Comment : faire pivoter du texte
Mise à jour : novembre 2007
Le .NET Compact Framework fournit la classe LogFont pour créer des effets de texte pivoté. Cela correspond à la structure LOGFONT Windows CE native (police logique) que vous utilisez avec la méthode FromLogFont pour retourner un objet Font.
Exemple
L'exemple de code suivant dessine une chaîne de 45 degrés au centre du formulaire. Il définit une méthode CreateRotatedFont qui, à partir des paramètres de l'angle de rotation et du texte à pivoter, retourne une police pivotée, à l'aide de la classe LogFont. Le texte pivoté est dessiné sur le formulaire dans le gestionnaire d'événements OnPaint.
Cet exemple affecte la valeur 96 ppp, mais vous devez affecter une valeur appropriée pour le périphérique cible. La valeur peut être déterminée via la propriété DpiY d'un objet Graphics. Cet exemple de code contient une formule pour mettre à l'échelle la police pour les périphériques avec différentes valeurs ppp.
Imports System
Imports System.Drawing
Imports System.Windows.Forms
Imports Microsoft.WindowsCE.Forms
Public Class Form1
Inherits System.Windows.Forms.Form
' Declare objects to draw the text.
Private rotatedFont As System.Drawing.Font
Private redBrush As SolidBrush
' Specify the text to roate, the rotation angle,
' and the base font.
Private rTxt As String = "abc ABC 123"
Private rAng As Integer = 45
' Determine the vertial DPI setting for scaling the font on the
' device you use for developing the application.
' You will need this value for properly scaling the font on
' devices with a different DPI.
' In another application, get the DpiY property from a Graphics object
' on the device you use for application development:
'
' Dim g As Graphics = Me.CreateGraphics()
' Dim curDPI As Integer = g.DpiY
Private Const curDPI As Integer = 96
' Note that capabilities for rendering a font are
' dependant on the device.
Private rFnt As String = "Arial"
Public Sub New()
MyBase.New()
' Display OK button to close application.
Me.MinimizeBox = False
Me.Text = "Rotated Font"
' Create rotatedFont and redBrush objects in the custructor of
' the form so that they can be resued when the form is repainted.
Me.rotatedFont = CreateRotatedFont(rFnt, rAng)
Me.redBrush = New SolidBrush(Color.Red)
End Sub
' Method to create a rotated font using a LOGFONT structure.
Private Function CreateRotatedFont(ByVal fontname As String, _
ByVal angleInDegrees As Integer) As Font
Dim logf As LogFont = New Microsoft.WindowsCE.Forms.LogFont
' Create graphics object for the form, and obtain
' the current DPI value at design time. In this case,
' only the vertical resolution is petinent, so the DpiY
' property is used.
Dim g As Graphics = Me.CreateGraphics
' Scale an 18-point font for current screen vertical DPI.
logf.Height = Fix(-18.0F * g.DpiY / curDPI)
' Convert specified rotation angle to tenths of degrees.
logf.Escapement = (angleInDegrees * 10)
' Orientation is the same as Escapement in mobile platforms.
logf.Orientation = logf.Escapement
logf.FaceName = fontname
' Set LogFont enumerations.
logf.CharSet = LogFontCharSet.Default
logf.OutPrecision = LogFontPrecision.Default
logf.ClipPrecision = LogFontClipPrecision.Default
logf.Quality = LogFontQuality.ClearType
logf.PitchAndFamily = LogFontPitchAndFamily.Default
' Explicitly dispose any drawing objects created.
g.Dispose()
Return System.Drawing.Font.FromLogFont(logf)
End Function
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
If (Me.rotatedFont Is Nothing) Then
Return
End If
' Draw the text to the screen using the LogFont, starting at
' the specified coordinates on the screen.
e.Graphics.DrawString(rTxt, Me.rotatedFont, Me.redBrush, _
75, 125, New StringFormat( _
(StringFormatFlags.NoWrap Or StringFormatFlags.NoClip)))
End Sub
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
' Dispose created graphic objects. Although they are
' disposed by the garbage collector when the application
' terminates, a good practice is to dispose them when they
' are no longer needed.
