skia2/experimental/svg/model/SkSVGGradient.cpp
Florin Malita df007e1a7a [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>
2017-10-09 19:36:44 +00:00

100 lines
3.5 KiB
C++

/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkSVGGradient.h"
#include "SkSVGRenderContext.h"
#include "SkSVGStop.h"
#include "SkSVGValue.h"
void SkSVGGradient::setHref(const SkSVGStringType& href) {
fHref = std::move(href);
}
void SkSVGGradient::setGradientTransform(const SkSVGTransformType& t) {
fGradientTransform = t;
}
void SkSVGGradient::setSpreadMethod(const SkSVGSpreadMethod& spread) {
fSpreadMethod = spread;
}
void SkSVGGradient::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;
default:
this->INHERITED::onSetAttribute(attr, v);
}
}
// https://www.w3.org/TR/SVG/pservers.html#LinearGradientElementHrefAttribute
void SkSVGGradient::collectColorStops(const SkSVGRenderContext& ctx,
StopPositionArray* pos,
StopColorArray* 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 SkSVGGradient*>(ref)->collectColorStops(ctx, pos, colors);
}
}
}
bool SkSVGGradient::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
StopColorArray colors;
StopPositionArray 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(this->onMakeShader(ctx, colors.begin(), pos.begin(), colors.count(), tileMode,
fGradientTransform.value()));
return true;
}