SkShapeText.h

#include "SkFontTypes.h"
#include <cstddef>
class SkFont;
class SkTextBlob;
template<typename T> class sk_sp;
sk_sp<SkTextBlob> SkShapeText(const void* text,
                              size_t byteLength,
                              const SkFont& font,
                              SkTextEncoding encoding = kUTF8_SkTextEncoding);

//////////////////////////////////////////////////////////////////

#include "SkUTF.h"
#include "SkShaper.h"

template <typename T, SkUnichar (*FN)(const T**, const T*)>
static SkString convert_to_utf8(const void* src, size_t srcBytes) {
    const T* ptr = (const T*)src;
    const T* stop = (const T*)((const char*)src + srcBytes);
    size_t count = 0;
    while (ptr < stop) {
        count += SkUTF::ToUTF8(FN(&ptr, stop), nullptr);
    }
    SkString result(count);
    ptr = (const T*)src;
    char* dst = result.writable_str();
    while (ptr < stop) {
        dst += SkUTF::ToUTF8(FN(&ptr, stop), dst);
    }
    return result;
}

sk_sp<SkTextBlob> SkShapeText(const void* text,
                              size_t byteLength,
                              const SkFont& font,
                              SkTextEncoding encoding) {
    SkString tmp;
    switch (encoding) {
        case kUTF8_SkTextEncoding:
            break;
        case SkTextEncoding::kUTF16:
            tmp = convert_to_utf8<uint16_t, SkUTF::NextUTF16>(text, byteLength);
            text = tmp.c_str(); byteLength = tmp.size();
            break;
        case SkTextEncoding::kUTF32:
            tmp = convert_to_utf8<int32_t, SkUTF::NextUTF32>(text, byteLength);
            text = tmp.c_str(); byteLength = tmp.size();
            break;
        default:
            return nullptr;
    }
    SkTextBlobBuilderRunHandler handler;
    SkShaper shaper(font.refTypeface());
    shaper.shape(&handler, font, (const char*)text, byteLength,
                 true, {0, 0}, FLT_MAX);
    return handler.makeBlob();
}