Add SkSVGCanvas

Add a public SVG canvas factory + move the SVG files from
experimental -> src/svg/.

Update current clients to the new API.

R=reed@google.com, mtklein@google.com, halcanary@google.com

Review URL: https://codereview.chromium.org/902583006

4 files changed, 811 insertions, 0 deletions

diff --git a/src/svg/SkSVGCanvas.cpp b/src/svg/SkSVGCanvas.cpp
new file mode 100644
index 0000000000..22a6e0bd9c
--- /dev/null
+++ b/src/svg/SkSVGCanvas.cpp
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkSVGCanvas.h"
+#include "SkSVGDevice.h"
+
+SkCanvas* SkSVGCanvas::Create(const SkRect& bounds, SkXMLWriter* writer) {
+    // TODO: pass full bounds to the device
+    SkISize size = bounds.roundOut().size();
+    SkAutoTUnref<SkBaseDevice> device(SkSVGDevice::Create(size, writer));
+
+    return SkNEW_ARGS(SkCanvas, (device));
+}
diff --git a/src/svg/SkSVGDevice.cpp b/src/svg/SkSVGDevice.cpp
new file mode 100644
index 0000000000..bf19a81a1d
--- /dev/null
+++ b/src/svg/SkSVGDevice.cpp
@@ -0,0 +1,651 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkSVGDevice.h"
+
+#include "SkBitmap.h"
+#include "SkDraw.h"
+#include "SkPaint.h"
+#include "SkParsePath.h"
+#include "SkPathOps.h"
+#include "SkShader.h"
+#include "SkStream.h"
+#include "SkTypeface.h"
+#include "SkUtils.h"
+#include "SkXMLWriter.h"
+
+namespace {
+
+static SkString svg_color(SkColor color) {
+    return SkStringPrintf("rgb(%u,%u,%u)",
+                          SkColorGetR(color),
+                          SkColorGetG(color),
+                          SkColorGetB(color));
+}
+
+static SkScalar svg_opacity(SkColor color) {
+    return SkIntToScalar(SkColorGetA(color)) / SK_AlphaOPAQUE;
+}
+
+// Keep in sync with SkPaint::Cap
+static const char* cap_map[]  = {
+    NULL,    // kButt_Cap (default)
+    "round", // kRound_Cap
+    "square" // kSquare_Cap
+};
+SK_COMPILE_ASSERT(SK_ARRAY_COUNT(cap_map) == SkPaint::kCapCount, missing_cap_map_entry);
+
+static const char* svg_cap(SkPaint::Cap cap) {
+    SkASSERT(cap < SK_ARRAY_COUNT(cap_map));
+    return cap_map[cap];
+}
+
+// Keep in sync with SkPaint::Join
+static const char* join_map[] = {
+    NULL,    // kMiter_Join (default)
+    "round", // kRound_Join
+    "bevel"  // kBevel_Join
+};
+SK_COMPILE_ASSERT(SK_ARRAY_COUNT(join_map) == SkPaint::kJoinCount, missing_join_map_entry);
+
+static const char* svg_join(SkPaint::Join join) {
+    SkASSERT(join < SK_ARRAY_COUNT(join_map));
+    return join_map[join];
+}
+
+// Keep in sync with SkPaint::Align
+static const char* text_align_map[] = {
+    NULL,     // kLeft_Align (default)
+    "middle", // kCenter_Align
+    "end"     // kRight_Align
+};
+SK_COMPILE_ASSERT(SK_ARRAY_COUNT(text_align_map) == SkPaint::kAlignCount,
+                  missing_text_align_map_entry);
+static const char* svg_text_align(SkPaint::Align align) {
+    SkASSERT(align < SK_ARRAY_COUNT(text_align_map));
+    return text_align_map[align];
+}
+
+static SkString svg_transform(const SkMatrix& t) {
+    SkASSERT(!t.isIdentity());
+
+    SkString tstr;
+    switch (t.getType()) {
+    case SkMatrix::kPerspective_Mask:
