Just-DataInspector/Utilities/Src/PaintUtil.cpp

#include "PaintUtil.hpp"

#include <algorithm>
#include <cmath>
#include <cstddef>
#include <functional>
#include <mutex>
#include <unordered_map>
#include <utility>
#include <string>

namespace jdi
{

	namespace
	{
		/**
		 * @brief 颜色样块补充描边的不透明度阈值。
		 *
		 * 不透明度低于该值时，色块自身与浅色背景的对比度已不足，需要额外描边才能辨识；
		 * 高于该值时按需求不绘制描边，保持与预设色块一致的纯净外观。
		 */
		const float kSwatchOutlineOpacity = 0.45f;

		/**
		 * @brief 矩形面积超过该阈值（逻辑像素²）且为不透明色时，改用 GDI 填充。
		 *
		 * GDI+ 的 FillRectangle 约 2.2ns/像素；面积过小时 GDI 的 GetHDC/ReleaseHDC
		 * 固定开销反而不划算，因此在阈值以下仍走 GDI+。
		 */
		const float kGdiFillAreaThreshold = 20000.0f;

		/**
		 * @brief 构造圆角矩形路径。
		 * @param [IN,OUT] path 目标路径对象。
		 * @param [IN] rect 目标矩形。
		 * @param [IN] radius 圆角半径。
		 */
		void BuildRoundRectPath(gd::GraphicsPath& path, const gd::RectF& rect, float radius)
		{
			if (rect.Width <= 0.0f || rect.Height <= 0.0f)
			{
				return;
			}

			float diameter = radius * 2.0f;
			if (diameter > rect.Width)
			{
				diameter = rect.Width;
			}
			if (diameter > rect.Height)
			{
				diameter = rect.Height;
			}
			if (diameter < 1.0f)
			{
				path.AddRectangle(rect);
				return;
			}

			const float right = rect.X + rect.Width;
			const float bottom = rect.Y + rect.Height;

			path.AddArc(rect.X, rect.Y, diameter, diameter, 180.0f, 90.0f);
			path.AddArc(right - diameter, rect.Y, diameter, diameter, 270.0f, 90.0f);
			path.AddArc(right - diameter, bottom - diameter, diameter, diameter, 0.0f, 90.0f);
			path.AddArc(rect.X, bottom - diameter, diameter, diameter, 90.0f, 90.0f);
			path.CloseFigure();
		}

		/**
		 * @brief 创建指定字号的界面字体。
		 * @param [IN] face 字体名称。
		 * @param [IN] pixelHeight 字符高度（像素）。
		 * @param [IN] bold 是否加粗。
		 * @return 字体句柄，失败返回 nullptr。
		 */
		HFONT CreateUiFont(const wchar_t* face, int pixelHeight, bool bold)
		{
			LOGFONTW logFont = {};
			logFont.lfHeight = -pixelHeight;
			logFont.lfWeight = bold ? FW_SEMIBOLD : FW_NORMAL;
			logFont.lfCharSet = DEFAULT_CHARSET;
			logFont.lfOutPrecision = OUT_TT_PRECIS;
			logFont.lfClipPrecision = CLIP_DEFAULT_PRECIS;
			logFont.lfQuality = CLEARTYPE_QUALITY;
			logFont.lfPitchAndFamily = DEFAULT_PITCH | FF_DONTCARE;
			wcsncpy(logFont.lfFaceName, face, LF_FACESIZE - 1);
			logFont.lfFaceName[LF_FACESIZE - 1] = L'\0';

			HFONT font = CreateFontIndirectW(&logFont);
			if (font == nullptr)
			{
				font = static_cast<HFONT>(GetStockObject(DEFAULT_GUI_FONT));
			}
			return font;
		}
	} // namespace

	namespace
	{
		/**
		 * @brief 文本宽度测量的缓存键（字体句柄 + 文本）。
		 */
		struct MeasureKey
		{
			HFONT font = nullptr;
			std::wstring text;
			bool operator==(const MeasureKey& other) const
			{
				return font == other.font && text == other.text;
			}
		};
		struct MeasureKeyHash
		{
			std::size_t operator()(const MeasureKey& key) const
			{
				std::size_t hash = std::hash<const void*>()(key.font);
				for (const wchar_t character : key.text)
				{
					hash = hash * 131u + static_cast<std::size_t>(character);
				}
				return hash;
			}
		};
		/** 上限保护：超过时整体清空（缓存只是加速手段，清空后重新填充即可）。 */
		constexpr std::size_t kMeasureCacheLimit = 4096;
		std::unordered_map<MeasureKey, float, MeasureKeyHash> g_measureCache;
		std::mutex g_measureMutex;
	} // namespace

