Template with an Image

A picture placeholder is a shape the layout already positioned and sized. There is no SetImage on PlaceHolder, so filling one means registering the image, adding the relationship to the slide, and assigning a blip fill to the placeholder’s shape properties. That is more schema work than the text placeholders in Use a Template need, and it is the reason this has its own guide.

Filling a picture placeholder

image, err := common.ImageFromFile("gophercolor.png")
if err != nil {
    return err
}
iRef, err := ppt.AddImage(image)
if err != nil {
    return err
}

imageRelID := slide.AddImageToRels(iRef)

pic, err := slide.GetPlaceholder(pml.ST_PlaceholderTypePic)
if err != nil {
    return err
}

spPr := dml.NewCT_ShapeProperties()
spPr.FillPropertiesChoice.BlipFill = dml.NewCT_BlipFillProperties()
spPr.FillPropertiesChoice.BlipFill.Blip = dml.NewCT_Blip()
spPr.FillPropertiesChoice.BlipFill.Blip.EmbedAttr = &imageRelID
spPr.FillPropertiesChoice.BlipFill.FillModePropertiesChoice.Stretch = dml.NewCT_StretchInfoProperties()
pic.X().SpPr = spPr

AddImageToRels is the piece that differs from ordinary image placement. It registers the image as a relationship of this slide and returns the relationship ID, without creating a picture shape. That ID goes into the blip’s embed attribute, which is what ties the placeholder’s fill to the image part.

Stretch with no fill rectangle means stretch to the shape, which for a placeholder is the box the layout drew. FillModePropertiesChoice also has a Tile alternative; set one of the two, since a blip fill with neither leaves the fill mode to the viewer.

Assigning pic.X().SpPr replaces the placeholder’s shape properties outright. Whatever geometry, line or effect the layout put there is gone, which is acceptable for a picture placeholder whose position comes from the layout’s transform rather than from its shape properties.

Ordering

ppt.AddImage registers the image with the package and slide.AddImageToRels attaches it to one slide, so the presentation-level call has to come first and the slide has to exist for the second. The example registers the image, adds the slide, then wires them together.

Templates ship with example slides. Remove them with RemoveSlide before adding your own, or the output carries both.

Limitations

The image fills the placeholder’s box as the layout sized it. Aspect ratio is not preserved: a stretch fill distorts a picture whose proportions do not match the box. If that matters, use slide.AddImage and size it yourself with RelativeHeight.

GetPlaceholder(pml.ST_PlaceholderTypePic) returns an error when the layout has no picture placeholder, which is most layouts. “Picture with Caption” is the usual one in a PowerPoint-authored template. Check the error; do not discard it the way the title and body lookups often are.

Validate checks the schema and the paragraph rule for text bodies. It does not check that a blip’s embed attribute names a relationship that exists, so a wrong or stale relationship ID produces a file that validates and then shows an empty frame in PowerPoint.

Run the example

The example opens template.potx, removes its slides, adds one from the “Picture with Caption” layout, sets the title and body text, fills the picture placeholder with gophercolor.png and writes mod.pptx. It prints the elapsed time on success.

git clone https://github.com/unidoc/unioffice-examples.git
cd unioffice-examples/presentation/use-template-with-image
go run main.go

If this is your first time using UniOffice, follow the getting started guide to create an API key and set up your development environment.

Sample input

Sample output