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dbaf0b0472
Raw Linux consoles support UTF-8, but we cannot assume that all UTF-8 characters are available. The default Fixed and Terminus fonts don’t contain half-block characters (`▀` and `▄`), but do contain the full-block character (`█`). Sometimes, Linux doesn’t have a framebuffer, so it falls back to VGA. When this happens, the full-block character could be anywhere in extended ASCII block, because we don’t know which code page is active. This PR introduces `--qr-format=auto` which tries to heuristically detect when Tailscale is printing to a raw Linux console, whether UTF-8 is enabled, and which block characters have been mapped in the console font. If Unicode characters are unavailable, the new `--qr-format=ascii` formatter uses `#` characters instead of full-block characters. Fixes #12935 Signed-off-by: Simon Law <sfllaw@tailscale.com>
15 lines
332 B
Go
15 lines
332 B
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build !linux
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package qrcodes
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import "io"
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func detectFormat(w io.Writer, inverse bool) (Format, error) {
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// Assume all terminals can support the full set of UTF-8 block
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// characters: (█, ▀, ▄). See #12935.
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return FormatSmall, nil
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}
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