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# Rotation of contents

Objects that are output with `<PlaceObject>` can be rotated. For this purpose, there is the attribute `rotate`, which expects an angle (in degrees), whereas positive values cause a clockwise rotation.

        <PlaceObject rotate="10">
          <Image file="_sampleb.pdf" width="3"/>
        </PlaceObject>

When an object is rotated, you need to specify the point around which it should rotate. The default setting is the upper left corner. With the attributes `origin-x` (`left`, `center` and `right`) and `origin-y` (`top`, `center`, `bottom`) you can define the axis of rotation. In addition to these values, numbers from 0 to 100 are also possible, the upper left corner is 0, 0 and the lower right corner is 100, 100.

| In examples repository on github there is a document in the `technical` directory which shows the effect of `origin-x` and `origin-y`.

## Rotate images

The attribute `rotate` is available for both `<PlaceObject>` and `<Image>`. The attribute at `<Image>` can only rotate images in 90 degree steps (positive values: clockwise). Therefore, in practice the rotation is rather controlled by `<PlaceObject>`. This minimal sample shows the difference:

    <Layout xmlns="urn:speedata.de:2009/publisher/en"
      xmlns:sd="urn:speedata:2009/publisher/functions/en">

      <Record element="data">
        <PlaceObject rotate="-90">
          <Image file="_sampleb.pdf" width="3cm"/>
        </PlaceObject>
        <ClearPage/>
        <PlaceObject>
          <Image file="_sampleb.pdf" width="3cm"  rotate="-90"/>
        </PlaceObject>
      </Record>
    </Layout>

Bear in mind that this rotation might also affect some given image dimensions.

The following example rotates an image 90 degrees counterclockwise if it is a portrait image. With the XPath command `sd:aspectratio(<filename>)` you can determine the aspect ratio of an image. If it is greater than 1, then it is a landscape image. The second image from the data file is rotated by 90° counterclockwise.

    <data>
      <img file="_samplea.pdf" />
      <img file="_sampleb.pdf" />
    </data>

Data

    <Layout xmlns:sd="urn:speedata:2009/publisher/functions/en"
      xmlns="urn:speedata.de:2009/publisher/en">

      <Record element="data">
        <ForAll select="img">
          <PlaceObject>
            <Image file="{@file}" width="5"
              rotate="{if ( sd:aspectratio(@file) &lt; 1 ) then '-90' else '0'}"/>
          </PlaceObject>
        </ForAll>
      </Record>
    </Layout>

The image is rotated 90 degrees if it is a portrait image.

| The curly brackets at `file` and `rotate` mean that the system jumps to XPath mode to evaluate the XPath expressions (access to the file attribute and the if-then query). See XPath and Layout Functions for more information.

Note: if the image in the argument of `sd:aspectratio()` is not available in the filesystem, the value is taken from the placeholder image (section Image not found?). To check if an image is available at all, you can use the command `sd:file-exists(<filename>)`.

## Rotate via transformation

Using the command `<Transformation>` (see section Transformation and in the reference the command description) you can also rotate contents. The matrix has the form “cos θ sin θ -sin θ cos θ 0 0”, for a rotation of 90 degrees thus “0 1 -1 0 0 0”. This is shown in the section Image behind the text.

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