refactor: simplify code

packages/element/src/linearElementEditor.ts

@@ -8,7 +8,6 @@ import {
   pointDistance,
   vectorFromPoint,
   line,
-  linesIntersectAt,
   curveLength,
   curvePointAtLength,
 } from "@excalidraw/math";
@@ -29,6 +28,7 @@ import {
   deconstructLinearOrFreeDrawElement,
   isPathALoop,
   snapLinearElementPoint,
+  snapToDiscreteAngle,
   type SnapLine,
   type Store,
 } from "@excalidraw/element";
@@ -397,45 +397,16 @@ export class LinearElementEditor {
               pointFrom(referencePointCoords[0], referencePointCoords[1]),
             );
 
-            const firstSnapLine = snapLines[0];
+            const result = snapToDiscreteAngle(
-            if (
+              snapLines,
-              firstSnapLine.type === "points" &&
-              firstSnapLine.points.length > 1
-            ) {
-              const snapLine = line(
-                firstSnapLine.points[0],
-                firstSnapLine.points[1],
-              );
-              const intersection = linesIntersectAt<GlobalPoint>(
               angleLine,
-                snapLine,
+              pointFrom(gridX, gridY),
+              referencePointCoords,
             );
 
-              if (intersection) {
+            dxFromReference = result.dxFromReference;
-                dxFromReference = intersection[0] - referencePointCoords[0];
+            dyFromReference = result.dyFromReference;
-                dyFromReference = intersection[1] - referencePointCoords[1];
+            _snapLines = result.snapLines;
-
-                const furthestPoint = firstSnapLine.points.reduce(
-                  (furthest, point) => {
-                    const distance = pointDistance(intersection, point);
-                    if (distance > furthest.distance) {
-                      return { point, distance };
-                    }
-                    return furthest;
-                  },
-                  {
-                    point: firstSnapLine.points[0],
-                    distance: pointDistance(
-                      intersection,
-                      firstSnapLine.points[0],
-                    ),
-                  },
-                );
-
-                firstSnapLine.points = [furthestPoint.point, intersection];
-                _snapLines = [firstSnapLine];
-              }
-            }
           } else if (snapLines.length > 0) {
             const snappedGridX = effectiveGridX + snapOffset.x;
             const snappedGridY = effectiveGridY + snapOffset.y;
@@ -1237,49 +1208,16 @@ export class LinearElementEditor {
             pointFrom(lastCommittedPointCoords[0], lastCommittedPointCoords[1]),
           );
 
-          const firstSnapLine = _snapLines[0];
+          const result = snapToDiscreteAngle(
-          if (
+            _snapLines,
-            firstSnapLine.type === "points" &&
-            firstSnapLine.points.length > 1
-          ) {
-            const snapLine = line(
-              firstSnapLine.points[0],
-              firstSnapLine.points[1],
-            );
-            const intersection = linesIntersectAt<GlobalPoint>(
             angleLine,
-              snapLine,
+            pointFrom(gridX, gridY),
+            lastCommittedPointCoords,
           );
 
-            if (intersection) {
+          dxFromLastCommitted = result.dxFromReference;
-              dxFromLastCommitted =
+          dyFromLastCommitted = result.dyFromReference;
-                intersection[0] - lastCommittedPointCoords[0];
+          snapLines = result.snapLines;
-              dyFromLastCommitted =
-                intersection[1] - lastCommittedPointCoords[1];
-
-              const furthestPoint = firstSnapLine.points.reduce(
-                (furthest, point) => {
-                  const distance = pointDistance(intersection, point);
-                  if (distance > furthest.distance) {
-                    return { point, distance };
-                  }
-                  return furthest;
-                },
-                {
-                  point: firstSnapLine.points[0],
-                  distance: pointDistance(
-                    intersection,
-                    firstSnapLine.points[0],
-                  ),
-                },
-              );
-
-              firstSnapLine.points = [furthestPoint.point, intersection];
-              snapLines = [firstSnapLine];
-            }
-          } else {
-            snapLines = [];
-          }
         } else if (_snapLines.length > 0) {
           const snappedGridX = effectiveGridX + snapOffset.x;
           const snappedGridY = effectiveGridY + snapOffset.y;

