WPF GDI+字符串绘制成图片（二）

原文:WPF GDI+字符串绘制成图片（二）

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/BYH371256/article/details/83412533

本章讲述：在WPF中，使用GDI+技术，把字符串数据绘制成图片；文字可分为：居左显示、居中显示、居右显示。

完整的例子参考网址：

1、XAML 前端设计

<Window x:Class="WPF_GDI_Test.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <Border Margin="1" BorderThickness="1" BorderBrush="Gray">
            <StackPanel Orientation="Horizontal" VerticalAlignment="Top">
                <Button Margin="10" Content="左对齐" Height="25" Width="50" Click="Button_Click"/>
                <Button Margin="10" Content="居中对齐" Height="25" Width="60" Click="Button_Click_1"/>
                <Button Margin="10" Content="右对齐" Height="25" Width="50" Click="Button_Click_2"/>
            </StackPanel>
        </Border>
        <Border Margin="1" BorderThickness="1" BorderBrush="Gray">
            <Image x:Name="img" />
        </Border>
    </StackPanel>
</Window>

2、后台逻辑主要代码

private List<string> SourStrs;
private string path = System.Windows.Forms.Application.StartupPath + "\\11.png";
private int mapwidth = 1920;
private int mapheight = 1080;
private float fontSize;
private string fontFamily;

public MainWindow()
{
	InitializeComponent();

	Drawing();
}

private void Drawing()
{
	fontFamily = "Microsoft YaHei";
	fontSize = 100f;
	string str1 = "一个实用的C#字符串操作类，内置了14个字符串处理函数，几乎囊括了所有常用到的字符串处理操作，比如转换字符串，获取指定字符分";
	int strlen = str1.Length;
	int num = Encoding.Default.GetBytes(str1).Length;
	Font font = new Font(fontFamily, fontSize);
	this.DrawingTextImage(str1, font, 1920, 1080);
}

private void DrawingTextImage(string txt, Font font, int w, int h)
{
	int strlen = txt.Length;
	int num = Encoding.Default.GetBytes(txt).Length;
	Bitmap map = new Bitmap(1920, 1080);
	Graphics g = Graphics.FromImage(map);
	g.PageUnit = GraphicsUnit.Pixel;
	g.SmoothingMode = SmoothingMode.HighQuality;
	g.Clear(Color.Black);
	g.DrawRectangle(new Pen(Color.Red, 4f), 10, 10, 0x76c, 0x424);
	SizeF size1 = this.Get_StrWidth1(g, "字", font);
	SizeF size2 = this.Get_StrWidth1(g, "H", font);
	int n = (int)(((float)w) / size2.Width);
	char[] txtSour = txt.ToArray<char>();
	List<string> bkstrs = this.GetStrList(g, font, txt, 1080);
	this.SourStrs = bkstrs;
	int row = 0;
	foreach (string tmp in bkstrs)
	{
		g.DrawString(tmp, font, Brushes.OrangeRed, (float)0f, (float)(row * size2.Height));
		row++;
	}
	g.Dispose();
	map.Save(this.path, System.Drawing.Imaging.ImageFormat.Png);
	map.Dispose();
	this.BitmpToImageSource(this.path);
}

//居左、居中、居右显示
private void DrawStringBitmap(int mode)
{
	Bitmap map = new Bitmap(1920, 1080);
	Graphics g = Graphics.FromImage(map);
	g.PageUnit = GraphicsUnit.Pixel;
	g.SmoothingMode = SmoothingMode.HighQuality;
	g.Clear(Color.Black);
	g.DrawRectangle(new Pen(Color.Red, 4f), 10, 10, 0x76c, 0x424);
	Font font = new Font(this.fontFamily, this.fontSize);
	float row = 0f;
	float tmph = this.Get_StrWidth1(g, "H", font).Height;
	foreach (string tmp in this.SourStrs)
	{
		SizeF size = this.Get_StrWidth1(g, tmp, font);
		float x = 0f;
		switch (mode)
		{
			case 0:
				x = 0f;
				break;

