XCEngine/new_editor/app/Rendering/Native/NativeRendererText.cpp

#include "NativeRendererSupport.h"

#include <algorithm>
#include <cmath>

namespace XCEngine::UI::Editor::Host {

using namespace NativeRendererSupport;

float NativeRenderer::MeasureTextWidth(
    const ::XCEngine::UI::Editor::UIEditorTextMeasureRequest& request) const {
    if (!m_dwriteFactory || request.text.empty()) {
        return 0.0f;
    }

    const std::wstring text = Utf8ToWide(request.text);
    if (text.empty()) {
        return 0.0f;
    }

    const float dpiScale = ClampDpiScale(m_dpiScale);
    const float scaledFontSize = ResolveFontSize(request.fontSize) * dpiScale;
    IDWriteTextFormat* textFormat = GetTextFormat(scaledFontSize);
    if (textFormat == nullptr) {
        return 0.0f;
    }

    Microsoft::WRL::ComPtr<IDWriteTextLayout> textLayout;
    HRESULT hr = m_dwriteFactory->CreateTextLayout(
        text.c_str(),
        static_cast<UINT32>(text.size()),
        textFormat,
        4096.0f,
        scaledFontSize * 2.0f,
        textLayout.ReleaseAndGetAddressOf());
    if (FAILED(hr) || !textLayout) {
        return 0.0f;
    }

    DWRITE_TEXT_METRICS textMetrics = {};
    hr = textLayout->GetMetrics(&textMetrics);
    if (FAILED(hr)) {
        return 0.0f;
    }

    DWRITE_OVERHANG_METRICS overhangMetrics = {};
    float width = textMetrics.widthIncludingTrailingWhitespace;
    if (SUCCEEDED(textLayout->GetOverhangMetrics(&overhangMetrics))) {
        width += (std::max)(overhangMetrics.left, 0.0f);
        width += (std::max)(overhangMetrics.right, 0.0f);
    }

    return std::ceil(width) / dpiScale;
}

IDWriteTextFormat* NativeRenderer::GetTextFormat(float fontSize) const {
    if (!m_dwriteFactory) {
        return nullptr;
    }

    const float resolvedFontSize = ResolveFontSize(fontSize);
    const int key = static_cast<int>(std::lround(resolvedFontSize * 10.0f));
    const auto found = m_textFormats.find(key);
    if (found != m_textFormats.end()) {
        return found->second.Get();
    }

    Microsoft::WRL::ComPtr<IDWriteTextFormat> textFormat;
    const HRESULT hr = m_dwriteFactory->CreateTextFormat(
        L"Segoe UI",
        nullptr,
        DWRITE_FONT_WEIGHT_REGULAR,
        DWRITE_FONT_STYLE_NORMAL,
        DWRITE_FONT_STRETCH_NORMAL,
        resolvedFontSize,
        L"",
        textFormat.ReleaseAndGetAddressOf());
    if (FAILED(hr)) {
        return nullptr;
    }

    textFormat->SetTextAlignment(DWRITE_TEXT_ALIGNMENT_LEADING);
    textFormat->SetParagraphAlignment(DWRITE_PARAGRAPH_ALIGNMENT_NEAR);
    textFormat->SetWordWrapping(DWRITE_WORD_WRAPPING_NO_WRAP);

    IDWriteTextFormat* result = textFormat.Get();
    m_textFormats.emplace(key, std::move(textFormat));
    return result;
}

D2D1_COLOR_F NativeRenderer::ToD2DColor(const ::XCEngine::UI::UIColor& color) {
    return D2D1::ColorF(color.r, color.g, color.b, color.a);
}

std::wstring NativeRenderer::Utf8ToWide(std::string_view text) {
    if (text.empty()) {
        return {};
    }

    const int sizeNeeded = MultiByteToWideChar(
        CP_UTF8,
        0,
        text.data(),
        static_cast<int>(text.size()),
        nullptr,
        0);
    if (sizeNeeded <= 0) {
        return {};
    }

    std::wstring wideText(static_cast<size_t>(sizeNeeded), L'\0');
    MultiByteToWideChar(
        CP_UTF8,
        0,
        text.data(),
        static_cast<int>(text.size()),
        wideText.data(),
        sizeNeeded);
    return wideText;
}

} // namespace XCEngine::UI::Editor::Host