Figure 13.50. The Blend tool in Toolbox
This tool fills the selected area with a gradient blend of the foreground
and background colors by default, but there are many options. To make a
blend, drag the cursor in the direction you want the gradient to go, and
release the mouse button when you feel you have the right position and
size of your blend. The softness of the blend depends on how far you drag
the cursor. The shorter the drag distance, the sharper it will be.
There are an astonishing number of things you can do with this tool, and
the possibilities may seem a bit overwhelming at first. The two most
important options you have are the Gradient and the Shape. Clicking the
Gradient button in the tool options brings up a Gradient Select window,
allowing you to choose from among a variety of gradients supplied with
GIMP; you can also construct and save custom gradients. Further
information about gradients can be found in
Section 10, “
Section 3.4, “
For Shape, there are 11 options: Linear, Bilinear, Radial, Square, Conical
(symmetric), Conical (asymmetric), Shaped (angular), Shaped (spherical),
Shaped (dimpled), Spiral (clockwise), and Spiral (counterclockwise); these
are described in detail below. The Shaped options are the most
interesting: they cause the gradient to follow the shape of the selection
boundary, no matter how twisty it is. Unlike the other shapes, Shaped
gradients are not affected by the length or direction of the line you
draw: for them as well as every other type of gradient you are required to
click inside the selection and move the mouse, but a Shaped appears the
same no matter where you click or how you move.
Check out the Difference option in the Mode menu, where doing the same
thing (even with full opacity) will result in fantastic swirling
patterns, changing and adding every time you drag the cursor.
3.4.1. Activating the Tool
There are different possibilities to activate the tool:
3.4.2. Key modifiers (Defaults)
Ctrl is used to create straight lines that are
constrained to 15 degree absolute angles.
Figure 13.51. “Blend” tool options
Normally, tool options are displayed in a window attached under the
Toolbox as soon as you activate a tool. If they are not, you can access
them from the image menu bar through
→ → which opens the option window of the selected tool.
See the Brush Tools
Overview for a description of tool options that apply to many or
all brush tools.
A variety of gradient patterns can be selected from the drop-down
list. The tool causes a shading pattern that transitions from
foreground to background color or introducing others colors, in
the direction the user determines by drawing a line in the image.
For the purposes of drawing the gradient, the
check-box reverse the gradient direction with the effect, for
instance, of swapping the foreground and background colors.
The Offset value permits to increase the
“slope” of the gradient. It determines how far
from the clicked starting point the gradient will begin.
Shaped forms are not affected by this option.
“Blend” tool: Offset example
provides 11 shapes, which can be selected from the drop-down list.
Details on each of the shapes are given below.
Examples of gradient shapes
This gradient begins with the foreground color at the
starting point of the drawn line and transitions linearly to
the background color at the ending point.
This shape proceeds in both directions from the starting
point, for a distance determined by the length of the drawn
line. It is useful, for example, for giving the appearance
of a cylinder.
This gradient gives a circle, with foreground color at the
center and background color outside the circle. It gives the
appearance of a sphere without directional lighting.
Square-shaped gradient examples
There are four shapes that are some variant on a
Shaped (spherical), and
Shaped (dimpled). They all
put the foreground color at the center of a square,
whose center is at the start of the drawn line, and
whose half-diagonal is the length of the drawn line.
The four options provide a variety in the manner in
which the gradient is calculated; experimentation is
the best means of seeing the differences.
Conical (symmetric); Conical (asymmetric)
Conical gradient examples
The Conical (symmetrical) shape
gives the sensation of looking down at the tip of a
cone, which appears to be illuminated with the
background color from a direction determined by the
direction of the drawn line.
Conical (asymmetric) is similar to
Conical (symmetric) except that
the "cone" appears to have a ridge where the line is
Spiral (clockwise); Spiral
Spiral gradient examples
The Spiral shape provide spirals
whose repeat width is determined by the length of
the drawn line.
There are two repeat modes: Sawtooth Wave
and Triangular Wave. The Sawtooth
pattern is achieved by beginning with the foreground,
transitioning to the background, then starting over with the
foreground. The Triangular starts with the foreground,
transitions to the background, then transitions back to the
Dithering is fully explained in the
This a more sophisticated means of smoothing the "jagged" effect
of a sharp transition of color along a slanted or curved line.
Only tests can allow you to choose.