Widgets

Page.AddWidget and Page.AddWidgetVector "print" a go-widgets/toolkit widget tree onto a page, so any UI composed from toolkit widgets can be placed straight into a PDF. Two paths are offered, trading fidelity for selectability:

	Output	Text
AddWidget	an image XObject — pixel-identical to the screen	rasterised, not selectable
AddWidgetVector	PDF vector operators (fills, strokes, rounded rects, text-show)	real, selectable PDF text

Raster: AddWidget

import "github.com/go-widgets/toolkit"

root := toolkit.NewContainer(toolkit.NewBoxLayout())
btn := toolkit.NewButton("Submit", nil)
btn.Style = toolkit.ButtonProminent
root.AddWidget(btn)
root.AddWidget(toolkit.NewLabel("Status: ready"))

rect := pdfkit.Rect{X: pdfkit.Mm(20), Y: pdfkit.Mm(200), Width: pdfkit.Mm(80), Height: pdfkit.Mm(30)}
err := p.AddWidget(root, rect, nil)

AddWidget lays root out to fill rect (in points), renders the whole widget tree to an RGBA raster through a painter.PixelPainter, and places that raster as an image XObject at rect. Every widget renders exactly as it would on screen, at the cost of a bitmap: text cannot be selected or copied. opts may be nil — Font is ignored on this path.

Vector: AddWidgetVector

opts := &pdfkit.WidgetOptions{Font: font} // font: an already-loaded *pdfkit.Font
err := p.AddWidgetVector(root, rect, opts)

AddWidgetVector lays root out the same way, then runs it through a painter that emits PDF vector operators instead of pixels: fills and strokes stay crisp at any zoom, and text becomes real, selectable PDF text. A WidgetOptions.Font is required — it backs any run drawn through the toolkit's built-in bitmap font — so a nil or fontless opts returns an error (AddWidgetVector requires WidgetOptions.Font for selectable text).

A widget label set in a TrueType/OpenType toolkit font (a painter.Face, via toolkit.NewTrueTypeFont + toolkit.SetFont) goes further: that face's own bytes are embedded and the run is emitted as selectable Type0 text at the face's own size, so the label is not limited to the toolkit's built-in bitmap font either.

WidgetOptions

type WidgetOptions struct {
    Theme *toolkit.Theme // nil = toolkit.DefaultLight()
    Scale float64        // layout pixels per PDF point; <= 0 = DefaultWidgetScale (2)
    Font  *Font          // required by AddWidgetVector; ignored by AddWidget
}

Scale controls how many layout pixels the tree gets per PDF point before being placed in rect — a larger scale gives a crisper raster (AddWidget) and finer layout rounding on both paths. rect's width and height must both resolve to a positive pixel count at that scale, or both methods return an error.

Putting the two together

A common pattern is to draw the same tree once as a raster fallback and once as vector, stacked in the document so the vector copy carries the selectable text layer:

rect := pdfkit.Rect{X: pdfkit.Mm(20), Y: pdfkit.Mm(200), Width: pdfkit.Mm(80), Height: pdfkit.Mm(30)}

_ = p.AddWidget(root, rect, nil) // pixel-identical to the screen

rect.Y -= pdfkit.Mm(40)
_ = p.AddWidgetVector(root, rect, &pdfkit.WidgetOptions{Font: font}) // crisp + selectable

Next: the API reference for the complete signature list.