Posters in macOS Terminal as plain colored cells

Terminal.app draws block elements from the font, with the halves off the
cell's middle, so quadrant posters came out as rows of shifted dots. The
new cover style "cells" uses one background color per cell and no glyph;
auto picks it when TERM_PROGRAM is Apple_Terminal.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019reK4DUGYqDUjniWYJvwUW

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- **Posters in macOS Terminal:** Terminal.app draws the half and quarter blocks from the font, and
+  their halves do not meet at the middle of the cell, so posters looked like rows of shifted dots.
+  `auto` now draws them there as plain colored cells (new `ui.cover_style` value `cells`): coarser,
+  but even. For real images on macOS use Ghostty or kitty.
 - **Real images only when the terminal confirms it:** the terminal is asked whether it supports the
   Kitty graphics protocol before real-image posters are used, so terminals that only look like kitty
   or Ghostty no longer get graphics commands printed as text. On macOS the sextant blocks are no

README.md

@@ -16,11 +16,12 @@ A terminal UI to search for movies and series with [Radarr](https://radarr.video
   Radarr/Sonarr; search results are downloaded from the metadata provider's image host (TMDb,
   TheTVDB). Turn it off with `"ui": {"covers": false}`. `"ui": {"cover_style": ...}` picks the
   drawing: `auto` (default: real images where the terminal is known to support them, otherwise
-  sextants on terminals known to have the glyphs or when fontconfig finds an installed font with
-  them (not over SSH), else quadrants), `kitty` (force real images),
+  plain cells in macOS Terminal, sextants on terminals known to have the glyphs or when fontconfig
+  finds an installed font with them (not over SSH), else quadrants), `kitty` (force real images),
   `sextant` (2x3 pixels per cell, needs a font with the Symbols for Legacy Computing block) or
-  `quadrant` (2x2, every font has them). Inside tmux or screen the block styles are used. If a
-  poster looks wrong, set `quadrant`.
+  `quadrant` (2x2, every font has them) or `cells` (one colored cell per pixel, no glyphs; for
+  terminals whose block characters come out uneven, like macOS Terminal). Inside tmux or screen the
+  block styles are used. If a poster looks wrong, set `quadrant`, or `cells` if the rows look shifted.
 - **Calendar**: the next two weeks of movie releases (cinemas, digital, physical) and airing episodes
   in one list grouped by day, with poster and plot. Move by weeks, include unmonitored items, search
   for releases or start an automatic search from there.

