Implement Box Selection (drag to select multiple shapes) #33

New Issue

thib8956 · 2026-03-27T23:17:57Z

thib8956 commented

2026-03-27 23:17:57 +00:00

Overview

Add drag-to-select functionality for selecting multiple shapes within a rectangle.

Current State

Click selects single shape (in Controller.mousePressed)
Shift+click adds to selection
Selection uses SelectionAttributes

Implementation Plan

1. Controller changes

Add state: boxSelectOrigin (Point), boxSelectActive (boolean)
Add boxSelectionRectangle (Rectangle) for current drag area

2. Mouse handling

mousePressed: If click on empty area (no shape), start box selection. Store origin point. Clear current selection unless Shift is held.
mouseDragged: If boxSelectActive, update rectangle from origin to current point. Repaint to show selection box.
mouseReleased: Calculate final box rectangle. Find all shapes whose bounds intersect with box. Add to selection (or replace if no Shift). Clear box selection state, repaint.

3. Visual feedback

Draw semi-transparent rectangle during drag in ShapesView
Use XOR mode or overlay for drawing
Box outline: dashed line, gray color

4. Selection behavior

Default: box replaces current selection
Shift+drag: box adds to current selection
Box entirely within shape = shape selected
Partial overlap: select shape (standard behavior)

5. Intersection check

Use shape.getBounds().intersects(boxRect)
Handle composite shapes (SCollection) - check children

Files to modify

ui/Controller.java - mouse handling
ui/ShapesView.java - draw box overlay in paintComponent

Edge cases

Drag on existing selection: allow move instead of box select
Very small drag (< 5px): treat as click, select shape under point
Empty box: clear selection

## Overview Add drag-to-select functionality for selecting multiple shapes within a rectangle. ## Current State - Click selects single shape (in Controller.mousePressed) - Shift+click adds to selection - Selection uses SelectionAttributes ## Implementation Plan ### 1. Controller changes - Add state: boxSelectOrigin (Point), boxSelectActive (boolean) - Add boxSelectionRectangle (Rectangle) for current drag area ### 2. Mouse handling - mousePressed: If click on empty area (no shape), start box selection. Store origin point. Clear current selection unless Shift is held. - mouseDragged: If boxSelectActive, update rectangle from origin to current point. Repaint to show selection box. - mouseReleased: Calculate final box rectangle. Find all shapes whose bounds intersect with box. Add to selection (or replace if no Shift). Clear box selection state, repaint. ### 3. Visual feedback - Draw semi-transparent rectangle during drag in ShapesView - Use XOR mode or overlay for drawing - Box outline: dashed line, gray color ### 4. Selection behavior - Default: box replaces current selection - Shift+drag: box adds to current selection - Box entirely within shape = shape selected - Partial overlap: select shape (standard behavior) ### 5. Intersection check - Use shape.getBounds().intersects(boxRect) - Handle composite shapes (SCollection) - check children ## Files to modify - ui/Controller.java - mouse handling - ui/ShapesView.java - draw box overlay in paintComponent ## Edge cases - Drag on existing selection: allow move instead of box select - Very small drag (< 5px): treat as click, select shape under point - Empty box: clear selection

thib8956 referenced this issue from a commit

2026-03-27 23:57:48 +00:00

Implement #33: Box Selection (drag to select multiple shapes)

thib8956 referenced this issue

2026-03-27 23:58:05 +00:00

Implement #33: Box Selection #40

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Reference: thib8956/new-shapes#33