skia2/modules/canvaskit/paragraph_bindings.cpp

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/*
* Copyright 2019 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/core/SkColor.h"
#include "include/core/SkFontStyle.h"
#include "include/core/SkString.h"
#include "modules/skparagraph/include/DartTypes.h"
#include "modules/skparagraph/include/Paragraph.h"
#include "modules/skparagraph/include/ParagraphBuilder.h"
#include "modules/skparagraph/include/TextStyle.h"
#include "modules/skparagraph/src/ParagraphBuilderImpl.h"
#include "modules/skparagraph/src/ParagraphImpl.h"
#include <string>
#include <vector>
#include <emscripten.h>
#include <emscripten/bind.h>
#include "modules/canvaskit/WasmCommon.h"
using namespace emscripten;
namespace para = skia::textlayout;
struct SimpleFontStyle {
SkFontStyle::Slant slant;
SkFontStyle::Weight weight;
SkFontStyle::Width width;
};
struct SimpleTextStyle {
SimpleColor4f backgroundColor;
SimpleColor4f color;
uint8_t decoration;
SkScalar decorationThickness;
SkScalar fontSize;
SimpleFontStyle fontStyle;
SimpleColor4f foregroundColor;
uintptr_t /* const char** */ fontFamilies;
int numFontFamilies;
};
para::TextStyle toTextStyle(const SimpleTextStyle& s) {
para::TextStyle ts;
// textstype doesn't support a 4f color
//SkColor4f({s.color.r, s.color.g, s.color.b, s.color.a}
ts.setColor(s.color.toSkColor());
// TODO(nifong): when color was a uint, these were left unset if the color was white, was that
// important?
SkPaint p1;
p1.setColor4f(s.foregroundColor.toSkColor4f());
ts.setForegroundColor(p1);
SkPaint p2;
p2.setColor4f(s.backgroundColor.toSkColor4f());
ts.setBackgroundColor(p2);
if (s.fontSize != 0) {
ts.setFontSize(s.fontSize);
}
ts.setDecoration(para::TextDecoration(s.decoration));
if (s.decorationThickness != 0) {
ts.setDecorationThicknessMultiplier(s.decorationThickness);
}
const char** fontFamilies = reinterpret_cast<const char**>(s.fontFamilies);
if (s.numFontFamilies > 0 && fontFamilies != nullptr) {
std::vector<SkString> ff;
for (int i = 0; i< s.numFontFamilies; i++) {
ff.emplace_back(fontFamilies[i]);
}
ts.setFontFamilies(ff);
}
SkFontStyle fs(s.fontStyle.weight, s.fontStyle.width, s.fontStyle.slant);
ts.setFontStyle(fs);
return ts;
}
struct SimpleParagraphStyle {
bool disableHinting;
uintptr_t /* const char* */ ellipsisPtr;
size_t ellipsisLen;
SkScalar heightMultiplier;
size_t maxLines;
para::TextAlign textAlign;
para::TextDirection textDirection;
SimpleTextStyle textStyle;
};
para::ParagraphStyle toParagraphStyle(const SimpleParagraphStyle& s) {
para::ParagraphStyle ps;
if (s.disableHinting) {
ps.turnHintingOff();
}
if (s.ellipsisLen > 0) {
const char* ellipsisPtr = reinterpret_cast<const char*>(s.ellipsisPtr);
SkString eStr(ellipsisPtr, s.ellipsisLen);
ps.setEllipsis(eStr);
}
ps.setTextAlign(s.textAlign);
ps.setTextDirection(s.textDirection);
auto ts = toTextStyle(s.textStyle);
ps.setTextStyle(ts);
if (s.heightMultiplier != 0) {
ps.setHeight(s.heightMultiplier);
}
if (s.maxLines != 0) {
ps.setMaxLines(s.maxLines);
}
return ps;
}
struct SimpleTextBox {
SkRect rect;
// This isn't the most efficient way to represent this, but it is much easier to keep
// everything as floats when unpacking on the JS side.
