legacy: fix SCA when displaying the words

(cherry picked from commit f16c941ed4)

legacy/firmware/layout2.c

@@ -544,8 +544,9 @@ void layoutResetWord(const char *word, int pass, int word_pos, bool last) {
   oledDrawString(left, 0 * 9, action, FONT_STANDARD);
   oledDrawString(left, 2 * 9, word_pos < 10 ? index_str + 1 : index_str,
                  FONT_STANDARD);
-  oledDrawString(left, 3 * 9, word, FONT_STANDARD | FONT_DOUBLE);
-  oledHLine(OLED_HEIGHT - 13);
+  oledDrawStringCenter(OLED_WIDTH / 2, 4 * 9 - 3, word,
+                       FONT_FIXED | FONT_DOUBLE);
+  oledSCA(4 * 9 - 3 - 2, 4 * 9 - 3 + 15 + 2, OLED_WIDTH / 2);
   layoutButtonYes(btnYes);
   oledRefresh();
 }

legacy/oled.c

@@ -73,6 +73,13 @@ static bool is_debug_link = 0;
 #define OLED_OFFSET(x, y) (OLED_BUFSIZE - 1 - (x) - ((y) / 8) * OLED_WIDTH)
 #define OLED_MASK(x, y) (1 << (7 - (y) % 8))
 
+/*
+ * Return the state of the pixel at x, y
+ */
+bool oledGetPixel(int x, int y) {
+  return _oledbuffer[OLED_OFFSET(x, y)] & OLED_MASK(x, y);
+}
+
 /*
  * Draws a white pixel at x, y
  */
@@ -239,11 +246,11 @@ void oledDrawChar(int x, int y, char c, int font) {
     return;
   }
 
-  int zoom = (font & FONT_DOUBLE ? 2 : 1);
+  int zoom = (font & FONT_DOUBLE) ? 2 : 1;
   int char_width = fontCharWidth(font & 0x7f, c);
   const uint8_t *char_data = fontCharData(font & 0x7f, c);
 
-  if (x <= -char_width * zoom) {
+  if (x <= -char_width) {
     return;
   }
 
@@ -253,7 +260,7 @@ void oledDrawChar(int x, int y, char c, int font) {
         if (zoom <= 1) {
           oledDrawPixel(x + xo, y + yo);
         } else {
-          oledBox(x + xo * zoom, y + yo * zoom, x + (xo + 1) * zoom - 1,
+          oledBox(x + xo, y + yo * zoom, x + (xo + 1) - 1,
                   y + (yo + 1) * zoom - 1, true);
         }
       }
@@ -273,12 +280,12 @@ char oledConvertChar(const char c) {
 
 int oledStringWidth(const char *text, int font) {
   if (!text) return 0;
-  int size = (font & FONT_DOUBLE ? 2 : 1);
+  int space = (font & FONT_DOUBLE) ? 2 : 1;
   int l = 0;
   for (; *text; text++) {
     char c = oledConvertChar(*text);
     if (c) {
-      l += size * (fontCharWidth(font & 0x7f, c) + 1);
+      l += fontCharWidth(font & 0x7f, c) + space;
     }
   }
   return l;
@@ -287,12 +294,12 @@ int oledStringWidth(const char *text, int font) {
 void oledDrawString(int x, int y, const char *text, int font) {
   if (!text) return;
   int l = 0;
-  int size = (font & FONT_DOUBLE ? 2 : 1);
+  int space = (font & FONT_DOUBLE) ? 2 : 1;
   for (; *text; text++) {
     char c = oledConvertChar(*text);
     if (c) {
       oledDrawChar(x + l, y, c, font);
-      l += size * (fontCharWidth(font & 0x7f, c) + 1);
+      l += fontCharWidth(font & 0x7f, c) + space;
     }
   }
 }
@@ -413,3 +420,21 @@ void oledSwipeRight(void) {
     oledRefresh();
   }
 }
+
+/*
+ * Mitigate SCA on lines y1-y2 by setting exactly width pixels black
+ */
+void oledSCA(int y1, int y2, int width) {
+  y1 = MAX(y1, 0);
+  y2 = MIN(y2, OLED_HEIGHT - 1);
+  for (int y = y1; y <= y2; y++) {
+    int pix = 0;
+    for (int x = 0; x < OLED_WIDTH; x++) {
+      pix += oledGetPixel(x, y);
+    }
+    pix = MAX(width - pix, 0);
+    for (int x = 0 + (pix / 2); x < OLED_WIDTH - ((pix + 1) / 2); x++) {
+      oledInvertPixel(x, y);
+    }
+  }
+}

legacy/oled.h

@@ -39,6 +39,7 @@ void oledInvertDebugLink(void);
 
 void oledSetBuffer(uint8_t *buf);
 const uint8_t *oledGetBuffer(void);
+bool oledGetPixel(int x, int y);
 void oledDrawPixel(int x, int y);
 void oledClearPixel(int x, int y);
 void oledInvertPixel(int x, int y);
@@ -55,5 +56,6 @@ void oledHLine(int y);
 void oledFrame(int x1, int y1, int x2, int y2);
 void oledSwipeLeft(void);
 void oledSwipeRight(void);
+void oledSCA(int y1, int y2, int val);
 
 #endif