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Fix sub- and superscript ascent/descent

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This commit is contained in:
Laurenz 2023-02-01 14:57:52 +01:00
parent 137d2ab317
commit 6ca6f43703
1 changed files with 90 additions and 49 deletions
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139
library/src/math/attach.rs
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@ -50,19 +50,14 @@ impl LayoutMath for AttachNode {
fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> { fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> {
let base = ctx.layout_fragment(&self.base)?; let base = ctx.layout_fragment(&self.base)?;
let mut top = Frame::new(Size::zero()); ctx.style(ctx.style.for_subscript());
if let Some(node) = &self.top { let top = self.top.as_ref().map(|node| ctx.layout_frame(node)).transpose()?;
ctx.style(ctx.style.for_subscript()); ctx.unstyle();
top = ctx.layout_frame(node)?;
ctx.unstyle();
}
let mut bottom = Frame::new(Size::zero()); ctx.style(ctx.style.for_superscript());
if let Some(node) = &self.bottom { let bottom =
ctx.style(ctx.style.for_superscript()); self.bottom.as_ref().map(|node| ctx.layout_frame(node)).transpose()?;
bottom = ctx.layout_frame(node)?; ctx.unstyle();
ctx.unstyle();
}
let render_limits = self.base.is::<LimitsNode>() let render_limits = self.base.is::<LimitsNode>()
|| (!self.base.is::<ScriptsNode>() || (!self.base.is::<ScriptsNode>()
@ -77,7 +72,7 @@ impl LayoutMath for AttachNode {
if render_limits { if render_limits {
limits(ctx, base, top, bottom) limits(ctx, base, top, bottom)
} else { } else {
scripts(ctx, base, top, bottom, self.top.is_some() && self.bottom.is_some()) scripts(ctx, base, top, bottom)
} }
} }
} }
@ -150,9 +145,8 @@ impl LayoutMath for LimitsNode {
fn scripts( fn scripts(
ctx: &mut MathContext, ctx: &mut MathContext,
base: MathFragment, base: MathFragment,
sup: Frame, sup: Option<Frame>,
sub: Frame, sub: Option<Frame>,
both: bool,
) -> SourceResult<()> { ) -> SourceResult<()> {
let sup_shift_up = if ctx.style.cramped { let sup_shift_up = if ctx.style.cramped {
scaled!(ctx, superscript_shift_up_cramped) scaled!(ctx, superscript_shift_up_cramped)
@ -168,15 +162,22 @@ fn scripts(
let sub_drop_min = scaled!(ctx, subscript_baseline_drop_min); let sub_drop_min = scaled!(ctx, subscript_baseline_drop_min);
let space_after = scaled!(ctx, space_after_script); let space_after = scaled!(ctx, space_after_script);
let mut shift_up = sup_shift_up let mut shift_up = Abs::zero();
.max(base.ascent() - sup_drop_max) let mut shift_down = Abs::zero();
.max(sup_bottom_min + sup.descent());
let mut shift_down = sub_shift_down if let Some(sup) = &sup {
.max(base.descent() + sub_drop_min) shift_up = sup_shift_up
.max(sub.ascent() - sub_top_max); .max(base.ascent() - sup_drop_max)
.max(sup_bottom_min + sup.descent());
}
if both { if let Some(sub) = &sub {
shift_down = sub_shift_down
.max(base.descent() + sub_drop_min)
.max(sub.ascent() - sub_top_max);
}
if let (Some(sup), Some(sub)) = (&sup, &sub) {
let sup_bottom = shift_up - sup.descent(); let sup_bottom = shift_up - sup.descent();
let sub_top = sub.ascent() - shift_down; let sub_top = sub.ascent() - shift_down;
let gap = sup_bottom - sub_top; let gap = sup_bottom - sub_top;
@ -191,27 +192,48 @@ fn scripts(
} }
let italics = base.italics_correction(); let italics = base.italics_correction();
let top_delta = match base.class() { let sub_delta = -italics;
let sup_delta = match base.class() {
Some(MathClass::Large) => Abs::zero(), Some(MathClass::Large) => Abs::zero(),
_ => italics, _ => italics,
}; };
let bottom_delta = -italics;
let ascent = shift_up + sup.ascent(); let mut width = Abs::zero();
let descent = shift_down + sub.descent(); let mut ascent = base.ascent();
let height = ascent + descent; let mut descent = base.descent();
let width = base.width()
+ (sup.width() + top_delta).max(sub.width() + bottom_delta) if let Some(sup) = &sup {
+ space_after; ascent.set_max(shift_up + sup.ascent());
width.set_max(sup_delta + sup.width());
}