			case 1:
				x = (this.mapwidth - size.Width) / 2f;
				break;

			case 2:
				x = this.mapwidth - size.Width;
				break;
		}
		g.DrawString(tmp, font, Brushes.OrangeRed, x, row * size.Height);
		row++;
	}
	g.Dispose();
	map.Save(this.path, ImageFormat.Png);
	map.Dispose();
	this.BitmpToImageSource(this.path);
}

private double Get_StrWidth1(Graphics g, char txt, Font font)
{
	return (double)g.MeasureString(txt.ToString(), font).Width;
}

private double Get_StrWidth2(Graphics g, string txt, Font font)
{
	return (double)TextRenderer.MeasureText(g, txt, font, new System.Drawing.Size(0, 0)).Width;
}

private SizeF Get_StrWidth1(Graphics g, string txt, Font font)
{
	return TextRenderer.MeasureText(g, txt, font, new System.Drawing.Size(0, 0));
}

public static System.Windows.Media.FormattedText Get_StrWidth(string txt, double fontSize, string fontFamily)
{
	System.Windows.Media.FormattedText formattedText = new System.Windows.Media.FormattedText(
			txt,
			System.Globalization.CultureInfo.InvariantCulture,
			System.Windows.FlowDirection.LeftToRight,
				new System.Windows.Media.Typeface(fontFamily.ToString()),
				fontSize,
				System.Windows.Media.Brushes.Black
	  );

	return formattedText;
}

3、输入字符串处理逻辑

private int GetRowIndex(Graphics g, Font font, int ridex, string txt, int n, out string otxt, bool isend)
{
	int len = n;
	string tmptxt = txt.Substring(ridex, n);
	double txtw = 0.0;
	double maxw = 1920.0;
	double tmp = 0.0;
	do
	{
		tmp = this.Get_StrWidth1(g, tmptxt, font).Width;
		txtw = tmp;
		if (isend)
		{
			break;
		}
		if (txtw < maxw)
		{
			tmptxt = txt.Substring(ridex, ++len);
		}
		else
		{
			len--;
			tmptxt = tmptxt.Substring(0, len);
		}
	}
	while (txtw < maxw);
	otxt = tmptxt;
	return len;
}

private List<string> GetStrList(Graphics g, Font font, string txt, int maxh)
{
	List<string> bk = new List<string>();
	string tmptxt = null;
	int idex = 0;
	double tmph = 0.0;
	double w = 1920.0;
	SizeF size2 = this.Get_StrWidth1(g, "H", font);
	int n = (int)(w / ((double)size2.Width));
	int row = 0;
	bool isend = false;
	do
	{
		if ((idex + n) > txt.Length)
		{
			n = txt.Length - idex;
			isend = true;
		}
		idex += this.GetRowIndex(g, font, idex, txt, n, out tmptxt, isend);
		row++;
		tmph = row * size2.Height;
		if (maxh > tmph)
		{
			bk.Add(tmptxt);
		}
	}
	while (tmph < maxh);
	return bk;
}

4、保存图片

//保存图片
private void BitmpToImageSource(string filepath)
{
	System.IO.FileStream fs = new System.IO.FileStream(filepath, System.IO.FileMode.Open, System.IO.FileAccess.Read);
	byte[] buffer = new byte[fs.Length];
	fs.Read(buffer, 0, buffer.Length);
	fs.Close();
	fs.Dispose();

	System.IO.MemoryStream ms = new System.IO.MemoryStream(buffer);
	System.Windows.Media.Imaging.BitmapImage bitmapImage = new System.Windows.Media.Imaging.BitmapImage();
	bitmapImage.BeginInit();
	bitmapImage.StreamSource = ms;
	bitmapImage.EndInit();

	img.Source = bitmapImage;
}

5、按钮响应事件

private void Button_Click(object sender, RoutedEventArgs e)
{
	if (this.SourStrs != null)
	{
		DrawStringBitmap(0);//参数0：居左；1：居中；2：居右
	}
}

6、效果图