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e09b314405
skia2/modules/canvaskit/paragraph_bindings.cpp
Nathaniel Nifong e09b314405 Add ParagraphBuilder.pushPaintStyle to allow text to be colors with paints. 
Previously one could not color text with paints, even though TextStyle's foregroundColor and
backgroundColor fields are SkPaints. Canvaskit only exposed these as colors in order to allow
SimpleTextStyle to be a value object that would not have to be deleted by the user.

CanvasKit.Paint is a bound SkPaint. I wanted to allow a user to pass a paint to be used
in a text style without alterting SimpleTextStyle's status as a value-object.

So I've added a new bound method, pushPaintStyle which acts just like pushStyle but allows
a foreground and background paint to be supplied which are used to override the existing paints.

The user is responsible for deleting these paints.

Sorry for the kludgy design, if you have got a more elegant way, I'm open to suggestions.

Change-Id: Ib78464171346fe9f717f6d5b9d9428b1d0278498
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/307596
Commit-Queue: Nathaniel Nifong <nifong@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Julia Lavrova <jlavrova@google.com>
2020-08-04 13:23:06 +00:00

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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;
SkColor4f toSkColor4f(uintptr_t /* float* */ cPtr) {
float* fourFloats = reinterpret_cast<float*>(cPtr);
SkColor4f color = { fourFloats[0], fourFloats[1], fourFloats[2], fourFloats[3] };
return color;
}
struct SimpleFontStyle {
SkFontStyle::Slant slant;
SkFontStyle::Weight weight;
SkFontStyle::Width width;
};
struct SimpleTextStyle {
uintptr_t /* float* */ colorPtr;
uintptr_t /* float* */ foregroundColorPtr;
uintptr_t /* float* */ backgroundColorPtr;
uint8_t decoration;
SkScalar decorationThickness;
SkScalar fontSize;
SimpleFontStyle fontStyle;
uintptr_t /* const char** */ fontFamiliesPtr;
int fontFamiliesLen;
};
para::TextStyle toTextStyle(const SimpleTextStyle& s) {
para::TextStyle ts;
// textstyle.color doesn't support a 4f color, however the foreground and background fields below do.
ts.setColor(toSkColor4f(s.colorPtr).toSkColor());
// It is functionally important that these paints be unset when no value was provided.
if (s.foregroundColorPtr) {
SkPaint p1;
p1.setColor4f(toSkColor4f(s.foregroundColorPtr));
ts.setForegroundColor(p1);
}
if (s.backgroundColorPtr) {
SkPaint p2;
p2.setColor4f(toSkColor4f(s.backgroundColorPtr));
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.fontFamiliesPtr);
if (s.fontFamiliesLen > 0 && fontFamilies != nullptr) {
std::vector<SkString> ff;
for (int i = 0; i < s.fontFamiliesLen; 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);
}))
// A method of pushing a textStyle with paints instead of colors for foreground and
// background. Since SimpleTextStyle is a value object, it cannot contain paints, which are not primitives. This binding is here to accept them. Any color that is specified in the textStyle is overridden.
.function("_pushPaintStyle", optional_override([](para::ParagraphBuilderImpl& self,
SimpleTextStyle textStyle, SkPaint foreground, SkPaint background) {
auto ts = toTextStyle(textStyle);
ts.setForegroundColor(foreground);
ts.setBackgroundColor(background);
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("_colorPtr", &SimpleTextStyle::colorPtr)
.field("_foregroundColorPtr", &SimpleTextStyle::foregroundColorPtr)
.field("_backgroundColorPtr", &SimpleTextStyle::backgroundColorPtr)
.field("decoration", &SimpleTextStyle::decoration)
.field("decorationThickness", &SimpleTextStyle::decorationThickness)
.field("_fontFamiliesPtr", &SimpleTextStyle::fontFamiliesPtr)
.field("_fontFamiliesLen", &SimpleTextStyle::fontFamiliesLen)
.field("fontSize", &SimpleTextStyle::fontSize)
.field("fontStyle", &SimpleTextStyle::fontStyle);
// 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));
}
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