skia2/experimental/svg/model/SkSVGRenderContext.cpp
2016-08-29 05:54:42 -07:00

268 lines
10 KiB
C++

/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkCanvas.h"
#include "SkSVGAttribute.h"
#include "SkSVGRenderContext.h"
#include "SkSVGTypes.h"
namespace {
SkScalar length_size_for_type(const SkSize& viewport, SkSVGLengthContext::LengthType t) {
switch (t) {
case SkSVGLengthContext::LengthType::kHorizontal:
return viewport.width();
case SkSVGLengthContext::LengthType::kVertical:
return viewport.height();
case SkSVGLengthContext::LengthType::kOther:
return SkScalarSqrt(viewport.width() * viewport.height());
}
SkASSERT(false); // Not reached.
return 0;
}
// Multipliers for DPI-relative units.
constexpr SkScalar kINMultiplier = 1.00f;
constexpr SkScalar kPTMultiplier = kINMultiplier / 72.272f;
constexpr SkScalar kPCMultiplier = kPTMultiplier * 12;
constexpr SkScalar kMMMultiplier = kINMultiplier / 25.4f;
constexpr SkScalar kCMMultiplier = kMMMultiplier * 10;
} // anonymous ns
SkScalar SkSVGLengthContext::resolve(const SkSVGLength& l, LengthType t) const {
switch (l.unit()) {
case SkSVGLength::Unit::kNumber:
// Fall through.
case SkSVGLength::Unit::kPX:
return l.value();
case SkSVGLength::Unit::kPercentage:
return l.value() * length_size_for_type(fViewport, t) / 100;
case SkSVGLength::Unit::kCM:
return l.value() * fDPI * kCMMultiplier;
case SkSVGLength::Unit::kMM:
return l.value() * fDPI * kMMMultiplier;
case SkSVGLength::Unit::kIN:
return l.value() * fDPI * kINMultiplier;
case SkSVGLength::Unit::kPT:
return l.value() * fDPI * kPTMultiplier;
case SkSVGLength::Unit::kPC:
return l.value() * fDPI * kPCMultiplier;
default:
SkDebugf("unsupported unit type: <%d>\n", l.unit());
return 0;
}
}
SkRect SkSVGLengthContext::resolveRect(const SkSVGLength& x, const SkSVGLength& y,
const SkSVGLength& w, const SkSVGLength& h) const {
return SkRect::MakeXYWH(
this->resolve(x, SkSVGLengthContext::LengthType::kHorizontal),
this->resolve(y, SkSVGLengthContext::LengthType::kVertical),
this->resolve(w, SkSVGLengthContext::LengthType::kHorizontal),
this->resolve(h, SkSVGLengthContext::LengthType::kVertical));
}
namespace {
SkPaint::Cap toSkCap(const SkSVGLineCap& cap) {
switch (cap.type()) {
case SkSVGLineCap::Type::kButt:
return SkPaint::kButt_Cap;
case SkSVGLineCap::Type::kRound:
return SkPaint::kRound_Cap;
case SkSVGLineCap::Type::kSquare:
return SkPaint::kSquare_Cap;
default:
SkASSERT(false);
return SkPaint::kButt_Cap;
}
}
SkPaint::Join toSkJoin(const SkSVGLineJoin& join) {
switch (join.type()) {
case SkSVGLineJoin::Type::kMiter:
return SkPaint::kMiter_Join;
case SkSVGLineJoin::Type::kRound:
return SkPaint::kRound_Join;
case SkSVGLineJoin::Type::kBevel:
return SkPaint::kBevel_Join;
default:
SkASSERT(false);
return SkPaint::kMiter_Join;
}
}
void applySvgPaint(const SkSVGPaint& svgPaint, SkPaint* p) {
switch (svgPaint.type()) {
case SkSVGPaint::Type::kColor:
p->setColor(SkColorSetA(svgPaint.color(), p->getAlpha()));
break;
case SkSVGPaint::Type::kCurrentColor:
SkDebugf("unimplemented 'currentColor' paint type");
// Fall through.
case SkSVGPaint::Type::kNone:
// Fall through.
case SkSVGPaint::Type::kInherit:
break;
}
}
inline uint8_t opacity_to_alpha(SkScalar o) {
return SkTo<uint8_t>(SkScalarRoundToInt(o * 255));
}
// Commit the selected attribute to the paint cache.
