Documentation
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Overview ¶
Package thumbtypes names the content families a browser can rasterize into a tile, and which of them are drawn on a forced background and so need a second capture for dark mode.
It exists because the rule was written out four times -- once per store, once for the browser gate, once for the capturer's dispatch -- and the four copies stopped agreeing: a JSX resource was never offered although the capturer renders JSX, and an image asset was never offered although the capturer downscales images (#1568). This is the one Go definition; the one TypeScript definition is ui/src/lib/thumbnailSupport.ts, and TestGoAndBrowserAgree holds the two to each other.
A thumbnail is a property of a piece of content rather than of a kind, so nothing here knows whether the row it is asked about is a portal asset or a managed resource.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var Capturable = []string{
"svg", "html", "jsx", "markdown", "csv", "tab-separated", "json",
"yaml", "xml", "sql", "python", "javascript", "css", "text/plain",
"image/png", "image/jpeg", "image/gif", "image/webp",
"image/avif", "image/bmp", "image/x-icon", "image/vnd.microsoft.icon",
}
Capturable are the content families a browser can draw into a tile, as fragments of the media type rather than exact types: a stored type carries parameters and vendor prefixes ("text/markdown; charset=utf-8", "application/vnd.acme+json"), and every spelling of a family contains its fragment.
"json" covers both JSON families at once, newline-delimited included ("application/x-ndjson", "application/jsonl"); which of the two is drawn is a question only the capturer asks. "text/plain" is spelled in full because the bare word is a substring of "text/html", "text/csv" and "text/markdown", each of which is drawn differently.
The code families -- YAML, XML, SQL, Python, JavaScript, CSS -- and TSV are here because the viewer renders every one of them and a browser that can render it can draw a tile of it; they were absent, and each kept a content-type icon forever (#1754). Order carries the two overlaps: "svg" takes image/svg+xml before "xml" is reached, and "jsx" takes text/jsx before "javascript" is. SVG is first because it is the one family ahead of a themeable one that is not itself themeable; see ThemeableShadows.
The raster families are named one by one rather than as "image/", which is what a bare prefix would have cost: a capture DOWNSCALES a raster image by decoding it in the browser, and TIFF, HEIC and PSD are images a browser cannot decode at all. Offering one is offering work that fails every time, and the pending query is an ORDER BY ... LIMIT window, so a bulk upload of them would fill it and starve the documents behind them of a capture they could actually complete -- the same failure the PDF exclusion exists to prevent. These eight are the families every current browser decodes.
Everything else -- PDF, spreadsheets, archives, binaries -- has no renderer, keeps its content-type icon, and is never offered for capture.
var Themeable = []string{
"html", "jsx", "markdown", "csv", "tab-separated", "json",
"yaml", "xml", "sql", "python", "javascript", "css", "text/plain",
}
Themeable are the families drawn once per color scheme.
The families the portal lays out on its own surface are drawn on the scheme's background. HTML and JSX are drawn with the renderer emulating the scheme, which is what a document's own prefers-color-scheme rules answer to and what the viewer's frame does for a reader in that scheme: a dashboard with a dark stylesheet opened dark and had a white card (#1789). SVG and a raster image are drawn as stored and serve the one image in both modes, so reading their empty dark key as "pending" would offer them forever.
In Capturable's order, which is what the parity test compares.
Functions ¶
func DrawnAsDocument ¶ added in v1.133.0
DrawnAsDocument reports whether contentType is a document that lays itself out at page size -- HTML and JSX -- rather than a family the portal lays out on its own tile-sized surface. The two are drawn at different geometries.
func ILikePatterns ¶
ILikePatterns wraps content-type fragments as SQL ILIKE patterns, which is how the substring test the browser applies is asked of a column.
func IsThemeable ¶ added in v1.133.0
IsThemeable reports whether contentType is drawn on a forced background and so has a tile per color scheme.
A content type belongs to the family of the FIRST Capturable fragment it contains, which is how Capturable's order resolves overlaps: image/svg+xml contains both "svg" and "xml", is an SVG, and is drawn as stored. Asking only "does it contain a themeable fragment" would call it themeable, and a store asking that would owe every SVG a dark tile nothing ever draws.
func ThemeableShadows ¶ added in v1.133.0
func ThemeableShadows() []string
ThemeableShadows are the fragments that are not themeable and come before the themeable ones in Capturable's order. A content type is themeable exactly when it contains a themeable fragment and none of these, which is the form a store's SQL asks it in. That is exact only while every such fragment precedes all the themeable ones; a test holds the order to it.
Types ¶
This section is empty.
Source Files