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[skottie] Fix text-on-path tracking

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Tracking and line spacing computations require knowledge of cumulative
values for the whole line => we need two passes:

  1) compute cumulative values
  2) compute per-fragment position adjustments

Currently, #1 is implemented in the main onSync() loop (as we iterate
to compute fragment props) and #2 is post-applied via adjustLineProps(),
after the main loop.

The problem is adjustLineProps() is executed after positioning glyphs on
path, and tracking is not taken into account for path positioning
(instead it moves glyphs horizontally, unrelated to the path).

To fix this, we need tracking adjustments to be applied before
positioning on path (which is performed in fragmentMatrix()).

  - move the cumulative tracking computation to a dedicate lambda
    (compute_linewide_props)
  - move the fragment position adjustments to the main onSync() loop
    (that way they participate in path positioning)
  - to avoid executing the first pass unnecessarily, add flags to detect
    the presence of tracking and line spacing animators.


Change-Id: Ieef2afb53ffe14177eba0ef41dc5c71149cab070
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/518696
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@google.com>
This commit is contained in:
Florin Malita 2022-03-10 12:39:25 -05:00 committed by SkCQ
parent e70f2e0e0f
commit ca973cbea0
5 changed files with 84 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

133
modules/skottie/src/text/TextAdapter.cpp
View File

@ -234,8 +234,9 @@ sk_sp<TextAdapter> TextAdapter::Make(const skjson::ObjectValue& jlayer,
for (const skjson::ObjectValue* janimator : *janimators) {
if (auto animator = TextAnimator::Make(janimator, abuilder, adapter.get())) {
adapter->fHasBlurAnimator |= animator->hasBlur();
adapter->fRequiresAnchorPoint |= animator->requiresAnchorPoint();
adapter->fHasBlurAnimator |= animator->hasBlur();
adapter->fRequiresAnchorPoint |= animator->requiresAnchorPoint();
adapter->fRequiresLineAdjustments |= animator->requiresLineAdjustments();
adapter->fAnimators.push_back(std::move(animator));
}
@ -294,7 +295,8 @@ TextAdapter::TextAdapter(sk_sp<SkFontMgr> fontmgr, sk_sp<Logger> logger, AnchorP
, fLogger(std::move(logger))
, fAnchorPointGrouping(apg)
, fHasBlurAnimator(false)
, fRequiresAnchorPoint(false) {}
, fRequiresAnchorPoint(false)
, fRequiresLineAdjustments(false) {}
TextAdapter::~TextAdapter() = default;
@ -580,16 +582,43 @@ void TextAdapter::onSync() {
}
size_t grouping_span_index = 0;
SkV2 line_offset = { 0, 0 }; // cumulative line spacing
SkV2 current_line_offset = { 0, 0 }; // cumulative line spacing
auto compute_linewide_props = [this](const TextAnimator::ModulatorBuffer& buf,
const TextAnimator::DomainSpan& line_span) {
SkV2 total_spacing = {0,0};
float total_tracking = 0;
// Only compute these when needed.
if (fRequiresLineAdjustments) {
for (size_t i = line_span.fOffset; i < line_span.fOffset + line_span.fCount; ++i) {
const auto& props = buf[i].props;
total_spacing += props.line_spacing;
total_tracking += props.tracking;
}
// The first glyph does not contribute |before| tracking, and the last one does not
// contribute |after| tracking.
total_tracking -= 0.5f * (buf[line_span.fOffset].props.tracking +
buf[line_span.fOffset + line_span.fCount - 1].props.tracking);
}
return std::make_tuple(total_spacing, total_tracking);
};
// Finally, push all props to their corresponding fragment.
for (const auto& line_span : fMaps.fLinesMap) {
SkV2 line_spacing = { 0, 0 };
float line_tracking = 0;
bool line_has_tracking = false;
const auto [line_spacing, line_tracking] = compute_linewide_props(buf, line_span);
const auto align_offset = -line_tracking * align_factor(fText->fHAlign);
// Tracking requires special treatment: unlike other props, its effect is not localized
// to a single fragment, but requires re-alignment of the whole line.
// line spacing of the first line is ignored (nothing to "space" against)
if (&line_span != &fMaps.fLinesMap.front() && line_span.fCount) {
// For each line, the actual spacing is an average of individual fragment spacing
// (to preserve the "line").
current_line_offset += line_spacing / line_span.fCount;
}
float tracking_acc = 0;
for (size_t i = line_span.fOffset; i < line_span.fOffset + line_span.fCount; ++i) {
// Track the grouping domain span in parallel.
if (grouping_domain && i >= (*grouping_domain)[grouping_span_index].fOffset +