	void UiClearMeasureCache()
	{
		std::lock_guard<std::mutex> lock(g_measureMutex);
		g_measureCache.clear();
	}

	bool UiFonts::Create(UINT targetDpi)
	{
		Destroy();
		// 字体句柄会被重新创建，旧句柄可能被系统复用：必须作废按句柄缓存的文本宽度，
		// 否则复用同一句柄值的新字体会命中旧宽度（布局错位）。
		UiClearMeasureCache();
		dpi = (targetDpi == 0) ? 96u : targetDpi;

		const double scale = static_cast<double>(dpi) / 96.0;
		const int uiHeight = static_cast<int>(std::lround(14.0 * scale));
		const int smallHeight = static_cast<int>(std::lround(12.0 * scale));
		const int titleHeight = static_cast<int>(std::lround(15.0 * scale));
		const int monoHeight = static_cast<int>(std::lround(13.0 * scale));

		ui = CreateUiFont(L"Segoe UI", uiHeight, false);
		uiBold = CreateUiFont(L"Segoe UI Semibold", uiHeight, true);
		uiSmall = CreateUiFont(L"Segoe UI", smallHeight, false);
		uiSmallBold = CreateUiFont(L"Segoe UI Semibold", smallHeight, true);
		title = CreateUiFont(L"Segoe UI Semibold", titleHeight, true);
		mono = CreateUiFont(L"Consolas", monoHeight, false);
		monoSmall = CreateUiFont(L"Consolas", smallHeight, false);

		return ui != nullptr && uiBold != nullptr && uiSmall != nullptr && title != nullptr && mono != nullptr;
	}

	void UiFonts::Destroy()
	{
		const HFONT resources[] = {ui, uiBold, uiSmall, uiSmallBold, title, mono, monoSmall};
		for (const HFONT font : resources)
		{
			if (font != nullptr)
			{
				DeleteObject(font);
			}
		}
		ui = nullptr;
		uiBold = nullptr;
		uiSmall = nullptr;
		uiSmallBold = nullptr;
		title = nullptr;
		mono = nullptr;
		monoSmall = nullptr;
	}

	void UiFillRect(gd::Graphics& g, const gd::RectF& rect, std::uint32_t argb)
	{
		if (rect.Width <= 0.0f || rect.Height <= 0.0f)
		{
			return;
		}

		// 大面积且**不透明**的填充走 GDI 路线：GDI+ 的 FillRectangle 实测约 2.2ns/像素
		// （整个窗口背景 1.7M 像素约 0.9ms，信号面板背景约 1.9ms），
		// 而 GDI 的 FillRect 快一个数量级。半透明填充必须留在 GDI+（GDI 不做 alpha 混色）。
		// 顺序安全：GetHDC() 会先把已排队的 GDI+ 内容刷入 DC，本次填充之后再发生的 GDI+ 绘制
		// 会在 ReleaseHDC() 之后刷出、正确地覆盖在上面。
		const float area = rect.Width * rect.Height;
		if ((argb & 0xFF000000u) == 0xFF000000u && area >= kGdiFillAreaThreshold)
		{
			HDC hdc = g.GetHDC();
			if (hdc != nullptr)
			{
				RECT rc;
				rc.left = static_cast<LONG>(std::floor(rect.X));
				rc.top = static_cast<LONG>(std::floor(rect.Y));
				rc.right = static_cast<LONG>(std::ceil(rect.X + rect.Width));
				rc.bottom = static_cast<LONG>(std::ceil(rect.Y + rect.Height));
				HBRUSH brush = CreateSolidBrush(ToColorRef(argb));
				if (brush != nullptr)
				{
					FillRect(hdc, &rc, brush);
					DeleteObject(brush);
				}
				g.ReleaseHDC(hdc);
				return;
			}
		}

		gd::SolidBrush brush(ToGdiColor(argb));
		g.FillRectangle(&brush, rect);
	}

	void UiFillRoundRect(gd::Graphics& g, const gd::RectF& rect, float radius, std::uint32_t argb)
	{
		if (rect.Width <= 0.0f || rect.Height <= 0.0f)
		{
			return;
		}
		gd::GraphicsPath path;
		BuildRoundRectPath(path, rect, radius);
		gd::SolidBrush brush(ToGdiColor(argb));
		g.FillPath(&brush, &path);
	}

