256 lines
10 KiB
C#
256 lines
10 KiB
C#
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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System;
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using System.Collections.Generic;
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using Microsoft.Maui.Controls;
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using Microsoft.Maui.Graphics;
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using Microsoft.Maui.Platform.Linux.Rendering;
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using SkiaSharp;
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namespace Microsoft.Maui.Platform;
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public partial class SkiaEditor
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{
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protected override void OnDraw(SKCanvas canvas, SKRect bounds)
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{
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var paddingLeft = (float)Padding.Left;
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var paddingTop = (float)Padding.Top;
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var paddingRight = (float)Padding.Right;
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var paddingBottom = (float)Padding.Bottom;
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var fontSize = (float)FontSize;
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var lineHeight = (float)LineHeight;
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var cornerRadius = (float)CornerRadius;
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// Update wrap width if bounds changed and re-wrap text
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var newWrapWidth = bounds.Width - paddingLeft - paddingRight;
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if (Math.Abs(newWrapWidth - _wrapWidth) > 1)
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{
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_wrapWidth = newWrapWidth;
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UpdateLines();
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}
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// Draw background
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var bgColor = EditorBackgroundColor != null ? ToSKColor(EditorBackgroundColor) :
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(IsEnabled ? SkiaTheme.BackgroundWhiteSK : SkiaTheme.Gray100SK);
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using var bgPaint = new SKPaint
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{
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Color = bgColor,
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Style = SKPaintStyle.Fill,
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IsAntialias = true
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};
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canvas.DrawRoundRect(new SKRoundRect(bounds, cornerRadius), bgPaint);
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// Draw border only if BorderColor is not transparent
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if (BorderColor != null && BorderColor != Colors.Transparent && BorderColor.Alpha > 0)
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{
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using var borderPaint = new SKPaint
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{
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Color = IsFocused ? ToSKColor(CursorColor) : ToSKColor(BorderColor),
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Style = SKPaintStyle.Stroke,
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StrokeWidth = IsFocused ? 2 : 1,
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IsAntialias = true
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};
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canvas.DrawRoundRect(new SKRoundRect(bounds, cornerRadius), borderPaint);
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}
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// Setup text rendering
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using var font = new SKFont(SKTypeface.Default, fontSize);
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var lineSpacing = fontSize * lineHeight;
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// Clip to content area
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var contentRect = new SKRect(
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bounds.Left + paddingLeft,
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bounds.Top + paddingTop,
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bounds.Right - paddingRight,
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bounds.Bottom - paddingBottom);
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canvas.Save();
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canvas.ClipRect(contentRect);
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// Don't translate - let the text draw at absolute positions
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// canvas.Translate(0, -_scrollOffsetY);
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if (string.IsNullOrEmpty(Text) && !string.IsNullOrEmpty(Placeholder))
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{
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using var placeholderPaint = new SKPaint(font)
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{
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Color = GetEffectivePlaceholderColor(),
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IsAntialias = true
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};
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// Handle multiline placeholder text by splitting on newlines
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var placeholderLines = Placeholder.Split('\n');
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var y = contentRect.Top + fontSize;
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foreach (var line in placeholderLines)
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{
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canvas.DrawText(line, contentRect.Left, y, placeholderPaint);
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y += lineSpacing;
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}
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}
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else
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{
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var textColor = GetEffectiveTextColor();
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using var textPaint = new SKPaint(font)
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{
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Color = IsEnabled ? textColor : textColor.WithAlpha(128),
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IsAntialias = true
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};
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using var selectionPaint = new SKPaint
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{
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Color = ToSKColor(SelectionColor),
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Style = SKPaintStyle.Fill
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};
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var y = contentRect.Top + fontSize;
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var charIndex = 0;
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for (int lineIndex = 0; lineIndex < _lines.Count; lineIndex++)
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{
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var line = _lines[lineIndex];
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var x = contentRect.Left;
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// Draw selection for this line if applicable
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if (_selectionStart >= 0 && _selectionLength != 0)
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{
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// Handle both positive and negative selection lengths
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var selStart = _selectionLength > 0 ? _selectionStart : _selectionStart + _selectionLength;
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var selEnd = _selectionLength > 0 ? _selectionStart + _selectionLength : _selectionStart;
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var lineStart = charIndex;
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var lineEnd = charIndex + line.Length;
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if (selEnd > lineStart && selStart < lineEnd)
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{
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var selStartInLine = Math.Max(0, selStart - lineStart);
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var selEndInLine = Math.Min(line.Length, selEnd - lineStart);
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var startX = x + MeasureText(line.Substring(0, selStartInLine), font);
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var endX = x + MeasureText(line.Substring(0, selEndInLine), font);
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canvas.DrawRect(new SKRect(startX, y - fontSize, endX, y + lineSpacing - fontSize), selectionPaint);
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}
