From 8ecdf59dc6120a4e183d2bcf55ed8bef25b9e764 Mon Sep 17 00:00:00 2001
From: Thomas Klaehn <tkl@blackfinn.de>
Date: Fri, 14 Feb 2020 12:11:17 +0000
Subject: [PATCH] Analog clock drawing

---
 Makefile   |   1 +
 src/main.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 101 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index 2aabff8..a6049c5 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,7 @@ INCLUDES += $(EXTRA_INC)
 LIBS =
 
 LD_FLAGS += $(addprefix -L,$(EXTRA_LIB_DIR))
+LD_FLAGS += -lm
 
 ifneq "$(findstring $(MAKECMDGOALS), build_unit_test exec_unit_test coverage)" ""
 INCLUDES += test/inc
diff --git a/src/main.c b/src/main.c
index 21a15e2..5548ad9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,7 +1,9 @@
+#include <assert.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <math.h>
 
 #include "board.h"
 #include "driver.h"
@@ -9,17 +11,109 @@
 
 uint16_t image[240 * 240];
 
+static void bmp_draw_pixel(uint16_t *image, uint16_t x, uint16_t y, uint16_t color)
+{
+    assert(image != NULL);
+
+    image[x + 240 * y] = color;
+}
+
+#ifndef _swap_int16_t
+#define _swap_int16_t(a, b) { int16_t t = a; a = b; b = t; }
+#endif
+
+static void img_draw_line(uint16_t *image, int16_t x0, int16_t y0, int16_t x1, int16_t y1, uint16_t color)
+{
+    assert(image != NULL);
+
+    int16_t steep = abs(y1 - y0) > abs(x1 - x0);
+    if(steep) {
+        _swap_int16_t(x0, y0);
+        _swap_int16_t(x1, y1);
+    }
+    if(x0 > x1) {
+        _swap_int16_t(x0, x1);
+        _swap_int16_t(y0, y1);
+    }
+
+    int16_t dx, dy;
+    dx = x1 - x0;
+    dy = abs(y1 - y0);
+
+    int16_t err = dx / 2;
+    int16_t ystep;
+
+    if(y0 < y1) {
+        ystep = 1;
+    } else {
+        ystep = -1;
+    }
+
+    for(; x0 <= x1; x0++) {
+        if(steep) {
+            bmp_draw_pixel(image, y0, x0, color);
+        } else {
+            bmp_draw_pixel(image, x0, y0, color);
+        }
+        err -= dy;
+        if (err < 0) {
+            y0 += ystep;
+            err += dx;
+        }
+    }
+}
+
+static void img_load(uint16_t *dst, uint16_t *src, uint32_t length)
+{
+    for(uint32_t i = 0; i < length; i++) {
+        dst[i] = src[i];
+    }
+}
+
+static void img_set(uint16_t *dst, uint16_t value, uint32_t length)
+{
+    for (uint32_t i = 0; i < length; i++) {
+        image[i] = value;
+    }
+}
+
 int main(void)
 {
     drv_open(&lcd_drv);
-    for (uint16_t i = 0; i < 240 * 240; i++) {
-        image[i] = 0xffff;
+
+    double min_len = 80;
+    double std_len = 60;
+    double root_x = 120;
+    double root_y = 120;
+    double min_angle = 90;
+    double std_angle = 90;
+    double dest_x;
+    double dest_y;
+
+    while(1) {
+        img_load(image, clock_face, 240 * 240);
+
+        dest_x = root_x + min_len * cos(min_angle * M_PI / 180);
+        dest_y = root_y + min_len * sin(min_angle * M_PI / 180);
+        img_draw_line(image, (uint16_t)root_x, (uint16_t)root_y, (uint16_t)dest_x, (uint16_t)dest_y, 0xffff);
+        min_angle += 360 / 60;
+
+        dest_x = root_x + std_len * cos(std_angle * M_PI / 180);
+        dest_y = root_y + std_len * sin(std_angle * M_PI / 180);
+        img_draw_line(image, (uint16_t)root_x, (uint16_t)root_y, (uint16_t)dest_x, (uint16_t)dest_y, 0xffff);
+        std_angle += 360.0 / (60 * 12);
+
+        drv_write(&lcd_drv, (const char *)image, 240 * 240);
+        sleep(1);
+
+        if(min_angle >= 360.0) {
+            min_angle -= 360.0;
+        }
+        if(std_angle >= 360.0) {
+            std_angle -= 360.0;
+        }
     }
 
-    drv_write(&lcd_drv, (const char *)image, 240 * 240);
-    sleep(5);
-    drv_write(&lcd_drv, (const char *)clock_face, 240 * 240);
-    sleep(5);
     drv_close(&lcd_drv);
 
     return 0;