// 0.0 = RTL, 1.0 = LTr
SkScalar direction;
};
Float32Array GetRectsForRange(para::ParagraphImpl& self, unsigned start, unsigned end,
para::RectHeightStyle heightStyle, para::RectWidthStyle widthStyle) {
std::vector<para::TextBox> boxes = self.getRectsForRange(start, end, heightStyle, widthStyle);
// Pack these text boxes into an array of n groups of 5 SkScalar (floats)
if (!boxes.size()) {
return emscripten::val::null();
}
SimpleTextBox* rects = new SimpleTextBox[boxes.size()];
for (int i = 0; i< boxes.size(); i++) {
rects[i].rect = boxes[i].rect;
if (boxes[i].direction == para::TextDirection::kRtl) {
rects[i].direction = 0;
} else {
rects[i].direction = 1;
}
}
float* fPtr = reinterpret_cast<float*>(rects);
// Of note: now that we have cast rects to float*, emscripten is smart enough to wrap this
// into a Float32Array for us.
return Float32Array(typed_memory_view(boxes.size()*5, fPtr));
}
EMSCRIPTEN_BINDINGS(Paragraph) {
class_<para::Paragraph>("Paragraph");
// This "base<>" tells Emscripten that ParagraphImpl is a Paragraph and can get substituted
// in properly in drawParagraph. However, Emscripten will not let us bind pure virtual methods
// so we have to "expose" the ParagraphImpl in those cases.
class_<para::ParagraphImpl, base<para::Paragraph>>("ParagraphImpl")
.function("didExceedMaxLines", &para::Paragraph::didExceedMaxLines)
.function("getAlphabeticBaseline", &para::Paragraph::getAlphabeticBaseline)
.function("getGlyphPositionAtCoordinate", &para::ParagraphImpl::getGlyphPositionAtCoordinate)
.function("getHeight", &para::Paragraph::getHeight)
.function("getIdeographicBaseline", &para::Paragraph::getIdeographicBaseline)
.function("getLongestLine", &para::Paragraph::getLongestLine)
.function("getMaxIntrinsicWidth", &para::Paragraph::getMaxIntrinsicWidth)
.function("getMaxWidth", &para::Paragraph::getMaxWidth)
.function("getMinIntrinsicWidth", &para::Paragraph::getMinIntrinsicWidth)
.function("_getRectsForRange", &GetRectsForRange)
.function("getWordBoundary", &para::ParagraphImpl::getWordBoundary)
.function("layout", &para::ParagraphImpl::layout);
class_<para::ParagraphBuilderImpl>("ParagraphBuilder")
.class_function("Make", optional_override([](SimpleParagraphStyle style,
sk_sp<SkFontMgr> fontMgr)-> para::ParagraphBuilderImpl {
auto fc = sk_make_sp<para::FontCollection>();
fc->setDefaultFontManager(fontMgr);
auto ps = toParagraphStyle(style);
para::ParagraphBuilderImpl pbi(ps, fc);
return pbi;
}), allow_raw_pointers())
.function("addText", optional_override([](para::ParagraphBuilderImpl& self, std::string text) {
return self.addText(text.c_str(), text.length());
}))
.function("build", &para::ParagraphBuilderImpl::Build, allow_raw_pointers())
.function("pop", &para::ParagraphBuilderImpl::pop)
.function("pushStyle", optional_override([](para::ParagraphBuilderImpl& self,
SimpleTextStyle textStyle) {
auto ts = toTextStyle(textStyle);
self.pushStyle(ts);
}));
enum_<para::Affinity>("Affinity")
.value("Upstream", para::Affinity::kUpstream)
.value("Downstream", para::Affinity::kDownstream);
enum_<SkFontStyle::Slant>("FontSlant")
.value("Upright", SkFontStyle::Slant::kUpright_Slant)
.value("Italic", SkFontStyle::Slant::kItalic_Slant)
.value("Oblique", SkFontStyle::Slant::kOblique_Slant);
enum_<SkFontStyle::Weight>("FontWeight")
.value("Invisible", SkFontStyle::Weight::kInvisible_Weight)
.value("Thin", SkFontStyle::Weight::kThin_Weight)
.value("ExtraLight", SkFontStyle::Weight::kExtraLight_Weight)
.value("Light", SkFontStyle::Weight::kLight_Weight)
.value("Normal", SkFontStyle::Weight::kNormal_Weight)
.value("Medium", SkFontStyle::Weight::kMedium_Weight)
.value("SemiBold", SkFontStyle::Weight::kSemiBold_Weight)
.value("Bold", SkFontStyle::Weight::kBold_Weight)
