @r: rect whose width and height will be modified
+ * @max_size: rect containing the maximum width and height
+ */
+static inline void v4l2_rect_set_max_size(struct v4l2_rect *r,
+					  const struct v4l2_rect *max_size)
+{
+	if (r->width > max_size->width)
+		r->width = max_size->width;
+	if (r->height > max_size->height)
+		r->height = max_size->height;
+}
+
+/**
+ * v4l2_rect_map_inside()- r should be inside boundary.
+ * @r: rect that will be modified
+ * @boundary: rect containing the boundary for @r
+ */
+static inline void v4l2_rect_map_inside(struct v4l2_rect *r,
+					const struct v4l2_rect *boundary)
+{
+	v4l2_rect_set_max_size(r, boundary);
+	if (r->left < boundary->left)
+		r->left = boundary->left;
+	if (r->top < boundary->top)
+		r->top = boundary->top;
+	if (r->left + r->width > boundary->width)
+		r->left = boundary->width - r->width;
+	if (r->top + r->height > boundary->height)
+		r->top = boundary->height - r->height;
+}
+
+/**
+ * v4l2_rect_same_size() - return true if r1 has the same size as r2
+ * @r1: rectangle.
+ * @r2: rectangle.
+ *
+ * Return true if both rectangles have the same size.
+ */
+static inline bool v4l2_rect_same_size(const struct v4l2_rect *r1,
+				       const struct v4l2_rect *r2)
+{
+	return r1->width == r2->width && r1->height == r2->height;
+}
+
+/**
+ * v4l2_rect_intersect() - calculate the intersection of two rects.
+ * @r: intersection of @r1 and @r2.
+ * @r1: rectangle.
+ * @r2: rectangle.
+ */
+static inline void v4l2_rect_intersect(struct v4l2_rect *r,
+				       const struct v4l2_rect *r1,
+				       const struct v4l2_rect *r2)
+{
+	int right, bottom;
+
+	r->top = max(r1->top, r2->top);
+	r->left = max(r1->left, r2->left);
+	bottom = min(r1->top + r1->height, r2->top + r2->height);
+	right = min(r1->left + r1->width, r2->left + r2->width);
+	r->height = max(0, bottom - r->top);
+	r->width = max(0, right - r->left);
+}
+
+/**
+ * v4l2_rect_scale() - scale rect r by to/from
+ * @r: rect to be scaled.
+ * @from: from rectangle.
+ * @to: to rectangle.
+ *
+ * This scales rectangle @r horizontally by @to->width / @from->width and
+ * vertically by @to->height / @from->height.
+ *
+ * Typically @r is a rectangle inside @from and you want the rectangle as
+ * it would appear after scaling @from to @to. So the resulting @r will
+ * be the scaled rectangle inside @to.
+ */
+static inline void v4l2_rect_scale(struct v4l2_rect *r,
+				   const struct v4l2_rect *from,
+				   const struct v4l2_rect *to)
+{
+	if (from->width == 0 || from->height == 0) {
+		r->left = r->top = r->width = r->height = 0;
+		return;
+	}
+	r->left = (((r->left - from->left) * to->width) / from->width) & ~1;
+	r->width = ((r->width * to->width) / from->width) & ~1;
+	r->top = ((r->top - from->top) * to->height) / from->height;
+	r->height = (r->height * to->height) / from->height;
+}
+
+/**
+ * v4l2_rect_overlap() - do r1 and r2 overlap?
+ * @r1: rectangle.
+ * @r2: rectangle.
+ *
+ * Returns true if @r1 and @r2 overlap.
+ */
+static inline bool v4l2_rect_overlap(const struct v4l2_rect *r1,
+				     const struct v4l2_rect *r2)
+{
+	/*
+	 * IF the left side of r1 is to the right of the right side of r2 OR
+	 *    the left side of r2 is to the right of the right side of r1 THEN
+	 * they do not overlap.
+	 */
+	if (r1->left >= r2->left + r2->width ||
+	    r2->left >= r1->left + r1->width)
+		return false;
+	/*
+	 * IF the top side of r1 is below the bottom of r2 OR
+	 *    the top side of r2 is below the bottom of r1 THEN
+	 * they do not overlap.
+	 */
+	if (r1->top >= r2->top + r2->height ||
+	    r2->top >= r1->top + r1->height)
+		return false;
+	return true;
+}
+
+#endif