[sksg] Initial text support

Use the new node type for SkottieSlide2 labels.

TBR=

Change-Id: Icd6a4faf1c281bd83a2331c0072d1a6ed71acc09
Reviewed-on: https://skia-review.googlesource.com/102441
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

7 files changed, 157 insertions, 1 deletions

diff --git a/experimental/sksg/geometry/SkSGGeometryTransform.h b/experimental/sksg/geometry/SkSGGeometryTransform.h
index ea990c6f29..fe7e026031 100644
--- a/experimental/sksg/geometry/SkSGGeometryTransform.h
+++ b/experimental/sksg/geometry/SkSGGeometryTransform.h
@@ -50,7 +50,7 @@ private:
     const sk_sp<Matrix>       fMatrix;
     SkPath                    fTransformed;
 
-    typedef GeometryNode INHERITED;
+    using INHERITED = GeometryNode;
 };
 
 }
diff --git a/experimental/sksg/geometry/SkSGMerge.h b/experimental/sksg/geometry/SkSGMerge.h
index 69f824e011..54924d6475 100644
--- a/experimental/sksg/geometry/SkSGMerge.h
+++ b/experimental/sksg/geometry/SkSGMerge.h
@@ -55,6 +55,8 @@ private:
     std::vector<sk_sp<GeometryNode>> fGeos;
     SkPath                           fMerged;
     Mode                             fMode;
+
+    using INHERITED = GeometryNode;
 };
 
 } // namespace sksg
diff --git a/experimental/sksg/geometry/SkSGPath.h b/experimental/sksg/geometry/SkSGPath.h
index 6dd259394b..a398e2f0a4 100644
--- a/experimental/sksg/geometry/SkSGPath.h
+++ b/experimental/sksg/geometry/SkSGPath.h
@@ -38,6 +38,8 @@ private:
     explicit Path(const SkPath&);
 
     SkPath fPath;
+
+    using INHERITED = GeometryNode;
 };
 
 } // namespace sksg
diff --git a/experimental/sksg/geometry/SkSGRect.h b/experimental/sksg/geometry/SkSGRect.h
index a99c76ab98..f5fcb962c6 100644
--- a/experimental/sksg/geometry/SkSGRect.h
+++ b/experimental/sksg/geometry/SkSGRect.h
@@ -42,6 +42,8 @@ private:
     explicit Rect(const SkRect&);
 
     SkRect fRect;
+
+    using INHERITED = GeometryNode;
 };
 
 /**
@@ -65,6 +67,8 @@ private:
     explicit RRect(const SkRRect&);
 
     SkRRect fRRect;
+
+    using INHERITED = GeometryNode;
 };
 
