skia2/modules/svg/include/SkSVGText.h
Florin Malita 735ac97eb4 [svg] Relative postioning support for text
Introduce support for relative position adjustments [1]:

  - plumb dx, dy attributes
  - extend ScopedPosResolver to also handle the new attributes
  - introduce ShapeBuffer to store both utf8 text and position
    adjustments for shaping (replaces prev 'filtered' array).
  - position adjustments are cumulative (relative adjustments affect
    all following characters)
  - utf8 encoding is variable length; for simplicity, ensure that the
    pos adjustment array and the utf8 array are always the same size by
    repeating the pos adjustment times number of utf8 bytes
  - introduce a temporary buffer for retrieving utf8 cluster information
    from SkShaper
  - post-shaping, use the utf8 cluster info to map back to character
    indices and apply the associated position adjutment

[1] https://www.w3.org/TR/SVG11/text.html#TSpanElementDXAttribute

Bug: skia:10840
Change-Id: Ia9f227f91723400711ff2b5d260976290da1e2e5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/346636
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Tyler Denniston <tdenniston@google.com>
2020-12-22 19:19:12 +00:00

101 lines
2.7 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(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