+        SkDebugf("Can't handle perspective matrices.");
+        break;
+    case SkMatrix::kTranslate_Mask:
+        tstr.printf("translate(%g %g)", t.getTranslateX(), t.getTranslateY());
+        break;
+    case SkMatrix::kScale_Mask:
+        tstr.printf("scale(%g %g)", t.getScaleX(), t.getScaleY());
+        break;
+    default:
+        // http://www.w3.org/TR/SVG/coords.html#TransformMatrixDefined
+        //    | a c e |
+        //    | b d f |
+        //    | 0 0 1 |
+        tstr.printf("matrix(%g %g %g %g %g %g)",
+                    t.getScaleX(),     t.getSkewY(),
+                    t.getSkewX(),      t.getScaleY(),
+                    t.getTranslateX(), t.getTranslateY());
+        break;
+    }
+
+    return tstr;
+}
+
+static void append_escaped_unichar(SkUnichar c, SkString* text) {
+    switch(c) {
+    case '&':
+        text->append("&amp;");
+        break;
+    case '"':
+        text->append("&quot;");
+        break;
+    case '\'':
+        text->append("&apos;");
+        break;
+    case '<':
+        text->append("&lt;");
+        break;
+    case '>':
+        text->append("&gt;");
+        break;
+    default:
+        text->appendUnichar(c);
+        break;
+    }
+}
+
+static SkString svg_text(const void* text, size_t byteLen, const SkPaint& paint) {
+    SkString svgText;
+    int count = paint.countText(text, byteLen);
+
+    switch(paint.getTextEncoding()) {
+    case SkPaint::kGlyphID_TextEncoding: {
+        SkASSERT(count * sizeof(uint16_t) == byteLen);
+        SkAutoSTArray<64, SkUnichar> unichars(count);
+        paint.glyphsToUnichars((const uint16_t*)text, count, unichars.get());
+        for (int i = 0; i < count; ++i) {
+            append_escaped_unichar(unichars[i], &svgText);
+        }
+    } break;
+    case SkPaint::kUTF8_TextEncoding: {
+        const char* c8 = reinterpret_cast<const char*>(text);
+        for (int i = 0; i < count; ++i) {
+            append_escaped_unichar(SkUTF8_NextUnichar(&c8), &svgText);
+        }
+        SkASSERT(reinterpret_cast<const char*>(text) + byteLen == c8);
+    } break;
+    case SkPaint::kUTF16_TextEncoding: {
+        const uint16_t* c16 = reinterpret_cast<const uint16_t*>(text);
+        for (int i = 0; i < count; ++i) {
+            append_escaped_unichar(SkUTF16_NextUnichar(&c16), &svgText);
+        }
+        SkASSERT(SkIsAlign2(byteLen));
+        SkASSERT(reinterpret_cast<const uint16_t*>(text) + (byteLen / 2) == c16);
+    } break;
+    case SkPaint::kUTF32_TextEncoding: {
+        SkASSERT(count * sizeof(uint32_t) == byteLen);
+        const uint32_t* c32 = reinterpret_cast<const uint32_t*>(text);
+        for (int i = 0; i < count; ++i) {
+            append_escaped_unichar(c32[i], &svgText);
+        }
+    } break;
+    default:
+        SkFAIL("unknown text encoding");
+    }
+
+    return svgText;
+}
+
+struct Resources {
+    Resources(const SkPaint& paint)
+        : fPaintServer(svg_color(paint.getColor())) {}
+
+    SkString fPaintServer;
+    SkString fClip;
+};
+
+}
+
+// For now all this does is serve unique serial IDs, but it will eventually evolve to track
+// and deduplicate resources.
