Risuai 0.6.3 first commit

src/ts/exif.ts

@@ -0,0 +1,36 @@
+import extract from 'png-chunks-extract';
+import encode from 'png-chunks-encode';
+import textKey from 'png-chunk-text'
+
+export const PngMetadata = {
+    write: (pngBuffer: Uint8Array, metadata: Record<string, string>): Buffer => {
+        let chunks:{
+            name:string
+            data:Uint8Array
+        }[] = extract(Buffer.from(pngBuffer));
+
+        chunks = chunks.filter((v) => {
+            return v.name.toLocaleLowerCase() !== 'text'
+        })
+
+        for (const key in metadata) {
+            const value = metadata[key];
+            chunks.splice(-1, 0, textKey.encode(key, value))
+        }
+        const encoded = encode(chunks);
+        return encoded
+    },
+    filter: (pngBuffer: Uint8Array) => {
+        let chunks:{
+            name:string
+            data:Uint8Array
+        }[] = extract(Buffer.from(pngBuffer));
+
+        chunks = chunks.filter((v) => {
+            return v.name.toLocaleLowerCase() !== 'text'
+        })
+
+        const encoded = encode(chunks);
+        return encoded
+    }
+}