TIEShapeLayer gradient: gpgBottom uses the layer width where gpgTop uses the height

Each tile is one 210 × 130 shape layer rendered by ImageEn through TIELayer.CopyToBitmap, FillColor $00FF8000, FillColor2 $000080FF. The plot reads back the interpolation parameter t from the pixel colours along each layer's gradient axis.

Axis endpoints, from a plane fit over every pixel (residual 0.005)

direction	t at start	t at end	span	ramp length
gpgLeft	0.428	0.999	0.571	1.75 × width
gpgRight	0.001	0.572	0.571	1.75 × width
gpgTop	0.428	0.999	0.571	1.75 × height
gpgBottom	0.000	0.354	0.354	1.75 × width