4.14. Warp Transform

Warp Transform is a GEGL based brush-like tool which replaces the old iWarp filter and works directly on the image, on real things instead of a tiny preview window. You can use an erase mode to partially remove warping you applied. You have available options to adapt strength and size of warping.

4.14.1. 呼び出し方

There are different possibilities to activate the tool:

  • From the main menu: ToolsTransformWarp Transform.

  • By clicking the tool icon in the Toolbox.

  • By pressing the W keyboard shortcut.

4.14.2. オプション

図14.128 Warp Tool options

Warp Tool options

The available tool options can be accessed by double clicking the Warp Transform tool icon in toolbox.

Move pixels

Move pixels is the first item of a drop-down list which contains various warping methods:

  • Move pixels is the default method.

    図14.129 Move pixels example

    Move pixels example

  • Grow area

    図14.130 Grow example

    Grow example

  • Shrink area

    図14.131 Shrink example

    Shrink example

    Clicking 5 times at the center of the image with brush size = image size.


  • Swirl clockwise/counter-clockwise

    図14.132 Swirl example

    Swirl example

    Swirling clockwise the whole image (brush size = image size) with a circular movement of the brush.


  • Erase warping

  • Smooth warping

Adapting Size, Hardness, Strength, Spacing

  • Size: the size of the brush is increased.

  • Hardness

  • Strength: set displacement of pixels during warping. The maximum of displacement is on the brush diameter.

  • Spacing

補間アルゴリズム
[注記] 注記

An interpolation method is used during warping. See 補間アルゴリズム for a description of these methods.

Abyss policy

Abyss is a term used by GIMP developers for data outside the input buffer. The warp tool moves pixels from one point to another. Some pixels may come from outside the layer boundary. These pixels don't actually exist anywhere, and therefore don't have any associated color; yet, some color must be assigned to them.

Abyss policy has a drop-down list that allows you to fill empty areas in different manners:

  • None: this is the default option. Empty areas are transparent. An alpha layer is necessary for this option.

  • Clamp: each edge of the transformed layer stretches out indefinitely, so, for example, a pixel to the left of the layer boundary has the same color as the leftmost pixel of the layer with the same y coordinate. An alternative way to think of it is that each pixel outside the layer boundary has the same color as the closest pixel inside the layer boundary.

  • Loop: the transformed layer repeats itself in all directions, so that, for example, falling off the right edge of the layer takes you back to the left edge.

図14.133 Examples for Abyss policy options

Examples for Abyss policy options

High quality preview

preview is the image window, where you work, before pressing Enter to validate the transformation. With this option checked, preview is more accurate, but slower.

Real-time preview

Stroke

  • During motion

  • Periodically

Animate

This option allows you to generate several intermediate images between the original image and the final deformation of this image.

Frames to set the number of frames in this animation.

Create Animation button: to create the animation. A new image window is created. Export it as a GIF image, checking the As animation option in the export dialog.