Fix EDID reading in libfonts_get_output_dpi and make it use the output transformation

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 31 insertions, 0 deletions

diff --git a/common.h b/common.h
new file mode 100644
index 0000000..f39090e
--- /dev/null
+++ b/common.h
@@ -0,0 +1,31 @@
+/* See LICENSE file for copyright and license details. */
+#include "libfonts.h"
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+#define DOUBLE_TOLERANCE 0.000001
+
+
+static inline void
+transform(double *x_out, double *y_out, double x, double y, const struct libfonts_transformation *transformation)
+{
+	double a = transformation->m[0][0], b = transformation->m[0][1], c = transformation->m[0][2];
+	double d = transformation->m[1][0], e = transformation->m[1][1], f = transformation->m[1][2];
+	double g = transformation->m[2][0], h = transformation->m[2][1], i = transformation->m[2][2];
+	double w = g*x + h*y + i;
+	*x_out = (a*x + b*y + c) / w;
+	*y_out = (d*x + e*y + f) / w;
+}
+
+
+static inline int
+eq(double a, double b)
+{
+	return b - DOUBLE_TOLERANCE <= a && a <= b + DOUBLE_TOLERANCE;
+}