4.10. Unified Transform

Obrázek 14.111. Unified Transform tool

Unified Transform tool

This tool combines several tools: Rotate, Scale, Shear and Perspective, performing one or several of these actions at once in one single operation. Combining two or more options gives you almost infinite possibilities of transformation.

As the other transformation tools, this tool works on the active layer (default).

After selecting the Unified Transform tool in the toolbox, click on the image window. Several elements appear on the image window:

4.10.1. Activating the Tool

There are different possibilities to activate the tool:

  • From the main menu: ToolsTransform ToolsUnified transform.

  • By clicking the tool icon in the Toolbox.

  • By pressing the Shift+T keyboard shortcut.

4.10.2. Options

Obrázek 14.112. Unified Transform Tool Options

Unified Transform Tool Options

The available tool options can be accessed by double clicking the tool icon in the toolbox:

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These options are described in Transform tools common options.

Constrain

Move: when this option is unchecked, moving the layer is smooth. Checking the option constrains movement to 45° from center.

Scale: when this option is checked, the aspect ratio is preserved.

Obrázek 14.113. Scale Constraint Option

Scale Constraint Option

"Scale" option under "Constrain" not checked; "Scale" option under "From pivot" not checked

Scale Constraint Option

"Scale" option under "Constrain" checked; "Scale" option under "From pivot" not checked


Rotate: default rotation is smooth. When this option is checked, rotation goes by 15° steps.

Shear: normally, to shear the layer, you drag the corresponding icon along a layer edge. If this option is unchecked (default), you may move away from this edge. If this option is checked, shear handles remain on this edge.

Perspective: normally, to change perspective, you drag the corresponding icon along a layer edge. If this option is unchecked (default), you may move away from this edge. If this option is checked, perspective handles remain on this edge or on a diagonal.

Obrázek 14.114. Perspective Constraint Option

Perspective Constraint Option

"Perspective" option under "Constrain" not checked; "Perspective" option under "From pivot" not checked

Perspective Constraint Option

"Perspective" option under "Constrain" checked; "Perspective" option under "From pivot" not checked


From pivot

Scale:

Obrázek 14.115. Scale from pivot

Scale from pivot

"Scale" option under "Constrain" checked; "Scale" option under "From pivot" not checked

Scale from pivot

"Scale" option under "Constrain" checked; "Scale" option under "From pivot" also checked


Shear: When this option is unchecked (default), the opposite edge is fixed and the pivot moves with shearing. When the option is checked, shearing is performed around a fixed pivot and the opposite side is sheared by the same amount, but in the opposite direction.

Perspective: when this option is checked, the position of pivot is maintained.

Obrázek 14.116. Perspective from pivot

Perspective from pivot

"Perspective" option under "Constrain" checked; "Perspective" option under "From pivot" not checked

Perspective from pivot

"Perspective" option under "Constrain" checked; "Perspective" option under "From pivot" also checked


Pivot

Snap: if this option is checked, the pivot snaps to center or to corners when it comes close to them.

Lock: locks pivot.

4.10.3. Key modifiers

Key modifiers are active when an action (move, scale, rotate, etc.) is selected. Hold on:

  • Shift to check all Constrain unchecked options and uncheck already checked ones if a transformation handle is selected, or, if the pivot is selected, to snap pivot to center or corner,

  • Ctrl to check all From pivot unchecked options and uncheck already checked ones.

4.10.4. The Unified Transform adjustment dialog

Obrázek 14.117. The Unified Transform adjustment dialog

The Unified Transform adjustment dialog

When you click on the image window, the adjustment dialog appears.

Transform Matrix

The information window shows a mathematical representation of the perspective transformation. You can find more information about transformation matrices on Wikipedia.

Readjust button

With this button you can reset the transform handles back to the original square shape, while keeping the current transformation and zoom level. This enables you to create more complex transformations by making the transformation in several steps.