+class SkSVGDevice::ResourceBucket : ::SkNoncopyable {
+public:
+    ResourceBucket() : fGradientCount(0), fClipCount(0), fPathCount(0) {}
+
+    SkString addLinearGradient() {
+        return SkStringPrintf("gradient_%d", fGradientCount++);
+    }
+
+    SkString addClip() {
+        return SkStringPrintf("clip_%d", fClipCount++);
+    }
+
+    SkString addPath() {
+        return SkStringPrintf("path_%d", fPathCount++);
+    }
+
+private:
+    uint32_t fGradientCount;
+    uint32_t fClipCount;
+    uint32_t fPathCount;
+};
+
+class SkSVGDevice::AutoElement : ::SkNoncopyable {
+public:
+    AutoElement(const char name[], SkXMLWriter* writer)
+        : fWriter(writer)
+        , fResourceBucket(NULL) {
+        fWriter->startElement(name);
+    }
+
+    AutoElement(const char name[], SkXMLWriter* writer, ResourceBucket* bucket,
+                const SkDraw& draw, const SkPaint& paint)
+        : fWriter(writer)
+        , fResourceBucket(bucket) {
+
+        Resources res = this->addResources(draw, paint);
+
+        fWriter->startElement(name);
+
+        this->addPaint(paint, res);
+
+        if (!draw.fMatrix->isIdentity()) {
+            this->addAttribute("transform", svg_transform(*draw.fMatrix));
+        }
+    }
+
+    ~AutoElement() {
+        fWriter->endElement();
+    }
+
+    void addAttribute(const char name[], const char val[]) {
+        fWriter->addAttribute(name, val);
+    }
+
+    void addAttribute(const char name[], const SkString& val) {
+        fWriter->addAttribute(name, val.c_str());
+    }
+
+    void addAttribute(const char name[], int32_t val) {
+        fWriter->addS32Attribute(name, val);
+    }
+
+    void addAttribute(const char name[], SkScalar val) {
+        fWriter->addScalarAttribute(name, val);
+    }
+
+    void addText(const SkString& text) {
+        fWriter->addText(text.c_str(), text.size());
+    }
+
+    void addRectAttributes(const SkRect&);
+    void addPathAttributes(const SkPath&);
+    void addTextAttributes(const SkPaint&);
+
+private:
+    Resources addResources(const SkDraw& draw, const SkPaint& paint);
+    void addClipResources(const SkDraw& draw, Resources* resources);
+    void addShaderResources(const SkPaint& paint, Resources* resources);
+
+    void addPaint(const SkPaint& paint, const Resources& resources);
+
+    SkString addLinearGradientDef(const SkShader::GradientInfo& info, const SkShader* shader);
+
+    SkXMLWriter*    fWriter;
+    ResourceBucket* fResourceBucket;
+};
+
+void SkSVGDevice::AutoElement::addPaint(const SkPaint& paint, const Resources& resources) {
+    SkPaint::Style style = paint.getStyle();
+    if (style == SkPaint::kFill_Style || style == SkPaint::kStrokeAndFill_Style) {
+        this->addAttribute("fill", resources.fPaintServer);
+
+        if (SK_AlphaOPAQUE != SkColorGetA(paint.getColor())) {
+            this->addAttribute("fill-opacity", svg_opacity(paint.getColor()));
+        }
+    } else {
+        SkASSERT(style == SkPaint::kStroke_Style);
+        this->addAttribute("fill", "none");
+    }
+
+    if (style == SkPaint::kStroke_Style || style == SkPaint::kStrokeAndFill_Style) {
+        this->addAttribute("stroke", resources.fPaintServer);
+
+        SkScalar strokeWidth = paint.getStrokeWidth();
+        if (strokeWidth == 0) {
+            // Hairline stroke
+            strokeWidth = 1;
+            this->addAttribute("vector-effect", "non-scaling-stroke");
+        }
+        this->addAttribute("stroke-width", strokeWidth);
+
+        if (const char* cap = svg_cap(paint.getStrokeCap())) {
+            this->addAttribute("stroke-linecap", cap);
+        }
+
+        if (const char* join = svg_join(paint.getStrokeJoin())) {
+            this->addAttribute("stroke-linejoin", join);
+        }
+
+        if (paint.getStrokeJoin() == SkPaint::kMiter_Join) {
+            this->addAttribute("stroke-miterlimit", paint.getStrokeMiter());
+        }
+
+        if (SK_AlphaOPAQUE != SkColorGetA(paint.getColor())) {
+            this->addAttribute("stroke-opacity", svg_opacity(paint.getColor()));
+        }
+    } else {
+        SkASSERT(style == SkPaint::kFill_Style);
+        this->addAttribute("stroke", "none");
+    }
+
+    if (!resources.fClip.isEmpty()) {
+        this->addAttribute("clip-path", resources.fClip);
+    }
+}
+
+Resources SkSVGDevice::AutoElement::addResources(const SkDraw& draw, const SkPaint& paint) {
+    Resources resources(paint);
+
+    // FIXME: this is a weak heuristic and we end up with LOTS of redundant clips.
