Initial SVG model

experimental/svg/model/SkSVGDOM.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 "SkDOM.h"
+#include "SkParse.h"
+#include "SkParsePath.h"
+#include "SkSVGDOM.h"
+#include "SkSVGG.h"
+#include "SkSVGNode.h"
+#include "SkSVGPath.h"
+#include "SkSVGSVG.h"
+#include "SkSVGValue.h"
+#include "SkTSearch.h"
+
+namespace {
+
+SkColor ParseColor(const char* str) {
+    // FIXME: real parser
+    if (*str++ != '#') {
+        return SK_ColorBLACK;
+    }
+
+    uint32_t v;
+    const char* consumed = SkParse::FindHex(str, &v);
+
+    switch(consumed - str) {
+    case 6:
+        // matched '#xxxxxx'
+        break;
+    case 3:
+        // matched '#xxx;
+        v = ((v << 12) & 0x00f00000) |
+            ((v <<  8) & 0x000ff000) |
+            ((v <<  4) & 0x00000ff0) |
+            ((v <<  0) & 0x0000000f);
+        break;
+    default:
+        // failed
+        v = 0;
+        break;
+    }
+
+    return v | 0xff000000;
+}
+
+const char* ParseScalarPair(const char* str, SkScalar v[2]) {
+    str = SkParse::FindScalar(str, v);
+    if (str) {
+        const char* second = SkParse::FindScalar(str, v + 1);
+        if (!second) {
+            v[1] = v[0];
+        } else {
+            str = second;
+        }
+    }
+
+    return str;
+}
+
+SkMatrix ParseTransform(const char* str) {
+    SkMatrix m = SkMatrix::I();
+
+    // FIXME: real parser
+    if (!strncmp(str, "matrix(", 7)) {
+        SkScalar values[6];
+        str = SkParse::FindScalars(str + 7, values, 6);
+        if (str) {
+            m.setAffine(values);
+        }
+    } else if (!strncmp(str, "scale(", 6)) {
+        SkScalar values[2];
+        str = ParseScalarPair(str + 6, values);
+        if (str) {
+            m.setScale(values[0], values[1]);
+        }
+    } else if (!strncmp(str, "translate(", 10)) {
+        SkScalar values[2];
+        str = ParseScalarPair(str + 10, values);
+        if (str) {
+            m.setTranslate(values[0], values[1]);
+        }
+    } else if (!strncmp(str, "rotate(", 7)) {
+        SkScalar value;
+        str = SkParse::FindScalar(str + 7, &value);
+        if (str) {
+            m.setRotate(value);
+        }
+    }
+
+    return m;
+}
+
+bool SetPaintAttribute(const sk_sp<SkSVGNode>& node, SkSVGAttribute attr,
+                       const char* stringValue) {
+    node->setAttribute(attr, SkSVGColorValue(ParseColor(stringValue)));
+    return true;
+}
+
+bool SetPathDataAttribute(const sk_sp<SkSVGNode>& node, SkSVGAttribute attr,
+                          const char* stringValue) {
+    SkPath path;
+    if (!SkParsePath::FromSVGString(stringValue, &path)) {
+        return false;
+    }
+
+    node->setAttribute(attr, SkSVGPathValue(path));
+    return true;
+}
+
+bool SetTransformAttribute(const sk_sp<SkSVGNode>& node, SkSVGAttribute attr,
+                           const char* stringValue) {
+    node->setAttribute(attr, SkSVGTransformValue(ParseTransform(stringValue)));
+    return true;
+}
+
+template<typename T>
+struct SortedDictionaryEntry {
+    const char* fKey;
+    const T     fValue;
+};
+
+struct AttrParseInfo {
+    SkSVGAttribute fAttr;
+    bool (*fSetter)(const sk_sp<SkSVGNode>& node, SkSVGAttribute attr, const char* stringValue);
+};
+
+SortedDictionaryEntry<AttrParseInfo> gAttributeParseInfo[] = {
+    { "d",         { SkSVGAttribute::d,         SetPathDataAttribute  }},
+    { "fill",      { SkSVGAttribute::fill,      SetPaintAttribute     }},
+    { "stroke",    { SkSVGAttribute::stroke,    SetPaintAttribute     }},
+    { "transform", { SkSVGAttribute::transform, SetTransformAttribute }},
+};
+
+SortedDictionaryEntry<sk_sp<SkSVGNode>(*)()> gTagFactories[] = {
