#chrome: SpringBoard chrome layout metrics (iPhone Duo simulator)

Simulator duo-baseline-chrome (A9C09C26-9AD3-4DF7-809D-E155D2D3F544), iOS 27.1 24A94425, Xcode 27.1. Output: chrome.json (127,674 records, 31 runs, compact JSON, about 54 MB). Raw transcripts: raw/chrome/. Screenshots: raw/chrome/shots/<run>-{state,lock,hinge}-d{1,3}.png.

#Files

#Method

• The values come from introspection in SpringBoard, not from guesses. For each object, the probe takes every declared ObjC property and every zero-argument method whose name looks like a getter, through the class chain down to UIView, UIViewController or NSObject. It reads each one with KVC. A name filter skips mutators (vpDeny), and only object, scalar or pointer-free struct return types are read. Struct values made only of doubles are decoded as {objCType, fields}. *.view records give frameInWindow (convertRect:bounds toView:window), frame, bounds, transform, layer transform, hidden, alpha, safeAreaInsets, and label text and font size or image size where the view has them.
• The probes only read. The exceptions are the actions the matrix needs: the posture swap (tools/posture.zsh), lockUIFromSource:1 and _finishUIUnlockFromSource:14 on the primary scene's SBLockScreenManager, and simctl push. One experimental [[UIDevice currentDevice] setOrientation:] call (1, then 3) was made during open-landscapeLeft before it was clear how orientation works. It changed nothing; SpringBoard stayed at 1. Nothing was swizzled. CSQuickActionImageGlyphView was only read.
• Getters that crash or throw are skipped everywhere. They are listed in meta.skipped_getters.
• chrome.json leaves out two kinds of records, which are still in the transcripts. The first is pointer-only object descriptions that have no layout keyword. The second is non-layout getters on large state controllers. See meta.omitted*.

#Orientation: what actually happens

The cover (SB-main) is always interface orientation 1 for every -deviceOrientation, both on the home screen and on the lock screen. The inner scene does rotate. It follows the swap's -deviceOrientation with a 90° offset, which matches the panel's native 270° rotation:

UIScreen / coordinateSpace bounds for the inner stay 669×951 throughout this run. That run had already unfolded, so compare the README's 669×951 → 951×669 note for inner UIScreen.bounds, which screens.json covers. chrome.json names orientations with UIKit interface-orientation names (3 = landscapeRight, 4 = landscapeLeft). tools/smoke.zsh maps 3 → landscapeLeft and 4 → landscapeRight, which is the UIDeviceOrientation mapping, not the interface one. The README says the field is the interface orientation, so smoke.json's names for 3/4 would be swapped. Smoke only saw 1, so it is unaffected.

#Key metrics (points, window coordinates)

Status bar

• Cover: STUIStatusBarVisualProvider_AxisAlignableSplitV68Cover (→ AxisAlignableSplit → Split → Phone → iOS). It is a vertical right-hand status column. UIStatusBarManager.statusBarFrame = {389,0,77,678}; wrapper currentHeight/defaultHeight 77; _statusBarFrameIgnoringVisibility {0,0,466,77}. The foreground view is {378,0,88,176.33}. Sensor/cutout: sensorAreaRect = effectiveSensorAreaRect = cutout guide = UIScreen._exclusionArea = {399,30,37,37}. avoidanceFrame is {399.67,29.33,37,37}. Time label {≈400,83,≈36,19.33} (rounded bold 16 pt), round battery {394.67,106.67,47,47}. isVerticalLayout YES; _verticalCombinedBoundingBoxHeight 104; _peripheryInsets top 50.67; display corner radius 59.
• Inner: STUIStatusBarVisualProvider_AxisAlignableSplit2007 (→ AxisAlignableSplit2670 → AxisAlignableSplit).
  • Landscape-shaped (4/3): foreground {863,0,88,123.67}, time at {≈885,30.33}, battery {879.67,54,47,47}. UIStatusBarManager.statusBarFrame = {0,0,0,0} and wrapper currentHeight 0.
  • Portrait-shaped (1/2): foreground {581,0,88,123.67}, statusBarFrame {592,0,77,951}, height 77.
  • effectiveSensorAreaRect is {0,0,0,0} on the inner. sensorAreaRect still reports the cover's {399,30,37,37}. The cutout guide is empty.