+    bool hasClip   = !draw.fClipStack->isWideOpen();
+    bool hasShader = SkToBool(paint.getShader());
+
+    if (hasClip || hasShader) {
+        AutoElement defs("defs", fWriter);
+
+        if (hasClip) {
+            this->addClipResources(draw, &resources);
+        }
+
+        if (hasShader) {
+            this->addShaderResources(paint, &resources);
+        }
+    }
+
+    return resources;
+}
+
+void SkSVGDevice::AutoElement::addShaderResources(const SkPaint& paint, Resources* resources) {
+    const SkShader* shader = paint.getShader();
+    SkASSERT(SkToBool(shader));
+
+    SkShader::GradientInfo grInfo;
+    grInfo.fColorCount = 0;
+    if (SkShader::kLinear_GradientType != shader->asAGradient(&grInfo)) {
+        // TODO: non-linear gradient support
+        SkDebugf("unsupported shader type\n");
+        return;
+    }
+
+    SkAutoSTArray<16, SkColor>  grColors(grInfo.fColorCount);
+    SkAutoSTArray<16, SkScalar> grOffsets(grInfo.fColorCount);
+    grInfo.fColors = grColors.get();
+    grInfo.fColorOffsets = grOffsets.get();
+
+    // One more call to get the actual colors/offsets.
+    shader->asAGradient(&grInfo);
+    SkASSERT(grInfo.fColorCount <= grColors.count());
+    SkASSERT(grInfo.fColorCount <= grOffsets.count());
+
+    resources->fPaintServer.printf("url(#%s)", addLinearGradientDef(grInfo, shader).c_str());
+}
+
+void SkSVGDevice::AutoElement::addClipResources(const SkDraw& draw, Resources* resources) {
+    SkASSERT(!draw.fClipStack->isWideOpen());
+
+    SkPath clipPath;
+    (void) draw.fClipStack->asPath(&clipPath);
+
+    SkString clipID = fResourceBucket->addClip();
+    const char* clipRule = clipPath.getFillType() == SkPath::kEvenOdd_FillType ?
+                           "evenodd" : "nonzero";
+    {
+        // clipPath is in device space, but since we're only pushing transform attributes
+        // to the leaf nodes, so are all our elements => SVG userSpaceOnUse == device space.
+        AutoElement clipPathElement("clipPath", fWriter);
+        clipPathElement.addAttribute("id", clipID);
+
+        SkRect clipRect = SkRect::MakeEmpty();
+        if (clipPath.isEmpty() || clipPath.isRect(&clipRect)) {
+            AutoElement rectElement("rect", fWriter);
+            rectElement.addRectAttributes(clipRect);
+            rectElement.addAttribute("clip-rule", clipRule);
+        } else {
+            AutoElement pathElement("path", fWriter);
+            pathElement.addPathAttributes(clipPath);
+            pathElement.addAttribute("clip-rule", clipRule);
+        }
+    }
+
+    resources->fClip.printf("url(#%s)", clipID.c_str());
+}
+
+SkString SkSVGDevice::AutoElement::addLinearGradientDef(const SkShader::GradientInfo& info,
+                                                        const SkShader* shader) {
+    SkASSERT(fResourceBucket);
+    SkString id = fResourceBucket->addLinearGradient();
+
+    {
+        AutoElement gradient("linearGradient", fWriter);
+
+        gradient.addAttribute("id", id);