	void UiDrawRoundRect(gd::Graphics& g, const gd::RectF& rect, float radius, std::uint32_t argb, float width)
	{
		if (rect.Width <= 0.0f || rect.Height <= 0.0f)
		{
			return;
		}
		gd::GraphicsPath path;
		BuildRoundRectPath(path, rect, radius);
		gd::Pen pen(ToGdiColor(argb), width);
		g.DrawPath(&pen, &path);
	}

	void UiFillRoundRects(gd::Graphics& g, const std::vector<gd::RectF>& rects, float radius,
	                      std::uint32_t argb)
	{
		if (rects.empty())
		{
			return;
		}
		gd::GraphicsPath path;
		for (const gd::RectF& rect : rects)
		{
			if (rect.Width <= 0.0f || rect.Height <= 0.0f)
			{
				continue;
			}
			BuildRoundRectPath(path, rect, radius);
		}
		if (path.GetPointCount() > 0)
		{
			gd::SolidBrush brush(ToGdiColor(argb));
			g.FillPath(&brush, &path);
		}
	}

	std::uint32_t UiBlendOver(std::uint32_t background, std::uint32_t argb)
	{
		const unsigned int alpha = (argb >> 24) & 0xFFu;
		if (alpha >= 0xFFu)
		{
			return argb | 0xFF000000u;
		}
		if (alpha == 0u)
		{
			return background | 0xFF000000u;
		}
		const double ratio = static_cast<double>(alpha) / 255.0;
		std::uint32_t result = 0xFF000000u;
		for (int shift = 0; shift <= 16; shift += 8)
		{
			const double top = static_cast<double>((argb >> shift) & 0xFFu);
			const double bottom = static_cast<double>((background >> shift) & 0xFFu);
			const double mixed = bottom + (top - bottom) * ratio;
			result |= (static_cast<std::uint32_t>(mixed + 0.5) & 0xFFu) << shift;
		}
		return result;
	}

	void UiDrawSolidLines(gd::Graphics& g, const gd::RectF& clip, const float* segments,
	                      std::size_t segmentCount, std::uint32_t argb, int width)
	{
		if (segments == nullptr || segmentCount == 0 || (argb & 0xFF000000u) != 0xFF000000u)
		{
			return;
		}
		if (width < 1)
		{
			width = 1;
		}

		const int clipLeft = static_cast<int>(std::floor(clip.X));
		const int clipTop = static_cast<int>(std::floor(clip.Y));
		const int clipRight = static_cast<int>(std::ceil(clip.X + clip.Width));
		const int clipBottom = static_cast<int>(std::ceil(clip.Y + clip.Height));
		if (clipRight <= clipLeft || clipBottom <= clipTop)
		{
			return;
		}

		HDC hdc = g.GetHDC();
		if (hdc == nullptr)
		{
			return;
		}

		// GDI 绘制不受 GDI+ 裁剪约束，这里显式设置并随后完整还原 DC 状态。
		const int saved = SaveDC(hdc);
		if (saved != 0)
		{
			IntersectClipRect(hdc, clipLeft, clipTop, clipRight, clipBottom);
		}

		HPEN pen = CreatePen(PS_SOLID, width, ToColorRef(argb));
		if (pen != nullptr)
		{
			HGDIOBJ oldPen = SelectObject(hdc, pen);
			for (std::size_t index = 0; index < segmentCount; ++index)
			{
				const float* segment = segments + index * 4;
				MoveToEx(hdc, static_cast<int>(std::lround(segment[0])),
				         static_cast<int>(std::lround(segment[1])), nullptr);
				LineTo(hdc, static_cast<int>(std::lround(segment[2])),
				       static_cast<int>(std::lround(segment[3])));
			}
			SelectObject(hdc, oldPen);
			DeleteObject(pen);
		}

		if (saved != 0)
		{
			RestoreDC(hdc, saved);
		}
		g.ReleaseHDC(hdc);
	}

	void UiDrawLine(gd::Graphics& g, float x1, float y1, float x2, float y2, std::uint32_t argb, float width)
	{
		gd::Pen pen(ToGdiColor(argb), width);
		pen.SetStartCap(gd::LineCapFlat);
		pen.SetEndCap(gd::LineCapFlat);
		g.DrawLine(&pen, x1, y1, x2, y2);
	}

	void UiText(gd::Graphics& g, const std::wstring& text, HFONT font, const gd::RectF& rect, std::uint32_t argb,
	            TextAlign align)
	{
		if (text.empty() || font == nullptr || rect.Width <= 0.0f || rect.Height <= 0.0f)
		{
			return;
		}

