From ae698e5831a573e9a6f6e9431590954804219cbe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Boh=C3=A1=C4=8Dek?=
 <fandabohacek@gmail.com>
Date: Sun, 27 Jun 2021 15:35:12 +0200
Subject: [PATCH] feat: add renderer font scaling

---
 lib-gui/src/font.c     |  6 ++++--
 lib-gui/src/renderer.c | 44 +++++++++++++++++++++++++++++++-----------
 2 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/lib-gui/src/font.c b/lib-gui/src/font.c
index 4627f5d4a3540832123962af942e7d7273e6844a..74d3ffd1e145ff9e81ce38041b2bb049318406e1 100644
--- a/lib-gui/src/font.c
+++ b/lib-gui/src/font.c
@@ -18,10 +18,11 @@ size2d_t font_measure_text(font_t *font, char *text) {
     .y = font->size
   };
 
+  double scale = (double)font->size / font->font.height;
   size_t len = strlen(text);
   for (int i = 0; i < len; i++) {
     font_character_t character = font_get_character(font, text[i]);
-    size.x += character.width;
+    size.x += character.width * scale;
   }
 
   return size;
@@ -52,9 +53,10 @@ uint16_t font_fit_cut(font_t *font, size2d_t size, char *text) {
   size_t len = strlen(text);
 
   uint16_t x_size = 0;
+  double scale = (double)font->size / font->font.height;
   for (int i = 0; i < len; i++) {
     font_character_t character = font_get_character(font, text[i]);
-    x_size += character.width;
+    x_size += character.width * scale;
 
     if (x_size > size.x) {
       return i;
diff --git a/lib-gui/src/renderer.c b/lib-gui/src/renderer.c
index 8afe62e40d2d6b91b9384b9867b99d7928c210c4..497da14fdcb38c0f61207dcc15a339884a3ae721 100644
--- a/lib-gui/src/renderer.c
+++ b/lib-gui/src/renderer.c
@@ -69,9 +69,8 @@ size2d_t renderer_write_string(renderer_t *renderer, uint16_t bx, uint16_t by,
   }
 
   for (int i = 0; i < len; i++) {
-    font_character_t character = font_get_character(font, text[i]);
-    renderer_write_char(renderer, x, y, font, text[i], color);
-    x += character.width + font->char_spacing;
+    size2d_t size = renderer_write_char(renderer, x, y, font, text[i], color);
+    x += size.x;
   }
 
   size2d_t size = {.x = x - bx, .y = font->size + font->line_spacing};
@@ -79,26 +78,49 @@ size2d_t renderer_write_string(renderer_t *renderer, uint16_t bx, uint16_t by,
   return size;
 }
 
-size2d_t renderer_write_char(renderer_t *renderer, uint16_t x, uint16_t y,
+static coords_t renderer_get_char_xy(int64_t x, int64_t y, uint64_t downscale_i, uint64_t convert) {
+  uint16_t px = ((uint64_t)(downscale_i * (2 * x + 1))) /
+                    (convert * 2);
+  uint16_t py = ((uint64_t)(downscale_i * (2 * y + 1))) /
+    (convert * 2);
+
+  coords_t coords = {
+    .x = px,
+    .y = py
+  };
+
+  return coords;
+}
+
+size2d_t renderer_write_char(renderer_t *renderer, uint16_t bx, uint16_t by,
                              font_t *font, char c, display_pixel_t color) {
+  double scale = (double)font->size / font->font.height;
+  double downscale = 1 / scale;
+  uint64_t convert = 10000;
+
+  uint64_t downscale_i = downscale * convert;
+  uint64_t scale_i = scale * convert;
+
   coords_t beg = renderer_get_beg_coords(renderer);
   coords_t end = renderer_get_end_coords(renderer);
 
   font_character_t character = font_get_character(font, c);
-  for (int i = 0; i < font->font.height; i++) {
-    font_bits_t line_bits = character.bits[i]; // line
+  for (int y = 0; y < font->size; y++) {
+    uint16_t py = renderer_get_char_xy(0, y, downscale_i, convert).y;
+    font_bits_t line_bits = character.bits[py]; // line
 
-    for (int j = 0; j < character.width; j++) {
-      bool current = (line_bits >> (8*sizeof(font_bits_t) - j - 1)) & 1;
+    for (int x = 0; x < (character.width * scale_i) / convert; x++) {
+      uint16_t px = renderer_get_char_xy(x, y, downscale_i, convert).x;
+      bool current = (line_bits >> (8*sizeof(font_bits_t) - px - 1)) & 1;
 
-      if (current && coords_is_within(x + j, y + i, beg, end)) {
-        coords_t translated = coords_translate(renderer, x + j, y + i);
+      if (current && coords_is_within(bx + x, by + y, beg, end)) {
+        coords_t translated = coords_translate(renderer, bx + x, by + y);
         display_set_pixel(renderer->display, translated.x, translated.y, color);
       }
     }
   }
 
-  size2d_t size = {.x = character.width + font->char_spacing,
+  size2d_t size = {.x = (character.width * scale_i) / convert + font->char_spacing,
                    .y = font->size + font->line_spacing};
   return size;
 }