Initial SVG backend stubbing

This adds SkSVGDevice and a small utility for converting SKP files to SVG (skp2svg).

R=reed@google.com,jcgregorio@google.com
BUG=skia:3368

Review URL: https://codereview.chromium.org/892533002

3 files changed, 329 insertions, 0 deletions

diff --git a/experimental/svg/SkSVGDevice.cpp b/experimental/svg/SkSVGDevice.cpp
new file mode 100644
index 0000000000..4a662e7b94
--- /dev/null
+++ b/experimental/svg/SkSVGDevice.cpp
@@ -0,0 +1,187 @@
+/*
+ * 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 "SkStream.h"
+#include "SkXMLWriter.h"
+
+namespace {
+
+class AutoElement {
+public:
+    AutoElement(const char name[], SkXMLWriter* writer)
+        : fWriter(writer) {
+        fWriter->startElement(name);
+    }
+
+    ~AutoElement() {
+        fWriter->endElement();
+    }
+
+private:
+    SkXMLWriter* fWriter;
+};
+
+}
+
+SkBaseDevice* SkSVGDevice::Create(const SkISize& size, SkWStream* wstream) {
+    if (!SkToBool(wstream)) {
+        return NULL;
+    }
+
+    return SkNEW_ARGS(SkSVGDevice, (size, wstream));
+}
+
+SkSVGDevice::SkSVGDevice(const SkISize& size, SkWStream* wstream)
+    : fWriter(SkNEW_ARGS(SkXMLStreamWriter, (wstream))) {
+
+    fLegacyBitmap.setInfo(SkImageInfo::MakeUnknown(size.width(), size.height()));
+
+    fWriter->writeHeader();
+    fWriter->startElement("svg");
+    fWriter->addAttribute("xmlns", "http://www.w3.org/2000/svg");
+    fWriter->addAttribute("xmlns:xlink", "http://www.w3.org/1999/xlink");
+    fWriter->addS32Attribute("width", size.width());
+    fWriter->addS32Attribute("height", size.height());
+}
+
+SkSVGDevice::~SkSVGDevice() {
+    fWriter->endElement();
+    fWriter->flush();
+    SkDELETE(fWriter);
+}
+
+SkImageInfo SkSVGDevice::imageInfo() const {
+    return fLegacyBitmap.info();
+}
+
+const SkBitmap& SkSVGDevice::onAccessBitmap() {
+    return fLegacyBitmap;
+}
+
+void SkSVGDevice::addPaint(const SkPaint& paint) {
+    SkColor color = paint.getColor();
+    SkString colorStr;
+    colorStr.appendf("rgb(%u,%u,%u)", SkColorGetR(color), SkColorGetG(color), SkColorGetB(color));
+
+    SkPaint::Style style = paint.getStyle();
+    if (style == SkPaint::kFill_Style || style == SkPaint::kStrokeAndFill_Style) {
+        fWriter->addAttribute("fill", colorStr.c_str());
+    } else {
+        fWriter->addAttribute("fill", "none");
+    }
+
+    if (style == SkPaint::kStroke_Style || style == SkPaint::kStrokeAndFill_Style) {
+        fWriter->addAttribute("stroke", colorStr.c_str());
+        fWriter->addScalarAttribute("stroke-width", paint.getStrokeWidth());
+    } else {
+        fWriter->addAttribute("stroke", "none");
+    }
+}
+
+void SkSVGDevice::addTransform(const SkMatrix &t) {
+    if (t.isIdentity()) {
+        return;
+    }
+
+    SkString tstr;
+    tstr.appendf("matrix(%g %g %g %g %g %g)",
+                 SkScalarToFloat(t.getScaleX()), SkScalarToFloat(t.getSkewY()),
+                 SkScalarToFloat(t.getSkewX()), SkScalarToFloat(t.getScaleY()),
+                 SkScalarToFloat(t.getTranslateX()), SkScalarToFloat(t.getTranslateY()));
+    fWriter->addAttribute("transform", tstr.c_str());
+}
+
+void SkSVGDevice::drawPaint(const SkDraw&, const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawPoints(const SkDraw&, SkCanvas::PointMode mode, size_t count,
+                             const SkPoint[], const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawRect(const SkDraw& draw, const SkRect& r, const SkPaint& paint) {