SPECS.md

@@ -65,7 +65,7 @@ Notes:
 - **Status bar / help:** the bottom bar lists the keys that work in the current view or panel; the top right shows the connection state of each service; `F9` opens the full key reference.
 - **Posters:** the detail panes show the poster at the top right; the head (title, facts, path) and the plot are one text that flows along the poster's left side and continues at full width below it (text is wrapped by arr-tui itself, with a narrower width for the first lines); on panes too small for the poster, the text simply uses the full width. Two ways to draw the poster, chosen by `ui.cover_style`:
   - **Real images** (`kitty`, and `auto` in kitty/Ghostty): the Kitty graphics protocol with Unicode placeholders. The poster (kept up to 640 px tall) is uploaded as PNG (`a=t,f=100,q=2`, 4096-byte base64 chunks) and placed virtually with the cell footprint (`a=p,U=1,c=,r=`) right away. Every footprint (crop and cell size) is its own image id, placed once and never changed: Ghostty kept showing the old, small placement when the size of an existing one was changed, so a new size uploads under a new id and deletes the old one. The poster is shown by writing U+10EEEE placeholder characters whose combining marks give row and column (the 297-entry table from the protocol) and whose foreground color is the image id. Since it is ordinary text, popups, dialogs and view changes cover it correctly and tcell's diffing keeps it in place. The footprint uses the real cell size in pixels (the window's pixel size divided by its cell count, rounded down to whole pixels so padding around the grid does not skew it; all images are deleted whenever the window or cell size changes, block characters stand in while the size keeps changing, and real images are uploaded afresh once it has been stable for 300 ms, because uploading and placing for every intermediate size of a window drag raced with the terminal's own resizing) and a box whose shape is within 3% of the poster's; the remaining sliver is cropped from the poster's edges before upload (one upload per size, the previous one is deleted), because the terminal letterboxes an image that does not fit its box exactly. As a second safeguard the placeholder cells use the panes' background color, so anything the picture does not cover blends in (without it the terminal's own, slightly different, default background showed as grey bars beside the poster). Writes to the terminal go through the screen's tty on the UI goroutine, so they cannot interleave with drawing. Requires 24-bit color; otherwise, and inside tmux/screen, the block fallback is used. Terminals are recognised from `TERM`/`TERM_PROGRAM`/`KITTY_WINDOW_ID`/`GHOSTTY_RESOURCES_DIR`, and then asked before the screen starts (a Kitty graphics query followed by a device-attributes request, 300 ms timeout): only a terminal that answers the query gets real images, also with `cover_style: kitty`, because a terminal without the protocol prints the commands as text. The Log says which way posters are drawn. With `ARR_TUI_DEBUG_GFX=1` the Log (F7) lists every window size, the cell shape, every upload (poster size, crop, cells) and every change of what is drawn (image id, position, cells); with a path (`ARR_TUI_DEBUG_GFX=/tmp/arr-gfx.log`) the same lines also go to that file with millisecond timestamps, so they can be read without leaving the view that shows the problem. The go-termimg library was looked at and not used: its placeholder support is marked experimental, its diacritic table does not match the protocol's, and it writes images straight to the terminal instead of through the screen.
-  - **Block characters** (`quadrant`, `sextant`, and the fallback): every cell shows several pixels in the best two-color split (`quadrant`: 2×2 pixels, glyphs from the Block Elements range every font has; `sextant`: 2×3 pixels, sharper, glyphs from Symbols for Legacy Computing). `auto` picks sextants on kitty, WezTerm, foot and Ghostty, and on other terminals (not on macOS, whose terminals do not use fontconfig's fonts) when fontconfig lists a font with the sextant characters (`fc-list :charset=1fb00`, about 20 ms at startup; terminals draw glyphs their font lacks from fallback fonts; skipped over SSH because the installed fonts are the remote machine's), and quadrants otherwise.
+  - **Block characters** (`quadrant`, `sextant`, `cells`, and the fallback): every cell shows several pixels in the best two-color split (`quadrant`: 2×2 pixels, glyphs from the Block Elements range every font has; `sextant`: 2×3 pixels, sharper, glyphs from Symbols for Legacy Computing; `cells`: 1 pixel per cell drawn as background color only, because macOS Terminal draws block elements from the font with the halves off the cell's middle). `auto` picks cells in macOS Terminal (`TERM_PROGRAM=Apple_Terminal`), sextants on kitty, WezTerm, foot and Ghostty, and on other terminals (not on macOS, whose terminals do not use fontconfig's fonts) when fontconfig lists a font with the sextant characters (`fc-list :charset=1fb00`, about 20 ms at startup; terminals draw glyphs their font lacks from fallback fonts; skipped over SSH because the installed fonts are the remote machine's), and quadrants otherwise.
   Posters are JPEG, PNG, GIF or WebP (Radarr and Sonarr keep whatever bytes the provider sent under a `.jpg` name, which can be WebP), decoded and downscaled in the process; for any other format the Log says what the data looked like (e.g. AVIF, an HTML error page, or its first bytes). Library items fetch `/MediaCover/<id>/poster-250.jpg` from their Radarr/Sonarr instance with the API key (then the original `poster.jpg`; an instance that answers 200 with an HTML page, i.e. wants a login for `/MediaCover`, is also tried with the key as the `apikey` query parameter; and if the instance has no usable copy, the provider's `remoteUrl`, fetched without credentials); search results fall back to the provider's `remoteUrl` (fetched without credentials). Posters are cached in memory (the terminal's copies are deleted when the cache is dropped and on exit), failed downloads are not retried for two minutes and are written to the Log (F7) with the reason, and the poster shrinks or disappears when the pane is too short. `ui.covers: false` disables it.
 - **Calendar view (F5):** a two-week window (starting today, moved a week at a time with `[`/`]`, `t` returns to today) with the library's movie releases and airing episodes, grouped by day. Radarr `GET /calendar` supplies the cinema, digital and physical release dates (taken as written: midnight UTC means that calendar day) and Sonarr `GET /calendar?includeSeries=true` the episodes with their air time (shown in local time). Unmonitored items are included with `u`. A movie appears once per release date in the window. Each entry shows type, title, episode or release kind and status (downloaded / missing / upcoming); the detail pane shows poster and plot; `Enter`/`i` starts the release search and `s` an automatic search.
 - **Download notifications:** a background poller (independent of the visible view) reads SABnzbd's history every 15 s and announces downloads that reach `Completed` or `Failed` as a popup and log entry; the first poll only records the current state. `ui.notify_downloads` (default true) and `ui.bell` (default false, rings the terminal bell) control it. Connection errors are not reported here, the indicators and the log already do that.

internal/config/config.go

@@ -38,12 +38,14 @@ type UI struct {
 	// Bell also rings the terminal bell for those notifications (default false).
 	Bell bool `json:"bell,omitempty"`
 	// CoverStyle selects the block characters posters are drawn with:
-	// "quadrant" (2x2 pixels per cell, every font has the glyphs), "sextant"
+	// "quadrant" (2x2 pixels per cell, every font has the glyphs), "cells" (1
+	// pixel per cell, background colors only, for terminals that draw block
+	// glyphs unevenly such as macOS Terminal), "sextant"
 	// (2x3, sharper, needs a font with the Symbols for Legacy Computing
 	// block, e.g. kitty, WezTerm, foot, Ghostty), "kitty" (real images through
 	// the Kitty graphics protocol with Unicode placeholders: kitty and
 	// Ghostty) or "auto" (default: the Kitty protocol where the terminal is
-	// known to support it, else sextant on terminals known to draw them or when
+	// known to support it, else cells in macOS Terminal, sextant on terminals known to draw them or when
 	// fontconfig finds a font with the glyphs, else quadrant). The block styles are also the fallback for "kitty".
 	CoverStyle string `json:"cover_style,omitempty"`
 }
@@ -264,9 +266,9 @@ func (c *Config) Validate() error {
 		}
 	}
 	switch c.UI.CoverStyle {
-	case "", "auto", "quadrant", "sextant", "kitty":
+	case "", "auto", "quadrant", "sextant", "cells", "kitty":
 	default:
-		errs = append(errs, fmt.Errorf(`ui.cover_style: %q must be "auto", "kitty", "sextant" or "quadrant"`, c.UI.CoverStyle))
+		errs = append(errs, fmt.Errorf(`ui.cover_style: %q must be "auto", "kitty", "sextant", "quadrant" or "cells"`, c.UI.CoverStyle))
 	}
 	return errors.Join(errs...)
 }