if let Some(sub) = &sub {
descent.set_max(shift_down + sub.descent());
width.set_max(sub_delta + sub.width());
}
width += base.width() + space_after;
let base_pos = Point::with_y(ascent - base.ascent()); let base_pos = Point::with_y(ascent - base.ascent());
let sup_pos = Point::with_x(base.width() + top_delta); let base_width = base.width();
let sub_pos = Point::new(base.width() + bottom_delta, height - sub.height());
let class = base.class().unwrap_or(MathClass::Normal); let class = base.class().unwrap_or(MathClass::Normal);
let mut frame = Frame::new(Size::new(width, height)); let mut frame = Frame::new(Size::new(width, ascent + descent));
frame.set_baseline(ascent); frame.set_baseline(ascent);
frame.push_frame(base_pos, base.to_frame(ctx)); frame.push_frame(base_pos, base.to_frame(ctx));
frame.push_frame(sup_pos, sup);
frame.push_frame(sub_pos, sub); if let Some(sup) = sup {
let sup_pos =
Point::new(sup_delta + base_width, ascent - shift_up - sup.ascent());
frame.push_frame(sup_pos, sup);
}
if let Some(sub) = sub {
let sub_pos =
Point::new(sub_delta + base_width, ascent + shift_down - sub.ascent());
frame.push_frame(sub_pos, sub);
}
ctx.push(FrameFragment::new(frame).with_class(class)); ctx.push(FrameFragment::new(frame).with_class(class));
Ok(()) Ok(())
@ -221,31 +243,50 @@ fn scripts(
fn limits( fn limits(
ctx: &mut MathContext, ctx: &mut MathContext,
base: MathFragment, base: MathFragment,
top: Frame, top: Option<Frame>,
bottom: Frame, bottom: Option<Frame>,
) -> SourceResult<()> { ) -> SourceResult<()> {
let upper_gap_min = scaled!(ctx, upper_limit_gap_min); let upper_gap_min = scaled!(ctx, upper_limit_gap_min);
let upper_rise_min = scaled!(ctx, upper_limit_baseline_rise_min); let upper_rise_min = scaled!(ctx, upper_limit_baseline_rise_min);
let lower_gap_min = scaled!(ctx, lower_limit_gap_min); let lower_gap_min = scaled!(ctx, lower_limit_gap_min);
let lower_drop_min = scaled!(ctx, lower_limit_baseline_drop_min); let lower_drop_min = scaled!(ctx, lower_limit_baseline_drop_min);
let top_gap = upper_gap_min.max(upper_rise_min - top.descent()); let mut base_offset = Abs::zero();
let bottom_gap = lower_gap_min.max(lower_drop_min - bottom.ascent()); let mut width = base.width();
let mut height = base.height();
let delta = base.italics_correction() / 2.0; if let Some(top) = &top {
let width = base.width().max(top.width()).max(bottom.width()); let top_gap = upper_gap_min.max(upper_rise_min - top.descent());
let height = top.height() + top_gap + base.height() + bottom_gap + bottom.height(); width.set_max(top.width());
let base_pos = Point::new((width - base.width()) / 2.0, top.height() + top_gap); height += top.height() + top_gap;
let sup_pos = Point::with_x((width - top.width()) / 2.0 + delta); base_offset = top_gap + top.height();
let sub_pos = }
Point::new((width - bottom.width()) / 2.0 - delta, height - bottom.height());
if let Some(bottom) = &bottom {
let bottom_gap = lower_gap_min.max(lower_drop_min - bottom.ascent());
width.set_max(bottom.width());
height += bottom.height() + bottom_gap;
}
let base_pos = Point::new((width - base.width()) / 2.0, base_offset);
let class = base.class().unwrap_or(MathClass::Normal); let class = base.class().unwrap_or(MathClass::Normal);
let delta = base.italics_correction() / 2.0;
let mut frame = Frame::new(Size::new(width, height)); let mut frame = Frame::new(Size::new(width, height));
frame.set_baseline(base_pos.y + base.ascent()); frame.set_baseline(base_pos.y + base.ascent());
frame.push_frame(base_pos, base.to_frame(ctx)); frame.push_frame(base_pos, base.to_frame(ctx));
frame.push_frame(sub_pos, bottom);
frame.push_frame(sup_pos, top); if let Some(top) = top {
let top_pos = Point::with_x((width - top.width()) / 2.0 + delta);
frame.push_frame(top_pos, top);
}
if let Some(bottom) = bottom {
let bottom_pos =
Point::new((width - bottom.width()) / 2.0 - delta, height - bottom.height());
frame.push_frame(bottom_pos, bottom);
}
ctx.push(FrameFragment::new(frame).with_class(class)); ctx.push(FrameFragment::new(frame).with_class(class));
Ok(()) Ok(())