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authorMattias Andrée <maandree@kth.se>2021-11-10 23:35:27 +0100
committerMattias Andrée <maandree@kth.se>2021-11-10 23:35:27 +0100
commitd160d20b28b396f16fe81b4cb00d5fd4d183d9fd (patch)
tree57e12518776194ad5235accab7574001f82a9de3
parentAdd function prototype: libfonts_do_font_descriptions_match (diff)
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Store DPI in floating point instead of deci-integer + implement libfonts_get_output_dpi
Signed-off-by: Mattias Andrée <maandree@kth.se>
-rw-r--r--Makefile3
-rw-r--r--libfonts.h8
-rw-r--r--libfonts_get_output_dpi.c40
3 files changed, 46 insertions, 5 deletions
diff --git a/Makefile b/Makefile
index 2ea54db..dae5d3a 100644
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,8 @@ LIB_NAME = fonts
OBJ =\
- libfonts_calculate_subpixel_order.o
+ libfonts_calculate_subpixel_order.o\
+ libfonts_get_output_dpi.o
HDR =\
libfonts.h
diff --git a/libfonts.h b/libfonts.h
index 7f14a48..a31a5e9 100644
--- a/libfonts.h
+++ b/libfonts.h
@@ -87,8 +87,8 @@ enum libfonts_orientation {
};
struct libfonts_rendering_settings {
- uint16_t deci_dpi_x;
- uint16_t deci_dpi_y;
+ double dpi_x; /* actually pixels rather than dots */
+ double dpi_y;
enum libfonts_antialiasing horizontal_grey_text_antialiasing;
enum libfonts_antialiasing vertical_grey_text_antialiasing;
enum libfonts_antialiasing diagonal_grey_text_antialiasing;
@@ -107,8 +107,8 @@ struct libfonts_output {
int output_screen;
enum libfonts_orientation physical_screen_orientation;
enum libfonts_subpixel_order unrotated_subpixel_order;
- uint16_t deci_dpi_x;
- uint16_t deci_dpi_y;
+ double dpi_x;
+ double dpi_y;
struct libfonts_rendering_settings *rendering_settings;
};
diff --git a/libfonts_get_output_dpi.c b/libfonts_get_output_dpi.c
new file mode 100644
index 0000000..259702a
--- /dev/null
+++ b/libfonts_get_output_dpi.c
@@ -0,0 +1,40 @@
+/* See LICENSE file for copyright and license details. */
+#include "libfonts.h"
+#include <ctype.h>
+#include <string.h>
+#include <strings.h>
+
+
+int
+libfonts_get_output_dpi(struct libfonts_output *output, const char *edid)
+{
+ int width, height;
+ char width1, width2, height1, height2;
+
+ output->dpi_x = 0;
+ output->dpi_y = 0;
+
+ if (strncasecmp(edid, "00""FF""FF""FF""FF""FF""FF""00", 2 * 8) || strlen(edid) < 256)
+ return 0;
+
+ width1 = edid[21 * 2 + 0];
+ width2 = edid[21 * 2 + 0];
+ height1 = edid[22 * 2 + 0];
+ height2 = edid[22 * 2 + 0];
+
+ if (!isxdigit(width1) || !isxdigit(width2) || !isxdigit(height1) || !isxdigit(height2))
+ return 0;
+
+ width = ((width1 & 15) + (width1 > '9' ? 9 : 0)) << 4;
+ width |= (width2 & 15) + (width2 > '9' ? 9 : 0);
+ height = ((height1 & 15) + (height1 > '9' ? 9 : 0)) << 4;
+ height |= (height2 & 15) + (height2 > '9' ? 9 : 0);
+
+ if (!width || !height)
+ return 0;
+
+ output->dpi_x = (double)output->output_width / (double)width * 2.54;
+ output->dpi_y = (double)output->output_height / (double)height * 2.54;
+
+ return 1;
+}