如何在运行时即时从文本生成图像
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【中文标题】如何在运行时即时从文本生成图像【英文标题】：How to generate an image from text on fly at runtime 【发布时间】：2011-01-05 10:27:49 【问题描述】：任何人都可以指导如何从输入文本生成图像。图片可能有任何扩展名都没有关系。
【问题讨论】：
您的意思是像您从屏幕截图中获得的图像吗？当然，一些格式/扩展会比其他格式/扩展更好。 你是什么意思的文本输入？ 不，这不是屏幕截图，我们有输入文本框，我们使用的是 C# 【参考方案1】：使用imagemagick 在图像上呈现文本（在服务器上）
由于您使用的是 C#，因此您还可以直接使用 .Net 类进行位图和字体操作（使用如下类：System.Drawing.Bitmap 和 System.Drawing.Graphics）
【讨论】：
【参考方案2】：好的，假设你想在 C# 中的图像上绘制一个字符串，你需要在这里使用 System.Drawing 命名空间：
private Image DrawText(String text, Font font, Color textColor, Color backColor)
//first, create a dummy bitmap just to get a graphics object
Image img = new Bitmap(1, 1);
Graphics drawing = Graphics.FromImage(img);
//measure the string to see how big the image needs to be
SizeF textSize = drawing.MeasureString(text, font);
//free up the dummy image and old graphics object
img.Dispose();
drawing.Dispose();
//create a new image of the right size
img = new Bitmap((int) textSize.Width, (int)textSize.Height);
drawing = Graphics.FromImage(img);
//paint the background
drawing.Clear(backColor);
//create a brush for the text
Brush textBrush = new SolidBrush(textColor);
drawing.DrawString(text, font, textBrush, 0, 0);
drawing.Save();
textBrush.Dispose();
drawing.Dispose();
return img;
此代码将首先测量字符串，然后创建正确大小的图像。
如果要保存此函数的返回，只需调用返回图像的Save方法即可。
【讨论】：
“Image img = new Bitmap(0, 0);”行不起作用：您无法创建 0 尺寸的图像。改成“new Bitmap(1, 1)”，就可以了。 如果您在drawing.DrawString(text, font, textBrush, 0, 0); 行之前添加drawing.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;，您将获得更平滑的抗锯齿文本。
如果将字体大小加倍，然后将生成的图像大小缩小一半，您可以获得更好看的结果，这对小字体和符号字体特别有效。【参考方案3】：
我刚刚将answer 中提到的这个方法翻译成VB.NET 方法。也许这对某人有帮助。
Public Function DrawText(ByVal text As String, ByRef font As Font, ByRef textColor As Color, ByRef backColor As Color) As Image
' first, create a dummy bitmap just to get a graphics object
Dim img As Image = New Bitmap(1, 1)
Dim drawing As Graphics = Graphics.FromImage(img)
' measure the string to see how big the image needs to be
Dim textSize As SizeF = drawing.MeasureString(Text, Font)
' free up the dummy image and old graphics object
img.Dispose()
drawing.Dispose()
' create a new image of the right size
img = New Bitmap(CType(textSize.Width, Integer), CType(textSize.Height, Integer))
drawing = Graphics.FromImage(img)
' paint the background
drawing.Clear(BackColor)
' create a brush for the text
Dim textBrush As Brush = New SolidBrush(textColor)
drawing.DrawString(text, font, textBrush, 0, 0)
drawing.Save()
textBrush.Dispose()
drawing.Dispose()
Return img
End Function
编辑：修正错字。
【讨论】：
谢谢弗雷迪，你为我节省了很多精力。【参考方案4】：F#版本：
open System.Drawing
let drawText text font textColor backColor =
let size =
use dummyImg = new Bitmap(1, 1)
use drawing = Graphics.FromImage(dummyImg)
drawing.MeasureString(text, font)
let img = new Bitmap((int size.Width), (int size.Height))
use drawing = Graphics.FromImage(img)
use textBrush = new SolidBrush(textColor)
do
drawing.Clear(backColor)
drawing.DrawString(text, font, textBrush, PointF())
drawing.Save() |> ignore
img
【讨论】：
【参考方案5】：谢谢卡扎尔。使用 USING 处理使用后的图像/图形对象并引入最小尺寸参数的先前答案略有改进
private Image DrawTextImage(String currencyCode, Font font, Color textColor, Color backColor)