+        gradient.addAttribute("gradientUnits", "userSpaceOnUse");
+        gradient.addAttribute("x1", info.fPoint[0].x());
+        gradient.addAttribute("y1", info.fPoint[0].y());
+        gradient.addAttribute("x2", info.fPoint[1].x());
+        gradient.addAttribute("y2", info.fPoint[1].y());
+
+        if (!shader->getLocalMatrix().isIdentity()) {
+            this->addAttribute("gradientTransform", svg_transform(shader->getLocalMatrix()));
+        }
+
+        SkASSERT(info.fColorCount >= 2);
+        for (int i = 0; i < info.fColorCount; ++i) {
+            SkColor color = info.fColors[i];
+            SkString colorStr(svg_color(color));
+
+            {
+                AutoElement stop("stop", fWriter);
+                stop.addAttribute("offset", info.fColorOffsets[i]);
+                stop.addAttribute("stop-color", colorStr.c_str());
+
+                if (SK_AlphaOPAQUE != SkColorGetA(color)) {
+                    stop.addAttribute("stop-opacity", svg_opacity(color));
+                }
+            }
+        }
+    }
+
+    return id;
+}
+
+void SkSVGDevice::AutoElement::addRectAttributes(const SkRect& rect) {
+    // x, y default to 0
+    if (rect.x() != 0) {
+        this->addAttribute("x", rect.x());
+    }
+    if (rect.y() != 0) {
+        this->addAttribute("y", rect.y());
+    }
+
+    this->addAttribute("width", rect.width());
+    this->addAttribute("height", rect.height());
+}
+
+void SkSVGDevice::AutoElement::addPathAttributes(const SkPath& path) {
+    SkString pathData;
+    SkParsePath::ToSVGString(path, &pathData);
+    this->addAttribute("d", pathData);
+}
+
+void SkSVGDevice::AutoElement::addTextAttributes(const SkPaint& paint) {
+    this->addAttribute("font-size", paint.getTextSize());
+
+    SkTypeface::Style style = paint.getTypeface()->style();
+    if (style & SkTypeface::kItalic) {
+        this->addAttribute("font-style", "italic");
+    }
+    if (style & SkTypeface::kBold) {
+        this->addAttribute("font-weight", "bold");
+    }
+
+    SkAutoTUnref<const SkTypeface> tface(paint.getTypeface() ?
+        SkRef(paint.getTypeface()) : SkTypeface::RefDefault(style));
+    SkString familyName;
+    tface->getFamilyName(&familyName);
+    if (!familyName.isEmpty()) {
+        this->addAttribute("font-family", familyName);
+    }
+
+    if (const char* textAlign = svg_text_align(paint.getTextAlign())) {
+        this->addAttribute("text-anchor", textAlign);
+    }
+}
+
+SkBaseDevice* SkSVGDevice::Create(const SkISize& size, SkXMLWriter* writer) {
+    if (!writer) {
+        return NULL;
+    }
+
+    return SkNEW_ARGS(SkSVGDevice, (size, writer));
+}
+
+SkSVGDevice::SkSVGDevice(const SkISize& size, SkXMLWriter* writer)
+    : fWriter(writer)
+    , fResourceBucket(SkNEW(ResourceBucket)) {
+    SkASSERT(writer);
+
+    fLegacyBitmap.setInfo(SkImageInfo::MakeUnknown(size.width(), size.height()));
+
+    fWriter->writeHeader();
+
+    // The root <svg> tag gets closed by the destructor.
