Watch the Placeholder Behavior Video

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Bounding Boxes

Placeholders do just that. They hold a place for future content. This content is going to be fed in during final rendering on Idomoo servers. So how does this content replacement behaves? That depends on the bounding box created when setting up the placeholder.
Bounding boxes define the area that dynamic data fills. The eight square dots around the outline of a layer in After Effects represent the bounding box used. The two images below show an image dynamic layer with its bounding box, and a text dynamic layer with its bounding Box.

Text Bounding Boxes

To define a bounding box for text, type in some characters and choose a font size in an AE text layer.

The subsequent dynamic text's font size will shrink to fill the width of bounding box defined. Alignment, defined in After Effects, dictates where the text should align to in case it doesn't fill the width of the bounding box.
This placeholder supports as many lines of text as will be passed in the data. The width of the placeholder applies to all lines of text. Only a single font size per text layer is applied.

Description Font Size
Original placeholder 128
Longer text resulting in smaller font size 63
Shorter text left aligned 128
Shorter text right aligned 128
Same text resulting in smaller font size due to use of all capital characters, which are wider than the original. 116
All caps but less character resulting in same font size. 128
Descender characters such as Y and ascender characters such as T have no effect on size. 128

Image Bounding Boxes

To define a bounding box for images, use a PNG image as a layer in AE. The original resolution of the image (not the resulting size after scaling) is the bounding box of subsequent images.

Images placed in the bounding box will shrink or grow, while retaining aspect ratio, to fit centered in the bounding box.

Description Size (pixels)
Original image 400x400
Wider image is scaled down and centered 600x126 scales to 400x84
Taller image is scaled down and centered 128x800 scales to 64x400
Smaller image scales up 200x200 scales to 400x400