Add dst algorithm

src/file-renderer/index.js

@@ -1,5 +1,6 @@
 import { jDataView } from "./jdataview";
 import { pesRead } from "../format-readers/pes";
+import { dstRead } from "../format-readers/dst";
 import { Pattern } from "./pattern";
 
 String.prototype.endsWith = function (suffix) {
@@ -12,6 +13,8 @@ function displayFileText(filename, evt, canvas) {
   filename = filename.toLowerCase();
   if (filename.endsWith("pes")) {
     pesRead(view, pattern);
+  } else if (filename.endsWith("dst")) {
+    dstRead(view, pattern);
   }
   pattern.moveToPositive();
   pattern.drawShape(canvas);

src/format-readers/dst.js

@@ -0,0 +1,107 @@
+// @ts-nocheck
+import { stitchTypes } from "../file-renderer/pattern";
+
+function decodeExp(b2) {
+  let returnCode = 0;
+  if (b2 === 0xf3) {
+    return stitchTypes.end;
+  }
+  if ((b2 & 0xc3) === 0xc3) {
+    return stitchTypes.trim | stitchTypes.stop;
+  }
+  if (b2 & 0x80) {
+    returnCode |= stitchTypes.trim;
+  }
+  if (b2 & 0x40) {
+    returnCode |= stitchTypes.stop;
+  }
+  return returnCode;
+}
+
+export function dstRead(file, pattern) {
+  let flags,
+    x,
+    y,
+    prevJump = false,
+    thisJump = false,
+    b = [],
+    byteCount = file.byteLength;
+  file.seek(512);
+
+  while (file.tell() < byteCount - 3) {
+    b[0] = file.getUint8();
+    b[1] = file.getUint8();
+    b[2] = file.getUint8();
+    x = 0;
+    y = 0;
+    if (b[0] & 0x01) {
+      x += 1;
+    }
+    if (b[0] & 0x02) {
+      x -= 1;
+    }
+    if (b[0] & 0x04) {
+      x += 9;
+    }
+    if (b[0] & 0x08) {
+      x -= 9;
+    }
+    if (b[0] & 0x80) {
+      y += 1;
+    }
+    if (b[0] & 0x40) {
+      y -= 1;
+    }
+    if (b[0] & 0x20) {
+      y += 9;
+    }
+    if (b[0] & 0x10) {
+      y -= 9;
+    }
+    if (b[1] & 0x01) {
+      x += 3;
+    }
+    if (b[1] & 0x02) {
+      x -= 3;
+    }
+    if (b[1] & 0x04) {
+      x += 27;
+    }
+    if (b[1] & 0x08) {
+      x -= 27;
+    }
+    if (b[1] & 0x80) {
+      y += 3;
+    }
+    if (b[1] & 0x40) {
+      y -= 3;
+    }
+    if (b[1] & 0x20) {
+      y += 27;
+    }
+    if (b[1] & 0x10) {
+      y -= 27;
+    }
+    if (b[2] & 0x04) {
+      x += 81;
+    }
+    if (b[2] & 0x08) {
+      x -= 81;
+    }
+    if (b[2] & 0x20) {
+      y += 81;
+    }
+    if (b[2] & 0x10) {
+      y -= 81;
+    }
+    flags = decodeExp(b[2]);
+    thisJump = flags & stitchTypes.jump;
+    if (prevJump) {
+      flags |= stitchTypes.jump;
+    }
+    pattern.addStitchRel(x, y, flags, true);
+    prevJump = thisJump;
+  }
+  pattern.addStitchRel(0, 0, stitchTypes.end, true);
+  pattern.invertPatternVertical();
+}

src/lib/FileViewer.svelte

@@ -9,7 +9,7 @@
   let rejectedFiles;
   let areAcceptedFilesRendered = false;
   const fileRequirements = {
-    supportedFormats: [".pes"],
+    supportedFormats: [".pes", ".dst"],
     maxSize: 700000,
   };