+    fRootElement.reset(SkNEW_ARGS(AutoElement, ("svg", fWriter)));
+
+    fRootElement->addAttribute("xmlns", "http://www.w3.org/2000/svg");
+    fRootElement->addAttribute("xmlns:xlink", "http://www.w3.org/1999/xlink");
+    fRootElement->addAttribute("width", size.width());
+    fRootElement->addAttribute("height", size.height());
+}
+
+SkSVGDevice::~SkSVGDevice() {
+}
+
+SkImageInfo SkSVGDevice::imageInfo() const {
+    return fLegacyBitmap.info();
+}
+
+const SkBitmap& SkSVGDevice::onAccessBitmap() {
+    return fLegacyBitmap;
+}
+
+void SkSVGDevice::drawPaint(const SkDraw& draw, const SkPaint& paint) {
+    AutoElement rect("rect", fWriter, fResourceBucket, draw, paint);
+    rect.addRectAttributes(SkRect::MakeWH(SkIntToScalar(this->width()),
+                                          SkIntToScalar(this->height())));
+}
+
+void SkSVGDevice::drawPoints(const SkDraw&, SkCanvas::PointMode mode, size_t count,
+                             const SkPoint[], const SkPaint& paint) {
+    // todo
+    SkDebugf("unsupported operation: drawPoints()\n");
+}
+
+void SkSVGDevice::drawRect(const SkDraw& draw, const SkRect& r, const SkPaint& paint) {
+    AutoElement rect("rect", fWriter, fResourceBucket, draw, paint);
+    rect.addRectAttributes(r);
+}
+
+void SkSVGDevice::drawOval(const SkDraw& draw, const SkRect& oval, const SkPaint& paint) {
+    AutoElement ellipse("ellipse", fWriter, fResourceBucket, draw, paint);
+    ellipse.addAttribute("cx", oval.centerX());
+    ellipse.addAttribute("cy", oval.centerY());
+    ellipse.addAttribute("rx", oval.width() / 2);
+    ellipse.addAttribute("ry", oval.height() / 2);
+}
+
+void SkSVGDevice::drawRRect(const SkDraw&, const SkRRect& rr, const SkPaint& paint) {
+    // todo
+    SkDebugf("unsupported operation: drawRRect()\n");
+}
+
+void SkSVGDevice::drawPath(const SkDraw& draw, const SkPath& path, const SkPaint& paint,
+                           const SkMatrix* prePathMatrix, bool pathIsMutable) {
+    AutoElement elem("path", fWriter, fResourceBucket, draw, paint);
+    elem.addPathAttributes(path);
+}
+
+void SkSVGDevice::drawBitmap(const SkDraw&, const SkBitmap& bitmap,
+                             const SkMatrix& matrix, const SkPaint& paint) {
+    // todo
+    SkDebugf("unsupported operation: drawBitmap()\n");
+}
+
+void SkSVGDevice::drawSprite(const SkDraw&, const SkBitmap& bitmap,
+                             int x, int y, const SkPaint& paint) {
+    // todo
+    SkDebugf("unsupported operation: drawSprite()\n");
+}
+
+void SkSVGDevice::drawBitmapRect(const SkDraw&, const SkBitmap&, const SkRect* srcOrNull,
+                                 const SkRect& dst, const SkPaint& paint,
+                                 SkCanvas::DrawBitmapRectFlags flags) {
+    // todo
+    SkDebugf("unsupported operation: drawBitmapRect()\n");
+}
+
+void SkSVGDevice::drawText(const SkDraw& draw, const void* text, size_t len,
+                           SkScalar x, SkScalar y, const SkPaint& paint) {
+    AutoElement elem("text", fWriter, fResourceBucket, draw, paint);
+    elem.addTextAttributes(paint);
+    elem.addAttribute("x", x);
+    elem.addAttribute("y", y);
+    elem.addText(svg_text(text, len, paint));
+}
+
+void SkSVGDevice::drawPosText(const SkDraw& draw, const void* text, size_t len,
+                              const SkScalar pos[], int scalarsPerPos, const SkPoint& offset,
+                              const SkPaint& paint) {
+    SkASSERT(scalarsPerPos == 1 || scalarsPerPos == 2);
+
+    AutoElement elem("text", fWriter, fResourceBucket, draw, paint);
+    elem.addTextAttributes(paint);
+
+    SkString xStr;
+    SkString yStr;
+    for (int i = 0; i < paint.countText(text, len); ++i) {
+        xStr.appendf("%.8g, ", offset.x() + pos[i * scalarsPerPos]);
+
+        if (scalarsPerPos == 2) {
+            yStr.appendf("%.8g, ", offset.y() + pos[i * scalarsPerPos + 1]);
