nandi/frq · host_web.dart

nandi/frqpublic⑂ Fork 0

⑂ 23846db48565a450ee8a6a689892db23663ad48e

host_web.dart · 47 lines · 2.2 KBDart    Blame HistoryRaw
A web version, from the same core   1/// The same two things, in a browser, where there is neither.
3/// A page has no environment: `FRQ_AUTOCONNECT` is a thing you set before
4/// starting a process, and nothing here was started that way. And it has no
5/// filesystem the renderer could open — a picture a reader attaches arrives
6/// as a blob URL or not at all, and the path branch is never reached.
9import 'package:flutter/widgets.dart';
11String envOr(String name, String fallback) => fallback;
13ImageProvider? localImage(String path) => null;
15/// A picture from the network, drawn by the browser rather than decoded by
16/// Flutter.
18/// This is the one place the web build cannot simply use the same widget.
19/// Flutter fetches image bytes with an XMLHttpRequest so it can decode them
20/// into a texture, and an XHR is subject to CORS — so every avatar on
21/// `cdn.bsky.app` and every picture on freeq's media host failed with "No
22/// 'Access-Control-Allow-Origin' header", because neither sends one to a
23/// third-party page and neither has any reason to.
25/// An `<img>` element has never needed permission to display a picture, and
26/// `WebHtmlElementStrategy.prefer` is Flutter asking for exactly that: the
27/// browser loads and draws it, and Flutter positions the element. The cost is
28/// that such an image is outside the canvas — it cannot be blended or
29/// transformed like a texture — which for a face and a photograph in a
30/// conversation is no cost at all.
31Widget networkImage(String url,
32        {BoxFit fit = BoxFit.contain,
33        Widget Function()? onError}) =>
34    Image.network(url,
35        fit: fit,
36        webHtmlElementStrategy: WebHtmlElementStrategy.prefer,
37        errorBuilder: (_, _, _) =>
38            onError == null ? const SizedBox.shrink() : onError());
40/// No family is named on the web, and that is the fix rather than the gap.
42/// A browser is not painting with the machine's fonts: CanvasKit carries its
43/// own, and downloads a Noto face on demand for any glyph it cannot draw —
44/// emoji included. Naming a family it does not have defeats that, because a
45/// named family that is missing is a notdef box rather than a search. Every
46/// reaction chip drew ▯ until this list was empty.
47const List<String> emojiFonts = <String>[];

A web version, from the same core 23846db nandi 11h ago	1	/// The same two things, in a browser, where there is neither.
	2	///
	3	/// A page has no environment: `FRQ_AUTOCONNECT` is a thing you set before
	4	/// starting a process, and nothing here was started that way. And it has no
	5	/// filesystem the renderer could open — a picture a reader attaches arrives
	6	/// as a blob URL or not at all, and the path branch is never reached.
	7	library;
	8
	9	import 'package:flutter/widgets.dart';
	10
	11	String envOr(String name, String fallback) => fallback;
	12
	13	ImageProvider? localImage(String path) => null;
	14
	15	/// A picture from the network, drawn by the browser rather than decoded by
	16	/// Flutter.
	17	///
	18	/// This is the one place the web build cannot simply use the same widget.
	19	/// Flutter fetches image bytes with an XMLHttpRequest so it can decode them
	20	/// into a texture, and an XHR is subject to CORS — so every avatar on
	21	/// `cdn.bsky.app` and every picture on freeq's media host failed with "No
	22	/// 'Access-Control-Allow-Origin' header", because neither sends one to a
	23	/// third-party page and neither has any reason to.
	24	///
	25	/// An `<img>` element has never needed permission to display a picture, and
	26	/// `WebHtmlElementStrategy.prefer` is Flutter asking for exactly that: the
	27	/// browser loads and draws it, and Flutter positions the element. The cost is
	28	/// that such an image is outside the canvas — it cannot be blended or
	29	/// transformed like a texture — which for a face and a photograph in a
	30	/// conversation is no cost at all.
	31	Widget networkImage(String url,
	32	{BoxFit fit = BoxFit.contain,
	33	Widget Function()? onError}) =>
	34	Image.network(url,
	35	fit: fit,
	36	webHtmlElementStrategy: WebHtmlElementStrategy.prefer,
	37	errorBuilder: (_, _, _) =>
	38	onError == null ? const SizedBox.shrink() : onError());
	39
	40	/// No family is named on the web, and that is the fix rather than the gap.
	41	///
	42	/// A browser is not painting with the machine's fonts: CanvasKit carries its
	43	/// own, and downloads a Noto face on demand for any glyph it cannot draw —
	44	/// emoji included. Naming a family it does not have defeats that, because a
	45	/// named family that is missing is a notdef box rather than a search. Every
	46	/// reaction chip drew ▯ until this list was empty.
	47	const List<String> emojiFonts = <String>[];