Change Shapes of Selection in Photoshop (and Photopea)

Change shapes or move corner points of selection.

Simple way

• Select (polygonal lasco L)
• Ctrl+T to transform
• Hold Ctrl, use mouse to drag corners

Complex shape altering

• Select (polygonal lasco L)
• Ctrl+T to transform
• Click 'Warp' button (Photopea: on toolbar)
• Drag the corner points or other points

Warp will make many lines no longer straight, try these before Warp (and use Warp after for fine putting the corner points only):

• Skew, Perspective, Distort
• (All in Edit >> Transform, if using Photopea)