 } // namespace sksg
diff --git a/experimental/sksg/geometry/SkSGText.cpp b/experimental/sksg/geometry/SkSGText.cpp
new file mode 100644
index 0000000000..c149390023
--- /dev/null
+++ b/experimental/sksg/geometry/SkSGText.cpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkSGText.h"
+
+#include "SkCanvas.h"
+#include "SkPaint.h"
+#include "SkPath.h"
+#include "SkTArray.h"
+#include "SkTextBlob.h"
+#include "SkTypeface.h"
+
+namespace sksg {
+
+sk_sp<Text> Text::Make(sk_sp<SkTypeface> tf, const SkString& text) {
+    return sk_sp<Text>(new Text(std::move(tf), text));
+}
+
+Text::Text(sk_sp<SkTypeface> tf, const SkString& text)
+    : fTypeface(std::move(tf))
+    , fText(text) {}
+
+Text::~Text() = default;
+
+SkRect Text::onRevalidate(InvalidationController*, const SkMatrix&) {
+    // TODO: we could potentially track invals which don't require rebuilding the blob.
+
+    SkPaint font;
+    font.setFlags(fFlags);
+    font.setTypeface(fTypeface);
+    font.setTextSize(fSize);
+    font.setTextScaleX(fScaleX);
+    font.setTextSkewX(fSkewX);
+    font.setTextAlign(fAlign);
+    font.setHinting(fHinting);
+
+    // First, convert to glyphIDs.
+    font.setTextEncoding(SkPaint::kUTF8_TextEncoding);
+    SkSTArray<256, SkGlyphID, true> glyphs;
+    glyphs.reset(font.textToGlyphs(fText.c_str(), fText.size(), nullptr));
+    SkAssertResult(font.textToGlyphs(fText.c_str(), fText.size(), glyphs.begin()) == glyphs.count());
+    font.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+
+    // Next, build the cached blob.
+    SkTextBlobBuilder builder;
+    const auto& buf = builder.allocRun(font, glyphs.count(), 0, 0, nullptr);
+    if (!buf.glyphs) {
+        fBlob.reset();
+        return SkRect::MakeEmpty();
+    }
+
+    memcpy(buf.glyphs, glyphs.begin(), glyphs.count() * sizeof(SkGlyphID));
+
+    fBlob = builder.make();
+    return fBlob
+        ? fBlob->bounds().makeOffset(fPosition.x(), fPosition.y())
+        : SkRect::MakeEmpty();
+}
+
+void Text::onDraw(SkCanvas* canvas, const SkPaint& paint) const {
+    canvas->drawTextBlob(fBlob, fPosition.x(), fPosition.y(), paint);
+}
+
+SkPath Text::onAsPath() const {
+    // TODO
+    return SkPath();
+}
+
+void Text::onClip(SkCanvas* canvas, bool antiAlias) const {
+    canvas->clipPath(this->asPath(), antiAlias);
+}
+
+} // namespace sksg
diff --git a/experimental/sksg/geometry/SkSGText.h b/experimental/sksg/geometry/SkSGText.h
new file mode 100644
index 0000000000..eb43337a10
--- /dev/null
+++ b/experimental/sksg/geometry/SkSGText.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSGText_DEFINED
+#define SkSGText_DEFINED
+
+#include "SkSGGeometryNode.h"
+
+#include "SkPaintDefaults.h"
+#include "SkPoint.h"
+#include "SkString.h"
+
+class SkCanvas;
+class SkPaint;
+class SkTextBlob;
+class SkTypeface;
+
+namespace sksg {
+
+/**
+ * Concrete Geometry node, wrapping a (shaped) SkTextBlob.
+ */
+class Text final : public GeometryNode {
+public:
+    static sk_sp<Text> Make(sk_sp<SkTypeface> tf, const SkString& text);
+    ~Text() override;
+
+    SG_ATTRIBUTE(Text    , SkString      , fText    )
+    SG_ATTRIBUTE(Flags   , uint32_t      , fFlags   )
+    SG_ATTRIBUTE(Position, SkPoint       , fPosition)
+    SG_ATTRIBUTE(Size    , SkScalar      , fSize    )
+    SG_ATTRIBUTE(ScaleX  , SkScalar      , fScaleX  )
+    SG_ATTRIBUTE(SkewX   , SkScalar      , fSkewX   )
+    SG_ATTRIBUTE(Align   , SkPaint::Align, fAlign   )
+
+    // TODO: add shaping functionality.
+
+protected:
+    void onClip(SkCanvas*, bool antiAlias) const override;
+    void onDraw(SkCanvas*, const SkPaint&) const override;
+
+    SkRect onRevalidate(InvalidationController*, const SkMatrix&) override;
+    SkPath onAsPath() const override;
+
+private:
+    explicit Text(sk_sp<SkTypeface>, const SkString&);
+
+    const sk_sp<SkTypeface> fTypeface;
+    SkString                fText;
+    uint32_t                fFlags    = SkPaintDefaults_Flags;
+    SkPoint                 fPosition = SkPoint::Make(0, 0);
+    SkScalar                fSize     = SkPaintDefaults_TextSize;
+    SkScalar                fScaleX   = 1;
+    SkScalar                fSkewX    = 0;
+    SkPaint::Align          fAlign    = SkPaint::kLeft_Align;
+    SkPaint::Hinting        fHinting  = SkPaintDefaults_Hinting;
+
+    sk_sp<SkTextBlob> fBlob; // cached text blob
+
+    using INHERITED = GeometryNode;
+};
+
+} // namespace sksg
+
+#endif // SkSGText_DEFINED
diff --git a/experimental/sksg/geometry/SkSGTrimEffect.h b/experimental/sksg/geometry/SkSGTrimEffect.h
index 860cfafc25..e86ede83e6 100644
--- a/experimental/sksg/geometry/SkSGTrimEffect.h
+++ b/experimental/sksg/geometry/SkSGTrimEffect.h
@@ -47,6 +47,8 @@ private:
     SkScalar                  fStart  = 0, // starting t
                               fEnd    = 1, // ending t
                               fOffset = 0; // t offset
+
+    using INHERITED = GeometryNode;
 };
 
 } // namespace sksg