Curve Gradient Layer

Revision as of 13:20, 24 October 2011

About Curve Gradient Layer

As you already guessed, a Curve Gradient is a gradient that follows a curve. One side of the curve will be filled with the color at the beginning of the current gradient (see the Gradient Editor Dialog), and the other side will be filled by the color at the end of the gradient. In other words, the gradient will fully cover your canvas (as the other gradients do), and you'll have to play with the Blend Method if you want to bind it to a specific shape.

There are two ways to display a gradient: the default one (fast), and an improved one that can remove any render artifacts you have with the first one. To switch from one method to the other, check/uncheck the Fast parameter from the Params Panel.

Parameters of Curve Gradient Layer

The parameters of the Curve Gradient Layer are:

Name	Value	Type
Z Depth	0.000000	real
Amount	1.000000	real
Blend Method	Composite	integer
Orign	0.000000pt,0.000000pt	vector
Width	5.500000pt	real
Vertices	List	BLine
Gradient		gradient
Loop		bool
ZigZag		bool
Perpendicular		bool
Fast		bool

Creating a Curve Gradient

There are several ways to create a gradient that follows a curve.

• With the Bline Tool, check "Gradient" in the Tool Options dialog. It will create a gradient that follows the curve you draw.

• In the Layer menu (from the Canvas Menu Caret or with a right click on a layer in the Layers Panel), select Gradients > Curve Gradient. It will create a gradient with a default shape. On the Params Panel, right click on Vertices, and select Convert > BLine, so you can edit the shape of the gradient.

• To make a Curve Gradient follow an existing shape, place the Curve Gradient layer above the layer containing the shape in the Layers Panel. Select those two layers, then on the Params Panel, right-click on Vertices (greyed) and select Link.

• Alternately, to make a Curve Gradient follow an existing bline shape (outline, region, or other curve gradient), select the shape you want it to follow, right-click its Vertices parameter in the parameter dialog and chose Export from the menu. Type a name in the dialog that pops up. Then select the curve gradient layer where you want to use this exported shape. Open the Children dialog, find the shape you just exported and select it. Then right-click on the Vertices parameter of the Curve Gradient layer where you want to use the shape and select Connect from the menu.

Spreading the gradient

Your curve gradient is now created, but it may not look at all like a gradient. Instead it may looks like each side of the curve was filled with a solid color. That's because the width of the gradient is too small. Make sure that the Curve Gradient layer is selected, and in the Params Panel, increase the Width value. Your gradient will appear.

An easier way to increase the gradient size is to use the Width ducks. In the Canvas Menu select View > Show/Hide Ducks > Show width ducks. The width ducks appear in purple on the canvas. Grab one of them to adjust the width. Each width duck can be adjusted independently. The width of the gradient will follow the width of the BLine at each point, so it's possible to have the gradient very wide in some places and less wide in others.

Fast Option

Within the Params Panel of the curve gradient layer is a "fast" option. I'm unsure exactly what speed up it produces, but it does cause a visual artifact when the gradient is constrained with transparency as show in the Gradient Editor Dialog page, and curve vertices are set to width = 0.

The fast option can be turned off in the curve gradient layer's Params Panel.