tools/viewer/TextBoxSlide.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkCanvas.h"
#include "include/core/SkColorFilter.h"
#include "include/core/SkColorPriv.h"
#include "include/core/SkGraphics.h"
#include "include/core/SkPath.h"
#include "include/core/SkRegion.h"
#include "include/core/SkShader.h"
#include "include/core/SkStream.h"
#include "include/core/SkTextBlob.h"
#include "include/core/SkTypeface.h"
#include "include/effects/SkGradientShader.h"
#include "modules/skshaper/include/SkShaper.h"
#include "src/base/SkRandom.h"
#include "src/base/SkTime.h"
#include "src/base/SkUTF.h"
#include "src/core/SkOSFile.h"
#include "tools/fonts/FontToolUtils.h"
#include "tools/viewer/Slide.h"

typedef std::unique_ptr<SkShaper> (*ShaperFactory)();

static const char gText[] =
    "When in the Course of human events it becomes necessary for one people "
    "to dissolve the political bands which have connected them with another "
    "and to assume among the powers of the earth, the separate and equal "
    "station to which the Laws of Nature and of Nature's God entitle them, "
    "a decent respect to the opinions of mankind requires that they should "
    "declare the causes which impel them to the separation.";

class TextBoxSlide : public Slide {
public:
    TextBoxSlide(ShaperFactory fact, const char suffix[]) : fShaper(fact()) {
        fName = SkStringPrintf("TextBox_%s", suffix);
    }

    void load(SkScalar w, SkScalar h) override { fSize = {w, h}; }

    void resize(SkScalar w, SkScalar h) override { fSize = {w, h}; }

    void draw(SkCanvas* canvas) override {
        SkScalar width = fSize.width() / 3;
        drawTest(canvas, width, fSize.height(), SK_ColorBLACK, SK_ColorWHITE);
        canvas->translate(width, 0);
        drawTest(canvas, width, fSize.height(), SK_ColorWHITE, SK_ColorBLACK);
        canvas->translate(width, 0);
        drawTest(canvas, width, fSize.height()/2, SK_ColorGRAY, SK_ColorWHITE);
        canvas->translate(0, fSize.height()/2);
        drawTest(canvas, width, fSize.height()/2, SK_ColorGRAY, SK_ColorBLACK);
    }

private:
    void drawTest(SkCanvas* canvas, SkScalar w, SkScalar h, SkColor fg, SkColor bg) {
        SkAutoCanvasRestore acr(canvas, true);

        canvas->clipRect(SkRect::MakeWH(w, h));
        canvas->drawColor(bg);

        SkScalar margin = 20;

        SkPaint paint;
        paint.setColor(fg);

        for (int i = 9; i < 24; i += 2) {
            SkShaper::PurgeCaches();
            SkTextBlobBuilderRunHandler builder(gText, { margin, margin });
            SkFont srcFont(nullptr, SkIntToScalar(i));
            srcFont.setEdging(SkFont::Edging::kSubpixelAntiAlias);
            srcFont.setSubpixel(true);

            const char* utf8 = gText;
            size_t utf8Bytes = sizeof(gText) - 1;

            std::unique_ptr<SkShaper::BiDiRunIterator> bidi(
                    SkShaper::MakeBiDiRunIterator(utf8, utf8Bytes, 0xfe));
            if (!bidi) {
                return;
            }

            std::unique_ptr<SkShaper::LanguageRunIterator> language(
                    SkShaper::MakeStdLanguageRunIterator(utf8, utf8Bytes));
            if (!language) {
                return;
            }

            SkFourByteTag undeterminedScript = SkSetFourByteTag('Z','y','y','y');
            std::unique_ptr<SkShaper::ScriptRunIterator> script(
                    SkShaper::MakeScriptRunIterator(utf8, utf8Bytes, undeterminedScript));
            if (!script) {
                return;
            }

            std::unique_ptr<SkShaper::FontRunIterator> font(
                    SkShaper::MakeFontMgrRunIterator(utf8,
                                                     utf8Bytes,
                                                     srcFont,
                                                     ToolUtils::TestFontMgr(),
                                                     "Arial",
                                                     SkFontStyle::Bold(),
                                                     &*language));
            if (!font) {
                return;
            }

            fShaper->shape(utf8, utf8Bytes, *font, *bidi, *script, *language, w - margin, &builder);
            canvas->drawTextBlob(builder.makeBlob(), 0, 0, paint);

            canvas->translate(0, builder.endPoint().y());
        }
    }

    SkSize fSize;
    std::unique_ptr<SkShaper> fShaper;
};

DEF_SLIDE( return new TextBoxSlide([](){ return SkShaper::Make(SkFontMgr::RefEmpty()); }, "default"); );
#ifdef SK_SHAPER_CORETEXT_AVAILABLE
DEF_SLIDE( return new TextBoxSlide(SkShaper::MakeCoreText, "coretext"); );
#endif

class ShaperSlide : public Slide {
public:
    ShaperSlide() { fName = "shaper"; }

    void draw(SkCanvas* canvas) override {
        canvas->translate(10, 30);

        const char text[] = "world";

        for (SkScalar size = 30; size <= 30; size += 10) {
            this->drawTest(canvas, text, size, SkShaper::Make(SkFontMgr::RefEmpty()));
            canvas->translate(0, size + 5);
            #ifdef SK_SHAPER_CORETEXT_AVAILABLE
            this->drawTest(canvas, text, size, SkShaper::MakeCoreText());
            #endif
            canvas->translate(0, size*2);
        }
    }

private:
    void drawTest(SkCanvas* canvas, const char str[], SkScalar size,
                  std::unique_ptr<SkShaper> shaper) {
        if (!shaper) return;

        SkTextBlobBuilderRunHandler builder(str, {0, 0});
        SkFont srcFont;
        srcFont.setSize(size);
        srcFont.setEdging(SkFont::Edging::kSubpixelAntiAlias);
        srcFont.setSubpixel(true);

        size_t len = strlen(str);

        std::unique_ptr<SkShaper::BiDiRunIterator> bidi(
                SkShaper::MakeBiDiRunIterator(str, len, 0xfe));
        if (!bidi) {
            return;
        }

        std::unique_ptr<SkShaper::LanguageRunIterator> language(
                SkShaper::MakeStdLanguageRunIterator(str, len));
        if (!language) {
            return;
        }

        SkFourByteTag undeterminedScript = SkSetFourByteTag('Z','y','y','y');
        std::unique_ptr<SkShaper::ScriptRunIterator> script(
                SkShaper::MakeScriptRunIterator(str, len, undeterminedScript));
        if (!script) {
            return;
        }

        std::unique_ptr<SkShaper::FontRunIterator> font(
                SkShaper::MakeFontMgrRunIterator(str,
                                                 len,
                                                 srcFont,
                                                 ToolUtils::TestFontMgr(),
                                                 "Arial",
                                                 SkFontStyle::Bold(),
                                                 &*language));
        if (!font) {
            return;
        }

        shaper->shape(str, len, *font, *bidi, *script, *language, 2000, &builder);

        canvas->drawTextBlob(builder.makeBlob(), 0, 0, SkPaint());
    }

};

DEF_SLIDE( return new ShaperSlide; );