Naive copy&paste implementation of node resizer in svelte, some stuff pulled out to system

packages/system/src/index.ts

@@ -5,3 +5,4 @@ export * from './xydrag';
 export * from './xyhandle';
 export * from './xyminimap';
 export * from './xypanzoom';
+export * from './xyresizer';

packages/system/src/xyresizer/index.ts

@@ -0,0 +1,76 @@
+export type { D3DragEvent, SubjectPosition } from 'd3-drag';
+
+export type XYResizeParams = {
+  x: number;
+  y: number;
+  width: number;
+  height: number;
+};
+
+export type XYResizeParamsWithDirection = XYResizeParams & {
+  direction: number[];
+};
+
+export type XYResizeControlLinePosition = 'top' | 'bottom' | 'left' | 'right';
+
+export type XYResizeControlPosition =
+  | XYResizeControlLinePosition
+  | 'top-left'
+  | 'top-right'
+  | 'bottom-left'
+  | 'bottom-right';
+
+export enum ResizeControlVariant {
+  Line = 'line',
+  Handle = 'handle',
+}
+
+export const XY_RESIZER_HANDLE_CONTROLS: XYResizeControlPosition[] = [
+  'top-left',
+  'top-right',
+  'bottom-left',
+  'bottom-right',
+];
+export const XY_RESIZER_LINE_CONTROLS: XYResizeControlLinePosition[] = ['top', 'right', 'bottom', 'left'];
+
+type GetResizeDirectionParams = {
+  width: number;
+  prevWidth: number;
+  height: number;
+  prevHeight: number;
+  invertX: boolean;
+  invertY: boolean;
+};
+
+/**
+ * Get all connecting edges for a given set of nodes
+ * @param width - new width of the node
+ * @param prevWidth - previous width of the node
+ * @param height - new height of the node
+ * @param prevHeight - previous height of the node
+ * @param invertX - whether to invert the resize direction for the x axis
+ * @param invertY - whether to invert the resize direction for the y axis
+ * @returns array of two numbers representing the direction of the resize for each axis, 0 = no change, 1 = increase, -1 = decrease
+ */
+export function getResizeDirection({
+  width,
+  prevWidth,
+  height,
+  prevHeight,
+  invertX,
+  invertY,
+}: GetResizeDirectionParams) {
+  const deltaWidth = width - prevWidth;
+  const deltaHeight = height - prevHeight;
+
+  const direction = [deltaWidth > 0 ? 1 : deltaWidth < 0 ? -1 : 0, deltaHeight > 0 ? 1 : deltaHeight < 0 ? -1 : 0];
+
+  if (deltaWidth && invertX) {
+    direction[0] = direction[0] * -1;
+  }
+
+  if (deltaHeight && invertY) {
+    direction[1] = direction[1] * -1;
+  }
+  return direction;
+}