		HDC hdc = g.GetHDC();
		if (hdc == nullptr)
		{
			return;
		}

		HGDIOBJ oldFont = SelectObject(hdc, font);
		const int oldMode = SetBkMode(hdc, TRANSPARENT);
		const COLORREF oldColor = SetTextColor(hdc, ToColorRef(argb));

		RECT rc;
		rc.left = static_cast<LONG>(std::floor(rect.X));
		rc.top = static_cast<LONG>(std::floor(rect.Y));
		rc.right = static_cast<LONG>(std::ceil(rect.X + rect.Width));
		rc.bottom = static_cast<LONG>(std::ceil(rect.Y + rect.Height));

		UINT flags = DT_SINGLELINE | DT_VCENTER | DT_NOPREFIX | DT_END_ELLIPSIS;
		switch (align)
		{
		case TextAlign::CENTER:
			flags |= DT_CENTER;
			break;
		case TextAlign::RIGHT:
			flags |= DT_RIGHT;
			break;
		case TextAlign::LEFT:
		default:
			flags |= DT_LEFT;
			break;
		}

		DrawTextW(hdc, text.c_str(), static_cast<int>(text.size()), &rc, flags);

		SetTextColor(hdc, oldColor);
		SetBkMode(hdc, oldMode);
		SelectObject(hdc, oldFont);
		g.ReleaseHDC(hdc);
	}

	float UiMeasureTextWidth(HFONT font, const std::wstring& text)
	{
		if (text.empty() || font == nullptr)
		{
			return 0.0f;
		}

		// 记忆化：文本宽度只能走 GDI（GetDC + GetTextExtentPoint32W + ReleaseDC），
		// 单次约 10µs；而布局代码每帧会把同一批字符串**重复测量成百上千次**——
		// 例如浮动面板的几何是按「网格数 × 面板种类」反复重算的（5 网格 × 4 类 = 20 次，
		// 每次十来个字符串），实测光这一项就占 3ms 以上。字体与文本都相同的测量结果
		// 必然一致，因此按 (字体, 文本) 做一层缓存；字体被重建时由 `UiClearMeasureCache` 作废。
		const MeasureKey key{font, text};
		{
			std::lock_guard<std::mutex> lock(g_measureMutex);
			const auto found = g_measureCache.find(key);
			if (found != g_measureCache.end())
			{
				return found->second;
			}
		}

		HDC hdc = GetDC(nullptr);
		if (hdc == nullptr)
		{
			return 0.0f;
		}

		HGDIOBJ oldFont = SelectObject(hdc, font);
		SIZE size = {};
		GetTextExtentPoint32W(hdc, text.c_str(), static_cast<int>(text.size()), &size);
		SelectObject(hdc, oldFont);
		ReleaseDC(nullptr, hdc);

		const float width = static_cast<float>(size.cx);
		{
			std::lock_guard<std::mutex> lock(g_measureMutex);
			if (g_measureCache.size() >= kMeasureCacheLimit)
			{
				g_measureCache.clear();
			}
			g_measureCache.emplace(key, width);
		}
		return width;
	}

	std::wstring UiEllipsize(const std::wstring& text, HFONT font, float maxWidth)
	{
		if (text.empty() || font == nullptr || maxWidth <= 0.0f)
		{
			return std::wstring();
		}
		if (UiMeasureTextWidth(font, text) <= maxWidth)
		{
			return text;
		}

		const std::wstring ellipsis = L"…";
		const float ellipsisWidth = UiMeasureTextWidth(font, ellipsis);
		if (ellipsisWidth > maxWidth)
		{
			return std::wstring();
		}

		std::wstring result = text;
		while (!result.empty())
		{
			result.pop_back();
			if (UiMeasureTextWidth(font, result) + ellipsisWidth <= maxWidth)
			{
				return result + ellipsis;
			}
		}
		return ellipsis;
	}

	void UiDrawPlusIcon(gd::Graphics& g, const gd::RectF& rect, std::uint32_t argb, float strokeWidth)
	{
		const float cx = rect.X + rect.Width * 0.5f;
		const float cy = rect.Y + rect.Height * 0.5f;
		const float arm = std::min(rect.Width, rect.Height) * 0.3f;
		UiDrawLine(g, cx - arm, cy, cx + arm, cy, argb, strokeWidth);
		UiDrawLine(g, cx, cy - arm, cx, cy + arm, argb, strokeWidth);
	}

