[SVGDom] Add more presentation attributes.

experimental/svg/model/SkSVGRenderContext.cpp

 /*
  * 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;
 }
 
 } // 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();
-        break;
     case SkSVGLength::Unit::kPercentage:
         return l.value() * length_size_for_type(fViewport, t) / 100;
-        break;
     default:
         SkDebugf("unsupported unit type: <%d>\n", l.unit());
-        break;
+        return 0;
     }
-
-    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));
 }
 
-SkSVGPresentationContext::SkSVGPresentationContext() {}
+namespace {
 
-SkSVGPresentationContext::SkSVGPresentationContext(const SkSVGPresentationContext& o) {
-    this->initFrom(o);
-}
-
-SkSVGPresentationContext& SkSVGPresentationContext::operator=(const SkSVGPresentationContext& o) {
-    this->initFrom(o);
-    return *this;
-}
-
-void SkSVGPresentationContext::initFrom(const SkSVGPresentationContext& other) {
-    if (other.fFill.isValid()) {
-        fFill.set(*other.fFill.get());
-    } else {
-        fFill.reset();
-    }
-
-    if (other.fStroke.isValid()) {
-        fStroke.set(*other.fStroke.get());
-    } else {
-        fStroke.reset();
+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& SkSVGPresentationContext::ensureFill() {
-    if (!fFill.isValid()) {
-        fFill.init();
-        fFill.get()->setStyle(SkPaint::kFill_Style);
-        fFill.get()->setAntiAlias(true);
+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;
     }
-    return *fFill.get();
 }
 
-SkPaint& SkSVGPresentationContext::ensureStroke() {
-    if (!fStroke.isValid()) {
-        fStroke.init();
-        fStroke.get()->setStyle(SkPaint::kStroke_Style);
-        fStroke.get()->setAntiAlias(true);
+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;
     }
-    return *fStroke.get();
 }
 
-void SkSVGPresentationContext::setFillColor(SkColor color) {
-    this->ensureFill().setColor(color);
+// 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);
 }
 
-void SkSVGPresentationContext::setStrokeColor(SkColor color) {
-    this->ensureStroke().setColor(color);
+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(static_cast<uint8_t>(*attrs.fFillOpacity.get() * 255));
+}
+
+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(static_cast<uint8_t>(*attrs.fStrokeOpacity.get() * 255));
+}
+
+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.canvas(),
-                         other.lengthContext(),
-                         other.presentationContext()) {}
+    : 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
+}
+
+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;
+}