46 lines
1.7 KiB
Dart
46 lines
1.7 KiB
Dart
import 'dart:typed_data';
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Future<Uint8List> pixelBufferToBmp(
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Uint8List pixelBuffer, int width, int height) async {
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final rowSize = (width * 3 + 3) & ~3;
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final padding = rowSize - (width * 3);
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final fileSize = 54 + rowSize * height;
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final data = Uint8List(fileSize);
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final buffer = data.buffer;
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final bd = ByteData.view(buffer);
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// BMP file header (14 bytes)
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bd.setUint16(0, 0x4D42, Endian.little); // 'BM'
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bd.setUint32(2, fileSize, Endian.little);
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bd.setUint32(10, 54, Endian.little); // Offset to pixel data
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// BMP info header (40 bytes)
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bd.setUint32(14, 40, Endian.little); // Info header size
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bd.setInt32(18, width, Endian.little);
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bd.setInt32(22, -height, Endian.little); // Negative for top-down
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bd.setUint16(26, 1, Endian.little); // Number of color planes
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bd.setUint16(28, 24, Endian.little); // Bits per pixel (RGB)
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bd.setUint32(30, 0, Endian.little); // No compression
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bd.setUint32(34, rowSize * height, Endian.little); // Image size
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bd.setInt32(38, 2835, Endian.little); // X pixels per meter
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bd.setInt32(42, 2835, Endian.little); // Y pixels per meter
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// Pixel data (BMP stores in BGR format)
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for (var y = 0; y < height; y++) {
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for (var x = 0; x < width; x++) {
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final srcIndex = (y * width + x) * 4; // RGBA format
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final dstIndex = 54 + y * rowSize + x * 3; // BGR format
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data[dstIndex] = pixelBuffer[srcIndex + 2]; // Blue
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data[dstIndex + 1] = pixelBuffer[srcIndex + 1]; // Green
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data[dstIndex + 2] = pixelBuffer[srcIndex]; // Red
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// Alpha channel is discarded
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}
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// Add padding to the end of each row
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for (var p = 0; p < padding; p++) {
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data[54 + y * rowSize + width * 3 + p] = 0;
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}
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}
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return data;
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} |