+    { "g"   , []() -> sk_sp<SkSVGNode> { return SkSVGG::Make();    }},
+    { "path", []() -> sk_sp<SkSVGNode> { return SkSVGPath::Make(); }},
+    { "svg" , []() -> sk_sp<SkSVGNode> { return SkSVGSVG::Make();  }},
+};
+
+struct ConstructionContext {
+    ConstructionContext() : fParent(nullptr) { }
+    ConstructionContext(const ConstructionContext& other, const sk_sp<SkSVGNode>& newParent)
+        : fParent(newParent.get()) { }
+
+    const SkSVGNode* fParent;
+};
+
+void parse_node_attributes(const SkDOM& xmlDom, const SkDOM::Node* xmlNode,
+                           const sk_sp<SkSVGNode>& svgNode) {
+    const char* name, *value;
+    SkDOM::AttrIter attrIter(xmlDom, xmlNode);
+    while ((name = attrIter.next(&value))) {
+        const int attrIndex = SkStrSearch(&gAttributeParseInfo[0].fKey,
+                                          SkTo<int>(SK_ARRAY_COUNT(gAttributeParseInfo)),
+                                          name, sizeof(gAttributeParseInfo[0]));
+        if (attrIndex < 0) {
+            SkDebugf("unhandled attribute: %s\n", name);
+            continue;
+        }
+
+        SkASSERT(SkTo<size_t>(attrIndex) < SK_ARRAY_COUNT(gAttributeParseInfo));
+        const auto& attrInfo = gAttributeParseInfo[attrIndex].fValue;
+        if (!attrInfo.fSetter(svgNode, attrInfo.fAttr, value)) {
+            SkDebugf("could not parse attribute: '%s=\"%s\"'\n", name, value);
+        }
+    }
+}
+
+sk_sp<SkSVGNode> construct_svg_node(const SkDOM& dom, const ConstructionContext& ctx,
+                                    const SkDOM::Node* xmlNode) {
+    const char* elem = dom.getName(xmlNode);
+    const SkDOM::Type elemType = dom.getType(xmlNode);
+
+    if (elemType == SkDOM::kText_Type) {
+        SkASSERT(dom.countChildren(xmlNode) == 0);
+        // TODO: text handling
+        return nullptr;
+    }
+
+    SkASSERT(elemType == SkDOM::kElement_Type);
+
+    const int tagIndex = SkStrSearch(&gTagFactories[0].fKey,
+                                     SkTo<int>(SK_ARRAY_COUNT(gTagFactories)),
+                                     elem, sizeof(gTagFactories[0]));
+    if (tagIndex < 0) {
+        SkDebugf("unhandled element: <%s>\n", elem);
+        return nullptr;
+    }
+
+    SkASSERT(SkTo<size_t>(tagIndex) < SK_ARRAY_COUNT(gTagFactories));
+    sk_sp<SkSVGNode> node = gTagFactories[tagIndex].fValue();
+    parse_node_attributes(dom, xmlNode, node);
+
+    ConstructionContext localCtx(ctx, node);
+    for (auto* child = dom.getFirstChild(xmlNode, nullptr); child;
+         child = dom.getNextSibling(child)) {
+        sk_sp<SkSVGNode> childNode = construct_svg_node(dom, localCtx, child);
+        if (childNode) {
+            node->appendChild(std::move(childNode));
+        }
+    }
+
+    return node;
+}
+
+} // anonymous namespace
+
+SkSVGDOM::SkSVGDOM(const SkSize& containerSize)
+    : fContainerSize(containerSize) {
+}
+
+sk_sp<SkSVGDOM> SkSVGDOM::MakeFromDOM(const SkDOM& xmlDom, const SkSize& containerSize) {
+    sk_sp<SkSVGDOM> dom = sk_make_sp<SkSVGDOM>(containerSize);
+
+    ConstructionContext ctx;
+    dom->fRoot = construct_svg_node(xmlDom, ctx, xmlDom.getRootNode());
+
+    return dom;
+}
+
+sk_sp<SkSVGDOM> SkSVGDOM::MakeFromStream(SkStream& svgStream, const SkSize& containerSize) {
+    SkDOM xmlDom;
+    if (!xmlDom.build(svgStream)) {
+        return nullptr;
+    }
+
+    return MakeFromDOM(xmlDom, containerSize);
+}
+
+void SkSVGDOM::render(SkCanvas* canvas) const {
+    if (fRoot) {
+        fRoot->render(canvas);
+    }
+}
+
+void SkSVGDOM::setContainerSize(const SkSize& containerSize) {
+    // TODO: inval
+    fContainerSize = containerSize;
+}