[SVGDom] Factor out common gradient logic

In preparation of radial gradient support, move common logic into an
abstract base class (SkSVGGradient).

Change-Id: Ie5361048ca8fddd9070c573c8daef0d0f57dc95e
Reviewed-on: https://skia-review.googlesource.com/57108
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Robert Phillips <robertphillips@google.com>

1 files changed, 5 insertions, 78 deletions

diff --git a/experimental/svg/model/SkSVGLinearGradient.cpp b/experimental/svg/model/SkSVGLinearGradient.cpp
index 4bbed1c354..14939d1371 100644
--- a/experimental/svg/model/SkSVGLinearGradient.cpp
+++ b/experimental/svg/model/SkSVGLinearGradient.cpp
@@ -8,23 +8,10 @@
 #include "SkGradientShader.h"
 #include "SkSVGLinearGradient.h"
 #include "SkSVGRenderContext.h"
-#include "SkSVGStop.h"
 #include "SkSVGValue.h"
 
 SkSVGLinearGradient::SkSVGLinearGradient() : INHERITED(SkSVGTag::kLinearGradient) {}
 
-void SkSVGLinearGradient::setHref(const SkSVGStringType& href) {
-    fHref = std::move(href);
-}
-
-void SkSVGLinearGradient::setGradientTransform(const SkSVGTransformType& t) {
-    fGradientTransform = t;
-}
-
-void SkSVGLinearGradient::setSpreadMethod(const SkSVGSpreadMethod& spread) {
-    fSpreadMethod = spread;
-}
-
 void SkSVGLinearGradient::setX1(const SkSVGLength& x1) {
     fX1 = x1;
 }
@@ -43,21 +30,6 @@ void SkSVGLinearGradient::setY2(const SkSVGLength& y2) {
 
 void SkSVGLinearGradient::onSetAttribute(SkSVGAttribute attr, const SkSVGValue& v) {
     switch (attr) {
-    case SkSVGAttribute::kGradientTransform:
-        if (const auto* t = v.as<SkSVGTransformValue>()) {
-            this->setGradientTransform(*t);
-        }
-        break;
-    case SkSVGAttribute::kHref:
-        if (const auto* href = v.as<SkSVGStringValue>()) {
-            this->setHref(*href);
-        }
-        break;
-    case SkSVGAttribute::kSpreadMethod:
-        if (const auto* spread = v.as<SkSVGSpreadMethodValue>()) {
-            this->setSpreadMethod(*spread);
-        }
-        break;
     case SkSVGAttribute::kX1:
         if (const auto* x1 = v.as<SkSVGLengthValue>()) {
             this->setX1(*x1);
@@ -83,36 +55,10 @@ void SkSVGLinearGradient::onSetAttribute(SkSVGAttribute attr, const SkSVGValue&
     }
 }
 
-// https://www.w3.org/TR/SVG/pservers.html#LinearGradientElementHrefAttribute
-void SkSVGLinearGradient::collectColorStops(const SkSVGRenderContext& ctx,
-                                            SkSTArray<2, SkScalar, true>* pos,
-                                            SkSTArray<2, SkColor, true>* colors) const {
-    // Used to resolve percentage offsets.
-    const SkSVGLengthContext ltx(SkSize::Make(1, 1));
-
-    for (const auto& child : fChildren) {
-        if (child->tag() != SkSVGTag::kStop) {
-            continue;
-        }
-
-        const auto& stop = static_cast<const SkSVGStop&>(*child);
-        colors->push_back(SkColorSetA(stop.stopColor(),
-                                      SkScalarRoundToInt(stop.stopOpacity() * 255)));
-        pos->push_back(SkTPin(ltx.resolve(stop.offset(), SkSVGLengthContext::LengthType::kOther),
-                              0.f, 1.f));
-    }
-
-    SkASSERT(colors->count() == pos->count());
-
-    if (pos->empty() && !fHref.value().isEmpty()) {
-        const auto* ref = ctx.findNodeById(fHref);
-        if (ref && ref->tag() == SkSVGTag::kLinearGradient) {
-            static_cast<const SkSVGLinearGradient*>(ref)->collectColorStops(ctx, pos, colors);
-        }
-    }
-}
-
-bool SkSVGLinearGradient::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
+sk_sp<SkShader> SkSVGLinearGradient::onMakeShader(const SkSVGRenderContext& ctx,
+                                                  const SkColor* colors, const SkScalar* pos,
+                                                  int count, SkShader::TileMode tm,
+                                                  const SkMatrix& localMatrix) const {
     const auto& lctx = ctx.lengthContext();
     const auto x1 = lctx.resolve(fX1, SkSVGLengthContext::LengthType::kHorizontal);
     const auto y1 = lctx.resolve(fY1, SkSVGLengthContext::LengthType::kVertical);
@@ -120,25 +66,6 @@ bool SkSVGLinearGradient::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* pain
     const auto y2 = lctx.resolve(fY2, SkSVGLengthContext::LengthType::kVertical);
 
     const SkPoint pts[2] = { {x1, y1}, {x2, y2}};
-    SkSTArray<2, SkColor , true> colors;
-    SkSTArray<2, SkScalar, true> pos;
-
-    this->collectColorStops(ctx, &pos, &colors);
-    // TODO:
-    //       * stop (lazy?) sorting
-    //       * href loop detection
-    //       * href attribute inheritance (not just color stops)
-    //       * objectBoundingBox units support
-
-    static_assert(static_cast<SkShader::TileMode>(SkSVGSpreadMethod::Type::kPad) ==
-                  SkShader::kClamp_TileMode, "SkSVGSpreadMethod::Type is out of sync");
-    static_assert(static_cast<SkShader::TileMode>(SkSVGSpreadMethod::Type::kRepeat) ==
-                  SkShader::kRepeat_TileMode, "SkSVGSpreadMethod::Type is out of sync");
-    static_assert(static_cast<SkShader::TileMode>(SkSVGSpreadMethod::Type::kReflect) ==
-                  SkShader::kMirror_TileMode, "SkSVGSpreadMethod::Type is out of sync");
-    const auto tileMode = static_cast<SkShader::TileMode>(fSpreadMethod.type());
 
-    paint->setShader(SkGradientShader::MakeLinear(pts, colors.begin(), pos.begin(), colors.count(),
-                                                  tileMode, 0, &fGradientTransform.value()));
-    return true;
+    return SkGradientShader::MakeLinear(pts, colors, pos, count, tm, 0, &localMatrix);
 }