	void UiDrawCrossIcon(gd::Graphics& g, const gd::RectF& rect, std::uint32_t argb, float strokeWidth)
	{
		const float cx = rect.X + rect.Width * 0.5f;
		const float cy = rect.Y + rect.Height * 0.5f;
		const float arm = std::min(rect.Width, rect.Height) * 0.3f;
		UiDrawLine(g, cx - arm, cy - arm, cx + arm, cy + arm, argb, strokeWidth);
		UiDrawLine(g, cx + arm, cy - arm, cx - arm, cy + arm, argb, strokeWidth);
	}

	void UiDrawTriangleIcon(gd::Graphics& g, const gd::RectF& rect, std::uint32_t argb, IconDirection direction)
	{
		const float cx = rect.X + rect.Width * 0.5f;
		const float cy = rect.Y + rect.Height * 0.5f;
		const float arm = std::min(rect.Width, rect.Height) * 0.28f;

		gd::PointF points[3];
		switch (direction)
		{
		case IconDirection::LEFT:
			points[0] = gd::PointF(cx + arm * 0.7f, cy - arm);
			points[1] = gd::PointF(cx - arm * 0.7f, cy);
			points[2] = gd::PointF(cx + arm * 0.7f, cy + arm);
			break;
		case IconDirection::RIGHT:
			points[0] = gd::PointF(cx - arm * 0.7f, cy - arm);
			points[1] = gd::PointF(cx + arm * 0.7f, cy);
			points[2] = gd::PointF(cx - arm * 0.7f, cy + arm);
			break;
		case IconDirection::UP:
			points[0] = gd::PointF(cx - arm, cy + arm * 0.7f);
			points[1] = gd::PointF(cx, cy - arm * 0.7f);
			points[2] = gd::PointF(cx + arm, cy + arm * 0.7f);
			break;
		case IconDirection::DOWN:
		default:
			points[0] = gd::PointF(cx - arm, cy - arm * 0.7f);
			points[1] = gd::PointF(cx, cy + arm * 0.7f);
			points[2] = gd::PointF(cx + arm, cy - arm * 0.7f);
			break;
		}

		gd::SolidBrush brush(ToGdiColor(argb));
		g.FillPolygon(&brush, points, 3);
	}

	double UiSliderRatioFromX(const gd::RectF& trackRect, float x)
	{
		if (trackRect.Width <= 0.0f)
		{
			return 0.0;
		}
		const double ratio = static_cast<double>(x - trackRect.X) / static_cast<double>(trackRect.Width);
		if (ratio < 0.0)
		{
			return 0.0;
		}
		if (ratio > 1.0)
		{
			return 1.0;
		}
		return ratio;
	}
		double UiColorLuminance(std::uint32_t color)
		{
			const double r = static_cast<double>((color >> 16) & 0xFFu);
			const double g = static_cast<double>((color >> 8) & 0xFFu);
			const double b = static_cast<double>(color & 0xFFu);
			return (0.299 * r + 0.587 * g + 0.114 * b) / 255.0;
		}

		UiInk UiContrastInk(std::uint32_t background)
		{
			// 极值文字/描边色（Solarized base3 / base02 / base03），亮度差很大，
			// 因此任意底色下文字与底色之间都有充足对比。
			const std::uint32_t kInkLight = 0xFFFDF6E3u;
			const std::uint32_t kInkDark = 0xFF073642u;
			const std::uint32_t kOutlineLight = 0xFFFDF6E3u;
			const std::uint32_t kOutlineDark = 0xFF002B36u;
			/** 向底色互补色混入的比例：线性响应信号配色，同时把对比度损失限制在 15% 以内。 */
			const double kTint = 0.15;

			const double luminance = UiColorLuminance(background);
			// 底色越亮 → 文字越暗（取最大对比的一侧）。
			const bool darkText = (luminance >= 0.5);
			// 底色的互补色：相对亮度恰为 1 - 底色亮度。
			const std::uint32_t complement = 0xFF000000u | ((~background) & 0x00FFFFFFu);

