feat(logo): add stamp_logo_png() to brand file-based PNG outputs

civilytics_logo()/make_logo_grob() brand ggplot/grobs, but flextables and other outputs are rendered to PNG first and can't use them. stamp_logo_png() is the raster analogue: it resolves the SAME brand asset that make_logo_grob() uses (via the type/variant switch) and composites it into a corner of an existing PNG in place, so file-based tables stay visually consistent with logo-branded plots. Dependency-free by design — uses only png + grid + grDevices (all already imported), no magick. Configurable type/variant/position/width/margin; preserves the image's pixel dimensions. Adds tests (21 assertions).
2026-06-22 16:33:08 -04:00
parent 41162597cf
commit 5fc8155965
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+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/logo.R
+\name{stamp_logo_png}
+\alias{stamp_logo_png}
+\title{Stamp the Civilytics logo onto a saved raster (PNG) image}
+\usage{
+stamp_logo_png(
+  path,
+  type = c("wordmark", "mark"),
+  variant = c("light", "dark"),
+  position = c("bottom-right", "bottom-left", "top-right", "top-left"),
+  width_frac = 0.15,
+  margin_frac = 0.02
+)
+}
+\arguments{
+\item{path}{Character. Path to the PNG to stamp. The file is overwritten
+in place at its original pixel dimensions.}
+
+\item{type}{Character. `"wordmark"` (default) or `"mark"`. As in
+[make_logo_grob()].}
+
+\item{variant}{Character. `"light"` (default, dark logo for light
+backgrounds) or `"dark"` (reverse logo for dark backgrounds).}
+
+\item{position}{Character. Corner placement: `"bottom-right"` (default),
+`"bottom-left"`, `"top-right"`, or `"top-left"`.}
+
+\item{width_frac}{Numeric. Logo width as a fraction of the image width
+(default `0.15`). Height follows from the logo's aspect ratio.}
+
+\item{margin_frac}{Numeric. Padding from the edges as a fraction of the
+image width (default `0.02`).}
+}
+\value{
+`path`, invisibly.
+}
+\description{
+The raster analogue of [civilytics_logo()] for outputs that are already
+rendered to a file rather than held as a ggplot/grob — e.g. a `flextable`
+exported to PNG, or any `grDevices::png()` / `ragg::agg_png()` output.
+Resolves the *same* brand asset that [make_logo_grob()] uses, so file-based
+tables stay visually consistent with logo-branded plots, and composites it
+into a corner of the image. Pure base-graphics + grid + png — no new
+package dependencies.
+}
+\examples{
+\dontrun{
+# Brand a table exported to PNG so it matches civilytics_logo()-branded plots
+ragg::agg_png("table.png", width = 8, height = 4, units = "in", res = 200)
+plot(flextable::flextable(head(mtcars)))
+dev.off()
+stamp_logo_png("table.png")                         # wordmark, bottom-right
+stamp_logo_png("table.png", type = "mark", position = "bottom-left")
+}
+}