.value("ExtraBold", SkFontStyle::Weight::kExtraBold_Weight)
.value("Black" , SkFontStyle::Weight::kBlack_Weight)
.value("ExtraBlack", SkFontStyle::Weight::kExtraBlack_Weight);
enum_<SkFontStyle::Width>("FontWidth")
.value("UltraCondensed", SkFontStyle::Width::kUltraCondensed_Width)
.value("ExtraCondensed", SkFontStyle::Width::kExtraCondensed_Width)
.value("Condensed", SkFontStyle::Width::kCondensed_Width)
.value("SemiCondensed", SkFontStyle::Width::kSemiCondensed_Width)
.value("Normal", SkFontStyle::Width::kNormal_Width)
.value("SemiExpanded", SkFontStyle::Width::kSemiExpanded_Width)
.value("Expanded", SkFontStyle::Width::kExpanded_Width)
.value("ExtraExpanded", SkFontStyle::Width::kExtraExpanded_Width)
.value("UltraExpanded", SkFontStyle::Width::kUltraExpanded_Width);
enum_<para::RectHeightStyle>("RectHeightStyle")
.value("Tight", para::RectHeightStyle::kTight)
.value("Max", para::RectHeightStyle::kMax)
.value("IncludeLineSpacingMiddle", para::RectHeightStyle::kIncludeLineSpacingMiddle)
.value("IncludeLineSpacingTop", para::RectHeightStyle::kIncludeLineSpacingTop)
.value("IncludeLineSpacingBottom", para::RectHeightStyle::kIncludeLineSpacingBottom);
enum_<para::RectWidthStyle>("RectWidthStyle")
.value("Tight", para::RectWidthStyle::kTight)
.value("Max", para::RectWidthStyle::kMax);
enum_<para::TextAlign>("TextAlign")
.value("Left", para::TextAlign::kLeft)
.value("Right", para::TextAlign::kRight)
.value("Center", para::TextAlign::kCenter)
.value("Justify", para::TextAlign::kJustify)
.value("Start", para::TextAlign::kStart)
.value("End", para::TextAlign::kEnd);
enum_<para::TextDirection>("TextDirection")
.value("LTR", para::TextDirection::kLtr)
.value("RTL", para::TextDirection::kRtl);
value_object<para::PositionWithAffinity>("PositionWithAffinity")
.field("pos", &para::PositionWithAffinity::position)
.field("affinity", &para::PositionWithAffinity::affinity);
value_object<SimpleFontStyle>("FontStyle")
.field("slant", &SimpleFontStyle::slant)
.field("weight", &SimpleFontStyle::weight)
.field("width", &SimpleFontStyle::width);
value_object<SimpleParagraphStyle>("ParagraphStyle")
.field("disableHinting", &SimpleParagraphStyle::disableHinting)
.field("_ellipsisPtr", &SimpleParagraphStyle::ellipsisPtr)
.field("_ellipsisLen", &SimpleParagraphStyle::ellipsisLen)
.field("heightMultiplier", &SimpleParagraphStyle::heightMultiplier)
.field("maxLines", &SimpleParagraphStyle::maxLines)
.field("textAlign", &SimpleParagraphStyle::textAlign)
.field("textDirection", &SimpleParagraphStyle::textDirection)
.field("textStyle", &SimpleParagraphStyle::textStyle);
value_object<SimpleTextStyle>("TextStyle")
.field("backgroundColor", &SimpleTextStyle::backgroundColor)
.field("color", &SimpleTextStyle::color)
.field("decoration", &SimpleTextStyle::decoration)
.field("decorationThickness", &SimpleTextStyle::decorationThickness)
.field("_fontFamilies", &SimpleTextStyle::fontFamilies)
.field("fontSize", &SimpleTextStyle::fontSize)
.field("fontStyle", &SimpleTextStyle::fontStyle)
.field("foregroundColor", &SimpleTextStyle::foregroundColor)
.field("_numFontFamilies", &SimpleTextStyle::numFontFamilies);
// The U stands for unsigned - we can't bind a generic/template object, so we have to specify it
// with the type we are using.
value_object<para::SkRange<size_t>>("URange")
.field("start", &para::SkRange<size_t>::start)
.field("end", &para::SkRange<size_t>::end);
// TextDecoration should be a const because they can be combined
constant("NoDecoration", int(para::TextDecoration::kNoDecoration));
constant("UnderlineDecoration", int(para::TextDecoration::kUnderline));
constant("OverlineDecoration", int(para::TextDecoration::kOverline));
constant("LineThroughDecoration", int(para::TextDecoration::kLineThrough));
}