@ -601,27 +630,28 @@ void TextAdapter::onSync() {
const auto& props = buf[i].props;
const auto& frag = fFragments[i];
this->pushPropsToFragment(props, frag, fGroupingAlignment * .01f, // percentage
// AE tracking is defined per glyph, based on two components: |before| and |after|.
// BodyMovin only exports "balanced" tracking values, where before = after = tracking/2.
//
// Tracking is applied as a local glyph offset, and contributes to the line width for
// alignment purposes.
//
// No |before| tracking for the first glyph, nor |after| tracking for the last one.
const auto track_before = i > line_span.fOffset
? props.tracking * 0.5f : 0.0f,
track_after = i < line_span.fOffset + line_span.fCount - 1
? props.tracking * 0.5f : 0.0f;
const auto frag_offset = current_line_offset +
SkV2{align_offset + tracking_acc + track_before, 0};
tracking_acc += track_before + track_after;
this->pushPropsToFragment(props, frag, frag_offset, fGroupingAlignment * .01f, // %
grouping_domain ? &(*grouping_domain)[grouping_span_index]
: nullptr);
line_tracking += props.tracking;
line_has_tracking |= !SkScalarNearlyZero(props.tracking);
line_spacing += props.line_spacing;
}
// line spacing of the first line is ignored (nothing to "space" against)
if (&line_span != &fMaps.fLinesMap.front()) {
// For each line, the actual spacing is an average of individual fragment spacing
// (to preserve the "line").
line_offset += line_spacing / line_span.fCount;
}
if (line_offset != SkV2{0, 0} || line_has_tracking) {
this->adjustLineProps(buf, line_span, line_offset, line_tracking);
}
}
}
@ -682,10 +712,10 @@ SkV2 TextAdapter::fragmentAnchorPoint(const FragmentRec& rec,
}
SkM44 TextAdapter::fragmentMatrix(const TextAnimator::ResolvedProps& props,
const FragmentRec& rec, const SkV2& anchor_point) const {
const FragmentRec& rec, const SkV2& frag_offset) const {
const SkV3 pos = {
props.position.x + rec.fOrigin.fX + anchor_point.x,
props.position.y + rec.fOrigin.fY + anchor_point.y,
props.position.x + rec.fOrigin.fX + frag_offset.x,
props.position.y + rec.fOrigin.fY + frag_offset.y,
props.position.z
};
@ -715,12 +745,13 @@ SkM44 TextAdapter::fragmentMatrix(const TextAnimator::ResolvedProps& props,
void TextAdapter::pushPropsToFragment(const TextAnimator::ResolvedProps& props,
const FragmentRec& rec,
const SkV2& frag_offset,
const SkV2& grouping_alignment,
const TextAnimator::DomainSpan* grouping_span) const {
const auto anchor_point = this->fragmentAnchorPoint(rec, grouping_alignment, grouping_span);
rec.fMatrixNode->setMatrix(
this->fragmentMatrix(props, rec, anchor_point)
this->fragmentMatrix(props, rec, anchor_point + frag_offset)
* SkM44::Rotate({ 1, 0, 0 }, SkDegreesToRadians(props.rotation.x))
* SkM44::Rotate({ 0, 1, 0 }, SkDegreesToRadians(props.rotation.y))
* SkM44::Rotate({ 0, 0, 1 }, SkDegreesToRadians(props.rotation.z))
@ -743,44 +774,4 @@ void TextAdapter::pushPropsToFragment(const TextAnimator::ResolvedProps& props,
}
}
void TextAdapter::adjustLineProps(const TextAnimator::ModulatorBuffer& buf,
const TextAnimator::DomainSpan& line_span,
const SkV2& line_offset,
float total_tracking) const {
SkASSERT(line_span.fCount > 0);
// AE tracking is defined per glyph, based on two components: |before| and |after|.
// BodyMovin only exports "balanced" tracking values, where before == after == tracking / 2.
//
// Tracking is applied as a local glyph offset, and contributes to the line width for alignment
// purposes.
// The first glyph does not contribute |before| tracking, and the last one does not contribute
// |after| tracking. Rather than spill this logic into applyAnimators, post-adjust here.
total_tracking -= 0.5f * (buf[line_span.fOffset].props.tracking +
buf[line_span.fOffset + line_span.fCount - 1].props.tracking);
const auto align_offset = -total_tracking * align_factor(fText->fHAlign);
float tracking_acc = 0;
for (size_t i = line_span.fOffset; i < line_span.fOffset + line_span.fCount; ++i) {
const auto& props = buf[i].props;
// No |before| tracking for the first glyph, nor |after| tracking for the last one.
const auto track_before = i > line_span.fOffset
? props.tracking * 0.5f : 0.0f,
track_after = i < line_span.fOffset + line_span.fCount - 1
? props.tracking * 0.5f : 0.0f,
fragment_offset = align_offset + tracking_acc + track_before;
const auto& frag = fFragments[i];
const auto m = SkM44::Translate(line_offset.x + fragment_offset,
line_offset.y) *
frag.fMatrixNode->getMatrix();
frag.fMatrixNode->setMatrix(m);
tracking_acc += track_before + track_after;
}
}
} // namespace skottie::internal

