Add method to draw a scrolling indicator

workspace/TS100/Core/Src/OLED.cpp

@@ -106,6 +106,25 @@ void OLED::drawChar(char c) {
 	cursor_x += fontWidth;
 }
 
+/*
+ * Draws a one pixel wide scrolling indicator. y is the upper vertical position
+ * of the indicator in pixels (0..<16).
+ */
+void OLED::drawScrollIndicator(uint8_t y, uint8_t height) {
+    union u_type {
+        uint16_t whole;
+        uint8_t strips[2];
+    } column;
+    
+    column.whole = (1 << height) - 1;
+    column.whole <<= y;
+    
+    // Draw a one pixel wide bar to the left with a single pixel as
+    // the scroll indicator.
+    fillArea(OLED_WIDTH - 1, 0, 1, 8, column.strips[0]);
+    fillArea(OLED_WIDTH - 1, 8, 1, 8, column.strips[1]);
+}
+
 void OLED::setRotation(bool leftHanded) {
 #ifdef MODEL_TS80
 	leftHanded = !leftHanded;