feat: Added the Logic for changing clipart to led hex (#958)

Co-authored-by: Aditya Gupta <[email protected]>

Author: Jhalakupadhyay

lib/bademagic_module/bluetooth/bluetooth.dart

@@ -6,13 +6,14 @@ import 'package:logger/logger.dart';
 
 class BadgeMagicBluetooth {
   static final Logger logger = Logger();
+  static DataToByteArrayConverter converter = DataToByteArrayConverter();
 
   static Future<void> writeCharacteristic(
     BluetoothDevice device,
     Guid characteristicId,
     Data data,
   ) async {
-    List<List<int>> dataChunks = convert(data);
+    List<List<int>> dataChunks = converter.convert(data);
     logger.d("Data to write: $dataChunks");
 
     try {

lib/bademagic_module/utils/byte_array_utils.dart

@@ -10,8 +10,12 @@ String toHex(List<int> bytes) {
   return buffer.toString().toUpperCase();
 }
 
+bool isValidHex(String input) {
+  return RegExp(r'^[0-9a-fA-F]+$').hasMatch(input);
+}
+
 List<int> hexStringToByteArray(String hexString) {
-  if (hexString.length % 2 != 0) {
+  if (hexString.length % 2 != 0 || !isValidHex(hexString)) {
     throw ArgumentError("Invalid hex string: $hexString");
   }
 

lib/bademagic_module/utils/converters.dart

@@ -6,17 +6,119 @@ class Converters {
   //then adds the hexstring to the list
   //thus generating the hex value of the message
   static List<String> messageTohex(String message) {
+    DataToByteArrayConverter converter = DataToByteArrayConverter();
     List<String> messages = [];
     int i = 0;
     while (i < message.length) {
       var ch = message[i];
-      logger.d("ch = $ch");
-      if (charCodes.containsKey(ch)) {
-        messages.add(charCodes[ch]!);
+      if (converter.charCodes.containsKey(ch)) {
+        messages.add(converter.charCodes[ch]!);
       }
       i++;
     }
-    logger.d("message to hex = $message");
     return messages;
   }
+
+  //function to convert the bitmap to the LED hex format
+  //it takes the 2D list of pixels and converts it to the LED hex format
+  static List<String> convertBitmapToLEDHex(List<List<int>> image) {
+    // Determine the height and width of the image
+    int height = image.length;
+    int width = image.isNotEmpty ? image[0].length : 0;
+
+    // Initialize variables to calculate padding and offsets
+    int finalSum = 0;
+
+    // Calculate and adjust for right-side padding
+    for (int j = 0; j < width; j++) {
+      int sum = 0;
+      for (int i = 0; i < height; i++) {
+        sum += image[i][j]; // Sum up pixel values in each column
+      }
+      if (sum == 0) {
+        // If column sum is zero, mark all pixels in that column as -1
+        for (int i = 0; i < height; i++) {
+          image[i][j] = -1;
+        }
+      } else {
+        // Otherwise, update finalSum and exit loop
+        finalSum += j;
+        break;
+      }
+    }
+
+    // Calculate and adjust for left-side padding
+    for (int j = width - 1; j >= 0; j--) {
+      int sum = 0;
+      for (int i = 0; i < height; i++) {
+        sum += image[i]
+            [j]; // Sum up pixel values in each column (from right to left)
+      }
+      if (sum == 0) {
+        // If column sum is zero, mark all pixels in that column as -1
+        for (int i = 0; i < height; i++) {
+          image[i][j] = -1;
+        }
+      } else {
+        // Otherwise, update finalSum and exit loop
+        finalSum += (height - j - 1);
+        break;
+      }
+    }
+
+    // Calculate padding difference to align height to a multiple of 8
+    int diff = 0;
+    if ((height - finalSum) % 8 > 0) {
+      diff = 8 - (height - finalSum) % 8;
+    }
+
+    // Calculate left and right offsets for padding
+    int rOff = (diff / 2).floor();
+    int lOff = (diff / 2).ceil();
+
+    // Initialize a new list to accommodate the padded image
+    List<List<int>> list =
+        List.generate(height, (i) => List.filled(width + rOff + lOff, 0));
+
+    // Fill the new list with the padded image data
+    for (int i = 0; i < height; i++) {
+      int k = 0;
+      for (int j = 0; j < rOff; j++) {
+        list[i][k++] = 0; // Fill right-side padding
+      }
+      for (int j = 0; j < width; j++) {
+        if (image[i][j] != -1) {
+          list[i][k++] = image[i][j]; // Copy non-padded pixels
+        }
+      }
+      for (int j = 0; j < lOff; j++) {
+        list[i][k++] = 0; // Fill left-side padding
+      }
+    }
+
+    // Convert each 8-bit segment into hexadecimal strings
+    List<String> allHexs = [];
+    for (int i = 0; i < list[0].length ~/ 8; i++) {
+      StringBuffer lineHex = StringBuffer();
+
+      for (int k = 0; k < height; k++) {
+        StringBuffer stBuilder = StringBuffer();
+
+        // Construct 8-bit segments for each row
+        for (int j = i * 8; j < i * 8 + 8; j++) {
+          stBuilder.write(list[k][j]);
+        }
+
+        // Convert binary string to hexadecimal
+        String hex = int.parse(stBuilder.toString(), radix: 2)
+            .toRadixString(16)
+            .padLeft(2, '0');
+        lineHex.write(hex); // Append hexadecimal to line
+      }
+
+      allHexs.add(lineHex.toString()); // Store completed hexadecimal line
+    }
+
+    return allHexs; // Return list of hexadecimal strings
+  }
 }