aboutsummaryrefslogtreecommitdiff
path: root/util/transform.c
blob: de3f8ef4e34cbbbae36694a5d94b23f1c1d5dceb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
#include <wlr/util/transform.h>

enum wl_output_transform wlr_output_transform_invert(
		enum wl_output_transform tr) {
	if ((tr & WL_OUTPUT_TRANSFORM_90) && !(tr & WL_OUTPUT_TRANSFORM_FLIPPED)) {
		tr ^= WL_OUTPUT_TRANSFORM_180;
	}
	return tr;
}

enum wl_output_transform wlr_output_transform_compose(
		enum wl_output_transform tr_a, enum wl_output_transform tr_b) {
	uint32_t flipped = (tr_a ^ tr_b) & WL_OUTPUT_TRANSFORM_FLIPPED;
	uint32_t rotation_mask = WL_OUTPUT_TRANSFORM_90 | WL_OUTPUT_TRANSFORM_180;
	uint32_t rotated;
	if (tr_b & WL_OUTPUT_TRANSFORM_FLIPPED) {
		// When a rotation of k degrees is followed by a flip, the
		// equivalent transform is a flip followed by a rotation of
		// -k degrees.
		rotated = (tr_b - tr_a) & rotation_mask;
	} else {
		rotated = (tr_a + tr_b) & rotation_mask;
	}
	return flipped | rotated;
}

void wlr_output_transform_coords(enum wl_output_transform tr, int *x, int *y) {
	if (tr & WL_OUTPUT_TRANSFORM_90) {
		int tmp = *x;
		*x = *y;
		*y = tmp;
	}
}