Add X3 fast LUT option

lib/GfxRenderer/GfxRenderer.h

@@ -230,6 +230,11 @@ class GfxRenderer {
   void writeGrayscalePlaneStrip(bool lsbPlane, const uint8_t* scratch, int yStart, int numRows) const;
   bool supportsStripGrayscale() const;
 
+  // X3-only: trade AA visual fidelity for ~2.2 s faster page-flip wall clock.
+  // No effect on X4 (its single grayscale LUT already runs at ~500 ms).
+  void setFastGrayscaleLut(bool fast) const { display.setFastGrayscaleLut(fast); }
+  bool getFastGrayscaleLut() const { return display.getFastGrayscaleLut(); }
+
   // Tiled grayscale strip target. While active, drawPixel(), clearScreen(),
   // fillPhysicalHSpanByte() and renderGlyphFast2Bit() operate on `scratch`
   // (panelWidthBytes * stripRows bytes, holding physical rows

lib/I18n/translations/english.yaml

@@ -97,6 +97,7 @@ STR_SLEEP_COVER_MODE: "Sleep Screen Cover Mode"
 STR_HIDE_BATTERY: "Hide Battery %"
 STR_EXTRA_SPACING: "Extra Paragraph Spacing"
 STR_TEXT_AA: "Text Anti-Aliasing"
+STR_FAST_AA: "Fast AA (X3 only)"
 STR_TEXT_DARKNESS: "Text Darkness"
 STR_EXTRA_DARK: "Extra Dark"
 STR_MAX_DARK: "Maximum"

lib/hal/HalDisplay.cpp

@@ -104,6 +104,10 @@ void HalDisplay::writeGrayscalePlaneStrip(bool lsbPlane, const uint8_t* rows, ui
 
 bool HalDisplay::supportsStripGrayscale() const { return einkDisplay.supportsStripGrayscale(); }
 
+void HalDisplay::setFastGrayscaleLut(bool fast) { einkDisplay.setFastGrayscaleLut(fast); }
+
+bool HalDisplay::getFastGrayscaleLut() const { return einkDisplay.getFastGrayscaleLut(); }
+
 uint16_t HalDisplay::getDisplayWidth() const { return einkDisplay.getDisplayWidth(); }
 
 uint16_t HalDisplay::getDisplayHeight() const { return einkDisplay.getDisplayHeight(); }

lib/hal/HalDisplay.h

@@ -61,6 +61,12 @@ class HalDisplay {
   void writeGrayscalePlaneStrip(bool lsbPlane, const uint8_t* rows, uint16_t yStart, uint16_t numRows);
   bool supportsStripGrayscale() const;
 
+  // X3-only knob: pick between the OEM 53-frame grayscale LUT (default, slow
+  // and accurate) and the 7-frame community LUT (fast, slightly darker
+  // mid-tones). No effect on X4. See EInkDisplay::setFastGrayscaleLut.
+  void setFastGrayscaleLut(bool fast);
+  bool getFastGrayscaleLut() const;
+
   // Runtime geometry passthrough
   uint16_t getDisplayWidth() const;
   uint16_t getDisplayHeight() const;