[SVGDom] Add <circle>, <ellipse> support

experimental/svg/model/SkSVGEllipse.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 "SkSVGEllipse.h"
+#include "SkSVGRenderContext.h"
+#include "SkSVGValue.h"
+
+SkSVGEllipse::SkSVGEllipse() : INHERITED(SkSVGTag::kEllipse) {}
+
+void SkSVGEllipse::setCx(const SkSVGLength& cx) {
+    fCx = cx;
+}
+
+void SkSVGEllipse::setCy(const SkSVGLength& cy) {
+    fCy = cy;
+}
+
+void SkSVGEllipse::setRx(const SkSVGLength& rx) {
+    fRx = rx;
+}
+
+void SkSVGEllipse::setRy(const SkSVGLength& ry) {
+    fRy = ry;
+}
+
+void SkSVGEllipse::onSetAttribute(SkSVGAttribute attr, const SkSVGValue& v) {
+    switch (attr) {
+    case SkSVGAttribute::kCx:
+        if (const auto* cx = v.as<SkSVGLengthValue>()) {
+            this->setCx(*cx);
+        }
+        break;
+    case SkSVGAttribute::kCy:
+        if (const auto* cy = v.as<SkSVGLengthValue>()) {
+            this->setCy(*cy);
+        }
+        break;
+    case SkSVGAttribute::kRx:
+        if (const auto* rx = v.as<SkSVGLengthValue>()) {
+            this->setRx(*rx);
+        }
+        break;
+    case SkSVGAttribute::kRy:
+        if (const auto* ry = v.as<SkSVGLengthValue>()) {
+            this->setRy(*ry);
+        }
+        break;
+    default:
+        this->INHERITED::onSetAttribute(attr, v);
+    }
+}
+
+void SkSVGEllipse::onDraw(SkCanvas* canvas, const SkSVGLengthContext& lctx,
+                          const SkPaint& paint) const {
+    const auto cx = lctx.resolve(fCx, SkSVGLengthContext::LengthType::kHorizontal);
+    const auto cy = lctx.resolve(fCy, SkSVGLengthContext::LengthType::kVertical);
+    const auto rx = lctx.resolve(fRx, SkSVGLengthContext::LengthType::kHorizontal);
+    const auto ry = lctx.resolve(fRy, SkSVGLengthContext::LengthType::kVertical);
+
+    if (rx > 0 && ry > 0) {
+        canvas->drawOval(SkRect::MakeXYWH(cx - rx / 2, cy - ry / 2, rx * 2, ry * 2), paint);
+    }
+}