return DrawTextImage(currencyCode, font, textColor, backColor, Size.Empty);
private Image DrawTextImage(String currencyCode, Font font, Color textColor, Color backColor, Size minSize)
//first, create a dummy bitmap just to get a graphics object
SizeF textSize;
using (Image img = new Bitmap(1, 1))
using (Graphics drawing = Graphics.FromImage(img))
//measure the string to see how big the image needs to be
textSize = drawing.MeasureString(currencyCode, font);
if (!minSize.IsEmpty)
textSize.Width = textSize.Width > minSize.Width ? textSize.Width : minSize.Width;
textSize.Height = textSize.Height > minSize.Height ? textSize.Height : minSize.Height;
//create a new image of the right size
Image retImg = new Bitmap((int)textSize.Width, (int)textSize.Height);
using (var drawing = Graphics.FromImage(retImg))
//paint the background
drawing.Clear(backColor);
//create a brush for the text
using (Brush textBrush = new SolidBrush(textColor))
drawing.DrawString(currencyCode, font, textBrush, 0, 0);
drawing.Save();
return retImg;
【讨论】：
【参考方案6】：这是 Panayiotis 版本的 Kazar 答案，带有可选参数和文档，适合添加到库类中。
/// <summary>
/// Creates an image containing the given text.
/// NOTE: the image should be disposed after use.
/// </summary>
/// <param name="text">Text to draw</param>
/// <param name="fontOptional">Font to use, defaults to Control.DefaultFont</param>
/// <param name="textColorOptional">Text color, defaults to Black</param>
/// <param name="backColorOptional">Background color, defaults to white</param>
/// <param name="minSizeOptional">Minimum image size, defaults the size required to display the text</param>
/// <returns>The image containing the text, which should be disposed after use</returns>
public static Image DrawText(string text, Font fontOptional=null, Color? textColorOptional=null, Color? backColorOptional=null, Size? minSizeOptional=null)
Font font = Control.DefaultFont;
if (fontOptional != null)
font = fontOptional;
Color textColor = Color.Black;
if (textColorOptional != null)
textColor = (Color)textColorOptional;
Color backColor = Color.White;
if (backColorOptional != null)
backColor = (Color)backColorOptional;
Size minSize = Size.Empty;
if (minSizeOptional != null)
minSize = (Size)minSizeOptional;
//first, create a dummy bitmap just to get a graphics object
SizeF textSize;
using (Image img = new Bitmap(1, 1))
using (Graphics drawing = Graphics.FromImage(img))
//measure the string to see how big the image needs to be
textSize = drawing.MeasureString(text, font);
if (!minSize.IsEmpty)
textSize.Width = textSize.Width > minSize.Width ? textSize.Width : minSize.Width;
textSize.Height = textSize.Height > minSize.Height ? textSize.Height : minSize.Height;
//create a new image of the right size
Image retImg = new Bitmap((int)textSize.Width, (int)textSize.Height);
using (var drawing = Graphics.FromImage(retImg))
//paint the background
drawing.Clear(backColor);
//create a brush for the text
using (Brush textBrush = new SolidBrush(textColor))
drawing.DrawString(text, font, textBrush, 0, 0);
drawing.Save();
return retImg;
【讨论】：
干得好。简单，有用，我喜欢你设置默认值！ 很好地处理最小高度和宽度。你能帮忙处理一下最大宽度吗，这样如果文本宽度超过最大宽度，剩余的数据将进入下一行，然后根据它创建图像。以上是关于如何在运行时即时从文本生成图像的主要内容，如果未能解决你的问题，请参考以下文章