packages/element/src/snapping.ts

@@ -1,5 +1,8 @@
 import {
   isCloseTo,
+  line,
+  linesIntersectAt,
+  pointDistance,
   pointFrom,
   pointRotateRads,
   rangeInclusive,
@@ -1643,3 +1646,79 @@ export const isActiveToolNonLinearSnappable = (
     activeToolType === TOOL_TYPE.text
   );
 };
+
+/**
+ * Snaps to discrete angle rotation logic.
+ * This function handles the common pattern of finding intersections between
+ * angle lines and snap lines, and updating the snap lines accordingly.
+ *
+ * @param snapLines - The original snap lines from snapping
+ * @param angleLine - The line representing the discrete angle constraint
+ * @param gridPosition - The grid position (original pointer position)
+ * @param referencePosition - The reference position (usually the start point)
+ * @returns Object containing updated snap lines and position deltas
+ */
+export const snapToDiscreteAngle = (
+  snapLines: SnapLine[],
+  angleLine: [GlobalPoint, GlobalPoint],
+  gridPosition: GlobalPoint,
+  referencePosition: GlobalPoint,
+): {
+  snapLines: SnapLine[];
+  dxFromReference: number;
+  dyFromReference: number;
+} => {
+  if (snapLines.length === 0) {
+    return {
+      snapLines: [],
+      dxFromReference: gridPosition[0] - referencePosition[0],
+      dyFromReference: gridPosition[1] - referencePosition[1],
+    };
+  }
+
+  const firstSnapLine = snapLines[0];
+  if (firstSnapLine.type === "points" && firstSnapLine.points.length > 1) {
+    const snapLine = line(firstSnapLine.points[0], firstSnapLine.points[1]);
+    const intersection = linesIntersectAt<GlobalPoint>(
+      line(angleLine[0], angleLine[1]),
+      snapLine,
+    );
+
+    if (intersection) {
+      const dxFromReference = intersection[0] - referencePosition[0];
+      const dyFromReference = intersection[1] - referencePosition[1];
+
+      const furthestPoint = firstSnapLine.points.reduce(
+        (furthest, point) => {
+          const distance = pointDistance(intersection, point);
+          if (distance > furthest.distance) {
+            return { point, distance };
+          }
+          return furthest;
+        },
+        {
+          point: firstSnapLine.points[0],
+          distance: pointDistance(intersection, firstSnapLine.points[0]),
+        },
+      );
+
+      const updatedSnapLine: PointSnapLine = {
+        type: "points",
+        points: [furthestPoint.point, intersection],
+      };
+
+      return {
+        snapLines: [updatedSnapLine],
+        dxFromReference,
+        dyFromReference,
+      };
+    }
+  }
+
+  // If no intersection found, return original snap lines with grid position
+  return {
+    snapLines,
+    dxFromReference: gridPosition[0] - referencePosition[0],
+    dyFromReference: gridPosition[1] - referencePosition[1],
+  };
+};

packages/excalidraw/components/App.tsx

@@ -17,7 +17,6 @@ import {
   vectorDot,
   vectorNormalize,
   line,
-  linesIntersectAt,
 } from "@excalidraw/math";
 
 import {
@@ -240,6 +239,7 @@ import {
   isActiveToolNonLinearSnappable,
   getSnapLinesAtPointer,
   snapLinearElementPoint,
+  snapToDiscreteAngle,
   isSnappingEnabled,
   getReferenceSnapPoints,
   getVisibleGaps,
@@ -6030,54 +6030,19 @@ class App extends React.Component<AppProps, AppState> {
                 pointFrom(lastCommittedX + rx, lastCommittedY + ry),
               );
 