template <SkSVGAttribute>
void commitToPaint(const SkSVGPresentationAttributes&,
const SkSVGLengthContext&,
SkSVGPresentationContext*);
template <>
void commitToPaint<SkSVGAttribute::kFill>(const SkSVGPresentationAttributes& attrs,
const SkSVGLengthContext&,
SkSVGPresentationContext* pctx) {
applySvgPaint(*attrs.fFill.get(), &pctx->fFillPaint);
}
template <>
void commitToPaint<SkSVGAttribute::kStroke>(const SkSVGPresentationAttributes& attrs,
const SkSVGLengthContext&,
SkSVGPresentationContext* pctx) {
applySvgPaint(*attrs.fStroke.get(), &pctx->fStrokePaint);
}
template <>
void commitToPaint<SkSVGAttribute::kFillOpacity>(const SkSVGPresentationAttributes& attrs,
const SkSVGLengthContext&,
SkSVGPresentationContext* pctx) {
pctx->fFillPaint.setAlpha(opacity_to_alpha(*attrs.fFillOpacity.get()));
}
template <>
void commitToPaint<SkSVGAttribute::kStrokeLineCap>(const SkSVGPresentationAttributes& attrs,
const SkSVGLengthContext&,
SkSVGPresentationContext* pctx) {
const auto& cap = *attrs.fStrokeLineCap.get();
if (cap.type() != SkSVGLineCap::Type::kInherit) {
pctx->fStrokePaint.setStrokeCap(toSkCap(cap));
}
}
template <>
void commitToPaint<SkSVGAttribute::kStrokeLineJoin>(const SkSVGPresentationAttributes& attrs,
const SkSVGLengthContext&,
SkSVGPresentationContext* pctx) {
const auto& join = *attrs.fStrokeLineJoin.get();
if (join.type() != SkSVGLineJoin::Type::kInherit) {
pctx->fStrokePaint.setStrokeJoin(toSkJoin(join));
}
}
template <>
void commitToPaint<SkSVGAttribute::kStrokeOpacity>(const SkSVGPresentationAttributes& attrs,
const SkSVGLengthContext&,
SkSVGPresentationContext* pctx) {
pctx->fStrokePaint.setAlpha(opacity_to_alpha(*attrs.fStrokeOpacity.get()));
}
template <>
void commitToPaint<SkSVGAttribute::kStrokeWidth>(const SkSVGPresentationAttributes& attrs,
const SkSVGLengthContext& lctx,
SkSVGPresentationContext* pctx) {
auto strokeWidth = lctx.resolve(*attrs.fStrokeWidth.get(),
SkSVGLengthContext::LengthType::kOther);
pctx->fStrokePaint.setStrokeWidth(strokeWidth);
}
} // anonymous ns
SkSVGPresentationContext::SkSVGPresentationContext()
: fInherited(SkSVGPresentationAttributes::MakeInitial()) {
fFillPaint.setStyle(SkPaint::kFill_Style);
fStrokePaint.setStyle(SkPaint::kStroke_Style);
// TODO: drive AA off presentation attrs also (shape-rendering?)
fFillPaint.setAntiAlias(true);
fStrokePaint.setAntiAlias(true);
// Commit initial values to the paint cache.
SkSVGLengthContext dummy(SkSize::Make(0, 0));
commitToPaint<SkSVGAttribute::kFill>(fInherited, dummy, this);
commitToPaint<SkSVGAttribute::kFillOpacity>(fInherited, dummy, this);
commitToPaint<SkSVGAttribute::kStroke>(fInherited, dummy, this);
commitToPaint<SkSVGAttribute::kStrokeLineCap>(fInherited, dummy, this);
commitToPaint<SkSVGAttribute::kStrokeLineJoin>(fInherited, dummy, this);
commitToPaint<SkSVGAttribute::kStrokeOpacity>(fInherited, dummy, this);
commitToPaint<SkSVGAttribute::kStrokeWidth>(fInherited, dummy, this);
}
SkSVGRenderContext::SkSVGRenderContext(SkCanvas* canvas,
const SkSVGLengthContext& lctx,
const SkSVGPresentationContext& pctx)
: fLengthContext(lctx)
, fPresentationContext(pctx)
, fCanvas(canvas)
, fCanvasSaveCount(canvas->getSaveCount()) {}
SkSVGRenderContext::SkSVGRenderContext(const SkSVGRenderContext& other)
: SkSVGRenderContext(other.fCanvas,
*other.fLengthContext,
*other.fPresentationContext) {}
SkSVGRenderContext::~SkSVGRenderContext() {
fCanvas->restoreToCount(fCanvasSaveCount);
}
void SkSVGRenderContext::applyPresentationAttributes(const SkSVGPresentationAttributes& attrs) {
#define ApplyLazyInheritedAttribute(ATTR) \
do { \
/* All attributes should be defined on the inherited context. */ \
SkASSERT(fPresentationContext->fInherited.f ## ATTR.isValid()); \
const auto* value = attrs.f ## ATTR.getMaybeNull(); \
if (value && *value != *fPresentationContext->fInherited.f ## ATTR.get()) { \
/* Update the local attribute value */ \
fPresentationContext.writable()->fInherited.f ## ATTR.set(*value); \
/* Update the cached paints */ \
commitToPaint<SkSVGAttribute::k ## ATTR>(attrs, *fLengthContext, \
fPresentationContext.writable()); \
} \
} while (false)
ApplyLazyInheritedAttribute(Fill);
ApplyLazyInheritedAttribute(FillOpacity);
ApplyLazyInheritedAttribute(Stroke);
ApplyLazyInheritedAttribute(StrokeLineCap);
ApplyLazyInheritedAttribute(StrokeLineJoin);
ApplyLazyInheritedAttribute(StrokeOpacity);
ApplyLazyInheritedAttribute(StrokeWidth);
#undef ApplyLazyInheritedAttribute
// Uninherited attributes. Only apply to the current context.
if (auto* opacity = attrs.fOpacity.getMaybeNull()) {
SkPaint opacityPaint;
opacityPaint.setAlpha(opacity_to_alpha(opacity->value()));
// Balanced in the destructor, via restoreToCount().
fCanvas->saveLayer(nullptr, &opacityPaint);
}
}
const SkPaint* SkSVGRenderContext::fillPaint() const {
const SkSVGPaint::Type paintType = fPresentationContext->fInherited.fFill.get()->type();
return paintType != SkSVGPaint::Type::kNone ? &fPresentationContext->fFillPaint : nullptr;
}
const SkPaint* SkSVGRenderContext::strokePaint() const {
const SkSVGPaint::Type paintType = fPresentationContext->fInherited.fStroke.get()->type();
return paintType != SkSVGPaint::Type::kNone ? &fPresentationContext->fStrokePaint : nullptr;
}