diff --git a/embed/extmod/modtrezorui/display-stm32.h b/embed/extmod/modtrezorui/display-stm32.h
index 696d89a80e..64f7746cf6 100644
--- a/embed/extmod/modtrezorui/display-stm32.h
+++ b/embed/extmod/modtrezorui/display-stm32.h
@@ -43,15 +43,15 @@ static void display_unsleep(void)
 #endif
 }
 
-static uint16_t BUFFER_OFFSET_X = 0, BUFFER_OFFSET_Y = 0;
+static struct {
+    uint16_t x, y;
+} BUFFER_OFFSET;
 
 static void display_set_window(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1)
 {
 #if DISPLAY_ILI9341V || DISPLAY_ST7789V
-    x0 += BUFFER_OFFSET_X;
-    x1 += BUFFER_OFFSET_X;
-    y0 += BUFFER_OFFSET_Y;
-    y1 += BUFFER_OFFSET_Y;
+    x0 += BUFFER_OFFSET.x; x1 += BUFFER_OFFSET.x;
+    y0 += BUFFER_OFFSET.y; y1 += BUFFER_OFFSET.y;
     CMD(0x2A); DATA(x0 >> 8); DATA(x0 & 0xFF); DATA(x1 >> 8); DATA(x1 & 0xFF); // column addr set
     CMD(0x2B); DATA(y0 >> 8); DATA(y0 & 0xFF); DATA(y1 >> 8); DATA(y1 & 0xFF); // row addr set
     CMD(0x2C);
@@ -66,8 +66,8 @@ void display_set_orientation(int degrees)
     #define MY  (1 << 7)
     // MADCTL: Memory Data Access Control
     // reference section 9.3 in the ILI9341 manual; 8.12 in the ST7789V manual
-    BUFFER_OFFSET_X = 0;
-    BUFFER_OFFSET_Y = 0;
+    BUFFER_OFFSET.x = 0;
+    BUFFER_OFFSET.y = 0;
     uint8_t display_command_parameter = 0;
     switch (degrees) {
         case 0:
@@ -78,11 +78,11 @@ void display_set_orientation(int degrees)
             break;
         case 180:
             display_command_parameter = MX | MY;
-            BUFFER_OFFSET_Y = MAX_DISPLAY_RESY - DISPLAY_RESY;
+            BUFFER_OFFSET.y = MAX_DISPLAY_RESY - DISPLAY_RESY;
             break;
         case 270:
             display_command_parameter = MV | MY;
-            BUFFER_OFFSET_X = MAX_DISPLAY_RESY - DISPLAY_RESX;
+            BUFFER_OFFSET.x = MAX_DISPLAY_RESY - DISPLAY_RESX;
             break;
     }
     CMD(0x36); DATA(display_command_parameter);
diff --git a/embed/extmod/modtrezorui/display-unix.h b/embed/extmod/modtrezorui/display-unix.h
index e71d9b651d..d23da93eb4 100644
--- a/embed/extmod/modtrezorui/display-unix.h
+++ b/embed/extmod/modtrezorui/display-unix.h
@@ -15,19 +15,30 @@
 static SDL_Renderer *RENDERER;
 static SDL_Surface *BUFFER;
 static SDL_Texture *TEXTURE;
-static int POSX, POSY, SX, SY, EX, EY;
+
+static struct {
+    struct {
+        uint16_t x, y;
+    } start;
+    struct {
+        uint16_t x, y;
+    } end;
+    struct {
+        uint16_t x, y;
+    } pos;
+} PIXELWINDOW;
 
 void PIXELDATA(uint16_t c) {
     if (!RENDERER) {
         display_init();
     }
-    if (POSX <= EX && POSY <= EY) {
-        ((uint16_t *)BUFFER->pixels)[POSX + POSY * BUFFER->pitch / sizeof(uint16_t)] = c;
+    if (PIXELWINDOW.pos.x <= PIXELWINDOW.end.x && PIXELWINDOW.pos.y <= PIXELWINDOW.end.y) {
+        ((uint16_t *)BUFFER->pixels)[PIXELWINDOW.pos.x + PIXELWINDOW.pos.y * BUFFER->pitch / sizeof(uint16_t)] = c;
     }
-    POSX++;
-    if (POSX > EX) {
-        POSX = SX;
-        POSY++;
+    PIXELWINDOW.pos.x++;
+    if (PIXELWINDOW.pos.x > PIXELWINDOW.end.x) {
+        PIXELWINDOW.pos.x = PIXELWINDOW.start.x;
+        PIXELWINDOW.pos.y++;
     }
 }
 #else
@@ -71,9 +82,9 @@ static void display_set_window(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y
     if (!RENDERER) {
         display_init();
     }
-    SX = x0; SY = y0;
-    EX = x1; EY = y1;
-    POSX = SX; POSY = SY;
+    PIXELWINDOW.start.x = x0; PIXELWINDOW.start.y = y0;
+    PIXELWINDOW.end.x = x1; PIXELWINDOW.end.y = y1;
+    PIXELWINDOW.pos.x = x0; PIXELWINDOW.pos.y = y0;
 #endif
 }