C# GDI+如何正确获取单个字符角点并绘制外接矩形框

我编写的C# GDI+绘图代码及当前输出如下：

现有代码：

Bitmap bitmap = new Bitmap(600, 300, PixelFormat.Format32bppArgb);
Graphics g = Graphics.FromImage(bitmap);
GraphicsPath path = new GraphicsPath();
StringFormat format = new StringFormat();
Rectangle rect = new Rectangle(0, 0, 600, 300);
SolidBrush Brush = new SolidBrush(Color.White);
g.FillRectangle(Brush, rect);


g.SmoothingMode = SmoothingMode.AntiAlias;
format.Alignment = StringAlignment.Center;
format.LineAlignment = StringAlignment.Center;
path.AddString(textBox1.Text, FontFamily.GenericSansSerif, (int)FontStyle.Bold, 128, rect, format);

Brush = new SolidBrush(Color.Blue);
g.FillPath(Brush, path);

float x = path.GetBounds().X;
float y = path.GetBounds().Y;
float w = path.GetBounds().Width / textBox1.Text.Length;
float h = path.GetBounds().Height;

Pen redPen = new Pen(Color.Red, 2);
for (int i = 0; i < textBox1.Text.Length+1; i++)
{
    rect = new Rectangle((int)x, (int)y, (int)w*i, (int)h);
    g.DrawRectangle(redPen, rect);
}

pictureBox1.Image = bitmap;

问题原因 #

当前代码的实现逻辑存在错误：直接将整个字符串的总宽度按字符数平均分配，默认所有字符宽度相等，遇到非等宽字符（如中文、不同宽度的英文字母）时，计算出的矩形和实际字符位置不匹配，无法正确获取每个字符的角点坐标。
我需要为每个字符绘制并填充外接矩形，预期效果如下：

将原逻辑改为逐个字符测量实际尺寸，再分别绘制字符和对应外接矩形即可，修改后代码如下：

Bitmap bitmap = new Bitmap(600, 300, PixelFormat.Format32bppArgb);
Graphics g = Graphics.FromImage(bitmap);
StringFormat format = new StringFormat();
Rectangle totalRect = new Rectangle(0, 0, 600, 300);
// 初始化背景
SolidBrush whiteBrush = new SolidBrush(Color.White);
g.FillRectangle(whiteBrush, totalRect);
g.SmoothingMode = SmoothingMode.AntiAlias;
format.LineAlignment = StringAlignment.Center;

string inputText = textBox1.Text;
Font drawFont = new Font(FontFamily.GenericSansSerif, 128, FontStyle.Bold);
// 计算字符串总宽度，实现整体居中对齐
SizeF totalTextSize = g.MeasureString(inputText, drawFont);
float currentX = (totalRect.Width - totalTextSize.Width) / 2;
float baseY = totalRect.Height / 2;

SolidBrush textBrush = new SolidBrush(Color.Blue);
Pen borderPen = new Pen(Color.Red, 2);

// 逐个处理每个字符
for (int i = 0; i < inputText.Length; i++)
{
    char currentChar = inputText[i];
    // 测量当前字符实际宽高
    SizeF charSize = g.MeasureString(currentChar.ToString(), drawFont);
    // 计算当前字符的外接矩形
    RectangleF charBounds = new RectangleF(currentX, baseY - charSize.Height / 2, charSize.Width, charSize.Height);
    // 绘制字符
    g.DrawString(currentChar.ToString(), drawFont, textBrush, charBounds.Location);
    // 绘制字符外接矩形
    g.DrawRectangle(borderPen, charBounds.X, charBounds.Y, charBounds.Width, charBounds.Height);
    // 偏移X坐标到下一个字符起始位置
    currentX += charSize.Width;
}

pictureBox1.Image = bitmap;

// 释放GDI资源，避免内存泄漏
drawFont.Dispose();
whiteBrush.Dispose();
textBrush.Dispose();
borderPen.Dispose();
g.Dispose();

修改点说明：

• 废弃原逻辑中均分字符串宽度的错误计算方式，改为单独测量每个字符的实际尺寸
• 先计算整个字符串的总宽度，保证字符串整体居中，和原排版需求一致
• 每个字符的外接矩形完全匹配字符实际绘制位置，无偏移
• 补充了GDI资源释放逻辑，避免长期运行出现内存泄漏

内容的提问来源于stack exchange，提问作者AndrePer