+        }
+    }
+
+    if (scalarsPerPos != 2) {
+        yStr.appendScalar(offset.y());
+    }
+
+    elem.addAttribute("x", xStr);
+    elem.addAttribute("y", yStr);
+    elem.addText(svg_text(text, len, paint));
+}
+
+void SkSVGDevice::drawTextOnPath(const SkDraw&, const void* text, size_t len, const SkPath& path,
+                                 const SkMatrix* matrix, const SkPaint& paint) {
+    SkString pathID = fResourceBucket->addPath();
+
+    {
+        AutoElement defs("defs", fWriter);
+        AutoElement pathElement("path", fWriter);
+        pathElement.addAttribute("id", pathID);
+        pathElement.addPathAttributes(path);
+
+    }
+
+    {
+        AutoElement textElement("text", fWriter);
+        textElement.addTextAttributes(paint);
+
+        if (matrix && !matrix->isIdentity()) {
+            textElement.addAttribute("transform", svg_transform(*matrix));
+        }
+
+        {
+            AutoElement textPathElement("textPath", fWriter);
+            textPathElement.addAttribute("xlink:href", SkStringPrintf("#%s", pathID.c_str()));
+
+            if (paint.getTextAlign() != SkPaint::kLeft_Align) {
+                SkASSERT(paint.getTextAlign() == SkPaint::kCenter_Align ||
+                         paint.getTextAlign() == SkPaint::kRight_Align);
+                textPathElement.addAttribute("startOffset",
+                    paint.getTextAlign() == SkPaint::kCenter_Align ? "50%" : "100%");
+            }
+
+            textPathElement.addText(svg_text(text, len, paint));
+        }
+    }
+}
+
+void SkSVGDevice::drawVertices(const SkDraw&, SkCanvas::VertexMode, int vertexCount,
+                               const SkPoint verts[], const SkPoint texs[],
+                               const SkColor colors[], SkXfermode* xmode,
+                               const uint16_t indices[], int indexCount,
+                               const SkPaint& paint) {
+    // todo
+    SkDebugf("unsupported operation: drawVertices()\n");
+}
+
+void SkSVGDevice::drawDevice(const SkDraw&, SkBaseDevice*, int x, int y,
+                             const SkPaint&) {
+    // todo
+    SkDebugf("unsupported operation: drawDevice()\n");
+}
diff --git a/src/svg/SkSVGDevice.h b/src/svg/SkSVGDevice.h
new file mode 100644
index 0000000000..fdfc8c3e03
--- /dev/null
+++ b/src/svg/SkSVGDevice.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSVGDevice_DEFINED
+#define SkSVGDevice_DEFINED
+
+#include "SkDevice.h"
+
+class SkXMLWriter;
+
+class SkSVGDevice : public SkBaseDevice {
+public:
+    static SkBaseDevice* Create(const SkISize& size, SkXMLWriter* writer);
+
+    virtual SkImageInfo imageInfo() const SK_OVERRIDE;
+
+protected:
+    virtual void drawPaint(const SkDraw&, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPoints(const SkDraw&, SkCanvas::PointMode mode, size_t count,
+                            const SkPoint[], const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawRect(const SkDraw&, const SkRect& r, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawOval(const SkDraw&, const SkRect& oval, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawRRect(const SkDraw&, const SkRRect& rr, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPath(const SkDraw&, const SkPath& path,
+                          const SkPaint& paint,
+                          const SkMatrix* prePathMatrix = NULL,
+                          bool pathIsMutable = false) SK_OVERRIDE;
+
+    virtual void drawBitmap(const SkDraw&, const SkBitmap& bitmap,
+                            const SkMatrix& matrix, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawSprite(const SkDraw&, const SkBitmap& bitmap,
+                            int x, int y, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawBitmapRect(const SkDraw&, const SkBitmap&,
+                                const SkRect* srcOrNull, const SkRect& dst,
