Add link annotation support to SkSVGDevice.

This CL implements |SkSVGDevice::drawAnnotation|, overridden from
|SKBaseDevice|.  |drawAnnotation| supports annotating rectangular areas
of a Skia device.  Previous to this change, annotations are being used
in |SkPDFDevice| to include hyperlinked rectangular areas in .pdf
documents.  This CL implements the SVG equivalent of this PDF feature.

BUG=skia:7581

Docs-Preview: https://skia.org/?cl=104680
Change-Id: I92ae01ceb7ae10cd2010bebab2a58dcfe48ef253
Reviewed-on: https://skia-review.googlesource.com/104680
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>

2 files changed, 29 insertions, 1 deletions

diff --git a/src/svg/SkSVGDevice.cpp b/src/svg/SkSVGDevice.cpp
index 4a1f2b750a..6bb971d764 100644
--- a/src/svg/SkSVGDevice.cpp
+++ b/src/svg/SkSVGDevice.cpp
@@ -7,9 +7,11 @@
 
 #include "SkSVGDevice.h"
 
+#include "SkAnnotationKeys.h"
 #include "SkBase64.h"
 #include "SkBitmap.h"
 #include "SkChecksum.h"
+#include "SkClipOpPriv.h"
 #include "SkClipStack.h"
 #include "SkData.h"
 #include "SkDraw.h"
@@ -22,7 +24,6 @@
 #include "SkTypeface.h"
 #include "SkUtils.h"
 #include "SkXMLWriter.h"
-#include "SkClipOpPriv.h"
 
 namespace {
 
@@ -621,6 +622,32 @@ void SkSVGDevice::drawPaint(const SkPaint& paint) {
                                           SkIntToScalar(this->height())));
 }
 
+void SkSVGDevice::drawAnnotation(const SkRect& rect, const char key[], SkData* value) {
+    if (!value) {
+        return;
+    }
+
+    if (!strcmp(SkAnnotationKeys::URL_Key(), key) ||
+        !strcmp(SkAnnotationKeys::Link_Named_Dest_Key(), key)) {
+        this->cs().save();
+        this->cs().clipRect(rect, this->ctm(), kIntersect_SkClipOp, true);
+        SkRect transformedRect = this->cs().bounds(this->getGlobalBounds());
+        this->cs().restore();
+        if (transformedRect.isEmpty()) {
+            return;
+        }
+
+        SkString url(static_cast<const char*>(value->data()), value->size() - 1);
+        AutoElement a("a", fWriter);
+        a.addAttribute("xlink:href", url.c_str());
+        {
+            AutoElement r("rect", fWriter);
+            r.addAttribute("fill-opacity", "0.0");
+            r.addRectAttributes(transformedRect);
+        }
+    }
+}
+
 void SkSVGDevice::drawPoints(SkCanvas::PointMode mode, size_t count,
                              const SkPoint pts[], const SkPaint& paint) {
     SkPath path;
diff --git a/src/svg/SkSVGDevice.h b/src/svg/SkSVGDevice.h
index 0e22910412..222e55d83c 100644
--- a/src/svg/SkSVGDevice.h
+++ b/src/svg/SkSVGDevice.h
@@ -19,6 +19,7 @@ public:
 
 protected:
     void drawPaint(const SkPaint& paint) override;
+    void drawAnnotation(const SkRect& rect, const char key[], SkData* value) override;
     void drawPoints(SkCanvas::PointMode mode, size_t count,
                     const SkPoint[], const SkPaint& paint) override;
     void drawRect(const SkRect& r, const SkPaint& paint) override;