13
modules/skottie/src/text/TextAdapter.h
View File

@ -69,12 +69,8 @@ private:
void buildDomainMaps(const Shaper::Result&);
void pushPropsToFragment(const TextAnimator::ResolvedProps&, const FragmentRec&,
const SkV2&, const TextAnimator::DomainSpan*) const;
void adjustLineProps(const TextAnimator::ModulatorBuffer&,
const TextAnimator::DomainSpan&,
const SkV2& line_offset,
float line_tracking) const;
const SkV2& frag_offset, const SkV2& grouping_alignment,
const TextAnimator::DomainSpan*) const;
SkV2 fragmentAnchorPoint(const FragmentRec&, const SkV2&,
const TextAnimator::DomainSpan*) const;
@ -116,8 +112,9 @@ private:
struct PathInfo;
std::unique_ptr<PathInfo> fPathInfo;
bool fHasBlurAnimator : 1,
fRequiresAnchorPoint : 1;
bool fHasBlurAnimator : 1,
fRequiresAnchorPoint : 1,
fRequiresLineAdjustments : 1;
};
} // namespace internal

9
modules/skottie/src/text/TextAnimator.cpp
View File

@ -182,11 +182,14 @@ TextAnimator::TextAnimator(std::vector<sk_sp<RangeSelector>>&& selectors,
const AnimationBuilder* abuilder,
AnimatablePropertyContainer* acontainer)
: fSelectors(std::move(selectors))
, fRequiresAnchorPoint(false) {
, fRequiresAnchorPoint(false)
, fRequiresLineAdjustments(false) {
acontainer->bind(*abuilder, jprops["p" ], fTextProps.position);
acontainer->bind(*abuilder, jprops["t" ], fTextProps.tracking);
acontainer->bind(*abuilder, jprops["ls"], fTextProps.line_spacing);
// Tracking and line spacing affect all line fragments.
fRequiresLineAdjustments |= acontainer->bind(*abuilder, jprops["t" ], fTextProps.tracking);
fRequiresLineAdjustments |= acontainer->bind(*abuilder, jprops["ls"], fTextProps.line_spacing);
// Scale and rotation are anchor-point-dependent.
fRequiresAnchorPoint |= acontainer->bind(*abuilder, jprops["s"], fTextProps.scale);

18
modules/skottie/src/text/TextAnimator.h
View File

@ -87,7 +87,8 @@ public:
bool hasBlur() const { return fHasBlur; }
bool requiresAnchorPoint() const { return fRequiresAnchorPoint; }
bool requiresAnchorPoint() const { return fRequiresAnchorPoint; }
bool requiresLineAdjustments() const { return fRequiresLineAdjustments; }
private:
TextAnimator(std::vector<sk_sp<RangeSelector>>&&,
@ -100,13 +101,14 @@ private:
const std::vector<sk_sp<RangeSelector>> fSelectors;
AnimatedProps fTextProps;
bool fHasFillColor : 1,
fHasStrokeColor : 1,
fHasFillOpacity : 1,
fHasStrokeOpacity : 1,
fHasOpacity : 1,
fHasBlur : 1,
fRequiresAnchorPoint : 1; // animator sensitive to transform origin?
bool fHasFillColor : 1,
fHasStrokeColor : 1,
fHasFillOpacity : 1,
fHasStrokeOpacity : 1,
fHasOpacity : 1,
fHasBlur : 1,
fRequiresAnchorPoint : 1, // animator sensitive to transform origin?
fRequiresLineAdjustments : 1; // animator effects line-wide fragment adjustments
};
} // namespace internal

