From 4d2e8f9ad1d76cf02cae360e029b690f11030988 Mon Sep 17 00:00:00 2001
From: Daishi Kato <dai-shi@users.noreply.github.com>
Date: Mon, 18 May 2020 17:36:30 +0900
Subject: [PATCH] feat: resize multiple elements including two-point lines
 (#1607)

---
 src/element/bounds.ts         |  4 +++-
 src/element/resizeElements.ts |  2 +-
 src/points.ts                 | 27 +++++++++++++++++----------
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/src/element/bounds.ts b/src/element/bounds.ts
index 11d6f426..b77055cf 100644
--- a/src/element/bounds.ts
+++ b/src/element/bounds.ts
@@ -114,6 +114,7 @@ const getLinearElementAbsoluteCoords = (
   element: ExcalidrawLinearElement,
 ): [number, number, number, number] => {
   if (element.points.length < 2 || !getShapeForElement(element)) {
+    // XXX this is just a poor estimate and not very useful
     const { minX, minY, maxX, maxY } = element.points.reduce(
       (limits, [x, y]) => {
         limits.minY = Math.min(limits.minY, y);
@@ -219,6 +220,7 @@ const getLinearElementRotatedBounds = (
   cy: number,
 ): [number, number, number, number] => {
   if (element.points.length < 2 || !getShapeForElement(element)) {
+    // XXX this is just a poor estimate and not very useful
     const { minX, minY, maxX, maxY } = element.points.reduce(
       (limits, [x, y]) => {
         [x, y] = rotate(element.x + x, element.y + y, cx, cy, element.angle);
@@ -311,7 +313,7 @@ export const getResizedElementAbsoluteCoords = (
   nextWidth: number,
   nextHeight: number,
 ): [number, number, number, number] => {
-  if (!isLinearElement(element) || element.points.length <= 2) {
+  if (!isLinearElement(element)) {
     return [
       element.x,
       element.y,
diff --git a/src/element/resizeElements.ts b/src/element/resizeElements.ts
index a1ddde05..20bbb3de 100644
--- a/src/element/resizeElements.ts
+++ b/src/element/resizeElements.ts
@@ -407,7 +407,7 @@ export const canResizeMutlipleElements = (
   return elements.every(
     (element) =>
       ["rectangle", "diamond", "ellipse"].includes(element.type) ||
-      (isLinearElement(element) && element.points.length > 2),
+      isLinearElement(element),
   );
 };
 
diff --git a/src/points.ts b/src/points.ts
index 733592da..451a0df9 100644
--- a/src/points.ts
+++ b/src/points.ts
@@ -18,21 +18,28 @@ export function rescalePoints(
   const prevMinDimension = Math.min(...prevDimValues);
   const prevDimensionSize = prevMaxDimension - prevMinDimension;
 
-  const dimensionScaleFactor = nextDimensionSize / prevDimensionSize;
+  const dimensionScaleFactor =
+    prevDimensionSize === 0 ? 1 : nextDimensionSize / prevDimensionSize;
 
   let nextMinDimension = Infinity;
 
-  const scaledPoints = prevPoints.map((prevPoint) =>
-    prevPoint.map((value, currentDimension) => {
-      if (currentDimension !== dimension) {
-        return value;
-      }
-      const scaledValue = value * dimensionScaleFactor;
-      nextMinDimension = Math.min(scaledValue, nextMinDimension);
-      return scaledValue;
-    }),
+  const scaledPoints = prevPoints.map(
+    (prevPoint) =>
+      prevPoint.map((value, currentDimension) => {
+        if (currentDimension !== dimension) {
+          return value;
+        }
+        const scaledValue = value * dimensionScaleFactor;
+        nextMinDimension = Math.min(scaledValue, nextMinDimension);
+        return scaledValue;
+      }) as [number, number],
   );
 
+  if (scaledPoints.length === 2) {
+    // we don't tranlate two-point lines
+    return scaledPoints;
+  }
+
   const translation = prevMinDimension - nextMinDimension;
 
   const nextPoints = scaledPoints.map(