Initial commit

app/laser-toolkit/_lib/conversions.ts

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+// /var/www/makearmy.io/app/app/laser-toolkit/_lib/conversions.ts
+
+// ---------- DPI / LPI / DPCM ----------
+export function dpiToLpi(dpi: number) {
+  return dpi; // 1:1 if treating “lines” as rows in raster (common convention)
+}
+export function dpiToDpcm(dpi: number) {
+  return dpi / 2.54;
+}
+export function lpiToDpi(lpi: number) {
+  return lpi; // same note as above
+}
+export function lpiToDpcm(lpi: number) {
+  return lpi / 2.54;
+}
+export function dpcmToDpi(dpcm: number) {
+  return dpcm * 2.54;
+}
+export function dpcmToLpi(dpcm: number) {
+  return dpcm * 2.54;
+}
+
+// ---------- Power & Lens Scaler ----------
+// Simple “keep energy density roughly constant” heuristic:
+// newSpeed ≈ oldSpeed * (toPower / fromPower) * (fromField / toField)
+export function scaleSpeed(
+  oldSpeed_mm_s: number,
+  fromPower_W: number,
+  toPower_W: number,
+  fromField_mm: number,
+  toField_mm: number
+) {
+  if (fromPower_W <= 0 || toPower_W <= 0 || fromField_mm <= 0 || toField_mm <= 0) {
+    return oldSpeed_mm_s;
+  }
+  const k = (toPower_W / fromPower_W) * (fromField_mm / toField_mm);
+  return oldSpeed_mm_s * k;
+}
+