skia2/modules/svg/include/SkSVGText.h
Florin Malita 2d059fcc22 [svg] Text rotate support
Implement support for text 'rotate' attribute:
https://www.w3.org/TR/SVG11/text.html#TSpanElementRotateAttribute.

Unlike other character-positioning attributes (x/y/dx/dy), rotate

  - is not cumulative
  - only applies to its respective node scope (does not affect other
    fragments in the current chunk)
  - has different padding semantics: if there are fewer rotate
    values than characters, the remaining characters use the last
    specified value from the closest ancestor

To the last point, we now have to discriminate three states:

  - unspecified (default -> 0)
  - explicit value for the given character index
  - implicit value (last value in the closest ancestor)

Local implicit values override implicit ancestor values -- but not
explicit ancestor values.

High level changes:

  - plumb 'rotate' attribute
  - expand per-character position info (ShapeBuffer) to include rotation
  - expand per-glyph position info (RunRec) to include rotation
  - expand PosAttrs to include rotation and add specific inheritance
    rules (see above)
  - pass computed rotation values to RSX blob buffers

Bug: skia:10840
Change-Id: Ia19ec5e8bb6fea06d49a9bd72ace575c2ffd100e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/348877
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Tyler Denniston <tdenniston@google.com>
2021-01-05 17:43:51 +00:00

102 lines
2.8 KiB
C++

/*
* Copyright 2019 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkSVGText_DEFINED
#define SkSVGText_DEFINED
#include <vector>
#include "modules/svg/include/SkSVGTransformableNode.h"
#include "modules/svg/include/SkSVGTypes.h"
class SkSVGTextContext;
// Base class for text-rendering nodes.
class SkSVGTextFragment : public SkSVGTransformableNode {
public:
void renderText(const SkSVGRenderContext&, SkSVGTextContext*, SkSVGXmlSpace) const;
protected:
explicit SkSVGTextFragment(SkSVGTag t) : INHERITED(t) {}
virtual void onRenderText(const SkSVGRenderContext&, SkSVGTextContext*,
SkSVGXmlSpace) const = 0;
private:
SkPath onAsPath(const SkSVGRenderContext&) const final;
using INHERITED = SkSVGTransformableNode;
};
// Base class for nestable text containers (<text>, <tspan>, etc).
class SkSVGTextContainer : public SkSVGTextFragment {
public:
SVG_ATTR(X, std::vector<SkSVGLength>, {})
SVG_ATTR(Y, std::vector<SkSVGLength>, {})
SVG_ATTR(Dx, std::vector<SkSVGLength>, {})
SVG_ATTR(Dy, std::vector<SkSVGLength>, {})
SVG_ATTR(Rotate, std::vector<SkSVGNumberType>, {})
SVG_ATTR(XmlSpace, SkSVGXmlSpace, SkSVGXmlSpace::kDefault)
void appendChild(sk_sp<SkSVGNode>) final;
protected:
explicit SkSVGTextContainer(SkSVGTag t) : INHERITED(t) {}
private:
void onRender(const SkSVGRenderContext&) const final;
void onRenderText(const SkSVGRenderContext&, SkSVGTextContext*, SkSVGXmlSpace) const final;
bool parseAndSetAttribute(const char*, const char*) override;
std::vector<sk_sp<SkSVGTextFragment>> fChildren;
using INHERITED = SkSVGTextFragment;
};
class SkSVGText final : public SkSVGTextContainer {
public:
static sk_sp<SkSVGText> Make() { return sk_sp<SkSVGText>(new SkSVGText()); }
private:
SkSVGText() : INHERITED(SkSVGTag::kText) {}
using INHERITED = SkSVGTextContainer;
};
class SkSVGTSpan final : public SkSVGTextContainer {
public:
static sk_sp<SkSVGTSpan> Make() { return sk_sp<SkSVGTSpan>(new SkSVGTSpan()); }
private:
SkSVGTSpan() : INHERITED(SkSVGTag::kTSpan) {}
using INHERITED = SkSVGTextContainer;
};
class SkSVGTextLiteral final : public SkSVGTextFragment {
public:
static sk_sp<SkSVGTextLiteral> Make() {
return sk_sp<SkSVGTextLiteral>(new SkSVGTextLiteral());
}
SVG_ATTR(Text, SkSVGStringType, SkSVGStringType())
private:
SkSVGTextLiteral() : INHERITED(SkSVGTag::kTextLiteral) {}
void onRender(const SkSVGRenderContext&) const override {}
void onRenderText(const SkSVGRenderContext&, SkSVGTextContext*, SkSVGXmlSpace) const override;
void appendChild(sk_sp<SkSVGNode>) override {}
using INHERITED = SkSVGTextFragment;
};
#endif // SkSVGText_DEFINED