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InstantPage V2: TextView clipping inset

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Design and plan, then the implementation: grow InstantPageV2TextView
frame by 4pt on each side to avoid clipping descenders and italic
overhangs.
This commit is contained in:
isaac 2026-05-20 00:33:04 +08:00
parent c32ef046b7
commit 50da64adfa
1 changed files with 12 additions and 3 deletions
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15
submodules/InstantPageUI/Sources/InstantPageRenderer.swift
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@ -98,13 +98,21 @@ extension InstantPageItemView {
// MARK: - Text view (port of V1 InstantPageTextItem.drawInTile)
/// Per-side padding applied to `InstantPageV2TextView`'s backing store, beyond the
/// item's typographic frame. Marker rounded rects extend ±2pt past their run, italic
/// or accented glyphs can overhang past the line's advance width, and the last line's
/// underline sits 2pt below `lineFrame.maxY`. The view grows by this amount on each
/// side and the draw context translates by the same amount so visual position is
/// unchanged.
private let v2TextViewClippingInset: CGFloat = 4.0
final class InstantPageV2TextView: UIView, InstantPageItemView {
let item: InstantPageV2TextItem
var itemFrame: CGRect { return self.item.frame }
init(item: InstantPageV2TextItem) {
self.item = item
super.init(frame: item.frame)
super.init(frame: item.frame.insetBy(dx: -v2TextViewClippingInset, dy: -v2TextViewClippingInset))
self.backgroundColor = .clear
self.isOpaque = false
self.contentMode = .redraw
@ -120,14 +128,15 @@ final class InstantPageV2TextView: UIView, InstantPageItemView {
context.saveGState()
context.textMatrix = CGAffineTransform(scaleX: 1.0, y: -1.0)
// No translateBy here — the view's coordinate origin is already local to the text item.
context.translateBy(x: v2TextViewClippingInset, y: v2TextViewClippingInset)
let textItem = self.item.textItem
let boundsWidth = textItem.frame.size.width
let intersectRect = rect.offsetBy(dx: -v2TextViewClippingInset, dy: -v2TextViewClippingInset)
for line in textItem.lines {
let lineFrame = v2FrameForLine(line, boundingWidth: boundsWidth, alignment: textItem.alignment)
if !rect.intersects(lineFrame) {
if !intersectRect.intersects(lineFrame) {
continue
}