V1_commit_RGC

SuiviREForamteur/node_modules/fast-png/lib-esm/helpers/decodeInterlaceNull.js

@@ -0,0 +1,57 @@
+import { unfilterAverage, unfilterNone, unfilterPaeth, unfilterSub, unfilterUp, } from './unfilter';
+const uint16 = new Uint16Array([0x00ff]);
+const uint8 = new Uint8Array(uint16.buffer);
+const osIsLittleEndian = uint8[0] === 0xff;
+const empty = new Uint8Array(0);
+export function decodeInterlaceNull(params) {
+    const { data, width, height, channels, depth } = params;
+    const bytesPerPixel = Math.ceil(depth / 8) * channels;
+    const bytesPerLine = Math.ceil((depth / 8) * channels * width);
+    const newData = new Uint8Array(height * bytesPerLine);
+    let prevLine = empty;
+    let offset = 0;
+    let currentLine;
+    let newLine;
+    for (let i = 0; i < height; i++) {
+        currentLine = data.subarray(offset + 1, offset + 1 + bytesPerLine);
+        newLine = newData.subarray(i * bytesPerLine, (i + 1) * bytesPerLine);
+        switch (data[offset]) {
+            case 0:
+                unfilterNone(currentLine, newLine, bytesPerLine);
+                break;
+            case 1:
+                unfilterSub(currentLine, newLine, bytesPerLine, bytesPerPixel);
+                break;
+            case 2:
+                unfilterUp(currentLine, newLine, prevLine, bytesPerLine);
+                break;
+            case 3:
+                unfilterAverage(currentLine, newLine, prevLine, bytesPerLine, bytesPerPixel);
+                break;
+            case 4:
+                unfilterPaeth(currentLine, newLine, prevLine, bytesPerLine, bytesPerPixel);
+                break;
+            default:
+                throw new Error(`Unsupported filter: ${data[offset]}`);
+        }
+        prevLine = newLine;
+        offset += bytesPerLine + 1;
+    }
+    if (depth === 16) {
+        const uint16Data = new Uint16Array(newData.buffer);
+        if (osIsLittleEndian) {
+            for (let k = 0; k < uint16Data.length; k++) {
+                // PNG is always big endian. Swap the bytes.
+                uint16Data[k] = swap16(uint16Data[k]);
+            }
+        }
+        return uint16Data;
+    }
+    else {
+        return newData;
+    }
+}
+function swap16(val) {
+    return ((val & 0xff) << 8) | ((val >> 8) & 0xff);
+}
+//# sourceMappingURL=decodeInterlaceNull.js.map