Introduction
The Anchor tool is used to keep the position of a frame in relation to the corresponding document edge absolutely or relatively when the document is resized.
By clicking the tool in the tool bar (left or right mouse button) the user is able to choose if the tool should be used absolutely or relatively.
The Anchor tool can be used on the sides (not the angles) of a frame by clicking on the frame handles on the center of the side.
Understanding InDesign’s default behaviour
If an InDesign document is adapted without the Dylation tools, the frames on it move. InDesign positions the frames depending on how the document was created.
With facing pages (default setting when creating a new document), the inner edge is always fixed. In the case of a horizontal change, the border on the right-hand side is shifted accordingly, and in the case of a left-hand side, the left-hand side. Vertically, the side grows or shrinks equally upwards and downwards.
 |  |
left page | right page |
In the case of a single page, the change in size is always calculated both horizontally and vertically from the middle of the page.
 |
single page |
To illustrate this, a 100 x 100 mm page with a 10x10 mm2 square at the position x=10 mm and y=10 mm is adapted to different formats.
Facing page, right side
 | |
Original | |
 |  |
1. Scaling (width +20%, height +20%) | 2. Scaling (width -20%, height -20%) |
 |  |
3. Distortion (width 0%, height -40%) | 4. Distortion (width +20%, height -20%) |
The left margin is fixed due to the page definition (right double page). Therefore, the horizontal position after scaling is unchanged by +20% and the vertical position is 10 mm lower than in the original - the side has been enlarged by 10 mm at the top and bottom.
The same applies to a reduction of the page size. The horizontal position is unchanged after scaling by -20% and the vertical position is 10 mm higher than in the original - the side has been reduced by 10 mm at the top and bottom.
After the -40% distortion (height) the square is 20 mm higher than the original.
After distortion of +20% (width) and -20% (height) the square is also 10 mm higher than the original.
Single Page
| |
Original | |
 |  |
1. Scaling (width +20%, height +20%) | 2. Scaling (width -20%, height -20%) |
|  |
3. Distortion (width 0%, height -40%) | 4. Distortion (width +20%, height -20%) |
Using the Anchor absolutely
If an Anchor is used absolutely on a frame on the left, it keeps the absolute distance between frame side and page side on the left independent from the scaling.
Example:
If the distance between frame side and page side is set to 5 centimetres on the left in the original document, the distance of 5 centimetres between frame side and page side will always be kept.
Position control on one side only
Before adaption
After adaption
Position control on two or more sides
If the Anchor is used absolutely on two or more sides, all distances on the chosen sides will be kept (5 centimetres remain 5 centimetres) independently of scaling. As a result the frame will be adapted.
Before adaption
After adaption
Using the Anchor relatively
If an Anchor is used relatively, it keeps the relative distance between frame side and page side relative to the degree of scaling.
Example:
If the relative distance is set to 5 centimetres between frame side and page edge in the original document, the 5 centimetres will be multiplied by the scaling factor used in the adaption of the document.
If the document is scaled to a width of 125%, the distance between frame side and page edge would be increased by the factor of 1.25.
2 cm * 1.25 = 2.5 cm
Position control on one side only
Before adaption
After adaption
Position control on two or more sides
If the anchor is used relatively on two or more sides, all distances between frame side and page edge will increase/decrease by the same factor.
Before adaption
After adaption
Scaling factor: 250 mm / 200 mm = 1.25
Distance left side: 20 mm * 1.25 = 25 mm
Distance right side: 120 mm * 1.25 = 150 mm