Faster TFTColor processing (#10814)

src/graphics/TFTColorRegions.h

@@ -67,6 +67,29 @@ uint16_t resolveTFTColorPixel(int16_t x, int16_t y, bool isset, uint16_t default
 // Resolve effective region-mapped OFF color at a coordinate in native-endian RGB565.
 uint16_t resolveTFTOffColorAt(int16_t x, int16_t y, uint16_t defaultOffColor);
 
+// -- Per-row fast path for the hot pixel loops in TFTDisplay::display() --------
+// resolveTFTColorPixel() is O(regions) per pixel; for a full 800x480 repaint that
+// dominates redraw time. Regions are vertically localized, so cull to the regions
+// overlapping the current row once per row, then resolve each pixel against only
+// those (inlined here, so no per-pixel cross-TU call).
+extern uint8_t tftColorRowRegions[MAX_TFT_COLOR_REGIONS]; // indices into colorRegions[], ascending
+extern uint8_t tftColorRowCount;
+
+// Build tftColorRowRegions for row y. Call once per row before resolveTFTColorPixelRow().
+void beginTFTColorRow(int16_t y);
+
+// Resolve one pixel against the current row's active regions (set by beginTFTColorRow()).
+// Highest-index region wins, matching resolveTFTColorPixel()'s precedence.
+inline uint16_t resolveTFTColorPixelRow(int16_t x, bool isset, uint16_t defaultOnColor, uint16_t defaultOffColor)
+{
+    for (int j = static_cast<int>(tftColorRowCount) - 1; j >= 0; j--) {
+        const TFTColorRegion &r = colorRegions[tftColorRowRegions[j]];
+        if (x >= r.x && x < r.x + r.width)
+            return isset ? r.onColorBe : r.offColorBe;
+    }
+    return isset ? defaultOnColor : defaultOffColor;
+}
+
 // -- Theme engine ------------------------------------------------------
 // Each theme has four fields that work together:
 //