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}
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// Determine if pre-edit text should be displayed on this line
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var (cursorLine, cursorCol) = GetLineColumn(_cursorPosition);
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var displayLine = line;
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var hasPreEditOnThisLine = !string.IsNullOrEmpty(_preEditText) && cursorLine == lineIndex;
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if (hasPreEditOnThisLine)
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{
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// Insert pre-edit text at cursor position within this line
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var insertPos = Math.Min(cursorCol, line.Length);
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displayLine = line.Insert(insertPos, _preEditText);
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}
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// Draw the text with font fallback for emoji/CJK support
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DrawTextWithFallback(canvas, displayLine, x, y, textPaint, SKTypeface.Default);
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// Draw underline for pre-edit (composition) text
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if (hasPreEditOnThisLine)
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{
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DrawPreEditUnderline(canvas, textPaint, line, x, y, contentRect);
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}
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// Draw cursor if on this line
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if (IsFocused && _cursorVisible)
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{
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if (cursorLine == lineIndex)
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{
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// Account for pre-edit text when calculating cursor position
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var textToCursor = line.Substring(0, Math.Min(cursorCol, line.Length));
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var cursorX = x + MeasureText(textToCursor, font);
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// If there's pre-edit text, cursor goes after it
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if (hasPreEditOnThisLine && _preEditText.Length > 0)
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{
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cursorX += MeasureText(_preEditText, font);
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}
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using var cursorPaint = new SKPaint
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{
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Color = ToSKColor(CursorColor),
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Style = SKPaintStyle.Stroke,
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StrokeWidth = 2,
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IsAntialias = true
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};
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canvas.DrawLine(cursorX, y - fontSize + 2, cursorX, y + 2, cursorPaint);
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}
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}
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y += lineSpacing;
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charIndex += line.Length + 1;
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}
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}
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canvas.Restore();
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// Draw scrollbar if needed
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var totalHeight = _lines.Count * fontSize * lineHeight;
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if (totalHeight > contentRect.Height)
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{
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DrawScrollbar(canvas, bounds, contentRect.Height, totalHeight);
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}
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}
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private float MeasureText(string text, SKFont font)
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{
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if (string.IsNullOrEmpty(text)) return 0;
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using var paint = new SKPaint(font);
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return paint.MeasureText(text);
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}
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private void DrawScrollbar(SKCanvas canvas, SKRect bounds, float viewHeight, float contentHeight)
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{
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var scrollbarWidth = 6f;
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var scrollbarMargin = 2f;
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var paddingTop = (float)Padding.Top;
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var scrollbarHeight = Math.Max(20, viewHeight * (viewHeight / contentHeight));
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var scrollbarY = bounds.Top + paddingTop + (_scrollOffsetY / contentHeight) * (viewHeight - scrollbarHeight);
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using var paint = new SKPaint
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{
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Color = SkiaTheme.Shadow25SK,
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Style = SKPaintStyle.Fill,
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IsAntialias = true
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};
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canvas.DrawRoundRect(new SKRoundRect(
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new SKRect(
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bounds.Right - scrollbarWidth - scrollbarMargin,
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scrollbarY,
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bounds.Right - scrollbarMargin,
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scrollbarY + scrollbarHeight),
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scrollbarWidth / 2), paint);
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}
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/// <summary>
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/// Draws text with font fallback for emoji, CJK, and other scripts.
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/// </summary>
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private void DrawTextWithFallback(SKCanvas canvas, string text, float x, float y, SKPaint paint, SKTypeface preferredTypeface)
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=> TextRenderingHelper.DrawTextWithFallback(canvas, text, x, y, paint, preferredTypeface, (float)FontSize);
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/// <summary>
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/// Draws underline for IME pre-edit (composition) text.
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/// </summary>
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private void DrawPreEditUnderline(SKCanvas canvas, SKPaint paint, string displayText, float x, float y, SKRect bounds)
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=> TextRenderingHelper.DrawPreEditUnderline(canvas, paint, displayText, _cursorPosition, _preEditText, x, y);
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protected override Size MeasureOverride(Size availableSize)
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{
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if (AutoSize)
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{
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var fontSize = (float)FontSize;
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var lineHeight = (float)LineHeight;
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var lineSpacing = fontSize * lineHeight;
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var verticalPadding = Padding.Top + Padding.Bottom;
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var height = Math.Max(lineSpacing + verticalPadding, _lines.Count * lineSpacing + verticalPadding);
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return new Size(
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availableSize.Width < double.MaxValue ? availableSize.Width : 200,
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Math.Min(height, availableSize.Height < double.MaxValue ? availableSize.Height : 200));
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}
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return new Size(
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availableSize.Width < double.MaxValue ? Math.Min(availableSize.Width, 200) : 200,
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availableSize.Height < double.MaxValue ? Math.Min(availableSize.Height, 150) : 150);
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}
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}
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