screenshot

Screenshot for visual regression testing.

Captures pixel-level rendering data. The mock backend returns empty stubs (no pixel data). Headless and windowed backends capture real RGBA pixel data.

save_png/2 writes raw RGBA data as a minimal valid PNG file using pure Erlang (:zlib for deflate, :erlang.crc32 for chunk CRCs).

Types

Screenshot

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A screenshot capture.

pub type Screenshot {
  Screenshot(
    name: String,
    hash: String,
    width: Int,
    height: Int,
    pixels: BitArray,
  )
}

Constructors

Screenshot(
  name: String,
  hash: String,
  width: Int,
  height: Int,
  pixels: BitArray,
)

Values

assert_screenshot

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pub fn assert_screenshot(
  screenshot: Screenshot,
  name: String,
  path: String,
) -> Nil

Assert that a screenshot matches its golden file.

Screenshots with an empty hash (mock backend) are silently accepted. Otherwise creates or compares golden files in the given directory. Set PLUSHIE_UPDATE_SCREENSHOTS=1 to force-update golden files.

empty

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pub fn empty(name: String) -> Screenshot

Create an empty screenshot stub (for mock backends).

save_png

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pub fn save_png(screenshot: Screenshot, path: String) -> Nil

Save a screenshot as a minimal valid PNG file. No-op when pixels are empty (mock backend stubs).