internal/config/config_test.go

@@ -100,7 +100,7 @@ func TestShowCovers(t *testing.T) {
 
 func TestCoverStyleValidation(t *testing.T) {
 	base := `{"radarr":{"url":"http://r","apikey":"k"},"sonarr":{"url":"http://s","apikey":"k"},"sabnzbd":{"url":"http://a","apikey":"k"},"ui":{"cover_style":`
-	for _, ok := range []string{`"auto"`, `"quadrant"`, `"sextant"`, `"kitty"`, `""`} {
+	for _, ok := range []string{`"auto"`, `"quadrant"`, `"sextant"`, `"cells"`, `"kitty"`, `""`} {
 		if _, err := Parse([]byte(base + ok + `}}`)); err != nil {
 			t.Errorf("%s rejected: %v", ok, err)
 		}

internal/ui/cover.go

@@ -95,6 +95,10 @@ var (
 	// sextantStyle (2×3 pixels): sharper, but the glyphs live in the Symbols
 	// for Legacy Computing block, which many fonts lack.
 	sextantStyle = coverStyle{"sextant", 2, 3, sextantGlyph}
+	// cellsStyle (1 pixel per cell): only background colors, no glyphs at all.
+	// Coarse, but exact in terminals that draw block elements from the font
+	// with the halves off the cell's middle (macOS Terminal).
+	cellsStyle = coverStyle{"cells", 1, 1, func(int) rune { return ' ' }}
 )
 
 // quadrants[mask] is the glyph that fills the quadrants set in mask
@@ -127,14 +131,21 @@ func sextantGlyph(mask int) rune {
 }
 
 // coverStyleFor resolves the block-character style for the setting. "auto"
-// picks sextants on terminals known to have the glyphs and quadrants everywhere
-// else.
+// picks sextants on terminals known to have the glyphs, plain cells in macOS
+// Terminal and quadrants everywhere else.
 func coverStyleFor(setting string, env func(string) string) coverStyle {
 	switch setting {
 	case "sextant":
 		return sextantStyle
 	case "quadrant":
 		return quadrantStyle
+	case "cells":
+		return cellsStyle
+	}
+	// Terminal.app draws block elements from the font, and their halves do
+	// not meet at the cell's middle: rows of a poster come out uneven.
+	if env("TERM_PROGRAM") == "Apple_Terminal" {
+		return cellsStyle
 	}
 	term, program := strings.ToLower(env("TERM")), strings.ToLower(env("TERM_PROGRAM"))
 	for _, known := range []string{"kitty", "foot", "ghostty", "wezterm"} {

internal/ui/cover_test.go

@@ -275,6 +275,9 @@ func TestCoverStyleFor(t *testing.T) {
 		{"auto", nil, "quadrant"},
 		{"quadrant", map[string]string{"TERM": "xterm-kitty"}, "quadrant"},
 		{"sextant", nil, "sextant"},
+		{"auto", map[string]string{"TERM": "xterm-256color", "TERM_PROGRAM": "Apple_Terminal"}, "cells"},
+		{"cells", map[string]string{"TERM": "xterm-kitty"}, "cells"},
+		{"quadrant", map[string]string{"TERM_PROGRAM": "Apple_Terminal"}, "quadrant"},
 	} {
 		if got := coverStyleFor(tc.setting, env(tc.env)).name; got != tc.want {
 			t.Errorf("%q %v = %s, want %s", tc.setting, tc.env, got, tc.want)
@@ -347,3 +350,11 @@ func TestDescribeBytesAndTheErrorItGives(t *testing.T) {
 		}
 	}
 }
+
+func TestCellsStyleIsFlat(t *testing.T) {
+	c := color.RGBA{10, 200, 30, 255}
+	ch, fg, bg := cellsStyle.bestCell([]color.RGBA{c})
+	if ch != ' ' || fg != c || bg != c {
+		t.Errorf("got %q %v %v", ch, fg, bg)
+	}
+}

internal/ui/settings.go

@@ -26,7 +26,7 @@ type settingsValues struct {
 	notify, bell                                      bool
 }
 
-var coverStyles = []string{"auto", "kitty", "sextant", "quadrant"}
+var coverStyles = []string{"auto", "kitty", "sextant", "quadrant", "cells"}
 
 // settingsFrom reads the settings in use.
 func settingsFrom(c *config.Config) settingsValues {