Figure 6-9 Call Graphics.DrawString to add text to a Graphics object. in C#

Print QR Code 2d barcode in C# Figure 6-9 Call Graphics.DrawString to add text to a Graphics object.

Of course, it s much easier to add text to a form using Label objects. However, Graphics.DrawString also enables you to add text to Images and Bitmaps. This is useful for adding visible copyright information to a picture, adding timestamps to images, and annotating charts.

The .NET Framework gives you control over the alignment and direction of text using the StringFormat class. After creating and configuring a StringFormat object, you can provide it to the Graphics.DrawString method to control how text is formatted. The most important members of the StringFormat class are:

FormatFlags Gets or sets a StringFormatFlags enumeration that contains format-

DirectionRightToLeft Text is displayed from right to left. DirectionVertical Text is vertically aligned. DisplayFormatControl Control characters such as the left-to-right mark are

default, layout continues until the end of the text or until no more lines are visible as a result of clipping, whichever comes first. Note that the default

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settings allow the last line to be partially obscured by a formatting rectangle that is not a whole multiple of the line height. To ensure that only whole lines are seen, specify this value and be careful to provide a formatting rectangle at least as tall as the height of one line.

By default, the boundary rectangle returned by the MeasureString method excludes the space at the end of each line. Set this flag to include that space in measurement.

NoClip Overhanging parts of glyphs, and unwrapped text reaching outside the formatting rectangle are allowed to show. By default, all text and glyph parts reaching outside the formatting rectangle are clipped. NoFontFallback Fallback to alternate fonts for characters not supported in

the requested font is disabled. Any missing characters are displayed with the fonts-missing glyph, usually an open square.

is disabled. This flag is implied when a point is passed instead of a rectangle, or when the specified rectangle has a zero line length.

Character Specifies that the text is trimmed to the nearest character. EllipsisCharacter Specifies that the text is trimmed to the nearest character,

The following code demonstrates the use of the StringFormat class and produces the output shown in Figure 6-10:

' VB Dim G As Graphics = Me.CreateGraphics ' Construct a new Rectangle Dim R As Rectangle = New Rectangle(New Point(40, 40), New Size(80, 80)) ' Construct 2 new StringFormat objects Dim F1 As StringFormat = New StringFormat(StringFormatFlags.NoClip) Dim F2 As StringFormat = New StringFormat(f1) ' Set the LineAlignment and Alignment properties for ' both StringFormat objects to different values F1.LineAlignment = StringAlignment.Near f1.Alignment = StringAlignment.Center f2.LineAlignment = StringAlignment.Center f2.Alignment = StringAlignment.Far f2.FormatFlags = StringFormatFlags.DirectionVertical ' Draw the bounding rectangle and a string for each ' StringFormat object G.DrawRectangle(Pens.Black, R) G.DrawString("Format1", Me.Font, Brushes.Red, CType(R, RectangleF), F1) G.DrawString("Format2", Me.Font, Brushes.Red, CType(R, RectangleF), F2) // C# Graphics g = this.CreateGraphics(); // Construct a new Rectangle. Rectangle r = new Rectangle(new Point(40, 40), new Size(80, 80)); // Construct 2 new StringFormat objects StringFormat f1 = new StringFormat(StringFormatFlags.NoClip); StringFormat f2 = new StringFormat(f1); // Set the LineAlignment and Alignment properties for // both StringFormat objects to different values. f1.LineAlignment = StringAlignment.Near; f1.Alignment = StringAlignment.Center; f2.LineAlignment = StringAlignment.Center; f2.Alignment = StringAlignment.Far; f2.FormatFlags = StringFormatFlags.DirectionVertical; // Draw the bounding rectangle and a string for each // StringFormat object. g.DrawRectangle(Pens.Black, r); g.DrawString("Format1", this.Font, Brushes.Red, (RectangleF)r, f1); g.DrawString("Format2", this.Font, Brushes.Red, (RectangleF)r, f2);

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Figure 6-10

In this lab, you add a copyright logo to a picture before writing it to the disk, and you update a pie chart to display a legend. If you encounter a problem completing an exercise, the completed projects are available on the companion CD in the Code folder.