			UiInk ink;
			ink.text = MixColor(darkText ? kInkDark : kInkLight, complement, kTint);
			ink.text = WithAlpha(ink.text, 0xFFu);
			ink.outline = MixColor(darkText ? kOutlineLight : kOutlineDark, complement, kTint);
			ink.outline = WithAlpha(ink.outline, 0x99u);
			return ink;
		}
	void UiDrawCheckBox(gd::Graphics& g, const gd::RectF& rect, int state, float radius)
	{
		const Theme& theme = SolarizedLight();
		const float centerY = rect.Y + rect.Height * 0.5f;

		if (state == 1)
		{
			UiFillRoundRect(g, rect, radius, theme.accent);
			gd::Pen pen(ToGdiColor(theme.textOnAccent), std::max(1.4f, rect.Height * 0.11f));
			pen.SetStartCap(gd::LineCapRound);
			pen.SetEndCap(gd::LineCapRound);
			g.DrawLine(&pen, rect.X + rect.Width * 0.22f, centerY, rect.X + rect.Width * 0.42f,
			           rect.Y + rect.Height * 0.72f);
			g.DrawLine(&pen, rect.X + rect.Width * 0.42f, rect.Y + rect.Height * 0.72f,
			           rect.X + rect.Width * 0.78f, rect.Y + rect.Height * 0.28f);
		}
		else if (state == 2)
		{
			UiFillRoundRect(g, rect, radius, theme.accentSoft);
			UiDrawRoundRect(g, rect, radius, theme.accent, 1.0f);
			UiFillRect(g, gd::RectF(rect.X + rect.Width * 0.22f, centerY - rect.Height * 0.08f,
			                        rect.Width * 0.56f, rect.Height * 0.16f),
			           theme.accent);
		}
		else
		{
			UiFillRoundRect(g, rect, radius, theme.cardBg);
			UiDrawRoundRect(g, rect, radius, theme.borderStrong, 1.0f);
		}
	}

	void UiDrawSlider(gd::Graphics& g, const gd::RectF& track, double ratio, std::uint32_t fillColor,
	                  bool active, float scale)
	{
		if (track.Width <= 0.0f || track.Height <= 0.0f)
		{
			return;
		}

		if (ratio < 0.0)
		{
			ratio = 0.0;
		}
		if (ratio > 1.0)
		{
			ratio = 1.0;
		}

		const float radius = track.Height * 0.5f;
		UiFillRoundRect(g, track, radius, 0x2A657B83u);

		// 已填充部分严格止于圆钮中心，最小值时不会留下超出圆钮的填充残留。
		const float fillWidth = static_cast<float>(ratio) * track.Width;
		if (fillWidth > 0.5f)
		{
			UiFillRoundRect(g, gd::RectF(track.X, track.Y, fillWidth, track.Height), radius, fillColor);
		}

		const float knobRadius = radius + (active ? 2.5f * scale : 0.8f * scale);
		const float knobX = track.X + static_cast<float>(ratio) * track.Width;

		gd::SolidBrush knob(ToGdiColor(0xFFFFFFFFu));
		gd::Pen knobPen(ToGdiColor(0xFF586E75u), 1.4f * scale);
		g.FillEllipse(&knob, knobX - knobRadius, track.Y + radius - knobRadius, knobRadius * 2.0f,
		              knobRadius * 2.0f);
		g.DrawEllipse(&knobPen, knobX - knobRadius, track.Y + radius - knobRadius, knobRadius * 2.0f,
		              knobRadius * 2.0f);
	}

	float UiEditTextLeft(const gd::RectF& rect, const TextEdit& edit, HFONT font, float scale,
	                     float& innerWidth)
	{
		innerWidth = std::max(4.0f, rect.Width - 12.0f * scale);
		const float textLeft = rect.X + 6.0f * scale;

		const std::wstring& text = edit.Text();
		if (text.empty())
		{
			return textLeft;
		}

		const float textWidth = UiMeasureTextWidth(font, text);
		if (textWidth <= innerWidth)
		{
			return textLeft;
		}

		// 保证插入符可见：插入符超出右边界时向左滚动，并夹到总可滚动范围内。
		const float caretX = UiMeasureTextWidth(font, text.substr(0, edit.Caret()));
		float scroll = 0.0f;
		if (caretX > innerWidth)
		{
			scroll = caretX - innerWidth;
		}
		const float maximum = textWidth - innerWidth;
		scroll = std::max(0.0f, std::min(scroll, maximum));
		return textLeft - scroll;
	}

	std::size_t UiEditOffsetAt(HFONT font, const std::wstring& text, float localX)
	{
		if (text.empty() || font == nullptr)
		{
			return 0;
		}
		if (localX <= 0.0f)
		{
			return 0;
		}