1
resources/skottie/skottie-textpath-tracking.json Normal file
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@ -0,0 +1 @@
{"v":"5.8.3","fr":60,"ip":0,"op":301,"w":500,"h":500,"nm":"tpath tracking","ddd":0,"assets":[],"fonts":{"list":[{"origin":0,"fPath":"","fClass":"","fFamily":"Google Sans","fWeight":"","fStyle":"Bold","fName":"GoogleSans-Bold","ascent":75.6476929411292}]},"layers":[{"ddd":0,"ind":1,"ty":5,"nm":"Foo Bar Baz","sr":1,"ks":{"o":{"a":0,"k":100,"ix":11},"r":{"a":0,"k":0,"ix":10},"p":{"a":0,"k":[250,250,0],"ix":2,"l":2},"a":{"a":0,"k":[0,0,0],"ix":1,"l":2},"s":{"a":0,"k":[100,100,100],"ix":6,"l":2}},"ao":0,"hasMask":true,"masksProperties":[{"inv":false,"mode":"n","pt":{"a":0,"k":{"i":[[66.274,0],[0,-66.274],[-66.274,0],[0,66.274]],"o":[[-66.274,0],[0,66.274],[66.274,0],[0,-66.274]],"v":[[0,-120],[-120,0],[0,120],[120,0]],"c":true},"ix":1},"o":{"a":0,"k":100,"ix":3},"x":{"a":0,"k":0,"ix":4},"nm":"Mask 1"}],"t":{"d":{"k":[{"s":{"s":72,"f":"GoogleSans-Bold","t":"Foo Bar Baz","ca":0,"j":2,"tr":0,"lh":96,"ls":0,"fc":[0,0.522,0]},"t":0}]},"p":{"m":0,"f":{"a":0,"k":377,"ix":5},"l":{"a":0,"k":0,"ix":6},"a":{"a":0,"k":0,"ix":4},"p":{"a":0,"k":1,"ix":3},"r":{"a":0,"k":1,"ix":2}},"m":{"g":1,"a":{"a":0,"k":[0,0],"ix":2}},"a":[{"nm":"Animator 1","s":{"t":0,"xe":{"a":0,"k":0,"ix":7},"ne":{"a":0,"k":0,"ix":8},"a":{"a":0,"k":100,"ix":4},"b":1,"rn":0,"sh":1,"sm":{"a":0,"k":100,"ix":6},"r":1},"a":{"t":{"a":1,"k":[{"i":{"x":[0.336],"y":[0.999]},"o":{"x":[0.669],"y":[0.001]},"t":0,"s":[-35]},{"i":{"x":[0.336],"y":[0.997]},"o":{"x":[0.665],"y":[-0.001]},"t":150,"s":[50]},{"t":300,"s":[-35]}],"ix":89}}}]},"ip":0,"op":301,"st":0,"bm":0},{"ddd":0,"ind":2,"ty":4,"nm":"Shape Layer 1","sr":1,"ks":{"o":{"a":0,"k":100,"ix":11},"r":{"a":0,"k":0,"ix":10},"p":{"a":0,"k":[250,250,0],"ix":2,"l":2},"a":{"a":0,"k":[0,0,0],"ix":1,"l":2},"s":{"a":0,"k":[100,100,100],"ix":6,"l":2}},"ao":0,"shapes":[{"d":1,"ty":"el","s":{"a":0,"k":[240,240],"ix":2},"p":{"a":0,"k":[0,0],"ix":3},"nm":"Ellipse Path 1","mn":"ADBE Vector Shape - Ellipse","hd":false},{"ty":"st","c":{"a":0,"k":[1,0,0,1],"ix":3},"o":{"a":0,"k":100,"ix":4},"w":{"a":0,"k":5,"ix":5},"lc":1,"lj":1,"ml":4,"bm":0,"nm":"Stroke 1","mn":"ADBE Vector Graphic - Stroke","hd":false}],"ip":0,"op":301,"st":0,"bm":0},{"ddd":0,"ind":3,"ty":1,"nm":"Medium Yellow Solid 1","sr":1,"ks":{"o":{"a":0,"k":100,"ix":11},"r":{"a":0,"k":0,"ix":10},"p":{"a":0,"k":[250,250,0],"ix":2,"l":2},"a":{"a":0,"k":[600,600,0],"ix":1,"l":2},"s":{"a":0,"k":[100,100,100],"ix":6,"l":2}},"ao":0,"sw":1200,"sh":1200,"sc":"#ffffbd","ip":0,"op":301,"st":0,"bm":0}],"markers":[]}