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Generate an HTML iframe for the COG Viewer

Source: R/ngr_str_viewer_cog.R
ngr_str_viewer_cog.Rd

Creates an HTML <iframe> tag that embeds the COG viewer at viewer.a11s.one with a cache-busting version parameter. Bump v when the viewer has breaking changes to invalidate stale browser caches across all reports.

Usage

ngr_str_viewer_cog(
  url,
  v = 2L,
  viewer_base = "https://viewer.a11s.one/",
  width = "100%",
  height = "600"
)

Arguments

url

character A single string specifying the full URL of the COG file (e.g., an S3 HTTPS URL).

v

integer Cache-busting version parameter appended to the viewer URL. Default is 2L. Bump this in the package when viewer.html has breaking changes (e.g., TiTiler path updates) to force browsers to fetch the latest viewer for all reports on rebuild.

viewer_base

character A single string specifying the base URL of the viewer. Default is "https://viewer.a11s.one/".

width

character A single string specifying the iframe width. Default is "100%".

height

character A single string specifying the iframe height in pixels. Default is "600".

Value

character A single string containing the HTML <iframe> tag. Pass to knitr::asis_output() for rendering in report chunks.

Details

The viewer URL is constructed as <viewer_base>?v=<v>&cog=<url>. The v parameter is ignored by the viewer JavaScript but changes the URL enough to bypass stale browser caches.

See also

Other string: ngr_str_dir_from_path(), ngr_str_extract_between(), ngr_str_link_url()

Examples

ngr_str_viewer_cog("https://stac-dem-bc.s3.us-west-2.amazonaws.com/dem_pouce_coupe_2023.tif")
#> [1] "<iframe src=\"https://viewer.a11s.one/?v=2&cog=https://stac-dem-bc.s3.us-west-2.amazonaws.com/dem_pouce_coupe_2023.tif\" scrolling=\"no\" title=\"COG Viewer\" width=\"100%\" height=\"600\" frameBorder=\"0\"></iframe>"

# In a report chunk:
# knitr::asis_output(ngr_str_viewer_cog("https://bucket.s3.amazonaws.com/ortho.tif"))