29 lines
1.2 KiB
TypeScript
29 lines
1.2 KiB
TypeScript
// Create a minimal EXIF segment with orientation
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export const createExifOrientation = (orientation: number) => {
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const tiffHeader = Buffer.from("49492A0008000000", "hex");
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const ifdEntry = Buffer.concat([
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Buffer.from("0100", "hex"), // Number of IFD entries
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Buffer.from("1201030001000000", "hex"), // Tag, Type, Count
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Buffer.from(orientation.toString(16).padStart(2, "0"), "hex"), // Orientation value
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Buffer.from("0000", "hex"), // No more IFDs
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Buffer.from("0000000000", "hex"), // padding??
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]);
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const exifData = Buffer.concat([Buffer.from("457869660000", "hex"), tiffHeader, ifdEntry]);
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const segmentLength = Buffer.from([(exifData.length + 2) >> 8, (exifData.length + 2) & 0xff]);
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const exifHeader = Buffer.concat([Buffer.from("FFE1", "hex"), segmentLength]);
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return Buffer.concat([exifHeader, exifData]);
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};
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export const addExifToJpeg = (jpegData: Buffer, exifSegment: Buffer) => {
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// Check for existing EXIF (simplified check)
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if (jpegData.includes(Buffer.from("FFE1", "hex"))) {
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throw new Error("JPEG already contains EXIF segment");
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}
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const soiEnd = 2; // After FFD8
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const modifiedJpeg = Buffer.concat([jpegData.subarray(0, soiEnd), exifSegment, jpegData.subarray(soiEnd)]);
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return modifiedJpeg;
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};
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