如何在运行时从文本动态生成图像

任何人都可以指导如何从输入文本生成图像。图像可能有任何扩展没有关系。

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使用 意象魔术在图像上呈现文本(在服务器上)

因为您是在 C # 中，所以也可以使用。直接用于位图和字体操作的 Net 类(类如: System.Drawing.Bitmap和 System.Drawing.Graphics)

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最佳答案

好的，假设您想在 C # 中的图像上绘制一个字符串，那么您需要使用 System。在这里绘制名称空间:

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，然后创建大小正确的图像。

如果要保存此函数的返回值，只需调用返回图像的 Save 方法。

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我刚刚将 回答中提到的这个方法转换成了一个 VB.NET 方法。

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 : 修正打字错误。

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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
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谢谢你，卡扎。对前面使用 USING 处理使用后的图像/图形对象的答案稍作改进，并引入了最小尺寸参数

    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;
}
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下面是 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;
}

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