		// 逐字符累加宽度，找到距离最近的字符边界（文本通常很短，线性扫描足够）。
		float previous = 0.0f;
		for (std::size_t index = 0; index < text.size(); ++index)
		{
			const float current = UiMeasureTextWidth(font, text.substr(0, index + 1));
			if (localX < current)
			{
				// 落在本字符的左半 → 取左边界，右半 → 取右边界。
				return (localX - previous <= current - localX) ? index : (index + 1);
			}
			previous = current;
		}
		return text.size();
	}

	void UiTextAtClipped(gd::Graphics& g, const std::wstring& text, HFONT font, float x, const gd::RectF& rect,
	                     std::uint32_t argb, const gd::RectF& clipRect)
	{
		if (text.empty() || font == nullptr || clipRect.Width <= 0.0f || clipRect.Height <= 0.0f)
		{
			return;
		}

		HDC hdc = g.GetHDC();
		if (hdc == nullptr)
		{
			return;
		}

		HGDIOBJ oldFont = SelectObject(hdc, font);
		const int oldMode = SetBkMode(hdc, TRANSPARENT);
		const COLORREF oldColor = SetTextColor(hdc, ToColorRef(argb));

		TEXTMETRICW metrics = {};
		GetTextMetricsW(hdc, &metrics);
		const int baselineY = static_cast<int>(
		    std::floor(rect.Y + (rect.Height - static_cast<float>(metrics.tmHeight)) * 0.5f));

		RECT clip = {};
		clip.left = static_cast<LONG>(std::floor(clipRect.X));
		clip.top = static_cast<LONG>(std::floor(clipRect.Y));
		clip.right = static_cast<LONG>(std::ceil(clipRect.X + clipRect.Width));
		clip.bottom = static_cast<LONG>(std::ceil(clipRect.Y + clipRect.Height));

		// ETO_CLIPPED 让 GDI 在指定矩形内裁剪，长文本不会再画到输入框之外。
		ExtTextOutW(hdc, static_cast<int>(std::floor(x)), baselineY, ETO_CLIPPED, &clip, text.c_str(),
		            static_cast<UINT>(text.size()), nullptr);

		SetTextColor(hdc, oldColor);
		SetBkMode(hdc, oldMode);
		SelectObject(hdc, oldFont);
		g.ReleaseHDC(hdc);
	}

	void UiDrawEditField(gd::Graphics& g, const gd::RectF& rect, const TextEdit& edit, HFONT font, float scale)
	{
		if (rect.Width <= 0.0f || rect.Height <= 0.0f || font == nullptr)
		{
			return;
		}

		const Theme& theme = SolarizedLight();
		const float corner = 3.0f * scale;

		UiFillRoundRect(g, rect, corner, theme.cardBg);
		UiDrawRoundRect(g, rect, corner, theme.accent, 1.6f);

		UiDrawEditFieldContent(g, rect, edit, font, scale);
	}

	void UiDrawEditFieldContent(gd::Graphics& g, const gd::RectF& rect, const TextEdit& edit, HFONT font,
	                            float scale)
	{
		if (rect.Width <= 0.0f || rect.Height <= 0.0f || font == nullptr)
		{
			return;
		}

		const Theme& theme = SolarizedLight();
		const std::wstring& text = edit.Text();
		const float innerLeft = rect.X + 6.0f * scale;

		float innerWidth = 0.0f;
		const float textLeft = UiEditTextLeft(rect, edit, font, scale, innerWidth);
		const gd::RectF clipRect(innerLeft, rect.Y + 1.0f * scale, innerWidth, rect.Height - 2.0f * scale);

		if (text.empty())
		{
			// 空内容仍绘制插入符，保持焦点可见。
			UiDrawLine(g, textLeft, rect.Y + 4.0f * scale, textLeft, rect.Y + rect.Height - 4.0f * scale,
			           theme.accent, 1.4f * scale);
			return;
		}

		// 光标与选区端点对应的像素位置（以文本左端为原点）。
		const float caretX = UiMeasureTextWidth(font, text.substr(0, edit.Caret()));
		const float selBeginX =
		    edit.HasSelection() ? UiMeasureTextWidth(font, text.substr(0, edit.SelectionBegin())) : 0.0f;
		const float selEndX =
		    edit.HasSelection() ? UiMeasureTextWidth(font, text.substr(0, edit.SelectionEnd())) : 0.0f;

		const bool fullSelection =
		    edit.HasSelection() && edit.SelectionBegin() == 0 && edit.SelectionEnd() == text.size();

		const int saveState = g.Save();
		g.SetClip(clipRect, gd::CombineModeIntersect);

