![](/img/trans.png)
[英]System.Drawing.Graphics.DrawString() looks weird on Ubuntu
[英]System.Drawing.Graphics.DrawString - “Parameter is not valid” exception
有时微软的异常消息令人愤怒无益。 我创建了一个很好的小MVC方法来呈现文本。 方法体如下。 当它到达“DrawString”方法时,我得到一个异常,说“参数无效”。
请注意,我能说的最好的字体构造正确(我只是在10pt使用Arial),rect大小是正面且有效的看起来,画笔是白色的SolidBrush并且格式标志不影响输出;即如果我从调用中排除格式标志,我仍然会收到错误。
DrawString调用就在底部附近。
public ActionResult RenderText(
string fontFamily,
float pointSize,
string foreColor,
string backColor,
bool isBold,
bool isItalic,
bool isVertical,
string align,
string[] allText,
int textIndex)
{
// method renders a horizontal or vertical text image, taking all the text strings that will be rendered in each image
// and sizing the final bitmap according to which text would take the most space, thereby making it possible to render
// a selection of text images all at the same size.
Response.ContentType = "image/png";
var fmt = StringFormat.GenericTypographic;
if(isVertical)
fmt.FormatFlags = StringFormatFlags.DirectionVertical;
Func<string,StringAlignment> getAlign = (s => {
switch(s.ToLower())
{
case "right": return StringAlignment.Far;
case "center": return StringAlignment.Center;
default: return StringAlignment.Near;
}
});
fmt.LineAlignment = isVertical ? StringAlignment.Center : getAlign(align);
fmt.Alignment = isVertical ? getAlign(align) : StringAlignment.Center;
var strings = (allText ?? new string[0]).Where(t => t.Length > 0).ToList();
if(strings.Count == 0)
strings.Add("[Missing Text]");
FontStyle style = FontStyle.Regular;
if(isBold)
if(isItalic)
style = FontStyle.Bold | FontStyle.Italic;
else
style = FontStyle.Bold;
else if(isItalic)
style = FontStyle.Italic;
Font font = new Font(fontFamily, pointSize, style, GraphicsUnit.Point);
Color fc = foreColor.IsHexColorString() ? foreColor.ToColorFromHex() : foreColor.ToColor();
Color bc = backColor.IsHexColorString() ? backColor.ToColorFromHex() : backColor.ToColor();
var maxSize = new Size(0,0);
using(var tmp = new Bitmap(100, 200))
using(var gfx = Graphics.FromImage(tmp))
foreach(var txt in strings)
{
var size = gfx.MeasureString(txt, font, 1000, fmt);
maxSize = new Size(
Math.Max(Convert.ToInt32(isVertical ? size.Height : size.Width), maxSize.Width),
Math.Max(Convert.ToInt32(isVertical ? size.Width : size.Height), maxSize.Width)
);
}
using(var bmp = new Bitmap(maxSize.Width, maxSize.Height))
{
using(var gfx = Graphics.FromImage(bmp))
{
gfx.CompositingMode = CompositingMode.SourceCopy;
gfx.CompositingQuality = CompositingQuality.HighQuality;
gfx.SmoothingMode = SmoothingMode.HighQuality;
gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;
var rect = new RectangleF(new PointF(0,0), maxSize);
gfx.FillRectangle(new SolidBrush(bc), rect);
gfx.DrawString(strings[textIndex], font, new SolidBrush(fc), rect, fmt);
}
bmp.Save(Response.OutputStream, ImageFormat.Png);
}
return new EmptyResult();
}
好吧,我发现了问题的原因。 一些非常模糊的东西。 删除此行时代码有效:
gfx.CompositingMode = CompositingMode.SourceCopy;
在调试时可以提供什么帮助,使方法更小。 例如,您可以替换
FontStyle style = FontStyle.Regular;
if(isBold)
if(isItalic)
style = FontStyle.Bold | FontStyle.Italic;
else
style = FontStyle.Bold;
else if(isItalic)
style = FontStyle.Italic;
通过
FontStyle style = GetFontStyle(isBold, isItalic);
和
public FontStyle GetFontStyle(bool isBold, bool isItalic)
{
if(isBold)
if(isItalic)
return FontStyle.Bold | FontStyle.Italic;
else
return FontStyle.Bold;
else if(isItalic)
return FontStyle.Italic;
else
return FontStyle.Regular;
}
它使您的代码更具可读性,并使其他人更容易为您提供帮助。
真的没有冒犯意味着!
亲切的问候,Ans Vlug
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.