Merge branch 'gas_sensor_mq-135' of https://github.com/rahul31124/pslab-android into gas_sensor_mq-135

Author: rahul31124

assets/icons/l.png

@@ -0,0 +1,136 @@
+import 'package:pslab/communication/peripherals/i2c.dart';
+import 'package:pslab/communication/science_lab.dart';
+import 'package:pslab/others/logger_service.dart';
+
+class SSD1306 {
+  static const String tag = "SH1106_Hardware";
+  static const int address = 0x3C;
+
+  static const int _commandMode = 0x00;
+  static const int _dataMode = 0x40;
+
+  final I2C i2c;
+  List<int> _lastBuffer = List.filled(1024, -1);
+
+  SSD1306._(this.i2c);
+
+  static Future<SSD1306> create(I2C i2c, ScienceLab scienceLab) async {
+    final display = SSD1306._(i2c);
+    await display._initialize(scienceLab);
+    return display;
+  }
+
+  Future<void> _initialize(ScienceLab scienceLab) async {
+    if (!scienceLab.isConnected()) throw Exception("ScienceLab device absent");
+
+    try {
+      final List<int> initSequence = [
+        0xAE,
+        0xD5,
+        0x80,
+        0xA8,
+        0x3F,
+        0xD3,
+        0x00,
+        0x40,
+        0xAD,
+        0x8B,
+        0x33,
+        0xA1,
+        0xC8,
+        0xDA,
+        0x12,
+        0x81,
+        0xFF,
+        0xD9,
+        0x1F,
+        0xDB,
+        0x40,
+        0xA4,
+        0xA6,
+        0xAF,
+      ];
+
+      for (int cmd in initSequence) {
+        await i2c.write(address, [cmd], _commandMode);
+      }
+      await clearDisplay();
+    } catch (e) {
+      logger.e("[$tag] Fatal initialization error: $e");
+      rethrow;
+    }
+  }
+
+  Future<void> _setPosition(int column, int page) async {
+    int offsetColumn = column + 2;
+    await i2c.write(address, [0xB0 + page], _commandMode);
+    await i2c.write(address, [offsetColumn & 0x0F], _commandMode);
+    await i2c.write(address, [0x10 | (offsetColumn >> 4)], _commandMode);
+  }
+
+  Future<void> clearDisplay() async {
+    try {
+      for (int page = 0; page < 8; page++) {
+        await i2c.write(address, [0xB0 + page], _commandMode);
+        await i2c.write(address, [0x00], _commandMode);
+        await i2c.write(address, [0x10], _commandMode);
+
+        for (int chunk = 0; chunk < 132; chunk += 16) {
+          int size = (chunk + 16 > 132) ? 132 - chunk : 16;
+          await i2c.write(address, List.filled(size, 0x00), _dataMode);
+        }
+      }
+      _lastBuffer = List.filled(1024, 0);
+    } catch (e) {
+      logger.e("[$tag] Error during clearDisplay: $e");
+    }
+  }
+
+  Future<void> sendFrameBuffer(List<int> buffer) async {
+    if (buffer.length != 1024) return;
+
+    try {
+      for (int page = 0; page < 8; page++) {
+        int startIdx = page * 128;
+        int firstCol = -1;
+        int lastCol = -1;
+
+        for (int i = 0; i < 128; i++) {
+          if (buffer[startIdx + i] != _lastBuffer[startIdx + i]) {
+            if (firstCol == -1) firstCol = i;
+            lastCol = i;
+          }
+        }
+
+        if (firstCol != -1) {
+          int length = lastCol - firstCol + 1;
+
+          try {
+            await _setPosition(firstCol, page);
+
+            for (int chunk = 0; chunk < length; chunk += 16) {
+              int chunkSize = (chunk + 16 > length) ? length - chunk : 16;
+              List<int> bytes = buffer.sublist(startIdx + firstCol + chunk,
+                  startIdx + firstCol + chunk + chunkSize);
+              await i2c.write(address, bytes, _dataMode);
+            }
+          } catch (e) {
+            // --- THE LAG KILLER ---
+            // If the Android USB throws a 500ms timeout, DO NOT KEEP LOOPING.
+            // Abort this frame entirely so the Flutter UI thread unfreezes instantly!
+            _lastBuffer =
+                List.filled(1024, -1); // Reset cache to heal on next tick
+            return;
+          }
+
+          // Only update cache if the write was perfectly successful
+          for (int i = firstCol; i <= lastCol; i++) {
+            _lastBuffer[startIdx + i] = buffer[startIdx + i];
+          }
+        }
+      }
+    } catch (e) {
+      _lastBuffer = List.filled(1024, -1);
+    }
+  }
+}