Home screen

• Root grid on both displays: 4 columns × 6 rows (maximumIconCount 24). Icons are 60×60 at scale 3 with a 15.6 corner radius; the icon view is 60×74. Label font is SFUI-Medium 12 pt (label config: baseline offset 16, height 26, extra width 37).
• Cover: portrait insets {top 54, left 27, bottom 70, right 115}, with the right inset reserved for the side dock. effectiveIconSpacing is 28×38.8. The list spans {0,0,466,678}; the first icon is at {27,54}. numberOfLandscape* is 0 (no landscape config).
• Inner: portrait insets {82,145.5,219,145.5} and landscape insets {54,0,65,0}; landscape rows×cols 6×4; effectiveIconSpacing 28×38.
  • Landscape-shaped: the list is 324 wide, at x=470 (open), 459.33 (open after landscapeRight) or 512.67 (book), and 669 tall.
  • Portrait-shaped: the list spans {0,0,669,951}; the first icon is at {145.67,82}.
• Dock: SBFloatingDock* (iPad-style floating dock). SBDockView is not present. The dock list grid is 1×4 portrait, 4×1 landscape (capacity 4). Dock icons are 60×60 in a 48×48 list cell.
  • Cover: the side dock is a vertical column at the right edge. SBFloatingDockView {376.17,45,84,678}; platter 72×72 at {382.17,348} for 1 icon; floatingDockHeight 84.
  • Inner landscape-shaped: also a right-hand column, {861.17,45,84,669}.
  • Inner portrait-shaped: a horizontal bottom dock, {0,851,669,100}; floatingDockHeight 100; platter 244×92.
  • The search button (48×48) sits under the dock: {394.33,606} on the cover, {879.33,597} on the inner.
• App Library (SBHLibraryPodFolderView) and the Today view list exist on both displays.
• Wallpaper: _SBWallpaperSecureWindow is portrait-anchored. It stays {0,0,669,951} on the inner even while every other inner window is 951×669; on the cover it is 466×678. The wallpaper is a PosterBoard scene (PBUIPosterSceneLayerHostView). SBWallpaperController exists per scene, and its wallpaperConfigurationManager reports wallpaperSize {466,678} with wallpaperSizeType "iPhone (N56)". SBWallpaperHingeProgressController stores no progress value. It only gates: _enabled and _backlightOn are YES on the lit display and NO on the other.

Lock screen (cover sheet)

• Quick actions: two CSQuickActionsButtons, 84×84, both at the same frame. They are hidden in every posture and orientation of this simulator.
  • Positions: cover {376,573}; inner landscape-shaped {861,564}; inner portrait-shaped {579,846}.
  • Button: iconImageSize 48×48, edgeInsets 18 on all sides, containerCornerRadius 24.
  • CSQuickActionImageGlyphView: frame 27×25 at {28.67,29.67} in the button ({10.67,11.67} in the 48-point icon area). Transform and layer transform are identity. contentMode 1 (aspect fit).
  • The image is 19.33×18 at @3x, so it renders aspect-fit at about 26.85×25.
  • Ratios: glyph/button width 0.321, height 0.298; glyph/iconImage 0.5625; image/glyph-view 0.716.
  • Caveat: the image is the SF symbol questionmark.app. The simulator has no torch or camera action configured, so this is a placeholder glyph, not the flashlight or camera glyph.
• Notifications. Three pushes to Preferences group into one stack of NCNotificationShortLookViews:
  • Cover: platter width 350 (bounds); the structured list is 370 at x=12 at boot and 378 at x=8 after open.
  • Inner, open, both shapes: platter 450; list 478, centred at x=236.5 (landscape-shaped) or x=95.5 (portrait-shaped).
  • Inner, book, landscape-shaped: platter 350; list 378 at x=498.25 (or 370 at 502.25), i.e. on the right half. Inner, book, portrait-shaped: 450.
  • The stacked platters behind are scaled 0.94 and 0.88. Short-look continuous corner radius is 23.5.
• Clock: CSProminentTimeView. The time is drawn by a SwiftUI TitleLabelView, so no UIFont is readable.
  • Cover {11,47,372,132.26}.
  • Inner open landscape-shaped {275.5,51.67,400,132.26}; book {487.25,51.67,400,132.26} (right half); portrait-shaped {134.5,64.67,400,132.26}.
  • The date (_UIAnimatingLabel) is SFUI-Semibold 22 pt.

#Missing / nil / errors

• On the cover, during open/book lock runs, CSCombinedListView(Controller), NCNotificationStructuredList*, NCNotificationListView, and CSProminentTimeView are nil: the cover sheet content is on the inner. The reverse holds in closed-after-open: the inner SBCoverSheetWindow still exists but has no content. In closed-boot (never unfolded) the inner scene has no SBCoverSheetWindow at all.
• Skipped because they crash or throw: SBWindowScene.liftToWakeController (stack overflow), UIWindowScene._preferredIntelligentAssistantVisibility / …Configuration / SBSUI_preferredSystemRootLayerTransform, SBIconView.iconImageAlignment, and SBIconListPageControl.maximumNumberOfPages.
• SBHIconListLayoutProvider location constants were resolved with dlsym where they exist. The call text marks the ones where a literal was used instead.
• Present but empty or zero: inner UIStatusBarManager.statusBarFrame (landscape-shaped), inner effectiveSensorAreaRect.