		// 选区高亮绘制在文本之下，整段选中时呈现“已全选”观感。
		// ⚠️ 这里**必须自己把矩形夹到内容区**：`UiFillRect` 对面积足够大的不透明矩形会走
		// GDI `FillRect` 快路径，而 GDI 绘制**不受 GDI+ 裁剪区约束**，长文本的全选高亮
		// （宽度等于整段文本宽度）因此会溢出到输入框之外。夹取之后矩形始终落在框内，
		// 既保留快路径又不越界。
		if (edit.HasSelection() && selEndX > selBeginX)
		{
			gd::RectF highlight(textLeft + selBeginX, rect.Y + 3.0f * scale, selEndX - selBeginX,
			                    rect.Height - 6.0f * scale);
			const float left = std::max(highlight.X, clipRect.X);
			const float right = std::min(highlight.X + highlight.Width, clipRect.X + clipRect.Width);
			const float top = std::max(highlight.Y, clipRect.Y);
			const float bottom = std::min(highlight.Y + highlight.Height, clipRect.Y + clipRect.Height);
			highlight = gd::RectF(left, top, right - left, bottom - top);
			UiFillRect(g, highlight, theme.accent);
		}

		// 长文本用 ETO_CLIPPING 交给 GDI 裁剪，避免字符画到输入框之外。
		UiTextAtClipped(g, text, font, textLeft, rect,
		                fullSelection ? theme.textOnAccent : theme.textStrong, clipRect);

		if (!fullSelection && edit.HasSelection() && selEndX > selBeginX)
		{
			// 局部选区：在反白底衬上重绘被选中的片段，其余文字保持常规颜色。
			const std::wstring selected =
			    text.substr(edit.SelectionBegin(), edit.SelectionEnd() - edit.SelectionBegin());
			UiTextAtClipped(g, selected, font, textLeft + selBeginX, rect, theme.textOnAccent, clipRect);
		}

		// 插入符。
		const float caretDrawX = textLeft + caretX;
		UiDrawLine(g, caretDrawX, rect.Y + 4.0f * scale, caretDrawX, rect.Y + rect.Height - 4.0f * scale,
		           theme.textStrong, 1.4f * scale);

		g.Restore(saveState);
	}

	bool UiEditFieldMouseDown(HFONT font, const gd::RectF& rect, TextEdit& edit, float scale, int x, int y)
	{
		if (!edit.Active() || font == nullptr || rect.Width <= 0.0f)
		{
			return false;
		}
		if (!UiPointInRect(rect, static_cast<float>(x), static_cast<float>(y)))
		{
			return false;
		}

		// 用与绘制完全相同的布局函数换算文本起点，保证点哪儿光标就落在哪儿。
		float innerWidth = 0.0f;
		const float textLeft = UiEditTextLeft(rect, edit, font, scale, innerWidth);
		edit.BeginDrag(UiEditOffsetAt(font, edit.Text(), static_cast<float>(x) - textLeft));
		return true;
	}

	bool UiEditFieldMouseMove(HFONT font, const gd::RectF& rect, TextEdit& edit, float scale, int x)
	{
		if (!edit.Active() || !edit.Dragging() || font == nullptr || rect.Width <= 0.0f)
		{
			return false;
		}

		float innerWidth = 0.0f;
		const float textLeft = UiEditTextLeft(rect, edit, font, scale, innerWidth);
		return edit.UpdateDrag(UiEditOffsetAt(font, edit.Text(), static_cast<float>(x) - textLeft));
	}

	bool UiSwatchNeedsOutline(float opacity)
	{
		return !(opacity >= kSwatchOutlineOpacity);
	}

	std::uint32_t UiDrawSwatch(gd::Graphics& g, const gd::RectF& rect, std::uint32_t color, float opacity,
	                           float radius, float scale)
	{
		double alpha = static_cast<double>(opacity);
		if (!(alpha > 0.0))
		{
			alpha = 0.0;
		}
		if (alpha > 1.0)
		{
			alpha = 1.0;
		}

		const std::uint32_t filled = WithAlpha(color, static_cast<unsigned int>(alpha * 255.0 + 0.5));
		if (rect.Width > 0.0f && rect.Height > 0.0f)
		{
			UiFillRoundRect(g, rect, radius, filled);

			// 透明度过低时色块本身难以辨识，补充一圈描边以保持可读性；可见时不绘制描边。
			if (UiSwatchNeedsOutline(opacity))
			{
				UiDrawRoundRect(g, rect, radius, SolarizedLight().borderStrong,
				                std::max(1.0f, scale));
			}
		}
		return filled;
	}

} // namespace jdi