[Feature] Enhanced MaskEditor to an Image Canvas (#4361)

Co-authored-by: duckcomfy <a@a.a>

src/extensions/core/maskEditorLayerFilenames.ts

@@ -0,0 +1,29 @@
+export interface ImageLayerFilenames {
+  maskedImage: string
+  paint: string
+  paintedImage: string
+  paintedMaskedImage: string
+}
+
+const paintedMaskedImagePrefix = 'clipspace-painted-masked-'
+
+export const imageLayerFilenamesByTimestamp = (
+  timestamp: number
+): ImageLayerFilenames => ({
+  maskedImage: `clipspace-mask-${timestamp}.png`,
+  paint: `clipspace-paint-${timestamp}.png`,
+  paintedImage: `clipspace-painted-${timestamp}.png`,
+  paintedMaskedImage: `${paintedMaskedImagePrefix}${timestamp}.png`
+})
+
+export const imageLayerFilenamesIfApplicable = (
+  inputImageFilename: string
+): ImageLayerFilenames | undefined => {
+  const isPaintedMaskedImageFilename = inputImageFilename.startsWith(
+    paintedMaskedImagePrefix
+  )
+  if (!isPaintedMaskedImageFilename) return undefined
+  const suffix = inputImageFilename.slice(paintedMaskedImagePrefix.length)
+  const timestamp = parseInt(suffix.split('.')[0], 10)
+  return imageLayerFilenamesByTimestamp(timestamp)
+}