How to: Rotating text 90 degrees in GDI+

转载：http://www.c-sharpcorner.com/Blogs/580/

One of the issues I ran into when using GDI+ is how to rotate a string and place it on the Y Axis of a Graph. Here is how I solved it.

You can use the StringFormatFlags.DirectionVertical in the DrawString command to rotate text.  Unfortunately, when drawing the graph it draws the text mirror-imaged the wrong way.  So much for StringFormat.

In order to rotate text 90 degrees,  you'll need to draw the text to a separate bitmap in memory and then draw the resulting image to the screen.

In your paint event handler code add the following:

SizeF labelSize = g.MeasureString(myLabel, GraphFont);
Bitmap stringmap = new Bitmap((int)labelSize.Height + 1, (int)labelSize.Width + 1);
Graphics gbitmap = Graphics.FromImage(stringmap);
gbitmap.SmoothingMode = SmoothingMode.AntiAlias;
// g.DrawString(m_LabelY, GraphFont, Brushes.Blue, new PointF(ClientRectangle.Left , ClientRectangle.Top + 100), theFormat);
gbitmap.TranslateTransform(0, labelSize.Width);
gbitmap.RotateTransform(-90);
gbitmap.DrawString(myLabel, GraphFont, Brushes.Blue, new PointF(0 , 0), new StringFormat());
g.DrawImage(stringmap, (float)ClientRectangle.Left, (float)ClientRectangle.Top + 100);
//And don't forget to dispose of your bitmap and graphics objects at the end of onpaint
gbitmap.Dispose();
stringmap.Dispose();

　　

方法二：不过这个方法绘制出来的字符串是从上到下，方向固定的

// Create string to draw.
String drawString = "Sample Text";
// Create font and brush.
Font drawFont = new Font("Arial", 16);
SolidBrush drawBrush = new SolidBrush(Color.Black);
// Create point for upper-left corner of drawing.
float x = 150.0F;float y = 50.0F;
// Set format of string.
StringFormat drawFormat = new StringFormat();
drawFormat.FormatFlags = StringFormatFlags.DirectionVertical;
// Draw string to screen.            
e.Graphics.DrawString(drawString, drawFont, drawBrush, x, y, drawFormat);