問題描述

我目前正在動態創建位圖并使用位圖中的圖形對象在其上繪制一個字符串，如下所示:

I am currently dynamically creating a bitmap and using the graphics object from the bitmap to draw a string on it like so:

System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(bmp);
graph.DrawString(text, font, brush, new System.Drawing.Point(0, 0));

這將返回一個矩形位圖，其中的字符串從左到右直接寫入.我也希望能夠畫出彩虹形狀的繩子.我怎樣才能做到這一點?

This returns a rectangular bitmap with the string written straight across from left to right. I would like to also be able to draw the string in the shape of a rainbow. How can I do this?

推薦答案

我最近遇到了這個問題(我正在渲染文本以??打印到 CD 上)，所以這是我的解決方案:

I recently had this problem (I was rendering text for printing onto CDs), so here's my solution:

private void DrawCurvedText(Graphics graphics, string text, Point centre, float distanceFromCentreToBaseOfText, float radiansToTextCentre, Font font, Brush brush)
{
    // Circumference for use later
    var circleCircumference = (float)(Math.PI * 2 * distanceFromCentreToBaseOfText);

    // Get the width of each character
    var characterWidths = GetCharacterWidths(graphics, text, font).ToArray();

    // The overall height of the string
    var characterHeight = graphics.MeasureString(text, font).Height;

    var textLength = characterWidths.Sum();

    // The string length above is the arc length we'll use for rendering the string. Work out the starting angle required to 
    // centre the text across the radiansToTextCentre.
    float fractionOfCircumference = textLength / circleCircumference;

    float currentCharacterRadians = radiansToTextCentre + (float)(Math.PI * fractionOfCircumference);

    for (int characterIndex = 0; characterIndex < text.Length; characterIndex++)
    {
        char @char = text[characterIndex];

        // Polar to cartesian
        float x = (float)(distanceFromCentreToBaseOfText * Math.Sin(currentCharacterRadians));
        float y = -(float)(distanceFromCentreToBaseOfText * Math.Cos(currentCharacterRadians));

        using (GraphicsPath characterPath = new GraphicsPath())
        {
            characterPath.AddString(@char.ToString(), font.FontFamily, (int)font.Style, font.Size, Point.Empty,
                                    StringFormat.GenericTypographic);

            var pathBounds = characterPath.GetBounds();

            // Transformation matrix to move the character to the correct location. 
            // Note that all actions on the Matrix class are prepended, so we apply them in reverse.
            var transform = new Matrix();

            // Translate to the final position
            transform.Translate(centre.X + x, centre.Y + y);

            // Rotate the character
            var rotationAngleDegrees = currentCharacterRadians * 180F / (float)Math.PI - 180F;
            transform.Rotate(rotationAngleDegrees);

            // Translate the character so the centre of its base is over the origin
            transform.Translate(-pathBounds.Width / 2F, -characterHeight);

            characterPath.Transform(transform);

            // Draw the character
            graphics.FillPath(brush, characterPath);
        }

        if (characterIndex != text.Length - 1)
        {
            // Move "currentCharacterRadians" on to the next character
            var distanceToNextChar = (characterWidths[characterIndex] + characterWidths[characterIndex + 1]) / 2F;
            float charFractionOfCircumference = distanceToNextChar / circleCircumference;
            currentCharacterRadians -= charFractionOfCircumference * (float)(2F * Math.PI);
        }
    }
}

private IEnumerable<float> GetCharacterWidths(Graphics graphics, string text, Font font)
{
    // The length of a space. Necessary because a space measured using StringFormat.GenericTypographic has no width.
    // We can't use StringFormat.GenericDefault for the characters themselves, as it adds unwanted spacing.
    var spaceLength = graphics.MeasureString(" ", font, Point.Empty, StringFormat.GenericDefault).Width;

    return text.Select(c => c == ' ' ? spaceLength : graphics.MeasureString(c.ToString(), font, Point.Empty, StringFormat.GenericTypographic).Width);
}

這篇關于如何將彎曲文本渲染為位圖?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！