-              // Find intersection with first snap line
+              const result = snapToDiscreteAngle(
-              const firstSnapLine = snapLines[0];
+                snapLines,
-              if (
-                firstSnapLine.type === "points" &&
-                firstSnapLine.points.length > 1
-              ) {
-                const snapLine = line(
-                  firstSnapLine.points[0],
-                  firstSnapLine.points[1],
-                );
-                const intersection = linesIntersectAt<GlobalPoint>(
                 angleLine,
-                  snapLine,
+                pointFrom(gridX, gridY),
+                pointFrom(lastCommittedX + rx, lastCommittedY + ry),
               );
 
-                if (intersection) {
+              dxFromLastCommitted = result.dxFromReference;
-                  dxFromLastCommitted = intersection[0] - rx - lastCommittedX;
+              dyFromLastCommitted = result.dyFromReference;
-                  dyFromLastCommitted = intersection[1] - ry - lastCommittedY;
-
-                  // Find the furthest point from the intersection
-                  const furthestPoint = firstSnapLine.points.reduce(
-                    (furthest, point) => {
-                      const distance = pointDistance(intersection, point);
-                      if (distance > furthest.distance) {
-                        return { point, distance };
-                      }
-                      return furthest;
-                    },
-                    {
-                      point: firstSnapLine.points[0],
-                      distance: pointDistance(
-                        intersection,
-                        firstSnapLine.points[0],
-                      ),
-                    },
-                  );
-
-                  firstSnapLine.points = [furthestPoint.point, intersection];
 
               this.setState({
-                    snapLines: [firstSnapLine],
+                snapLines: result.snapLines,
               });
-
-                  this.setState({
-                    snapLines: [firstSnapLine],
-                  });
-                }
-              }
             } else {
               const snappedGridX = effectiveGridX + snapOffset.x;
               const snappedGridY = effectiveGridY + snapOffset.y;
@@ -8814,52 +8779,19 @@ class App extends React.Component<AppProps, AppState> {
                   pointFrom(newElement.x, newElement.y),
                 );
 
-                const firstSnapLine = snapLines.find(
+                const result = snapToDiscreteAngle(
-                  (snapLine) =>
+                  snapLines,
-                    snapLine.type === "points" && snapLine.points.length > 2,
-                );
-                if (firstSnapLine && firstSnapLine.points.length > 1) {
-                  const snapLine = line(
-                    firstSnapLine.points[0],
-                    firstSnapLine.points[1],
-                  );
-                  const intersection = linesIntersectAt<GlobalPoint>(
                   angleLine,
-                    snapLine,
+                  pointFrom(gridX, gridY),
-                  );
+                  pointFrom(newElement.x, newElement.y),
-                  if (intersection) {
-                    dx = intersection[0] - newElement.x;
-                    dy = intersection[1] - newElement.y;
-
-                    // Find the furthest point from the intersection
-                    const furthestPoint = firstSnapLine.points.reduce(
-                      (furthest, point) => {
-                        const distance = pointDistance(intersection, point);
-                        if (distance > furthest.distance) {
-                          return { point, distance };
-                        }
-                        return furthest;
-                      },
-                      {
-                        point: firstSnapLine.points[0],
-                        distance: pointDistance(
-                          intersection,
-                          firstSnapLine.points[0],
-                        ),
-                      },
                 );
 
-                    firstSnapLine.points = [furthestPoint.point, intersection];
+                dx = result.dxFromReference;
+                dy = result.dyFromReference;
 
                 this.setState({
-                      snapLines: [firstSnapLine],
+                  snapLines: result.snapLines,
                 });
-                  } else {
-                    this.setState({
-                      snapLines: [],
-                    });
-                  }
-                }
               } else {
                 dx = gridX + snapOffset.x - newElement.x;
                 dy = gridY + snapOffset.y - newElement.y;