feat(ui): wip canvas nodes migration

invokeai/frontend/web/src/common/util/arrayBuffer.ts

@@ -0,0 +1,59 @@
+export const getIsImageDataPartiallyTransparent = (imageData: ImageData) => {
+  let hasTransparency = false;
+  let isFullyTransparent = true;
+  const len = imageData.data.length;
+  let i = 3;
+  for (i; i < len; i += 4) {
+    if (imageData.data[i] !== 0) {
+      isFullyTransparent = false;
+    } else {
+      hasTransparency = true;
+    }
+  }
+  return { hasTransparency, isFullyTransparent };
+};
+
+export const getImageDataTransparency = (imageData: ImageData) => {
+  let isFullyTransparent = true;
+  let isPartiallyTransparent = false;
+  const len = imageData.data.length;
+  let i = 3;
+  for (i; i < len; i += 4) {
+    if (imageData.data[i] === 255) {
+      isFullyTransparent = false;
+    } else {
+      isPartiallyTransparent = true;
+    }
+    if (!isFullyTransparent && isPartiallyTransparent) {
+      return { isFullyTransparent, isPartiallyTransparent };
+    }
+  }
+  return { isFullyTransparent, isPartiallyTransparent };
+};
+
+export const areAnyPixelsBlack = (imageData: ImageData) => {
+  const len = imageData.data.length;
+  let i = 0;
+  for (i; i < len; ) {
+    if (
+      imageData.data[i++] === 255 &&
+      imageData.data[i++] === 255 &&
+      imageData.data[i++] === 255 &&
+      imageData.data[i++] === 255
+    ) {
+      return true;
+    }
+  }
+  return false;
+};
+
+export const getIsImageDataWhite = (imageData: ImageData) => {
+  const len = imageData.data.length;
+  let i = 0;
+  for (i; i < len; ) {
+    if (imageData.data[i++] !== 255) {
+      return false;
+    }
+  }
+  return true;
+};