+                                const SkPaint& paint,
+                                SkCanvas::DrawBitmapRectFlags flags) SK_OVERRIDE;
+
+    virtual void drawText(const SkDraw&, const void* text, size_t len,
+                          SkScalar x, SkScalar y, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawPosText(const SkDraw&, const void* text, size_t len,
+                             const SkScalar pos[], int scalarsPerPos,
+                             const SkPoint& offset, const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawTextOnPath(const SkDraw&, const void* text, size_t len,
+                                const SkPath& path, const SkMatrix* matrix,
+                                const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawVertices(const SkDraw&, SkCanvas::VertexMode, int vertexCount,
+                              const SkPoint verts[], const SkPoint texs[],
+                              const SkColor colors[], SkXfermode* xmode,
+                              const uint16_t indices[], int indexCount,
+                              const SkPaint& paint) SK_OVERRIDE;
+
+    virtual void drawDevice(const SkDraw&, SkBaseDevice*, int x, int y,
+                            const SkPaint&) SK_OVERRIDE;
+    virtual const SkBitmap& onAccessBitmap() SK_OVERRIDE;
+
+private:
+    SkSVGDevice(const SkISize& size, SkXMLWriter* writer);
+    virtual ~SkSVGDevice();
+
+    class AutoElement;
+    class ResourceBucket;
+
+    SkXMLWriter*                  fWriter;
+    SkAutoTDelete<AutoElement>    fRootElement;
+    SkAutoTDelete<ResourceBucket> fResourceBucket;
+    SkBitmap                      fLegacyBitmap;
+};
+
+#endif // SkSVGDevice_DEFINED
diff --git a/src/svg/skp2svg.cpp b/src/svg/skp2svg.cpp
new file mode 100644
index 0000000000..ae6e54c885
--- /dev/null
+++ b/src/svg/skp2svg.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "LazyDecodeBitmap.h"
+#include "SkCommandLineFlags.h"
+#include "SkPicture.h"
+#include "SkStream.h"
+#include "SkSVGCanvas.h"
+#include "SkXMLWriter.h"
+
+DEFINE_string2(input, i, "", "input skp file");
+DEFINE_string2(output, o, "", "output svg file (optional)");
+
+// return codes:
+static const int kSuccess     = 0;
+static const int kInvalidArgs = 1;
+static const int kIOError     = 2;
+static const int kNotAnSKP    = 3;
+
+int tool_main(int argc, char** argv);
+int tool_main(int argc, char** argv) {
+    SkCommandLineFlags::SetUsage("Converts an SKP file to SVG.");
+    SkCommandLineFlags::Parse(argc, argv);
+
+    if (FLAGS_input.count() != 1) {
+        SkDebugf("Missing input file\n");
+        return kInvalidArgs;
+    }
+
+    SkFILEStream stream(FLAGS_input[0]);
+    if (!stream.isValid()) {
+        SkDebugf("Couldn't open file: %s\n", FLAGS_input[0]);
+        return kIOError;
+    }
+
+    SkAutoTUnref<SkPicture> pic(SkPicture::CreateFromStream(&stream, &sk_tools::LazyDecodeBitmap));
+    if (!SkToBool(pic.get())) {
+        SkDebugf("Could not load SKP: %s\n", FLAGS_input[0]);
+        return kNotAnSKP;
+    }
+
+    SkAutoTDelete<SkWStream> outStream;
+    if (FLAGS_output.count() > 0) {
+        SkFILEWStream* fileStream = SkNEW_ARGS(SkFILEWStream, (FLAGS_output[0]));
+        if (!fileStream->isValid()) {
+            SkDebugf("Couldn't open output file for writing: %s\n", FLAGS_output[0]);
+            return kIOError;
+        }
+        outStream.reset(fileStream);
+    } else {
+        outStream.reset(SkNEW(SkDebugWStream));
+    }
+
+    SkAutoTDelete<SkXMLWriter> xmlWriter(SkNEW_ARGS(SkXMLStreamWriter, (outStream.get())));
+    SkAutoTUnref<SkCanvas> svgCanvas(SkSVGCanvas::Create(pic->cullRect(), xmlWriter.get()));
+
+    pic->playback(svgCanvas);
+
+    return kSuccess;
+}
+
+#if !defined SK_BUILD_FOR_IOS
+int main(int argc, char * const argv[]) {
+    return tool_main(argc, (char**) argv);
+}
+#endif