+    AutoElement elem("rect", fWriter);
+
+    fWriter->addScalarAttribute("x", r.fLeft);
+    fWriter->addScalarAttribute("y", r.fTop);
+    fWriter->addScalarAttribute("width", r.width());
+    fWriter->addScalarAttribute("height", r.height());
+
+    this->addPaint(paint);
+    this->addTransform(*draw.fMatrix);
+}
+
+void SkSVGDevice::drawOval(const SkDraw&, const SkRect& oval, const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawRRect(const SkDraw&, const SkRRect& rr, const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawPath(const SkDraw& draw, const SkPath& path, const SkPaint& paint,
+                           const SkMatrix* prePathMatrix, bool pathIsMutable) {
+    AutoElement elem("path", fWriter);
+
+    SkString pathStr;
+    SkParsePath::ToSVGString(path, &pathStr);
+    fWriter->addAttribute("d", pathStr.c_str());
+
+    this->addPaint(paint);
+    this->addTransform(*draw.fMatrix);
+}
+
+void SkSVGDevice::drawBitmap(const SkDraw&, const SkBitmap& bitmap,
+                             const SkMatrix& matrix, const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawSprite(const SkDraw&, const SkBitmap& bitmap,
+                             int x, int y, const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawBitmapRect(const SkDraw&, const SkBitmap&, const SkRect* srcOrNull,
+                                 const SkRect& dst, const SkPaint& paint,
+                                 SkCanvas::DrawBitmapRectFlags flags) {
+    // todo
+}
+
+void SkSVGDevice::drawText(const SkDraw&, const void* text, size_t len,
+                           SkScalar x, SkScalar y, const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawPosText(const SkDraw&, const void* text, size_t len,const SkScalar pos[],
+                              int scalarsPerPos, const SkPoint& offset, const SkPaint& paint) {
+    // todo
+}
+
+void SkSVGDevice::drawTextOnPath(const SkDraw&, const void* text, size_t len, const SkPath& path,
+                                 const SkMatrix* matrix, const SkPaint& paint) {
+    // todo
+}
+
+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
+}
+
+void SkSVGDevice::drawDevice(const SkDraw&, SkBaseDevice*, int x, int y,
+                             const SkPaint&) {
+    // todo
+}
diff --git a/experimental/svg/SkSVGDevice.h b/experimental/svg/SkSVGDevice.h
new file mode 100644
index 0000000000..d6c48e2c0f
--- /dev/null
+++ b/experimental/svg/SkSVGDevice.h
@@ -0,0 +1,72 @@
+/*
+ * 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 SkWStream;
+class SkXMLWriter;
+
+class SkSVGDevice : public SkBaseDevice {
+public:
+    static SkBaseDevice* Create(const SkISize& size, SkWStream* wstream);
+
+    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, SkWStream* wstream);
+    virtual ~SkSVGDevice();
+
+    void addPaint(const SkPaint& paint);
+    void addTransform(const SkMatrix& t);
+
+    SkXMLWriter*  fWriter;
+    SkBitmap      fLegacyBitmap;
+};
+
+#endif // SkSVGDevice_DEFINED
diff --git a/experimental/svg/skp2svg.cpp b/experimental/svg/skp2svg.cpp
new file mode 100644
index 0000000000..95bb04a061
--- /dev/null
+++ b/experimental/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 "SkSVGDevice.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));
+    }
+
+    SkISize size = pic->cullRect().roundOut().size();
+    SkAutoTUnref<SkBaseDevice> svgDevice(SkSVGDevice::Create(size, outStream));
+    SkCanvas svgCanvas(svgDevice.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