Me.redBrush.Dispose()
Me.rotatedFont.Dispose()
MyBase.Dispose(disposing)
End Sub
Public Shared Sub Main()
Application.Run(New Form1)
End Sub
End Class
using System;
using System.Drawing;
using System.Windows.Forms;
using Microsoft.WindowsCE.Forms;
namespace LogFontDemo
{
public class Form1 : System.Windows.Forms.Form
{
// Declare objects to draw the text.
Font rotatedFont;
SolidBrush redBrush;
// Specify the text to roate, the rotation angle,
// and the base font.
private string rTxt = "abc ABC 123";
private int rAng = 45;
// Determine the vertial DPI setting for scaling the font on the
// device you use for developing the application.
// You will need this value for properly scaling the font on
// devices with a different DPI.
// In another application, get the DpiY property from a Graphics object
// on the device you use for application development:
//
// Graphics g = this.CreateGraphics();
// int curDPI = g.DpiY;
private const int curDPI = 96;
// Note that capabilities for rendering a font are
// dependant on the device.
private string rFnt = "Arial";
public Form1()
{
// Display OK button to close application.
this.MinimizeBox = false;
this.Text = "Rotated Font";
// Create rotatedFont and redBrush objects in the custructor of
// the form so that they can be resued when the form is repainted.
this.rotatedFont = CreateRotatedFont(rFnt, rAng);
this.redBrush = new SolidBrush(Color.Red);
}
// Method to create a rotated font using a LOGFONT structure.
Font CreateRotatedFont(string fontname, int angleInDegrees)
{
LogFont logf = new Microsoft.WindowsCE.Forms.LogFont();
// Create graphics object for the form, and obtain
// the current DPI value at design time. In this case,
// only the vertical resolution is petinent, so the DpiY
// property is used.
Graphics g = this.CreateGraphics();
// Scale an 18-point font for current screen vertical DPI.
logf.Height = (int)(-18f * g.DpiY / curDPI);
// Convert specified rotation angle to tenths of degrees.
logf.Escapement = angleInDegrees * 10;
// Orientation is the same as Escapement in mobile platforms.
logf.Orientation = logf.Escapement;
logf.FaceName = fontname;
// Set LogFont enumerations.
logf.CharSet = LogFontCharSet.Default;
logf.OutPrecision = LogFontPrecision.Default;
logf.ClipPrecision = LogFontClipPrecision.Default;
logf.Quality = LogFontQuality.ClearType;
logf.PitchAndFamily = LogFontPitchAndFamily.Default;
// Explicitly dispose any drawing objects created.
g.Dispose();
return Font.FromLogFont(logf);
}
protected override void OnPaint(PaintEventArgs e)
{
if(this.rotatedFont == null)
return;
// Draw the text to the screen using the LogFont, starting at
// the specified coordinates on the screen.
e.Graphics.DrawString(rTxt,
this.rotatedFont,
this.redBrush,
75,
125,
new StringFormat(StringFormatFlags.NoWrap |
StringFormatFlags.NoClip));
}
protected override void Dispose(bool disposing)
{
// Dispose created graphic objects. Although they are
// disposed by the garbage collector when the application
// terminates, a good practice is to dispose them when they
// are no longer needed.
this.redBrush.Dispose();
this.rotatedFont.Dispose();
base.Dispose(disposing);
}
static void Main()
{
Application.Run(new Form1());
}
}
}
Compilation du code
Cet exemple nécessite des références aux espaces de noms suivants :
Programmation fiable
Cet exemple crée des objets pour restituer la police, les objets Font et SolidBrush, dans le constructeur du formulaire afin qu'ils soient utilisés par la méthode OnPaint lorsque le formulaire se repeint. Il les dispose ensuite dans une substitution de la méthode Dispose du formulaire.
Voir aussi
Tâches
Texte pivoté avec LogFont, exemple