Just-DataInspector/Utilities/Src/PaintUtil.cpp

#include "PaintUtil.hpp"

#include <algorithm>
#include <cmath>

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;
		}
	}

	bool UiFonts::Create(UINT targetDpi)
	{
		Destroy();
		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 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 UiTextWidth(gd::Graphics& g, const std::wstring& text, HFONT font)
	{
		// 直接复用 UiMeasureTextWidth：后者用 GetDC(nullptr) 取度量 HDC，
		// 不会触发 **Graphics::GetHDC() 的 GDI+ 批次刷新**（实测每次约 5µs）。
		// UiEllipsize 会反复调用本函数（逐字符回退时每步一次），
		// 若走 GetHDC 路线，一个长名称就要刷新十几次，是拖拽掉帧的隐性来源之一。
		(void)g;
		return UiMeasureTextWidth(font, text);
	}

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

		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);

		return static_cast<float>(size.cx);
	}

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

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

		std::wstring result = text;
		while (!result.empty())
		{
			result.pop_back();
			if (UiTextWidth(g, result, font) + 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;
	}

	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);

		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；
		// 叠加上 GDI+ 裁剪，高亮同样不会越过输入框边界。
		if (edit.HasSelection() && selEndX > selBeginX)
		{
			const gd::RectF highlight(textLeft + selBeginX, rect.Y + 3.0f * scale, selEndX - selBeginX,
			                          rect.Height - 6.0f * scale);
			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