如何在运行时从动态文本生成图像

好的,假设您想在C中的图像上绘制一个字符串,您需要使用系统。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保存方法。

谢谢Kazar。对之前的答案进行了细微改进,用于处理使用后的图像/图形对象,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;
    }

我刚刚翻译了这里面提到的方法 answer 到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 固定排字。

使用 imagemagick 用于在图像上呈现文本(在服务器上)

由于您在C中,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 )

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